Desafios Ambientais na Aviação - Urbanismo (2024)

Prévia do material em texto

<p>TableofContents</p><p>Welcome</p><p>TableofContents</p><p>Title</p><p>BENTHAMSCIENCEPUBLISHERSLTD.</p><p>EndUserLicenseAgreement(fornon-institutional,personaluse)</p><p>UsageRules:</p><p>Disclaimer:</p><p>LimitationofLiability:</p><p>General:</p><p>PREFACE</p><p>CONSENTFORPUBLICATION</p><p>CONFLICTOFINTEREST</p><p>ACKNOWLEDGEMENTS</p><p>NOTICE</p><p>AviationandtheEnvironment</p><p>Abstract</p><p>AVIATIONANDENVIRONMENT</p><p>TheClimateChangeandAirTransport</p><p>AviationinaGlobalWarmingEnvironment</p><p>TheClimateChangeandAirTransport</p><p>EmissionControlPolicy</p><p>TheAviationIndustryInitiatives</p><p>AERONAUTICALINDUSTRYFACINGTHEENVIRONMENTAL</p><p>CHALLENGES</p><p>TheCleanSkyProject</p><p>TheERAinitiative</p><p>FuelEfficiency</p><p>Emissions</p><p>Noise</p><p>ELECTRICVEHICLESANDAVIATION</p><p>ElectricalAutomobiles</p><p>TheFutureoftheAirlinerswillbeMoreElectric?</p><p>EMISSIONFORECASTCONSIDERINGTHEINCORPORATIONOF</p><p>ELECTRICVEHICLESINTOTHEGROUNDTRANSPORTATIONSYSTEM</p><p>RoadTransportationandPollution</p><p>TheNoiseImpacts</p><p>CONCLUSIONS</p><p>References</p><p>AeronauticalTechnologyOverTime</p><p>Abstract</p><p>THEFLIGHTPIONEERS</p><p>FlyingwithStyle</p><p>TheFirstOperationalAirplane</p><p>THEFIRSTAIRLINERS</p><p>FromWartoPeace</p><p>InternationalServices</p><p>AdvancesinAeronauticalTechnology</p><p>TECHNOLOGICALLEGACYFROMWORLDWARII</p><p>Fighters</p><p>Bombers</p><p>CargoAirplanes</p><p>TheJetEngine</p><p>High-SpeedFlight</p><p>THEJETAGES</p><p>FromWartoPeaceII</p><p>High-CapacityTurbopropAirliners</p><p>Inception</p><p>Sud-AviationCaravelle</p><p>TheFirstJetAge</p><p>TheSecondJetAge</p><p>NeedforSpeed</p><p>MODERNAIRLINERS</p><p>GROUNDEFFECTAERIALVEHICLES</p><p>ALTERNATIVEFUELANDPOWER</p><p>CONCLUDINGREMARKS</p><p>SOMEMILESTONESINAIRCRAFTTECHNOLOGY</p><p>References</p><p>EntropyStatisticsandClusterAnalysisAppliedtoJetAirlinerandFighter</p><p>AircraftClassification</p><p>Abstract</p><p>INTRODUCTION</p><p>Objectives</p><p>HowProductsEvolve</p><p>MODELINGTECHNOLOGICALEVOLUTION</p><p>METHODOLOGYFORAIRPLANECLASSIFICATION</p><p>Entropy</p><p>ConvergenceandDiffusion</p><p>DendrogramandCopheneticCorrelationCoefficient</p><p>RESULTSOFAPPLICATION</p><p>Jetliners</p><p>FeaturedAircraft</p><p>Results</p><p>ClusterAnalysis</p><p>FighterAircraft</p><p>SomeFeaturedFightersandAttackAircraft</p><p>InterpretationoftheResultsObtainedwiththeFighterandAttackAircraft</p><p>Database</p><p>CONCLUDINGREMARKS</p><p>References</p><p>AircraftDesignPhases</p><p>Abstract</p><p>DESIGNINGAIRPLANES</p><p>AIRCRAFTPROGRAMPHASES</p><p>Overview</p><p>FeasibilityStudy</p><p>ConceptualStudies</p><p>PreliminaryDesign</p><p>DetailedDesign</p><p>Production</p><p>Materials</p><p>Tooling</p><p>Assembly</p><p>AircraftDelivery</p><p>CERTIFICATIONPROCESS</p><p>Overview</p><p>CertificationRequirements</p><p>CertificationTests</p><p>CONCLUSION</p><p>References</p><p>FeasibilityStudyofanAirplaneDevelopmentProgram</p><p>Abstract</p><p>OVERVIEW</p><p>ESTABLISHINGREQUIREMENTS</p><p>TheChallengingTaskofEstablishingProperRequirements</p><p>TheFailedProposaloftheSonicCruiser</p><p>Chance-VoughtCorsair:GroundedbyDesign</p><p>TechnologyAssessment</p><p>EMBRAER/FAMACBA-123andSAAB2000</p><p>VFW614:ANINTERESTINGCONCEPTATTHEWRONGTIME</p><p>EMBRAERERJ140:WHENPILOTSDICTATEAIRCRAFTDESIGN</p><p>MARKETANALYSIS</p><p>Introduction</p><p>SWOTMatrix</p><p>A50-seatNewAirplaneProgram</p><p>Team1Reporton50-seatRegionalJet</p><p>Team2Reporton50-seatRegionalJet</p><p>FINANCIALANALYSIS</p><p>Reasoning</p><p>Definitions</p><p>Mechanisms</p><p>Cashflow</p><p>1.InvestmentinNewProducts</p><p>2.Revenues</p><p>3.ProductionCostsandExpenses</p><p>FinancialIndicators</p><p>NetPresentValue(NPV)</p><p>InternalRateofReturn-IRR</p><p>Payback</p><p>Break-evenPoint</p><p>RecommendationsforFeasibilityAnalysis</p><p>PremisesfortheCalculationoftheViability</p><p>ViabilityMonitoring</p><p>ConsiderAnalysiswithPossibleRisks</p><p>ExampleofFinancialAnalysis</p><p>Non-recurringCosts</p><p>RecurringCost</p><p>STRATEGYANALYSIS</p><p>Overview</p><p>BarrierstoEntry</p><p>ThreatofSubstitutes</p><p>SupplierandPartnerPower</p><p>BuyerPower</p><p>Rivalry</p><p>ANALYSISOFCOMPETITORS</p><p>SomeMetrics</p><p>MeasuringCompetition</p><p>MappingtheEnemy</p><p>GAMETHEORY</p><p>Introduction</p><p>NashEquilibriumisnotOptimization</p><p>MixedStrategies</p><p>GAMETHEORYAPPLIEDTOAIRCRAFTDESIGN</p><p>Introduction</p><p>DevelopmentCostforaNew75-SeatAirliner</p><p>FinancialAnalysis</p><p>FuelPrice</p><p>MarketandRevenueEstimation</p><p>Re-enginingPrograms</p><p>CONCLUSION</p><p>References</p><p>EnvironmentalAspectsonAirplaneDesign</p><p>Abstract</p><p>AIRPLANENOISE</p><p>HistoricalAspects</p><p>NoiseMetrics</p><p>CertificationAspects</p><p>NoiseSources</p><p>NoiseModellingforAirplaneDesign</p><p>AIRPLANEEMISSIONS</p><p>HistoricalAspects</p><p>EngineEmissions</p><p>Overview</p><p>CarbonDioxide</p><p>WaterVapor</p><p>SulfurOxides</p><p>NitrogenOxides</p><p>UnburnedHydrocarbons</p><p>Particles</p><p>OtherEmissions</p><p>EmissionsTradeoff</p><p>CertificationAspects</p><p>EmissionsModellingforAirplaneDesign</p><p>ModelsforEmissionsProportionaltoFuelConsumption</p><p>ModelsforNOXemissions</p><p>CONCLUSIONS</p><p>References</p><p>AnInnovativeApproachforOptimalAirplaneDesignEncompassinganAirline</p><p>Network</p><p>Abstract</p><p>Introduction</p><p>Methodology</p><p>Overview</p><p>ReferenceAirplane</p><p>NetworkFixedParameters</p><p>Propulsion</p><p>Aerodynamics</p><p>WeightEstimation</p><p>CabinCrossSection</p><p>DesignDiagramVerification</p><p>TailSizing</p><p>MissionPerformance</p><p>OptimizationFeatures</p><p>ResultsandDiscussion</p><p>CONCLUDINGREMARKS</p><p>FUTUREDEVELOPMENTS</p><p>ACRONYMSANDSYMBOLS</p><p>References</p><p>FlightOperationsandEnvironment</p><p>Abstract</p><p>THEROLEOFFLIGHTOPERATIONS</p><p>FUELCONSERVATIONPROGRAMS</p><p>OPERATIONALTECHNIQUES</p><p>ReductionofLandingWeight</p><p>OEWManagement</p><p>ReserveFuelManagement</p><p>FlightPlanningandDispatch</p><p>TheOptimalFlightPlan</p><p>CenterofGravityManagement</p><p>In-flightStrategies</p><p>THECOSTINDEXCONCEPT</p><p>LEGACYFUELCONSERVATIONTECHNIQUESINVERTICALPROFILE</p><p>CruiseTechniques</p><p>ClimbandDescentTechniques</p><p>TheEnhancedCostOptimizationTechniqueinVerticalProfile</p><p>TheCostChallenge</p><p>AIRCRAFTCONDITIONMONITORING</p><p>Overview</p><p>DragDegradation</p><p>EngineDegradation</p><p>THEAIRTRAFFICMANAGEMENTROLE</p><p>Overview</p><p>On-GroundOperationManagement</p><p>DepartureManagement</p><p>DepartureNoiseVersusEmissions</p><p>EnrouteManagement</p><p>DescentManagement</p><p>ContinuousDescentOperations</p><p>AHarmonizedATM</p><p>ADVANCEDIDEAS</p><p>FlyingAirlinersinFormation</p><p>CatapultingAirplanes</p><p>HIGH-SPEEDTRAINVS.AIRTRAVEL</p><p>FINALCOMMENTS</p><p>References</p><p>FrontiersinAerospaceScience</p><p>(Volume3)</p><p>ConceptualDesignofGreenTransportAirplanes</p><p>Authoredby</p><p>BentoS.deMattos,</p><p>JoséA.T.G.Fregnani</p><p>&</p><p>PauloEduardoC.S.Magalhães</p><p>AircraftDesignDepartment,</p><p>InstitutoTecnológicodeAeronáutica(ITA),</p><p>SãoJosédosCampos,SãoPaulo,</p><p>Brazil</p><p>BENTHAMSCIENCEPUBLISHERSLTD.</p><p>EndUserLicenseAgreement(fornon-institutional,personaluse)</p><p>ThisisanagreementbetweenyouandBenthamSciencePublishersLtd.Please</p><p>readthisLicenseAgreementcarefullybeforeusingtheebook/echapter/ejournal</p><p>(“Work”).YouruseoftheWorkconstitutesyouragreementtothetermsand</p><p>conditionssetforthinthisLicenseAgreement.Ifyoudonotagreetotheseterms</p><p>andconditionsthenyoushouldnotusetheWork.</p><p>BenthamSciencePublishersagreestograntyouanon-exclusive,non-</p><p>transferablelimitedlicensetousetheWorksubjecttoandinaccordancewiththe</p><p>followingtermsandconditions.ThisLicenseAgreementisfornon-library,</p><p>personaluseonly.Foralibrary/institutional/multiuserlicenseinrespectofthe</p><p>Work,pleasecontact:permission@benthamscience.org.</p><p>UsageRules:</p><p>Allrightsreserved:TheWorkisthesubjectofcopyrightandBenthamScience</p><p>PublisherseitherownstheWork(andthecopyrightinit)orislicensedto</p><p>distributetheWork.Youshallnotcopy,reproduce,modify,remove,delete,</p><p>augment,addto,publish,transmit,sell,resell,createderivativeworksfrom,or</p><p>inanywayexploittheWorkormaketheWorkavailableforotherstodoanyof</p><p>thesame,inanyformorbyanymeans,inwholeorinpart,ineachcasewithout</p><p>thepriorwrittenpermissionofBenthamSciencePublishers,unlessstated</p><p>otherwiseinthisLicenseAgreement.</p><p>YoumaydownloadacopyoftheWorkononeoccasiontoonepersonal</p><p>computer(includingtablet,laptop,desktop,orothersuchdevices).Youmay</p><p>makeoneback-upcopyoftheWorktoavoidlosingit.ThefollowingDRM</p><p>(DigitalRightsManagement)policymayalsobeapplicabletotheWorkat</p><p>BenthamSciencePublishers’</p><p>-themassof</p><p>fuelrequiredtomoveapassengeramile,forvarioustransportjets.Datafrom</p><p>airportplanningmanualsthataircraftmanufacturersmadeavailableforthe</p><p>publicwereusedforthecalculationsoftheenergeticefficiency.Fromthegraph,</p><p>itisnotedthatmaximumefficiencyoccurswithaircraftwhichhaveabout3000</p><p>nmrange,withtypicalpassengerload,suchastheBoeing767-200.Fromthere,</p><p>theefficiencyfallsagainwithincreasedrangeuptoabout5200nauticalmiles.</p><p>Again,weseeanimprovementinefficiencyuntilwereachtheBoeing777-</p><p>200LR.Regionaljetstypicallyhavereachwithtypicalpayloadoflessthan2000</p><p>nauticalmiles.Itiseasytonotethatregionaljetspresentlowenergyefficiency</p><p>comparedtoaircraftofgreatercapacity.TheFokker70hasthesamewingofthe</p><p>Fokker100.Forthisreason,thewingareaofFokker70isoversizedtocarry79</p><p>passengersinasingleclassand,therefore,revealsanenergyefficiencyindex</p><p>relativelypoorcomparedtotheairplaneslistedinthechartofFig.(1.11).</p><p>AccordingtothegraphfromFig.(1.11),theBoeing787-9airlinerismore</p><p>efficientenergeticallythanthelarger777,AirbusA380andBoeing747-400.</p><p>Thekeytotheexceptionalperformanceofthe787Dreamliner(Fig.1.12)isits</p><p>suiteofinnovativetechnologiesanditsstructuraldesign,whichincludeshigh</p><p>flexiblewings.Compositematerialsmakeup50percentoftheprimarystructure</p><p>ofthe787,includingthefuselageandwing.Boeing787aninnovativesystems</p><p>architecturethatissimpler,morefunctionalandmoreefficientthanthatofother</p><p>airplanes.Forexample,onboardhealth-monitoringsystemsmonitorandreport</p><p>systemsmaintenancerequirementstoground-basedcomputersystems.</p><p>Advancesinenginetechnologyarethebiggestcontributortooverallfuel</p><p>efficiencyimprovementsontheDreamliner.The787isfittedwithnewengines</p><p>thatfeatureincreasedby-passratio,higheroverallpressureratio,advanced</p><p>materials,andelectricstart.Thedesignandbuildprocessofthe787hasadded</p><p>furtherefficiencygains.Forexample,manufacturingtheBoeing787fuselageas</p><p>one-piecesectionseliminated1,500aluminumsheetsand40,000-50,000</p><p>fastenerspersection.</p><p>Fig.(1.11))</p><p>Energeticefficiencyforsometransportairplanes.</p><p>Infact,Boeing787reflectsacompletelynovelapproachtoonboardsystems.</p><p>Virtuallyeverythingthathastraditionallybeenpoweredbybleedairfromthe</p><p>engineshasbeentransitionedtoanelectricarchitecture.Theaffectedsystems</p><p>include[37]:</p><p>Enginestart.</p><p>Auxiliarypowerunit(APUstart).</p><p>Wingiceprotection.</p><p>Cabinpressurization.</p><p>Hydraulicpumps.</p><p>Theonlyremainingbleedsystemonthe787istheanti-icesystemfortheengine</p><p>inlets.Theauxiliarypowerunit(APU)providesanexcellentillustrationofthe</p><p>benefitsofthemoreelectricarchitecture.Oneoftheprimaryfunctionsofa</p><p>conventionalAPUisdrivingalargepneumaticloadcompressor.The</p><p>replacementofthepneumaticloadcompressorwithstartergeneratorsresultsin</p><p>significantlyimprovedstartreliabilityandpoweravailability.Theuseofstarter</p><p>generatorsreducesmaintenancerequirementsandincreasesreliabilityduetothe</p><p>simplerdesignandlowerpartscount.Intermsofinflightstartreliability,the787</p><p>APUisexpectedtobeapproximatelyfourtimesmorereliablethanconventional</p><p>APUswithapneumaticloadcompressor.Anotherfundamentalarchitectural</p><p>changeonthe787istheuseofvariablefrequencyelectricalpowerandthe</p><p>integrationoftheenginegeneratorandstarterfunctionsintoasingleunit.This</p><p>changeenableseliminationoftheconstantspeeddrive(alsoknownasthe</p><p>integrateddrivegenerator,IDG),greatlyreducingthecomplexityofthe</p><p>generator.Inaddition,byusingtheenginegeneratorasthestartermotor(an</p><p>approachusedwithremarkablesuccessontheNext-Generation737APU),the</p><p>787hasbeenabletoeliminatethepneumaticstarterfromtheengine.When</p><p>comparedtothemorecomplex767IDG,theBoeing787startergeneratoris</p><p>predictedtohaveameantimebetweenfaults(MTBF)of30,000flighthours-a</p><p>300percentreliabilityimprovementcomparedtoitsin-servicecounterpart[37].</p><p>Fig.(1.12))</p><p>ArtisticviewofBoeing787-8.</p><p>EMISSIONFORECASTCONSIDERINGTHEINCORPORATIONOF</p><p>ELECTRICVEHICLESINTOTHEGROUNDTRANSPORTATION</p><p>SYSTEM</p><p>RoadTransportationandPollution</p><p>Electricalvehicleshavegainedsteadyacceptanceamongthepublicandare</p><p>beingsupportedbysomegovernmentalpoliciesworldwide,namelyduetoits</p><p>appealtoloweremissionsandalmostabsenceofnoise.InCaliforniaState,Tesla</p><p>Motorshasbeendevelopingpromisingelectricautomobilesasseeninbeforein</p><p>thisChapter.Appleisreportedlylookingtogobeyondsmartphones,laptopsand</p><p>wearablesandiscurrentintendstocomeupwiththecompany'sfirstApple-</p><p>brandedelectriccar.AccordingtoInsideEVs.com,totalsalesofEVsinthe</p><p>UnitedStatesrose23%annuallyin2014.</p><p>Boeingforecaststhatthedemandforairlinersrangingfromregionaljetstowide-</p><p>bodyairplaneswillgrowanaverageof3.6%ayearinthe2015-2034timeframe</p><p>[38].Airlinerfleetwillgrowfrom21,600in2014to43,560in2034[38].Ifin</p><p>comingdecadesthesalesorelectricvehiclessoars,considerablyreplacing</p><p>internalcombustionvehicles,noiseandemissionpercentagecausedbyroad</p><p>vehicleswilldropsignificantly.Inthispossiblescenario,thecontributionof</p><p>aviationtopollutionandnoiselevelswillbethenraisedtonewheights.Howthe</p><p>public,government,industryandacademywillacceptthis?Toprovideinsights</p><p>inthisquestion,thepresentsectionpresentssomeestimationoftheaviation’s</p><p>contributionstoCO2emissionsinthecontextofanincreasingEVfleet.</p><p>Toanswerthequestionoftheprecedingparagraph,itisnecessarytoutilize</p><p>existingestimationsofthepollutioncausedbydifferentmeansoftransportation</p><p>TheInternationalEnergyAgency(IEA)hasworkedwiththeworldBusiness</p><p>CouncilforSustainableDevelopment(WBCSD)initsSustainableMobility</p><p>Project(SMP)todevelopaglobaltransportspreadsheetmodelthatcanserve</p><p>bothorganizationsinconductingprojectionsandpolicyanalysis[39].TheSMP</p><p>transportspreadsheetmodelisdesignedtohandlealltransportmodesandmost</p><p>vehicletypes.Itproducesprojectionsofvehiclestocks,travel,energyuseand</p><p>otherindicatorsthrough2050forareferencecaseandforvariouspolicycases</p><p>andscenarios.Itisdesignedtohavesometechnology-orienteddetailandto</p><p>allowdetailedbottom-upmodelling.TheSMPemissionforecastforair</p><p>transportationutilizesasimplifiedapproach:passengerkilometers(revenue</p><p>passengerkilometers,RPK)aremultipliedbyenergyuseperRPK(energy</p><p>intensity)toderiveenergyuse.CO2emissionsareestimatedbasedonfueluse.</p><p>Domesticandinternationalairtravelineachregionistreatedtogether.Theroad</p><p>vehiclesweresupposedtoburnfossilsfuelsorsometypesofbiofuels.</p><p>Table1.7displaystheprojectionofCO2emissions[39]obtainedfromtheSMP</p><p>projectspreadsheet,whosedataandprojectionsaresummarizedinFig.(1.13).</p><p>AviationtotalCO2emissionswilljumpfrom13.2%in2000to19.5%inyear</p><p>2050.</p><p>Table1.7ProjectedCO2emissions(Gtandpercentage)bymodesuntil2050</p><p>(Source:IEAandWBCSD).</p><p>Year Road Aviation Maritime RoadTotal AviationTotal</p><p>2000 4.10 0,70 0.50 77.4% 13.2%</p><p>2005 4.30 0,80 0.60 75.4% 14.0%</p><p>2010 4.80 0.90 0.60 76.2% 14.3%</p><p>2015 5.20 1.00 0.80 74.3% 14.3%</p><p>2020 5.70 1.10 0.80 75.0% 14.5%</p><p>2025 6.10 1.30 0.80 74.4% 15.9%</p><p>2030 6.50 1.50 0,80 73.9% 17.0%</p><p>2035 7.00 1.60 0.80 74.5% 17.0%</p><p>2040 7.45 1.85 0.90 73.0% 18.1%</p><p>2045 8.00 2.00 1.00 72.7% 18.2%</p><p>2050 8.60 2.30 0.90 72.9% 19.5%</p><p>Fig.(1.13))</p><p>HistoricalandprojectedCO2emissionfromtransportbymodesinthe2000-</p><p>2050period(Source:IEAandWBCSD).</p><p>Tables1.8aand1.8bcontaintheestimationofaviationparticipationinglobal</p><p>CO2emissionsifelectricroadvehicles</p><p>increasinglyreplaceinternalcombustion</p><p>engines(ICE),withandwithoutdeintroductionofaviationbiofuels.These</p><p>kindsofalternativefuelsproduce,consideringthewholelogisticsvaluechain,in</p><p>average70%lessemissionswhencomparedwithfossilfuels[40].Inaddition,</p><p>bothtablesconsiderthatelectricalroadvehicleswillproduce80%less</p><p>emissionsthantheonesusingconventionalfossilfuelengines.Forinstance,not</p><p>consideringtheuseofaviationBiofuels,in2030,25%ofallroadvehicleswill</p><p>beelectricandtheaviationshareinemissionswillbe20%,3%aboveifnoEV</p><p>wouldcomposethefleetofroadvehicles.However,iftheuseaviationbiofuels</p><p>areconsidered,perIEdata,thisenergeticsourceisestimatedtobeusedin5%of</p><p>theflightsin2030),theaviationemissionssharedropsto19.4%.</p><p>Table1.8aAviationContributiononCO2EmissionsrelatedtoTransportation</p><p>Systems(withandwithoutEVintroduction).EVefficiencyof80%andairplanes</p><p>willnotusebiofuels.</p><p>Year EV NoEV WithEV delta</p><p>2000 0% 13,2% 13,2% 0,0%</p><p>2005 0% 14,0% 14,0% 0,0%</p><p>2010 0% 14,3% 14,3% 0,0%</p><p>2015 10% 14,3% 15,2% 0,9%</p><p>2020 15% 14,5% 15,9% 1,4%</p><p>2025 20% 15,9% 18,0% 2,1%</p><p>2030 25% 17,0% 20,0% 3,0%</p><p>2035 30% 17,0% 20,7% 3,7%</p><p>2040 50% 18,1% 25,6% 7,5%</p><p>2045 80% 18,2% 34,0% 15,8%</p><p>2050 100% 19,5% 46,7% 27,3%</p><p>Table1.8bAviationContributiononCO2EmissionsrelatedtoTransportation</p><p>Systems(withandwithoutEVintroduction).EVefficiencyof80%andairplanes</p><p>willutilizebiofuels.</p><p>Year Biofueluse NoEV WithEV delta</p><p>2000 0% 13,2% 13,2% 0,0%</p><p>2005 0% 14,0% 14,0% 0,0%</p><p>2010 0% 14,3% 14,3% 0,0%</p><p>2015 0% 14,3% 15,2% 0,9%</p><p>2020 1% 14,4% 15,8% 1,4%</p><p>2025 3% 15,6% 17,7% 2,1%</p><p>2030 5% 16,5% 19,4% 2,9%</p><p>2035 11% 15,9% 19,4% 3,5%</p><p>2040 18% 16,3% 23,2% 6,9%</p><p>2045 28% 15,1% 29,3% 14,1%</p><p>2050 43% 14,5% 38,1% 23,6%</p><p>Tables1.9aand1.9bconsiderlessefficientelectricalroadvehicles(20%less</p><p>emissionsthantheonesusingconventionalfossilfuelengines)withandwithout</p><p>aviationbiofuelsutilization.Fig.(1.14)plotsthedatacontainedinTables1.8a,</p><p>1.8b,Tables1.9aand1.9b.</p><p>Table1.9aAviationContributiononCO2EmissionsrelatedtoTransportation</p><p>Systems(withandwithoutEVintroduction).EVefficiencyof20%andno</p><p>aviationbiofuelsintroduction.</p><p>Year EV NoEV WithEV delta</p><p>2000 0% 13,2% 13,2% 9,4%</p><p>2005 0% 14,0% 14,0% 10,5%</p><p>2010 0% 14,3% 14,3% 9,5%</p><p>2015 10% 14,3% 14,5% 11,6%</p><p>2020 15% 14,4% 14,8% 10,8%</p><p>2025 20% 15,6% 16,3% 10,1%</p><p>2030 25% 16,5% 17,7% 9,4%</p><p>2035 30% 15,9% 17,8% 8,9%</p><p>2040 50% 16,3% 19,6% 9,5%</p><p>2045 80% 15,1% 20,6% 10,3%</p><p>2050 100% 14,5% 22,8% 8,9%</p><p>Table1.9bAviationContributiononCO2EmissionsrelatedtoTransportation</p><p>Systems(withandwithoutEVintroduction).Remark:EVefficiency20%and</p><p>aviationbiofuelsutilization.</p><p>Year Biofuels NoEV WithEV delta</p><p>2000 0% 13,2% 13,2% 0,0%</p><p>2005 0% 14,0% 14,0% 0,0%</p><p>2010 0% 14,3% 14,3% 0,0%</p><p>2015 0% 14,3% 14,5% 0,2%</p><p>2020 1% 14,4% 14,7% 0,3%</p><p>2025 3% 15,6% 16,0% 0,5%</p><p>2030 5% 16,5% 17,2% 0,6%</p><p>2035 11% 15,9% 16,7% 0,8%</p><p>2040 18% 16,3% 17,6% 1,3%</p><p>2045 28% 15,1% 17,2% 2,1%</p><p>2050 43% 14,5% 17,1% 2,7%</p><p>Fig.(1.14))</p><p>AviationcontributionwithglobalCO2emissionsconsideringanincreasingEV</p><p>fleetovertime.Maximumelectriccarefficiencywas80%,minimumefficiency</p><p>20%.</p><p>Consideringthepresenteddata,thefollowingremarksarerelevant:</p><p>TheaviationbiofuelsreductionofCO2emissionswaseffectivefrom2020,</p><p>accordingtoIEA[31].Forexample,by2050,considering100%ofroadvehicles</p><p>beingelectricalones,aviationcontributionwouldbeincreasedby27.3%ifno</p><p>biofuelsareused.Ifbiofuelsareutilized,thisfiguredropsto23.6%,adifference</p><p>by-3.7%.Improvementsupto-5.7%areobserved.</p><p>In2050underthemost“pessimisticscenario”foraviation,when100%ofthe</p><p>roadvehicleswouldbeelectrical(withmaximumefficiency80%)andno</p><p>biofuelsareused,theparticipationofaviationontransportCO2emissionswould</p><p>be46.7%,3.3timesgreaterthan2005levels(consideringthatnoEVsandno</p><p>biofuelsarepresent).</p><p>In2050,underthemost“optimistic”scenarioforaviation,if100%oftheroad</p><p>vehiclespresentonly20%efficiency(technologyhasnotevolvedsofar...)and</p><p>aviationbiofuelisusedon43%oftheflights[40],theparticipationofaviation</p><p>ontransportCO2wouldbe17.1%,approximately1.2timesgreaterthan2005</p><p>levels(consideringnoEVsandnobiofuelsarepresent).</p><p>Theevidentconclusionisthatevenintroducingbiofuelsonaviationoperations,</p><p>theincreasingdemandforelectricalroadvehicleswouldleadaviationtoa</p><p>scaling,increasingitsshareontransportationemissionsthroughouttheyear</p><p>2050,despitetheoverallemissionsreduction.Inotherwords,thereissubstantial</p><p>evidencethataviationwillbemoreandmoreinfocus(andsocial-political</p><p>pressure)throughouttheyearsregardingtheGHGemissions.Thisfact</p><p>obviouslyreinforcesthenecessityofimprovementsinaircraft/enginedesign,</p><p>alternativemotorization,andothersourcesofenergytopoweraircraftsystems</p><p>andimprovementsinoperationalefficiencies.</p><p>TheNoiseImpacts</p><p>Noisebelongstotheeverydaylifeinurbanenvironments.Transport,industry</p><p>andneighborsarecommonsourcesofnoise.Exposuretotransportnoisedisturbs</p><p>sleepinthelaboratory,butnotgenerallyinfieldstudieswhereadaptationoccurs.</p><p>Noiseinterferesincomplextaskperformance,modifiessocialbehaviorand</p><p>causesannoyance[41].Studiesofoccupationalandenvironmentalnoise</p><p>exposuresuggestanassociationwithhypertension,whereascommunitystudies</p><p>showonlyweakrelationshipsbetweennoiseandcardiovasculardisease.Aircraft</p><p>androadtrafficnoiseexposureareassociatedwithpsychologicalsymptomsbut</p><p>notwithclinicallydefinedpsychiatricdisorder[41].Inbothindustrialstudies</p><p>andcommunitystudies,noiseexposurerevealedaraiseincatecholamine</p><p>secretion[41].Inchildren,chronicaircraftnoiseexposureimpairsreading</p><p>comprehensionandlong-termmemoryandmaybeassociatedwithraisedblood</p><p>pressure[41].Furtherresearchisneededexaminingcopingstrategiesandthe</p><p>possiblehealthconsequencesofadaptationtonoise.</p><p>AnexperimentinGermanyhelpstoexplainhownoiseinterfereswithlearning.</p><p>AftertheoldMunich-Riemairportceasedoperationsin1992,thenewairportin</p><p>Freising,adistantsitefromthecity,begantooperateregularflightsfromandto</p><p>Munich.Testsundertakenonthird-andfourth-graders--beforethatswitch,soon</p><p>afteritandagainlater--showedthatstudentsneartheoldairportinitiallyscored</p><p>lowerthanothersinthetestsofmemoryandreadingbutimprovedafterthe</p><p>airportclosed,whiletheircounterpartslivingnearthenewairportexperienceda</p><p>declineinscoresaftertheswitchoccurred[42].</p><p>Whendealingwithaneworproposednoise,LAeqisoftenused[alsowritten</p><p>dBALeq];thistermistheEquivalentContinuousLevel.Theformaldefinitionis</p><p>whenanoisevariesovertime;theLeqistheequivalentcontinuoussoundwhich</p><p>wouldcontainthesamesoundenergyasthetimevaryingsound.However,itcan</p><p>bethoughasatypeofaverage,wherenoisyeventshaveaconsiderable</p><p>influence.LAeqisthemainunitusedforassessingtheoccupationalnoise.As</p><p>withallformsofaverage,itisimportanttoconsidertheperiodoverwhichthe</p><p>averageistaken.</p><p>AUKGovernmentresearchindicatesthatpeoplestartbeingconcernedby</p><p>aircraftnoiseat57dB,averagedover16hours(57dBLAeq)[43].Theyusethis</p><p>asthestartingpointinairportandaircraftnoisepolicies.Thenoisecontoursin</p><p>thevicinitiesofGatwickAirport[43]presentanirregularshapebecauseatthe</p><p>endsoftherunway(whereairplanestakeoffandland),morenoiseisgenerated</p><p>thanatthesides.Themapunderconsiderationshowsthecontoursfor2013,</p><p>combiningnoiseforallflights,regardlessofthewinddirectionandthereforeof</p><p>thedirection,theplaneswereflying.</p><p>Inthelast20years,the57dBnoisecontour</p><p>aroundtheGatwickairport</p><p>diminishedconsiderably.Thiscanbecreditedtothenewgenerationquieter</p><p>aircraft.Thus,thenumberofpeoplewholivewithin57-dBnoisecontourhas</p><p>reduced.In1993,therewere14,600peopleinthisnoisecontouraroundGatwick</p><p>[43];by2011,thiswasreducedto3,050[43].Thisisdespitearapidgrowthin</p><p>airtravelatthesametime,fromaround191,000flightsayearin1993to</p><p>244,741in2011.Thedatasurveyaboutthenumberofnoisecomplaintsby</p><p>aircrafttypeagainsttheGatwickAirportindicatesthatAirbusA319recordsboth</p><p>thehighernumbersofcomplaintsandmovements[43].</p><p>Tocomparethenoisecausedbyairplaneswiththatfromroadtraffic,astudy</p><p>carriedoutinthecityofSãoPauloprovidesvaluabledata:a-weightedsound</p><p>pressurelevel(Leq)fortheroadswithheavytrafficrangedfrom70.88to80.18</p><p>dB(A)andthemaximumpeakrangedfrom102.47to108.37dB(C)[44].Thus,</p><p>inlargecities,themainsourceofnoiseisthevehiculartrafficwhichis</p><p>frequentlycharacterizedbytrafficjams.Here,somesources:</p><p>Thesubstantialnumberofmotorvehicles,withmanyoftheminpoor</p><p>conservationconditions.</p><p>Disrespectfortrafficlaws.</p><p>Loudnoisesfromhorns,alarms,andfrictionoftiresonimperfectroadsurfaces</p><p>produceanuncomfortableenvironmentandmakelifequalitysignificantly</p><p>worse.</p><p>VerheijenandJabben[45]preformedanimportantstudywhere90%of</p><p>passengerroadvehiclesand80%oftheheavytrucksweresubstitutedwith</p><p>electricvehiclesinacityoftheNetherlands.Anoisereductionmapwasmadeof</p><p>theentirecityandanoverallnoisereductioninorderof3dBwaseffectively</p><p>measuredbythefirsttimeinseveralplaces.Thisstudyshowedthatelectriccars</p><p>couldmeanasignificantreductioninthenoiselevelonurbanroadswithspeed</p><p>below30km/h.Atspeedabove50km/h,electricandhybridcarsarenotquieter</p><p>thanconventionalcarsbecausethetire-roadnoiseincreaseswithspeedand</p><p>becomesthedominantnoisesource[45].Inaddition,LelongandMichelets[46]</p><p>showedthatreplacementofallcarswithelectriccarswouldgiveverylittle</p><p>effectsatpeakhoursandnoon.Thislackofreductionisexplainedbythefact</p><p>thatatthesehours,morebusesandtruckspopulatethestreetsandthesetypesof</p><p>vehiclesarenotexpectedtobereplacedbyelectricvehiclesinshortturn.Outof</p><p>peakhours,duringnightcurfewsforexample,differencesupto5dBswere</p><p>observed,revealingthatelectricalcarshaveaverygoodpotentialtolowernoise</p><p>levels.</p><p>Withtheincreasinguseofelectricalroadvehicles,reachinganadherence</p><p>between90%and100%upto2050,citieswillbemostlikelyquieterandthe</p><p>communitieswillthereforeperceiveaviationnoiseonvicinitiesofairportswith</p><p>moresensitivity.Inaviation,noisereductionsupto5dBmagnitudesarehardto</p><p>obtainwithoperationalmitigationsonlyandtherefore,thislevelofreduction</p><p>wouldprobablyreachonaircraftandenginedesignimprovements.</p><p>Althoughanoisereductionof3dBseemstobesmallatfirstglance,butthisis</p><p>not.Thenoisecontours(LAeq)aroundLondonCityAirport[47]revealthatin</p><p>theareabetweenthe57dB,thehighestacceptablenoiselevel,and60dB,itis</p><p>easilytoperceivethata3-dBnoisereductionhasaprofoundimpactonregions</p><p>closetoairports[47].</p><p>CONCLUSIONS</p><p>In2017,therehavebeenmanyannouncementsmakingthefutureofelectricroad</p><p>vehiclesverypromising:</p><p>Porscheismovingawayfromdiesel.theGermanautomakerispreparingforits</p><p>firstforayintotheelectricspace.PorscheisspendingUS$1.16billionto</p><p>overhaulitsStuttgartplanttointroducetheMissionEin2019.</p><p>TeslastarteddeliveringitsUS$35,000model3.</p><p>Volvo,nowaChinese-ownedfirm,bestknownforitsemphasisondriversafety,</p><p>hasbecomethefirsttraditionalautomakertosignaltheendoftheinternal</p><p>combustionengine.Volvoplanstolaunchfivefullyelectricmodelsbetween</p><p>2019and2021andarangeofhybridmodels.</p><p>AfterFranceannouncedinJuly2017thatitplansonbanningnewpetroland</p><p>dieselcarsby2040,theBritishgovernmentfollowedsuitannouncingsimilar</p><p>measures.</p><p>Electricroadvehicleswillcertainlybecomeaconsiderablepartofroadvehicles</p><p>inupcomingdecades,causingaprofoundimpactonpollutantemissionlevels</p><p>andtheurbannoise.</p><p>Urbannoisereductionprovidedbyelectricroadvehiclesissmall.Electriccars</p><p>couldmeanasignificantreductioninthenoiselevelonurbanroadswithspeed</p><p>below30km/h.Atspeedabove50km/h,electricandhybridcarsarenotquieter</p><p>thanconventionalcarsbecausethetire-roadnoiseincreaseswithspeedand</p><p>becomesthedominantnoisesource.</p><p>Themostsignificantcontributionofelectricvehicleswillthereforebein</p><p>pollutantemissionreductions.Biofuelscanbeintroducedinthermoelectric</p><p>powerstationstominimizethepowerdemandofelectricvehicles.</p><p>In2050,underthemost“pessimisticscenario”foraviation,when100%ofthe</p><p>roadvehiclessupposedlywouldbeelectrical(withmaximumefficiency80%)</p><p>andnobiofuelswouldbeused,theparticipationofaviationontransportCO2</p><p>emissionswouldbe46.7%,3.3timesgreaterthanthe2005levels(considering</p><p>thatnoEVsandnobiofuelsarepresent).</p><p>Introductionofbiofuelsintocommercialaviationisafarcryfromcompensating</p><p>theincreaseinthepercentageofaviationinCO2emissionsduetothe</p><p>introductionofelectricalroadvehicles.Radicalaircraftdesigntargeting</p><p>emissionreductionsmustthusbecomerealityastheonesenvisagedbyERAand</p><p>CleanSkyprograms.</p><p>References</p><p>[1] FederalAviationAdministrationAviationEmissions,Impacts&Mitigation:APrimer.FAAOfficeofEnvironmentandEnergy2015</p><p>[2] EarthScienceCommunicationsTeamatJetPropulsionLaboratoryGlobalClimateChangeNASA,September2017[Online].Available:https://climate.nasa.gov/.</p><p>[3] GrouponInternationalAviationandClimateChange(GIACC)GlobalAviationCO2EmissionsProjectionsto2050GIACC4thMeetingMontreal.2009</p><p>[4] EuropeanComissionFlightpathto2050:Europe'sVisionforAviationEuropeanUnion,HighLevelGroup,2011..</p><p>[5] TestC.D..EarlyElectricCars20.[Online].Available:http://chuckstoyland.com/national/electric/index.html.</p><p>[6] ElectricPowerResearchInstituteEnvironmentalAssessmentofaFullElectricTransportation.CaliforniaEelectricPowerResearchInstitute2015</p><p>[7] HartmanD.L.,TankA.K.,RusticucciM.,AlexanderV.L.,BrönnimannS.,CharabiY.,DentenerF.J.,DlugokenckyE.J.,EasterlingD.R.,KaplanA.,SodenB.J.,ThorneP.W.,WildM.,ZhaiP.M..Observations:AtmosphereandSurfaceIntergovermmentalPanelonClimateChangeNewYork2013..</p><p>[8] EuropeanCommissionClimateChange:CommissionProposesBringingAirTransportintoEUTradigingSchemes,Brussels:EuropeanCommissionPressrelease2006</p><p>[9] KawamuraK.,ParreninF.,LisieckiL.,UemuraR.,VimeuxF.,SeveringhausJ.P.,HutterliM.A.,NakazawaT.,AokiS.,JouzelJ.,RaymoM.E.,MatsumotoK.,NakataH.,MotoyamaH.,FujitaS.,Goto-AzumaK.,FujiiY.,WatanabeO..NorthernHemisphereforcingofclimaticcyclesinAntarcticaoverthepast360,000years.Nature2007448715691291610.1038/nature0601517713531</p><p>[10] WolffE.a.,BasilleI.,Jean-RobertP.,SchwanderJ..EPICADomeCCoreEDC96DielectricProfilingData.Ann.Glaciol.20032918993</p><p>[11] SiegenthalerU.,StockerT.F.,MonninE.,LüthiD.,SchwanderJ.,StaufferB.,RaynaudD.,BarnolaJ.M.,FischerH.,Masson-DelmotteV.,JouzelJ..Stablecarboncycle-climaterelationshipduringtheLatePleistocene.Science200531057521313131710.1126/science.112013016311332</p><p>[12] InternationalEnergyAgencyWorldEnergyOutlook2006.ParisIEA2006</p><p>[13] WikipediaGreenhouseGasWikipedia,theFreeEncyclopedia,18May2016.[Online].Available:https://en.wikipedia.org/wiki/Greenhouse_gas.</p><p>[14] BarnetA..CanAircraftTrailsaffectClimate?December2008.[Online].Available:http://www.nature.com/news/2008/081231/full/news.2008.1335.html.10.1038/news.2008.1335</p><p>[15] SternN..TheEconomicsofclimateChange:TheSternreview.NewYorkCambridgeUniversityPress200710.1017/CBO9780511817434</p><p>[16] ICAOAnnex16:EnvironmentalProtectioninConventiononInternationalCivilAviation,Montreal2008</p><p>[17] IPCC“WGIIIFormulationofResponseOptionStrategies,”inInternationalPanelonClimateChange.GeneveIPCC1990</p><p>[18] LeeD.S.,KöhlerI.,GroblerE.,SausenR.,Gallardo-KlennerL.,OlivierJ.J.,DentenerF.D..EstimationsofGlobalNOxEmissionsandtheirUncertainties.Atmos.Environ.1997311735174910.1016/S1352-2310(96)00327-5</p><p>[19] HidalgoH.,CrutzenP.J..TheTroposphericandStratosphericCompositionPerturbedbyNOxEmissionsofHigh-altitudeAircraft.J.Geophys.Res.1977825833586610.1029/JC082i037p05833</p><p>[20] JohnsonC.E.,HenshawJ.,McInnesG..ImpactofAircraftandSurfaceEmissionsofNitrogenOxidesonTroposphericOzoneandGlobalWarming.Nature1992355697110.1038/355069a0</p><p>[21] SchumannU..TheImpactofNitrogenOxidesEmissionsfromAircraftupontheatmosphereatFlightAltitudes-resultsfromtheAERONOXProject.Atmos.Environ.1997311723173310.1016/S1352-2310(96)00326-3</p><p>[22] GaussM.,IsaksenD.S..ImpactofaircraftNOxEmissionsontheAtmosphere-TradeoffstoreducetheImpact.Atmos.Chem.Phys.200661529154810.5194/acp-6-1529-2006</p><p>[23] MetzB.,DavidsonO.R.,BoschP.R.,DaveR.,MeyerL.A..ContributionofWorkingGroupIIItothefourthAssessmentReport.NewYorkCambridgeUniversityPress2007</p><p>[24] IntergovernmentalPanelonClimateChangeMitigationofClimateChange-ContributionofWorkinggroupIIItotheFourthAssessmentoftheIPCC.NewYorkCambridgeUniversityPress2007</p><p>[25] InternationalCivilAviationOrganizationGrouponInternationalAviationandclimateChange.MontrealICAO2009</p><p>[26] InternationalAirTransportAssociationTechnologyRodamap.MontrealIATA2013</p><p>[27] NolteP.a..QuantitativeAssessmentofTechnologyImpactonAviationFuelEfficiencyAirTransportOperationSymposiumDelft2012</p><p>[28] WikipediaFuelEconomyinAircraftWikipedia,theFreeEncyclopedia,11May2016.[Online].Available:https://en.wikipedia.org/wiki/Fuel_economy_in_aircraft</p><p>[29] MankinsJ.C..technologyReadinessLevels,AWhitepaperOfficeofSpaceAccessandTechnology,NASA,1995..</p><p>[30] RoyalCommissiononEnvironmentalPollutionTheEnvironmentalEffectsofCivilAircraftinFlight.LondonRoyalCommissiononEnvironmentalPollution2002</p><p>[31] CollierF..OverviewofNASA’sEnvironmentalResponsibleaviation(ERA):ANASAAeronauticsProjectFocusedonMidtremEnvironmentalGoals48thAIAAaerospaceSciencesMeeting,Orlando,2010.2010</p><p>[32] BarnstorffK..NASATestsGreenAviationTechnologyonBoeingecoDemonstratorNASA,April2015.[Online].Available:https://www.nasa.gov/aero/nasa-tests-green-aviation-technology-on-boeing-ecodemonstrator.html</p><p>[33] Wikipedia2017Wikipedia,September2017.[Online].Available:https://en.wikipedia.org/wiki/Chevrolet_Volt</p><p>[34] WikipediaTheFreeEncyclopedia,"TeslaModelS,"WikipediaSeptember2017.[Online].Available:https://en.wikipedia.org/wiki/Tesla_Model_S</p><p>[35] TheCleanEnergyMinisterialElectricVehiclesInitiative(EVI),EnergeticsIncorporated,[Online].Available:http://www.cleanenergyministerial.org/Our-Work/Initiatives/Electric-Vehicles</p><p>[36] ElectricVehicleInitiativeInternationalEnergyagency-UnderstandingtheElectricVehiclelandscapeto20202013https://www.iea.org/publications/globalevoutlook_2013.pdf</p><p>[37] TheBoeingCompanyBoeing787fromtheGroundUp.BoeingAeroMagazine2006</p><p>[38] TheBoeingCompanyCurrentMarketOutlook2015-20342014.http://www.boeing.com/resources/boeingdotcom/commercial/about-our-market/assets/downloads/Boeing_Current_Market_Outlook_2015.pdf</p><p>[39] FultonL.,EadsG..IEA/SMPModelDocumentationandreferencecaseProjection2004http://oldwww.wbcsd.org/web/publications/mobility/smp-model-document.pdf</p><p>[40] InternationalEnergyAgencyGlobalEnergyOutlook.ParisIEA2009</p><p>[41] StansfeldS.A.,MathesonM.P..NoisePollution:Non-auditoryEfefctsonhealth,”Britishmedical.Bulletin200368124325714757721</p><p>[42] WeissR..NoisePollutionTakesToolonhealthandHappiness,Washington:WashingtonPost,2007..</p><p>[43] GatwickAirportFlightPerformanceTeam2014AnnualReport.GatwickAirport,London,2015..</p><p>[44] Moura-De-SousaC.,ReginaAlvesCardosoM..UrbanNoiseintheCityofSãoPaulo,Brazil:AnImportantProblemofPublicHealth.NoiseHealth2002416576312537842</p><p>[45] LelongJ.,MicheletR..PassengerCars-PowerUnitandTyre-roadNoise,DrivingbehavuourInter-Noise2001,TheHague2001</p><p>[46] VerheijenE.,JabbenJ..EffectofElectriccarsonTrafficNoiseandSafetyNationalInstituteforPublichealthandTheEnvironment,Bilthoven2010</p><p>[47] LondonCityAirportLondonCityActionPlan2010-2015.LondonLondonCityAirport2009</p><p>AeronauticalTechnologyOverTime</p><p>BentoS.deMattos</p><p>Abstract</p><p>Thepresentchapterperformsananalysisoftheaviationfromthedawnof</p><p>aviationtoearly2017,highlightingtheEuropeanpioneeringworkinmany</p><p>aspectslikesupersonicflightandinnovativeaircraftconfigurations.Theworkof</p><p>aviationpioneersisalsoanalyzed.Anoverviewoftechnologicalevolutionsince</p><p>WorldWarItothepresentdaysiscarriedout,alsoaddressingsomenotable</p><p>eventsthatshapedthecommercialaviation.Specialattentionisgiventothe</p><p>developmentofsupersoniccivilaircraftanditsimpactontheenvironment.</p><p>Aircraftconceptsthatusedorarecurrentlyemployingalternativefuelsand</p><p>powerareshownanddiscussed.Alternativemeansoftransportationarealso</p><p>analyzed.Thechapteralsopresentsanappendixcontainingthemajoradvances</p><p>ofaeronauticaltechnology.Throughoutthischapter,thereaderwillnoticethat</p><p>someusualhistoricalconsiderationsarereviewed,andnewsanalysesare</p><p>provided.</p><p>Keywords:Aerodynamics,Airtransportation,Aircraftdesign,Aircraft</p><p>industry,Aircrafttechnology,Airline,Airliner,Alternativefuels,</p><p>Commercialaviation,Entropystatistics,Globalwarming,Supersonicflight,</p><p>WorldWarIIaircraft.</p><p>THEFLIGHTPIONEERS</p><p>FlyingwithStyle</p><p>Thebeginningoftheheavier-than-airflightwaspossiblethankstotheeffortsof</p><p>severalpioneers:TheLilienthalbrothers,theBrazilianSantos-Dumont,the</p><p>Wrightbrothers,HenriFarman,LouisBlériot,GabrielandCharlesHoisinand</p><p>manyothers.ThankstothespreadoftheFrenchRevolutionambienceamong</p><p>theaviationpioneersintheearlyXXcentury,aviationtookoffinFrance[1].</p><p>TheworkofSantos-Dumont,averyrichpersonwhosettleddowninFranceat</p><p>theendoftheXIXcentury,providesagoodpictureoftheeventsthatshaped</p><p>aviation.Forthisreason,thepresentchaptercarriesoutadeeperinvestigationof</p><p>hismasterpiece.</p><p>Dumontstartedhisaviationcareerbydesigningballoonsandairships,thelatter</p><p>makinghimaworldwidecelebrity.Afterhissuccesswithairships,Dumont</p><p>turnedhisattentiontotheairplanedesignandconstruction.Hesoonrealizedthat</p><p>the</p><p>internalcombustionenginewouldbeidealforpoweredflight.Severalearlier</p><p>flightattemptshadbeencarriedoutwithelectricandsteamengines.</p><p>Santos-DumontwontheDeutschdelaMertheAwardin1901.Theorganizing</p><p>committeeofthisawardestablishedthechallengeofaflighttourstartingfrom</p><p>theSaintCloudfieldencompassingaturnaroundtheEiffelTower(Fig.2.1).</p><p>Santos-DumontaccomplishedthistaskwithhisairshipNo.6.Hehadtriedthis</p><p>previouslywithhisairshipNo.5,butduetohydrogenleak,heendedup</p><p>crashingintotheHotelTrocadero(whichnolongerexistsinParistoday).</p><p>Santos-Dumontcontinuedtodevelopairships.Thesmallestofthem,wastheNo.</p><p>9,semi-rigid,dubbedLaBaladeuse(Fig.2.2).Itwasdesignedandbuilttobehis</p><p>personalaerialtransport[1]andfulfilledDumont’sexpectationsinregardto</p><p>performanceandmaneuverability.Dumontusedtoemploythisairshiptogoto</p><p>publicplacessuchasrestaurants,shopsandsnackbars,visitingfriendsand</p><p>he</p><p>wasoftenseenatclubs[1].HefrequentlyflewoverthehousesofParis,almost</p><p>scrapingtheirroofs.OnJuly14,1903,heallowedhisfriend,AidadeAcosta,a</p><p>Cubanmarriedwoman,topilottheaircraftonasmalltrip(Fig.2.2).</p><p>Fig.(2.1))</p><p>Amilestoneforaeronauticalengineering:Santos-DumontairshipsaroundEiffel</p><p>Towerin1901.Left–Number5sufferedhydrogenleakafterflyingroundthe</p><p>Eiffeltower[1].Manyhistoriansoftenmisinterpretthispicture,astheyreferto</p><p>theaircraftinthephotoasthenumber6.Right:Number6onthewaytowinthe</p><p>DeutschdelaMeurtheprize.</p><p>Fig.(2.2))</p><p>AidaD’Acosta,Dumont’sfriend,atcontrolsofhisNo.9airship.</p><p>Afterhissuccessdesigningandflyingairships,Dumontturnedhisattentionto</p><p>heavier-than-airmachines.Initially,heconceivedatwin-propellersingle-engine</p><p>monoplanebutlaterhebuiltabiplanebasedonanexistinggliderandperformed</p><p>someflightswithit.</p><p>InOctoberof1906,Santos-Dumontperformeda220-mflightwithhis14Bis</p><p>biplaneinFrance(Fig.2.3)[2].Dumont’sflightwascertifiedbyanAeroclubde</p><p>Francecommitteeasthefirstheavier-than-airflightinhistory.Acrowdpresent</p><p>ontheLeBagatellefieldalsowatchedtheairride.</p><p>Fig.(2.3))</p><p>Santos-Dumontflightswiththe14Bisbiplanein1906.</p><p>TheFirstOperationalAirplane</p><p>In1907,Santos-Dumontstartedworkonagroundbreakingairplane,goingback</p><p>tothemonoplaneconfigurationthathehadconsideredbeforetheflightswithhis</p><p>14Bisbiplane[1].Thus,theDemoisellehigh-wingmonoplanearose,whichwas</p><p>thefirstpracticalairplane[1].Demoiselleshapedthingsthatwouldcome,like</p><p>theBlériotXImonoplanethatcrossedtheEnglishChannel[2].Thesingle-</p><p>engineDemoiselleairplane(Fig.2.4)wasDumont’slastconcept,closinghis</p><p>aeronauticalactivitiesin1909.TheBrazilianaviationpioneerperformedmany</p><p>experimentswithDemoiselle,whichreceivedsuccessivedesignations–Number</p><p>19to22.TheDemoisellewasanextraordinaryexperienceintermsof</p><p>constructionandconfigurationbecauseDumontpioneeredageodesicbamboo</p><p>structurethatemployedsteelpianowiringforitsrigidity.</p><p>Fig.(2.4))</p><p>Demoisellewasthefirstpracticalairplane[1][3].</p><p>Demoisellewasproducedinmanycountries,includingGermany,France</p><p>(ClémentBayardCompany),Holland,andtheUnitedStates[3].Dumont</p><p>employedDemoiselleashispersonalmeansoftransportation[2].Thesmall</p><p>airplanecouldbetransportedinthebackofhiselectricautomobile(Fig.2.5),</p><p>whichwasadaptedforthispurpose[4].Heletothersmakeuseofhisdesign,in</p><p>agreementwiththephilosophyoftheFrenchRevolutionambiencethatprevailed</p><p>atthattimeinFrance[1].Thefuselageconsistedofaspeciallyreinforced</p><p>bambooboom,andthepilotfoundaccommodationbeneaththemainwheelsofa</p><p>bicyclelandinggear.Pitchanddirectionalcontrolwasprovidedbyacruciform</p><p>tailandrollcontrolbywingwarping(Number20).</p><p>Fig.(2.5))</p><p>Demoisellemonoplanebeingtransportedbyelectricautomobilein1909[3].</p><p>Demoisellewasproducedinmanycountries,includingGermany,France</p><p>(ClémentBayardCompany),Holland,andtheUnitedStates[4].Dumont</p><p>employedDemoiselleashispersonalmeansoftransportation[2].Thesmall</p><p>airplanecouldbetransportedinthebackofhiselectricautomobile(Fig.2.5),</p><p>whichwasadaptedforthispurpose[3].Heletothersmakeuseofhisdesign,in</p><p>agreementwiththephilosophyoftheFrenchRevolutionambiencethatprevailed</p><p>atthattimeinFrance[1].Thefuselageconsistedofaspeciallyreinforced</p><p>bambooboom,andthepilotfoundaccommodationbeneaththemainwheelsofa</p><p>bicyclelandinggear.Pitchanddirectionalcontrolwasprovidedbyacruciform</p><p>tailandrollcontrolbywingwarping(Number20).</p><p>Dumontsteadilyincreasedthewingspanofhisairplane.EarlierDemoiselle</p><p>versionspresentedawingspanof5.10mandanoveralllengthof8m.Gross</p><p>weightofDemoisellewas110kgwithSantos-Dumontatcontrols.Take-offrun</p><p>wastypically40m[3].Thepilotwasseatedbelowthefuselage-wingjunction,</p><p>justbehindthewheels,andcommandedthetailsurfacesusingasteeringwheel</p><p>[1].Concerningaerodynamics,Demoisellefeaturedairfoilwithmuchcamberat</p><p>thewingleading-edgeregion.Initially,Santos-Dumontemployedaliquid-</p><p>cooledDutheil&Chalmersenginedelivering20hp.Later,herepositionedthe</p><p>enginetoalowerlocation,placingitinfrontofthepilot.Healsoreplacedthe</p><p>formerenginebya24-hpAntonietteandintroducedsomewingreinforcements</p><p>[1].Duetostructuralproblemsandcontinuouslackofpower,Santos-Dumont</p><p>introducedadditionalmodificationsintotheDemoiselle’sconfiguration:a</p><p>triangularandshortenedfuselagemadeofbamboo;theenginewasmoved</p><p>backwards,butkeptit*positioninginfrontofthewingandincreasedwingspan.</p><p>ThisresultedintheconfigurationdesignatedNo.21[1].ThedesignofNo.22</p><p>waslikeNo.21.Santos-Dumonttestedopposed-cylinder(hepatentedasolution</p><p>forcoolingthiskindofengine)andcooled-waterengines,withpowersettings</p><p>rangingfrom20to40hp,inbothvariants[1].Aninterestingfeatureofthe</p><p>water-cooledvariantwastheliquid-coolantpipelinethatfollowedthewing</p><p>lowersidegeometryinordernottocausetoomuchaerodynamicdegradation</p><p>(Fig.2.6).</p><p>Fig.(2.6))</p><p>Demoisellewithconformalradiatorsonwinglowerside.</p><p>Deliveringoutstandingperformance,demandingaveryshorttakeofflengthand</p><p>beingabletoflyatspeedshigherthan100km/h,Demoisellewasthelastaircraft</p><p>builtbySantos-Dumont.HeusedtoperformflightswiththeairplaneinParis</p><p>andtonearbyplaces[3].Flightswerecontinuedatvarioustimesthrough1909,</p><p>includingthefirstcross-countryflightrecordedinhistory.TheDemoisellethat</p><p>wasfittedwithatwo-cylinderenginebecameratherpopular.Influencedbythe</p><p>spiritofFrenchrevolutionof1789,Santos-Dumontreleasedthedrawingsof</p><p>Demoisellefreeofcharge,believingthataviationwouldbethemainstreamofa</p><p>neweraofeconomicgrowth[1].ClémentBayard,anautomotiveandbicycle</p><p>maker,constructedseveralunitsofDemoiselle,whichweresoldfor50,000</p><p>Francseach.TimerequiredtobuildanexemplarofDemoisellewasjust15days.</p><p>Over300Demoiselleexemplarswerebuilt,makingitaverysuccessfulairplane</p><p>[4].</p><p>ThedesignofDemoiselleinfluencedtheconfigurationoftheBlériotXIairplane</p><p>(Fig.2.7),whichwasusedbyDumont’sfriendLouisBlériotfortheBritish</p><p>Channelcrossingin1909.BlériotXIwasatractor-configurationmonoplane</p><p>withapartiallycoveredbox-trussfuselagebuiltwithwirebracingtoguarantee</p><p>rigidity.Wingwarpingwasemployedforlateralcontrol.Thetailsurfaces</p><p>consistedofasmallbalancedall-movingruddermountedontherearmostpartof</p><p>thefuselageandahorizontalstabilizermountedunderthelowerlongerons.</p><p>Fig.(2.7))</p><p>BlériotXIasfirstbuilt(Photo:LibraryofCongress,publicdomain).</p><p>THEFIRSTAIRLINERS</p><p>FromWartoPeace</p><p>Table2.1displaystheimpressiveprogressofthesolutionoftheproblemof</p><p>heavier-than-airflight[2].AllachievementswererecordedbyAéro-Clubde</p><p>France.AlthoughWilburWrighthadsettleddowninFrancein1907,hewas</p><p>onlyabletodeliveraremarkableperformanceinlate1908,probablyafterhe</p><p>incorporatedEuropeantechnologyintoFlyer`sconfiguration.TheWrightsdid</p><p>nottakepartinthecompetitionorganizedbyScientificAmericanintheU.Sfor</p><p>thefirstkilometerflightjourney.TheBrotherswouldhavebeenrequiredto</p><p>installwheelsanddiscardthecatapultlaunchtocompeteforthe1908prize.</p><p>Curtisswonthecompetitionwithhis“JuneBug”biplaneinJuly1908.</p><p>Table2.1Progressiveflightrecords[2].</p><p>Aviator Place Date Distance/Time</p><p>Santos-Dumont Bagatelle 22Aug.1906 Fewseconds</p><p>Santos-Dumont Bagatelle 14Sept.1906 7-8m</p><p>Santos-Dumont Bagatelle 23Oct.1906 50m</p><p>Santos-Dumont Bagatelle 12Nov.1906 220m</p><p>HenryFarman</p><p>Issy 26Oct.1907 771m</p><p>HenryFarman Issy 13Jan.1908 1500m</p><p>HenryFarman Issy 21March1908 2004m</p><p>Delagrange Issy 10April1908 2500m</p><p>Delagrange Issy 11April1908 3925m</p><p>Delagrange Rome 27May1908 5km</p><p>Delagrange Rome 27May1908 9km</p><p>Delagrange Rome 30May1908 12.5km</p><p>Delagrange Milan 22June1908 17km</p><p>HenryFarman Gand 6July1908 19.7km</p><p>Delagrange Issy 6Sept.1908 24.727km</p><p>OrvilleWright FortMeyer 9Sept.1908 1h2min30s</p><p>OrvilleWright FortMeyer 10Sept.1908 1h5min57s</p><p>OrvilleWright FortMeyer 11Sept.1908 1h10min50s</p><p>OrvilleWright FortMeyer 12Sept.1908 1h15min20s</p><p>WilburWright Auvours 21Sept.1908 1h31min25s</p><p>WilburWright LeMans 18Dec.1908 1h54min22s</p><p>AftermanysuccessfulflightswithDemoiselle,Dumontceasedaeronautical</p><p>activitiesin1909becausehewassufferingfrommultiplesclerosis.However,</p><p>aviationwasinfiberoneyearbefore.HenriFarmanwasoneofDumont’sclosest</p><p>friends.In1908,heperformedthefirstkilometerflightinhistory[2].OnMarch</p><p>29ofthesameyear,HenriFarmancarriedaviationMaecenasErnestArchdeacon</p><p>aloftfor134monthefirstairplanepassengerflightintheWorld(Fig.2.8)[2].</p><p>OnMay14,1908,WilburWrightflewmechanicCharlesFurnas600min29</p><p>seconds,makinghimthefirstairplanepassengerintheUnitedStates.OnJune2,</p><p>1908,Farmanperformedaflightwithasinglepassengercovering1,241km[2].</p><p>OnOctober10,1908,WilburWrightheldthepassenger-carryingrecordwitha</p><p>flightof1h9min45secthatcovered80km[2].</p><p>Fig.(2.8))</p><p>HenriFarmanandhispassengerArchdeacon(1908)[2].</p><p>Aviationwasgainingevengreatermomentumfrom1909on.TheFrenchman</p><p>LouisBlériotcameoutofapartnershipwiththeVoisinbrothers,withwhomhe</p><p>hadbuiltgliders.Afterwards,hefoundedhisownaircraftmanufacturing</p><p>company.OneofhisconceptswastheBlériotAerobus1911[4],which</p><p>performedflightswithpassengersexposedtothewind(Fig.2.9).Sometime</p><p>later,theAerobuscabinwasclosed(Fig.2.9),yetprovidinglittlecomfortto</p><p>passengers.Therearereportsofflightsuptosixpassengers.TheAvroTypeF</p><p>andtheEtrichLuftlimousine,bothfrom1912,wereconceivedtocarry</p><p>passengersinanenclosedcabin(Fig.2.9)[4].</p><p>TheIlyaMuromets(Fig.2.10)aircraftasitappearedin1913[5]wasa</p><p>revolutionarydesign,intendedforcommercialservicewithitsspaciousfuselage</p><p>incorporatingapassengersaloonandwashroomonboard[6,7].DuringWorld</p><p>WarI,itbecamethefirstfour-enginebombertoequipadedicatedstrategic</p><p>bombingunit[6,7].TheIlyaMurometswasinitiallyconceivedandbuiltasa</p><p>luxuriousaircraft.Forthefirsttimeinaviationhistory,anairplanehadan</p><p>insulatedpassengersaloon,comfortablewickerchairs,abedroom,aloungeand</p><p>eventhefirstairbornetoilet[8].Theaircraftalsohadheatingandelectrical</p><p>lightinginpassengercabin[5].</p><p>Fig.(2.9))</p><p>Firstpassengerairplanes[1,4].</p><p>ImmediatelyafterWorldWarII,manytransportaircraftwerederivedfrom</p><p>combataircraftusedinthatconflict,especiallybombers.Therehavebeenmajor</p><p>technologicalleapsarisingfromthewarliketheuseofthickairfoils,water-</p><p>cooledengines,propeller-synchronousmachinegun,andaluminum</p><p>construction;thelatterpioneeredbytheGermancompanyJunkersFlugzeug-</p><p>undMotorenwerkeAG.TheGermanelectricitycompanyAEG(Allgemeine</p><p>Elektricitäts-Gemeinschaft(AEG)alsomanufacturedaircraftforthearmyduring</p><p>theFirstWorldWar.TheAEGJIwasusedbytheGermansinWorldWarIas</p><p>groundattackaircraft.Aftertheconflict,itrepresentedoneofthefirst</p><p>conversionsofmilitaryaircraftforcivilianusewiththeJ.IIvariant(Fig.2.11).</p><p>SoonafterWorldWarI,commercialaviationdevelopmentexperiencedan</p><p>exponentialgrowth.FrenchaviationpioneerHenriFarmansetupanairplane</p><p>manufacturingplant.Hedesignedandbuiltabombercapableofcarryinga</p><p>bombloadof1000kgfora1500-kmdistanttarget[9].Thebomberwas</p><p>undergoingsometestswhenWorldWarIcametoanend.Farmanreconfigured</p><p>thebomberturningitintoanairliner,whichreceivedF.60Goliathdesignation</p><p>(Fig.2.12).FarmansoonputtheGoliathintoserviceandmadeseveralpublic</p><p>flights.OnFebruary8,1919,theGoliathflewwith12passengersfromToussus-</p><p>le-NobletoRAFKenley,nearCroydon[9].NewEuropeanairlineswererapidly</p><p>acquiringtheF.60airliner.</p><p>Fig.(2.10))</p><p>SikorskyIlyaMurometsin1913(Publicdomainphoto).</p><p>Fig.(2.11))</p><p>TheAEGJ.IItransportairplanewasderivedfromthemilitaryplaneJ.I.</p><p>Fig.(2.12))</p><p>FarmanF.60Goliath.</p><p>InternationalServices</p><p>OnFebruary8th,1919,thefirstregularinternationalcommercialroutewas</p><p>openedbetweenParisandLondon[8]flownbyaFarmanF.60Goliathfrom</p><p>FarmanAirlines.Regularflightservicewithdailydeparturesbeganbetween</p><p>LondonandParisalsoin1919.Theconditionsaboardtheairplaneswerein</p><p>certaindegreeunpleasant,withpassengersexperiencingfreezingcold,</p><p>vibrations,unbearablenoise,andstrongturbulence[10].The1919Convention</p><p>ofParisendedthehopesofearlyaviationpioneersthattheskieswouldbe</p><p>borderlessandwithoutmuchcontrol[10].Instead,itwasdecreedthateach</p><p>countryhadcompleteandexclusivesovereigntyovertheairspaceaboveits</p><p>territory[10].</p><p>In1920,theCompagniedesGrandsExpressAériens(CGEA)beganscheduling</p><p>regularflightsbetweenLeBourgetandCroydon.TheCompagniedes</p><p>MessageriesAériennes(CMA)soonfollowedsuit.TheSociétéGénéralede</p><p>TransportsAérien(SGTA)openedaParis-BrusselsrouteinJuly1920,flownby</p><p>theGoliath.InMay1921,thisroutewasextendedtoAmsterdam.Belgianairline</p><p>SociétéNationalepourl'EtudedesTransportsAériens(SNETA)alsoopeneda</p><p>Brussels-LondonrouteinApril1921.</p><p>TheGoliathsufferedseveralfatalaccidentsalongitscareerasairliner.A</p><p>remarkableaccidentinvolvingthatplanetypetookplacein1922.TheDaimler</p><p>AirwaymailflightfromCroydontoLeBourgetoperatingaDeHavilland</p><p>DH.18AtookoffearlyinthemorningonApril7[11].Therewasjustonepilot</p><p>onboardaswellasayoungflightattendant.Justafternoon,aFarmanF.60</p><p>GoliathtookofffromLeBourgetheadingtoCroydon,flownbyitspilot,M.</p><p>Mire,withamechaniconboardaswell[11].Fewpassengershadpurchased</p><p>ticketsforthetripperformedwiththeGoliathairliner.Cloudsatlowaltitudes,</p><p>fogandalightdrizzlingrainmarkedtheweatherinthatregion.Exceptingthe</p><p>magneticcompass,navigationinstrumentsdidnotexistinthosedays.Because</p><p>thisthepilotsofbothairlinerswereflyingatthebaseoftheclouds,looking</p><p>downonthegroundforreferences[11].Thereby,bothaircraftwereflyingatthe</p><p>samealtitude.Atthetime,asinformalpractice,pilotsshouldoffsetfrom</p><p>navigationallandmarks,basedontheroadrules.Thus,aFrenchpilotwouldfly</p><p>uparoadway,offsettotherightsideandlookingdownontheroadtotheleft.</p><p>Opposingtrafficthereforewouldpassalsoontheleft.Thesameinformal</p><p>practicewasimplementedinEngland,thoughfewconsideredthepotential</p><p>internationalconflictbasedonEnglishroadwayrules,carshadrighthanddrive</p><p>anddroveontheleftsideoftheroads.Thus,theBritishpilotoftheDaimler</p><p>Airwayflightnaturallyoffsettohisleft,nottotheright.Thisputbothairplanes</p><p>onacollisioncoursewiththecloudbasedictatingtheiridenticalaltitude[11].</p><p>InthewakeofGoliath’saccident,aviationauthoritiesstartedtodiscusssafety</p><p>measures.Somenewruleswerethenrecommendedandapproved.First,the</p><p>midaircollisionresultedinauniversaldefinitionof“rightofway”intheair,</p><p>whereplanesshouldoffsettotherightwhenflyingoverroadsorlandmarksthat</p><p>onseeinganotheraircraftapproachhead-onthattheyshouldeachturntothe</p><p>righttotherebyavoidacollision[11].Theaccidentalsospurredthecreationof</p><p>theworld’sfirstairwaysystems,the</p><p>sameonesthatwecurrentlyusetoday,</p><p>combiningloweraltitudeairwayswiththe“J-routes”orairwayforjetaircraftat</p><p>higheraltitudes.Checkpoints(usuallyatnavigationalaids)areconnectedby</p><p>straightlineairwaysbetweenthem,enablingaircraftseparationbyaltitudeson</p><p>theairwaysandconverselygivingrisetothesystemofwesterlyheadingson</p><p>evenaltitudes(8,000ft,10,000ft,etc.)andeasterlyheadingsonoddaltitudes</p><p>(9,000ft,11,000ft,etc.).</p><p>In1926,theGermangovernmentformedanationalairline,Lufthansa.The</p><p>governmentsofFrance(AirFrance,1933)andBritain(BOAC,1939)followed</p><p>suit.TheearliestnationalairlinehadbeenfoundedbytheNetherlandsin1919,</p><p>KLM.By1929,KLMwasregularlyflyingthelongestscheduledrouteinthe</p><p>world,whichwasaneight-daytripfromtheNetherlandstoJakarta,Indonesia</p><p>(thentheDutchEastIndies).TheQueenslandandNorthernTerritoryAerial</p><p>ServicesLimited(Qantas)wasfoundedin1920asaprivatecompanybya</p><p>coupleofpilots.AVIANCA,formernationalcarrierofColombia,isoneof</p><p>earliestairlines,thefirstoneinSouthAmerica.ItwasfoundedonDecember5,</p><p>1919,whenitwasinitiallyregisteredunderthenameSCADT.</p><p>AdvancesinAeronauticalTechnology</p><p>Germanyemergedastheworldleaderofpassengerairtransportinthe1920s,</p><p>withthemostadvancedtechnology.In1904,thegreatresearcherLudwigPrandtl</p><p>oftheGöttingenUniversitydeliveredapioneerpaper,FluidFlowwithVery</p><p>SmallViscosity[12],inwhichhedescribedtheboundarylayerandits</p><p>importanceforfluiddynamics,particularlydragcreatedbystreamlinedbodies.</p><p>Thepaperalsodescribedflowseparationoftheboundarylayer,whichledtothe</p><p>conceptofstallofliftingsurfaces.Inaddition,Prandtldevelopedthefirst</p><p>theoriesaboutsupersonicshockwavesin1908,placingGermanyinthe</p><p>vanguardfortheunderstandingofthesupersonicflowbeforeWorldWarII.The</p><p>Prandtl-Meyerexpansionfansallowedfortheconstructionofsupersonicwind</p><p>tunnels.Prandtlhadlittletimetoworkfurtherontheproblemuntilthe1920s,</p><p>whenheworkedwithAdolfBusemannandcreatedamethodfordesigninga</p><p>supersonicnozzlein1929[13].Today,allsupersonicwindtunnelsandrocket</p><p>nozzlesaredesignedusingthesamemethod[13].</p><p>Asoliddevelopmentfortheunderstandingofsupersonicflowwouldhaveto</p><p>waitfortheworkofTheodorevonKármán,agraduatestudentofPrandtlat</p><p>GöttingenUniversity.Thisuniversityalsointroducedthethickairfoilconcept,</p><p>whichwasemployedforthebestfighterairplaneofWorldWarI,theFokker</p><p>D.VIIbiplane(Fig.2.13).Typically,thickairfoilspresentbetterstall</p><p>characteristicsandlift-to-dragratiothanthosethinneronesemployedin</p><p>previousairplanes.Sincethickerairfoilsenablelighterandstrongerwing</p><p>structure,theFokkerD.VIIdesignerscouldeliminatetheexternalstructural</p><p>bracing,which,inturn,reducedtheairplanedrag.Allthiscombinedreflectson</p><p>theairplaneperformance,increasingitconsiderably.</p><p>Fig.(2.13))</p><p>FokkerD.VII(PublicdomainphotosviaWikimediaCommons).</p><p>Prandtlalsodevelopedthemixinglengththeoryformodelthemomentum</p><p>transferbyReynoldsstresseswithinaturbulentboundarylayer[14].Sincea</p><p>longtime,itisofwidespreadwisdomthattheconceptofamixinglengthdoes</p><p>notadequatelymodelthecorrectphysicalphenomenonofthedetailedstructure</p><p>ofturbulence.Despitethis,mixinglengththeoriesareneverthelessmostuseful</p><p>toengineersasamethodforthecorrelationwithexperimentaldata[15].</p><p>JunkersrevolutionaryairplanemetalconstructionduringtheWorldWarIisthe</p><p>technologythatcanbeconsideredoneofthebiggestaviationadvancesfrom</p><p>WorldWarI[16].ItsJunkersD.ImonoplanewasinitiallyfundedbytheJunkers</p><p>companyalone[16].</p><p>Afterthefour-engineIlyaMuromets,JunkersF.13wasthesecondairplanethat</p><p>wasdesignedtocarrypassengersfromthebeginning.Thus,itwasnotacivil</p><p>variantofamilitaryconceptlikemostofitscontemporaryairplanesaccordingto</p><p>previoustextinthisChapter.ThisaircraftperformeditsfirstflightinJune1919.</p><p>Itwasanadvancedcantilever-wingmonoplane,withenclosedaccommodation</p><p>forfourpassengersinaheatedcabin[17].LikeallJunkersduralumin-structured</p><p>designs,F.13usedanaluminumalloyforitsstructure.Theairplanewascovered</p><p>withJunkers'patentedcorrugatedandstressedduraluminskin.Internally,the</p><p>wingwasbuiltuponninetubularcross-sectionduraluminsparskeptinplaceby</p><p>transversalduraluminbracing[18].Allcontrolsurfacescontainedhornsthat</p><p>providedlowercontrolforces.JunkersF.13wasproducedalongthirteenyears</p><p>andsawcommercialserviceforalmosttwentyyearsinseveralcountriesand</p><p>over300weresold[17].Rimowa,atraditionalGermancompanythatproduces</p><p>luggagemadeofaluminumandpolycarbonatepresentedatOshkoshairshow</p><p>2015areplicaofthevenerableF.13[18].Thecompanyismarketingtheairplane</p><p>willsellitfrom2017.The“new”F.13isfittedwitha450-hpPratt&WhitneyR-</p><p>985drivingaHamiltonStandardadjustablepropeller[18].</p><p>AfterWorldWarI,majoradvancementduringthe1920sinthedesignand</p><p>technologyofaircraftgaveaviationnewroles.Improvementsinwind-tunnel</p><p>testing,engineandairframedesign,andmaintenanceequipmentmadeforbetter-</p><p>performingairplanes.Thus,privateplanesbecamelessexpensiveand,inturn,</p><p>grewinnumberandpopularity.Saferairplanesattractmorepassengers,</p><p>increasingtheprofitabilityoftheairlines.</p><p>Thedevelopmentoftheautopilotstartedin1908,whenElmerSperryintroduced</p><p>atypeofgyrocompassthatwaslaterusedinshippilotingsystems(magnetic</p><p>compasseswereunreliableinsteel-hulledships)[19].In1914,Elmer’sson,</p><p>LawrenceSperry,demonstratedanautomaticgyrostabilizerinNewYorkState.</p><p>Agyroscopelinkedtosensorskeptthevehicleinlevelflight,travelingina</p><p>straightlinewithouthumanintervention.Twoyearslater,SperryandElmer</p><p>addedasteeringgyroscopetothestabilizergyroscopeanddevelopedthisway</p><p>thefirstautomaticpilot.In1929,Sperry'scompanytestedasimilardevicefor</p><p>aircraft,aswellasanotherdevice,theartificialhorizon[19].Theseinstruments,</p><p>whichenabledthepilottoflywithoutseeingthegroundbelow,wererapidly</p><p>installedaboardmailandcommercialairplanes.</p><p>Thefirstin-flightmoviethathasbeenrecordedwastheonethatwasshownin</p><p>1921aboardanAeromarineAirwaysairplaneshowingafilmcalledHowdy</p><p>Chicagotoitspassengers[20].TheLostWorldmotionpicturewasshownto</p><p>passengersofanImperialAirwaysflightonApril1925betweenLondon</p><p>(CroydonAirport)andParis[20].Inthesameyear,Lufthansaalsoofferedin-</p><p>flightmoviestopassengers.Thefactisthatasilentmoviewasidealoneatthat</p><p>timebecausethenoiseoftheenginesanywaydidnotallowthedialoguesand</p><p>musicfromthemovietobeheard.</p><p>TheCurtissCondor(Fig.2.14)wasoneofthefirstaircrafttoofferasoundproof</p><p>cabin[21].Itwasconsiderablequietinsideandpeoplecouldcarryona</p><p>conversationorlistentotheradio.Thiswasamazingtopassengersatthattime.</p><p>Inaddition,thewidefuselageallowedfor12sleepingberths.Theywere</p><p>operatedbyEasternAirTransport,AmericanAirwaysandSwissair.Condorwas</p><p>madeofold-fashionedframe-and-fabriccomponentswithatubularwingspar</p><p>andwaspoweredbytwo750-hpWrightCycloneSGR-1820-3engines.</p><p>Fig.(2.14))</p><p>CurtissCondor.</p><p>TheprimarystructuralmaterialofWorldWarIaircraftwaswood,whichwas</p><p>wellsuitedtothesmallworkshopsandskilledlaboroftheperiod.However,the</p><p>propertiesofwoodareanisotropic,andstrengthcharacteristicscanvary</p><p>dependingonsupplysource.Apotentialalternativewasmetal,butitwouldnot</p><p>beasimplematterofsubstitutingmetalforwood.Earlyattemptstouse</p><p>aluminumandsteeldidnotimmediatelysatisfythegoalofweightreduction.</p><p>Thelow</p><p>stresslevelsintheairframesofthisperiodrequiredonlyafractionof</p><p>theinherentloadbearingcapacityofmetal.</p><p>Thelate1920sandearly1930sregisteredastructuralevolutioninaeronautics</p><p>withthewidespreadmanufacturingofstreamlinedmetalaircraftwithsuch</p><p>featuresascowledmultipleengines,variable-pitchpropellers,retractinglanding</p><p>gear,andstressed-skinaluminumconstruction[22].Thetransitionfromthe</p><p>wood-and-fabricairplanetotheall-metalairplanewasessentiallycompleted</p><p>beforeWorldWarIIwithall-metalfightersliketheMe109andmultiple-engine</p><p>bombersandairliners,whoseexamplesaretheBoeingB-17andtheBoeing307</p><p>Stratoliner,respectively.</p><p>Metaldidindeedallowengineerstoextendperformanceparametersaffordedby</p><p>innovativestructuraldesign.Metalconstructionhasenabledaircrafttoendure</p><p>thegreaterstressesincurringathighspeedsandwhencarryinglargepayloads</p><p>andwerenotaffectbymoistureandartisanalfabrication.Indeed,itwouldnotbe</p><p>possibletoachievethesameperformanceofaBoeing777airlineroranF-18</p><p>fighteraircraftiftheywereconstructedofwoodinstead[22].</p><p>TheJunkers52wasanall-metalaircraftdesignedtotransport17passengers.It</p><p>isalsooneofthemostsuccessfultransportaircraftinhistory,with4,845units</p><p>manufactured.DesignedbyErnstZindeloftheJunkersfactoryinthecityof</p><p>Dessau,Germany,theinitialmodelwasfittedwithasingleengine,andwas</p><p>designatedJu52/1m.Theprototypemadeitsfirstflightin1931andwas</p><p>certifiedinthesameyear.Duetolackofinterestfrombuyers,mainlyfrom</p><p>DeutscheLufthansa,Junkersredesignedtheairplane,addingtotheaircrafttwo</p><p>enginestoimproveitsperformance.Themodifiedairplanereceivedthe</p><p>designationJu52/3m(Fig.2.15).TheaircraftwasfittedwithBMWenginesand</p><p>someexportmodelsalsousedPratt&WhitneyWasporBristolPegasusengines.</p><p>Thefirstaircraftwiththenewconfiguration,equippedwithPratt&Whitney</p><p>engines,weredeliveredtoLloydAeroBoliviano(LAB).TheextinctBrazilian</p><p>airlineVASP(ViaçãoAéreaSãoPaulo)acquiredtwoJu-52/3m,dubbedthe</p><p>CidadedeSãoPauloandCidadedoRiodeJaneiro.Assemblypartsofthetwo</p><p>aircraftwereshippedfromGermanytoBrazil,withthefinalassemblytaking</p><p>placeinBrazil.ThetwoaircraftinauguratetheSaoPaulo-RiorouteonAugust5,</p><p>1936.</p><p>TheJu52wasalsoakeyplayerinOperationMerkur(TheGermaninvasionof</p><p>Crete)in1941asaparatrooptransportaircraft.Thisoperationwasconsidereda</p><p>successbecausetheplannedgoalshavebeenachieved.However,thelossof</p><p>airplaneswaslargeandmorethanhalfofthe493aircraftthatparticipatedinthe</p><p>actionweredamagedordestroyed.Duetothehighhumanandmateriallossesof</p><p>thisoperation,furtheroffensiveusingairbornetroopswasnotcarriedoutby</p><p>GermanyanymoreinWorldWarII.EventheAllieshadinitiallyconsideredan</p><p>autogyroasmainforcetoretakecontinentalEuropefromGermany.Forthisrole,</p><p>theHafnerRotabuggywasconceived,whichwasaBritishexperimentalaircraft,</p><p>essentiallyaJeepWillysMBcombinedwitharotorkite,developedwiththe</p><p>intentionofproducingawayofair-droppingoff-roadvehicles[23].Although</p><p>initialtestsshowedthattheRotabuggywaspronetoseverevibrationatspeeds</p><p>greaterthan70km/h,thankstoimprovementstheRotabuggyachievedaflight</p><p>speedof113km/hinFebruary1944.However,theintroductionofgliderssuch</p><p>asAirspeedHorsathatwerecapableoftransportingroadvehiclesmadethe</p><p>Rotabuggysuperfluousandfurtherdevelopmentwascancelled.</p><p>Fig.(2.15))</p><p>JunkersJu52/3mattheNationalMuseumoftheUSAirForce(Photo:U.S.Air</p><p>Force,publicdomain).</p><p>ThenumberofJu52/mdeliveredtoLuftwaffeisunclear[24].Theairplanewas</p><p>versatile,seeinguseasbomber,paratroopertransporter,towinggliders,cargo</p><p>andpassengertransport,andadvancedtrainer.Theairplanealsosawserviceas</p><p>minelayer.</p><p>HugoJunkers,whohadpioneeredaseriesofinnovationinaviation,onceagain</p><p>broughtanewconceptwhendecidedtoemployaileronasflapontakeoffforthe</p><p>Ju52/3m.Theaileronscouldalsobeadjustedtolocallychangetheliftonthe</p><p>wingtogeneratelowerinduceddrag,thedragrelatedtotheliftandthatis</p><p>dependentontheloaddistributionalongthewingspan(chordxliftcoefficient).</p><p>TheBoeingModel247monoplanewasanimportantairlineroftheinterwar</p><p>period.Itenteredservicein1933andbroughtmanyadvancedtechnologiesat</p><p>thattimelikewingdeicingboots,cantileverconstruction,andautopilot[25].</p><p>UnitedAirlinesandBoeingbelongedtothesameholdingatthattime.Forthis</p><p>reason,UnitedAirlineswasgivenpriorityforBoeing247deliveries.Thus,TWA</p><p>approachedDouglastodevelopanairlinertocompetewithBoeing247andthe</p><p>DClinewasthencreated:DC-1,DC-2,andDC-3.TheDC-3,whichwentinto</p><p>servicein1936,waseasytomaintainanditwasconsideredareliableairplane.It</p><p>hadseveralinnovativedesignfeatures,asemi-retractablelandinggear,flexible</p><p>wingsofsimpleconstruction,andwithitstwo1,200-horsepowerenginesit</p><p>couldreachamaximumspeedof370mph.AvariantoftheDC-3,theC-47,</p><p>becametheflagshipofthemilitary'stransportfleetinWorldWarII.</p><p>BoeingresponsetoDC-3wastheBoeing307Stratoliner.In1935,Boeing</p><p>designedafour-engineairlinerbasedonitsB-17strategicbomber(Boeing</p><p>Model299),thenindevelopment[26].Theairplanereceivedthedesignation</p><p>Model307.Itcombinedthewings,tail,rudder,landinggear,andenginesfrom</p><p>theirproductionB-17Cwithanew,circularcross-sectionfuselage,whichwas</p><p>designedtoallowcabinpressurization[26].Thefirstorder,fortwo307s,was</p><p>placedin1937byPanAmericanAirways;PanAmsoonincreasedthistosix</p><p>exemplarsandasecondorderforfivefromTranscontinental&WesternAir</p><p>(TWA),promptingBoeingtobeginproductiononaninitialbatchoftheairliner.</p><p>WorldWarIIinterruptedthecommercialoperationoftheBoeing307butthey</p><p>wereemployedasmilitarytransportduringthewar.</p><p>TheFocke-Wulf200Condor(Fig.2.16)wasalong-rangepassengertransport</p><p>designedbyProf.KurtTankoftheGermancompanyFocke-WulfFlugzeugbau</p><p>AG.ProfessorHeinrichFocke,GeorgWulfandDr.WerberNaumannfounded</p><p>theFock-Wulfcompanyin1923.In1936,Prof.Fockewasremovedfromthe</p><p>companyduetopressurefromshareholders.in1937Prof.Fockeredirectedthe</p><p>focusofhisworktohelicoptersandfoundedthecompanyFockeAchgelisin</p><p>partnershipwithGerdAchgelis.ProfessorKurtTank,theTechnicalBoardand</p><p>thosewhohadworkedonthedevelopmentoftheFw44Stieglitz,werealso</p><p>responsibleforthedesignofseveralotherplanesFocke-Wulf,amongthem,the</p><p>Fw200airliner.</p><p>TheZeppelinCompanyhadestablishedregularpassengerflightswithairships</p><p>betweenGermanyandtheSouthandNorthAmerica.Mostofthoseflightswere</p><p>performedbythevenerableGrafZeppelin,whichwascapabletotransport20</p><p>passengers.TheHindenburgairshipperformedtentripsin1936.Theeastern</p><p>boundlegstoNorthAmericatook53to78hoursandthosebacktoGermany</p><p>lastedfrom43to61hours.Besidesbeingslowerthanland-basedairplanes,</p><p>passengercapacityofairshipsisverylowregardingtheirsizeandtheyarevery</p><p>expensivetooperate.</p><p>Thefirstprototype,theFw200V1,wasfittedwithadditionalfueltanks.It</p><p>performedseveralrecordflightsandwasthefirstairlinertoflynonstopbetween</p><p>BerlinandNewYorkCity[27].TheairplanetookofffromBerlin-Staakento</p><p>FloydBennettFieldinAugust1938andtheflightdurationwas24hoursand56</p><p>minutes[28].ThereturnflighttoBerlinwasperformedin19hours.These</p><p>flightshavemeantanendofairshipera,independentlyoftheHindenburg</p><p>disasterinMay1937.Thenon-stoplong-haulflightserabegan.</p><p>Fig.(2.16))</p><p>ThefirstFocke-WulfFw200“Brandenburg”(D-ACON)inflight.Thisairplane</p><p>firstflew</p><p>on27July1937(Photo:AustralianWarMemorial,publicdomain).</p><p>TheFw200wasoperatedbyDeutscheLufthansa,DDLDanishAirlines,and</p><p>Lufthansa'sBraziliansubsidiarySyndicatoCondor,thelatterwasnationalized</p><p>byGetulioVargasafterBrazilenteredtheWorldWarIIagainsttheGermans</p><p>[27].DaiNipponKKofJapanalsoorderedFw200airliners.However,these</p><p>couldnotbedeliveredtoJapanduetothewaroutbreakandLufthansatook</p><p>deliveryoftheminstead.OnApril14th,1945,anFw200flewLufthansa'slast</p><p>scheduledservicebeforetheendofWorldWarII,fromBarcelonatoBerlin[27].</p><p>OtherairlinescontinuedtooperatetheFw200aftertheendofWorldWarII.</p><p>MilitaryversionsoftheFocke-Wulf200werealsodeveloped.TheLuftwaffe</p><p>initiallyusedtheaircrafttosupporttheGermanNavybyconductingmaritime</p><p>patrolsandreconnaissancemissions,searchingforAlliedconvoysand</p><p>destroyersthatcouldbetargetingGermansubmarines[28].TheFw200could</p><p>alsocarrya900-kgbombload,rocketsanditcouldlaynavalmines.TheFw200</p><p>wasalsousedasacargoaircraft,notablyitprovidedequipmentandsuppliesto</p><p>theGermanforcesthatwereattackingthecityofStalingradin1942.However,</p><p>extraweightintroducedbymilitaryequipmentandhigherloadsassociatedtothe</p><p>airplane’snewflightenvelopeledtostructuralfailuresofthefuselageatlanding,</p><p>aproblemthatwasneverentirelysolvedbyFocke-Wulf.Latermodelswere</p><p>equippedwithLorenzFuG200HohentwiellowUHF-bandAirborneSurface</p><p>Vessel(ASV)radarinthenose.In1943,Fw200wasadaptedtocarrythe</p><p>HenschelHs293guidedmissile,whichwassteeredbyagauntletlikecurrent</p><p>joysticks.</p><p>TECHNOLOGICALLEGACYFROMWORLDWARII</p><p>Fighters</p><p>InWorldWarII,theaeronauticaltechnologyexperiencedanincredibleboost.</p><p>Besidesthedevelopmentofrocketry,thewarintroducedtechnologicalleapsin</p><p>aircraftdesignandimprovedconsiderablytheirperformance.Aerodynamically</p><p>refined,all-metalhigh-performancefightersweredevelopedduringtheconflict,</p><p>replacingwoodandfabricbiplanesandmonoplaneswithfixedlandinggear</p><p>fromtheperiodbetweenwars(Fig.2.17).Radaralsoexperiencedahuge</p><p>developmentanditsminiaturizationenabledthatnightfighterswereequipped</p><p>withradarequipmenttogiveeffectivecombattobomberairplanes.ByWar</p><p>outbreak,theBf109fighterequippedmostsquadrons(Geschwäder)ofthe</p><p>Luftwaffe.TheJapanesehaddevelopedtheextremelymaneuverableZero,in</p><p>partduetothenon-placementofprotectiveshields;theSpitfirewasthefrontline</p><p>workhorseoftheEnglishFighterCommandandtheUnitedStatesoperatedthe</p><p>outdatedCurtissP-40andGrummanWildcat.</p><p>Fig.(2.17))</p><p>SomealliedandAxisfightersofWorldWarII(Notinsamescale).</p><p>TheMesserschmittBf109(BfstandsforBayerischeFlugzeugwerke),</p><p>commonlyreferredasMe109,wasdesignedbyWillhemMesserschmittand</p><p>RobertLusserduringtheearlytomid-1930s[29].Theaircraftconstitutedthe</p><p>bulkfighterforceoftheLuftwaffeinWorldWarII,withapproximately35,000</p><p>beingbuilt[29].ThetypesawcombatintheSpanishCivilwarandcontinuedto</p><p>beproducedalongWorldWarII.ThefighterwasinitiallyfittedwithaRolls-</p><p>RoyceKestrelengine,laterreplacedbyaJumo210beforethebeginningof</p><p>WorldWarII.AirplanesproducedduringthewarreceivedbothDB601andthe</p><p>liquid-cooledinvertedV12DB605engine.TheReichsluftfarhtministerium</p><p>(RLM)openacompetitionforaMesserschmitt109successorandtheFocke-</p><p>Wulf190wasthewinner.</p><p>ThebackgroundthinkingbehindtheFocke-Wulf190wastoDienstpferd</p><p>(workhorse)notacavalryhorseliketheBf109.Forthisreason,Focke-Wulf</p><p>decidedforanair-cooled,14-cylinderBMW139radialengineinsteadofan</p><p>inlinewater-cooledone.Awater-cooledenginewouldbemoredifficultto</p><p>maintaininthebattlefrontandmorepronetobedamagedbyenemyfire.</p><p>TheBf109fighterwasfittedwithasimplemechanicalslatsystem.Slatsare</p><p>high-liftdevicesplacedatwingleadingedges.TheslatsystemofBf109was</p><p>conceivedtocountonramairpressuretokeeptheslatsintheirclosedposition</p><p>athigherspeeds.Theramairpressureexertsaforceagainstthebiasofsprings,</p><p>whichensurestheslatscanbeactuatedoutwardswhentheairplaneisflyingat</p><p>lowerspeedsorwhenitperformsaflightmaneuver.Inthislattercase,theinner</p><p>wingfacesalowerwindspeedthattriggerstheslatdeflectionandtherefore</p><p>increasestheliftofthatwing,withconsequentmaneuverabilityimprovementof</p><p>thefighter.</p><p>Infact,slatswerefirstdevelopedbytheGermanGustavLachmannin1918.An</p><p>airplaneaccidentin1917causedbystallledLachmantoidealizetheslat</p><p>mechanism.In1918,Lachmannpresentedapatentforleading-edgeslatsin</p><p>Germany.However,theGermanpatentofficeinitiallyrejecteditbecausethe</p><p>officialsdidnotbelieveinthepossibilityofincreasingliftbysplittingthewing</p><p>intotwoormorepieces.</p><p>IndependentlyofLachmann,HandleyPageLtdinGreatBritainalsodeveloped</p><p>theslottedwingtoincreasethemaximumliftcoefficientofwings.Theprocess</p><p>consistsinprovidinghigh-energyflowfrombelowthewingtothedecelerated</p><p>airflowonthewinguppersideafteritcontouredtheleadingedge.TheEnglish</p><p>airplanecompanyappliedforapatentin1919andtoavoidalegaldispute,they</p><p>reachedanagreementwithLachmann,whichbecameaDeHavilland’s</p><p>employee.In1919,DeHavillandD.H.9,aBritishbomberfromWorldWarI,</p><p>wasfittedwithslatsandsuccessfullyflown.Later,aD.H.4wasmodifiedasa</p><p>monoplanewithalargewingfittedwithfullspanleadingedgeandailerons</p><p>alongtheentirewingspan,whichcouldbedeployedinconjunctionwiththe</p><p>leading-edgeslatstoboostfieldperformance[30].Severalyearslater,having</p><p>subsequentlytakenemploymentattheHandley-Pageaircraftcompany,</p><p>Lachmannwasresponsibleforseveralaircraftdesigns,includingtheHandley</p><p>PageHampden[30].Licensingtheconceptbecameoneofthecompany'smajor</p><p>sourcesofincomeinthe1920s[30].Theoriginaldesignswereintheformofa</p><p>fixedslotinthefrontalpartofwings,anengineeringsolutionthatwasemployed</p><p>byBoeingforitsfour-engine307Stratoliner.</p><p>Slatsareusedforbothfighterandtransportaircraft.FieselerFi156Storch(Fig.</p><p>2.18)wasasmallGermanliaisonaircraftbuiltbyFieselerbeforeandduring</p><p>WorldWarII.Afixedslatranalongtheentirelengthoftheleadingedgeofthe</p><p>longwings,whileahingedandslottedsetofcontrolsurfacesranalongtheentire</p><p>lengthoftrailingedge[31].TheStorchisrenownedforitsremarkableshort</p><p>takeofflandingfieldlengthsandextremelylowstallingspeedof50km/h.TheFi</p><p>156cantakeoffinlessthan45mandlandin18m.</p><p>Fig.(2.18))</p><p>FieselerStorchatILA1992,BerlinSchönfeld(Photo:©1992BentoMattos).</p><p>TheNorthAmericanF-86Sabre,aveteranoftheKoreanWar,presentsslats</p><p>alongalargepartofthewingleadingedge(Fig.2.19).Thedesignteamofthe</p><p>Americanjetfighteroptedforusinganautomaticslatsystem,operated</p><p>independentlyofpilotcontrol[32].However,slatswereremovedinlater</p><p>versionsofthefighterinfavorofafixedleadingedge,whichenabledan</p><p>increasedinternalfuelcapacity.Thisisaninterestingpointofdebatebecausein</p><p>factslatsfeaturesomedrawbackssuchasincreasedwingweight,more</p><p>expensivemaintenance,theyimpactaircraftdispatchandwingfittedwithslats</p><p>presentsanarrowerwingbox,whichreducesthefuelstoragecapacity.Some</p><p>transportairplanesliketheFokker100havenoslatsanddespitethistheypresent</p><p>areasonablefieldperformance.</p><p>Fig.(2.19))</p><p>ThefirstversionsofNorthAmericanF-86Sabrewerefittedwithslats(Photos:</p><p>U.S.AirForceNationalMuseum,publicdomain).</p><p>BacktoMesserschmittBf109fighter,whichisobjectofanalysisinthepresent</p><p>Section,afterthefallofFrance,theLuftwafferealizedthattherangeofBf109E</p><p>neededtobeextended.Thus,Messerschmittredesignedtheairplane,clippedthe</p><p>wingtips,increaseditsfuelcapacityandimprovedthepilot’sshield,amonga</p><p>seriesofothermodifications.TheresultwastheBf109F,whichenteredservice</p><p>inNovember1940,andthatsoonbecamepraisedbyGermanpilotsthankstoits</p><p>goodmaneuverability.TheBf109Freceivedaredesignedenginecowling,the</p><p>propellerspinnerwasenlargedand,ingeneral,severalotheraerodynamic</p><p>improvementscontributedtoatopspeedof650km/h[33].Anewejector</p><p>exhaustarrangementwasalsoincorporated,andonlateraircraftametalshield</p><p>wasfittedovertheleft-handbankstodeflectexhaustfumesawayfromthe</p><p>superchargerair-intake.Anewthree-blade,light-alloypropellerunitwitha</p><p>reduceddiameterwasused;propellerpitchwaschangedelectrically,andwas</p><p>regulatedbyaconstant-speedunit,thoughamanualoverridewasstillprovided.</p><p>Thankstotheimprovedaerodynamicsandmorefuel-efficientenginesandall</p><p>othermodifications,theBf109Fofferedanincreasedmaximumrangeof650</p><p>kmcomparedwiththeBf109E'smaximumrangeofonly560kmoninternal</p><p>fuel[33].Rangecouldbeincreasedto1,700kmifexternallight-alloydroptanks</p><p>wereused.SeveralotherversionsoftheBf109wereproducedeachwith</p><p>varyingarmaments.TheBf109Gseries(Fig.2.20)wasverypopularandover</p><p>12,000unitswerebuilt.Intotal,over29,900Bf109sweremanufacturedduring</p><p>thewar[33].AlthoughtheBf109waspartiallyreplacedbytheFocke-WulfFw</p><p>190in1941,itcontinuedtoplayamajorroleintheLuftwaffe'sfighter</p><p>operations.</p><p>Fig.(2.20))</p><p>MesserschmittBf109(Photo:U.S.AirForce,publicdomain).</p><p>Bombers</p><p>Bombingofcities,militaryandindustrialfacilitieswereinwidespreaduse</p><p>duringWorldWarII.Alltypesofaircraftwereemployedforbombingmissions:</p><p>divebombersliketheJunkersJu87,mediumbombersfortacticaloperations,the</p><p>B-25MitchellandB-26Marauderbeinggoodrepresentativesofthiscategory,</p><p>heavybombersandadaptedfighteraircraftforthebombingrole.Besides,</p><p>mediumbomberswerealsomodifiedtoattacksurfaceshipsandsubmarines.</p><p>TheGermansusedmediumbombersforthestrategicrole,withthetwin-engine</p><p>HeinkelHe111andJunkersJu88systematicallybombingindustrialfacilitiesin</p><p>thebeginningofBattleofBritain.Fig.2.21showssomeAlliedandGerman</p><p>bombersemployedintheconflict.</p><p>Germany,EnglandandItalycarriedoutstrategicbombingmissionsinWorld</p><p>WarI.Germanyutilizedairships,besidesheavybombersinsuchmissions.</p><p>However,thesebombingmissionswerehighlyinaccurate.Accuratehigh-</p><p>altitudebombingwasalmostimpossiblebeforethedevelopmentofbombsights</p><p>[34].Tohitthetargetaccurately,airplaneshadtoflyatloweraltitudes,</p><p>becomingeasytargetsofanti-aircraftartilleryandfighters.Thedevelopmentof</p><p>thebombsighthelpedtoturnthestrategicbomberintoaneffectiveweapon[34].</p><p>Thedevicecompensatesforairresistance,whichwillcausethebombtotrail</p><p>behindtheplane,andcrosswinds.</p><p>Fig.(2.21))</p><p>SomealliedandGermanbombersofWorldWarII(Notinsamescale).</p><p>Inthe1930s,mechanicalcomputerswiththesufficientperformancecouldsolve</p><p>theequationsofmotionandtheywereincorporatedinthesedaysintonew</p><p>tachometricbombsights,themostfamousbeingtheNorden,thehighlysecret</p><p>bombsightfromtheUnitedStates[35].LaterinWorldWarII,tachometric</p><p>bombsightswereoftencombinedwithradarsystemstoallowaccuratebombing</p><p>throughcloudsoratnight.</p><p>Whenpost-warstudiesdemonstratedthatbombaccuracywasroughlyequal</p><p>whenopticallyorradarguided,opticalbombsightsweregenerallyremoved,and</p><p>therolepassedtodedicatedradarbombsights[34].</p><p>WorldWarIIsawthemassiveutilizationofheavybombersforstrategic</p><p>operations.Mostofthemwerelong-rangefour-engineairplanes.TheUnited</p><p>StatesandEnglanddemonstratedtheirsuperiorutilizationofstrategicairpower</p><p>duringthewar.BothcountriesheavilybombardedGermany:TheBritishwith</p><p>nightoperationstargetingcitiesandcivilians;theAmericansindaylight</p><p>missionsforthebombardmentofindustrialsfacilities.However,closetotheend</p><p>ofwar,theAmericansswitchedtheirstrategyandstartedtobombGermancities,</p><p>withBerlinbeinganeverydaytarget.</p><p>AgainsttheBritishnightbombingcampaign,theGermansdevelopedeffective</p><p>nightfighters.Thetwin-engineHeinkelHe219Uhu(Eagleowl)wasoneof</p><p>thembutitwasproducedinsmallnumbers.TheUhuinterceptorairplane</p><p>incorporatedseveralinnovations,includingtheLichtensteinSN-2advanced</p><p>VHF-bandinterceptradar,alsousedontheJu88GandBf110Gnightfighters</p><p>[36].Itwasalsothefirstoperationalmilitaryaircrafttobeequippedwith</p><p>ejectionseats.</p><p>StrategicbombingcampaignswerepartoftheUnitedStatesapproachagainst</p><p>Japan.TheNorthAmericanairraidsonJapanbeganeffectivelyinOctober1944</p><p>andescalatedintowidespreadbombingofJapaneseCitieswithnapalm,</p><p>culminatingintheatomicbombingsofHiroshimaandNagasakionAugust6th</p><p>and9th,1945,respectively.</p><p>TheBoeingB-29wastheairplanethattheUnitedStatesemployedforthe</p><p>strategicbombingcampaignonJapan(Fig.2.22).Thetypepresenteda</p><p>cantilevermidwingwithacrewoftentofourteenmen.Itwaspoweredbyfour</p><p>turbocharged2,200-hpair-cooledWrightradialengines.Frontandaftfuselage</p><p>ofB-29werepressurizedandasmalltunnellinkedthetworegionsofthe</p><p>airplane.Thisallowedforbombingfromhigheraltitudeswithoutthediscomfort</p><p>ofunpressurizedcabinslikethatofB-17andB-24.</p><p>Fig.(2.22))</p><p>BoeingB-29instaticdisplayattheNationalMuseumoftheU.S.AirForce,</p><p>Dayton,Ohio(Photo:U.S.AirForce,publicdomain).</p><p>Itisusuallythoughtthat,GermanylackedheavybombersinWorldWarII.</p><p>However,thefirstprototypeofitsHeinkelHe177heavybomberfirstflewin</p><p>November,1939[37].Initiallytheairplanedidnotseemuchsuccess.Thefour-</p><p>engineHeinkelHe177Grief(Fig.2.23),whichhadsimilarrangeandpayload</p><p>capacitytotheirAmericancounterparts[37].TheHeinkelHe177initially</p><p>possessedtwonacelles,witheachofthemaccommodatingapairofDB601</p><p>enginesdrivingasinglepropeller[37].Theassemblyoftwo601engineswas</p><p>designatedDB606.Theintentionbehindthisunusualengineconfigurationwas</p><p>toemploytheaircraftinmoderate-angledivebombingtoimproveaccuracyof</p><p>bombingmissions[37].Thecoupled-enginearrangementshouldcontributetoa</p><p>loweraircraftoveralldrag.Afteraseriesofenginefailurescausedbypoor</p><p>cooling,andventilationproblems,Heinkelconceivedanimprovementpackage</p><p>toavoidtheprogramshutdownbytheReichsluftfahrtministerium(RLM).</p><p>LuftwaffestaffnicknamedthebomberLuftwaffenfeuerzeug(“Luftwaffe’s</p><p>lighter”)[37].</p><p>Fig.(2.23))</p><p>HeinkelHe177(Source:WikimediaCommons,publicdomain).</p><p>DuetothecontinuingproblemswiththeDB606engineanditsinstallationinto</p><p>theHe177bomber,muchdevelopmentworkwasperformedtosolveengine</p><p>troubles.ThisincludedacompleteredesignoftheoriginalHe177,primarilyby</p><p>newerwingdesignsandlayoutstoimprovetheengineinstallation,in</p><p>conjunctionwiththeA-3subtype'slengthenedrearfuselage,intendedtocreatea</p><p>four-engineversionofGreif.Thefirstconcernsovertheproperengine</p><p>configurationfortheHe177bomber,whetheracoupled-enginearrangementor</p><p>fourseparateenginesshouldbeutilized,emergedinmid-November1938.By</p><p>thattime,ErnstHeinkelrequestedthattwooftheeightHe177prototypestobe</p><p>fittedoutwithfourindividualenginesinplaceofthecoupled-engine</p><p>arrangements,eventuallyspecifyingthattheV3andV4airframesgetfour</p><p>individualJunkersJumo211inaNovember17thmeeting.Heinkelcontinueto</p><p>improvetheHe177,startingwiththeHe177A-3/R2,whichfeaturedamodified</p><p>enginenacellewiththenewDaimler-BenzDB610,eachofwhich</p><p>election,actinginitssolediscretion:</p><p>25‘copy’commandscanbeexecutedevery7daysinrespectoftheWork.The</p><p>textselectedforcopyingcannotextendtomorethanasinglepage.Eachtimea</p><p>text‘copy’commandisexecuted,irrespectiveofwhetherthetextselectionis</p><p>madefromwithinonepageorfromseparatepages,itwillbeconsideredasa</p><p>separate/individual‘copy’command.</p><p>25pagesonlyfromtheWorkcanbeprintedevery7days.</p><p>3.Theunauthoriseduseordistributionofcopyrightedorotherproprietary</p><p>contentisillegalandcouldsubjectyoutoliabilityforsubstantialmoney</p><p>damages.Youwillbeliableforanydamageresultingfromyourmisuseofthe</p><p>WorkoranyviolationofthisLicenseAgreement,includinganyinfringementby</p><p>youofcopyrightsorproprietaryrights.</p><p>Disclaimer:</p><p>BenthamSciencePublishersdoesnotguaranteethattheinformationintheWork</p><p>iserror-free,orwarrantthatitwillmeetyourrequirementsorthataccesstothe</p><p>Workwillbeuninterruptedorerror-free.TheWorkisprovided"asis"without</p><p>warrantyofanykind,eitherexpressorimpliedorstatutory,including,without</p><p>limitation,impliedwarrantiesofmerchantabilityandfitnessforaparticular</p><p>purpose.TheentireriskastotheresultsandperformanceoftheWorkis</p><p>assumedbyyou.NoresponsibilityisassumedbyBenthamSciencePublishers,</p><p>itsstaff,editorsand/orauthorsforanyinjuryand/ordamagetopersonsor</p><p>propertyasamatterofproductsliability,negligenceorotherwise,orfromany</p><p>useoroperationofanymethods,productsinstruction,advertisem*ntsorideas</p><p>containedintheWork.</p><p>LimitationofLiability:</p><p>InnoeventwillBenthamSciencePublishers,itsstaff,editorsand/orauthors,be</p><p>liableforanydamages,including,withoutlimitation,special,incidentaland/or</p><p>consequentialdamagesand/ordamagesforlostdataand/orprofitsarisingoutof</p><p>(whetherdirectlyorindirectly)theuseorinabilitytousetheWork.Theentire</p><p>liabilityofBenthamSciencePublishersshallbelimitedtotheamountactually</p><p>paidbyyoufortheWork.</p><p>General:</p><p>AnydisputeorclaimarisingoutoforinconnectionwiththisLicense</p><p>AgreementortheWork(includingnon-contractualdisputesorclaims)willbe</p><p>governedbyandconstruedinaccordancewiththelawsoftheU.A.E.asapplied</p><p>intheEmirateofDubai.EachpartyagreesthatthecourtsoftheEmirateof</p><p>Dubaishallhaveexclusivejurisdictiontosettleanydisputeorclaimarisingout</p><p>oforinconnectionwiththisLicenseAgreementortheWork(includingnon-</p><p>contractualdisputesorclaims).</p><p>YourrightsunderthisLicenseAgreementwillautomaticallyterminatewithout</p><p>noticeandwithouttheneedforacourtorderifatanypointyoubreachanyterms</p><p>ofthisLicenseAgreement.InnoeventwillanydelayorfailurebyBentham</p><p>SciencePublishersinenforcingyourcompliancewiththisLicenseAgreement</p><p>constituteawaiverofanyofitsrights.</p><p>YouacknowledgethatyouhavereadthisLicenseAgreement,andagreetobe</p><p>boundbyitstermsandconditions.Totheextentthatanyothertermsand</p><p>conditionspresentedonanywebsiteofBenthamSciencePublishersconflict</p><p>with,orareinconsistentwith,thetermsandconditionssetoutinthisLicense</p><p>Agreement,youacknowledgethatthetermsandconditionssetoutinthis</p><p>LicenseAgreementshallprevail.</p><p>BenthamSciencePublishersLtd.ExecutiveSuiteY-2POBox7917,SaifZoneSharjah,U.A.E.Email:subscriptions@benthamscience.org</p><p>PREFACE</p><p>Aircraftmanufacturersandaviationareveryimportantindustries,bothinsocial</p><p>andeconomicaspects.AccordingtotheInternationalAirTransportAssociation</p><p>(IATA),aviationtransportedaround6.6billionpassengersin2015andprovides</p><p>approximately62.7millionrelatedjobsworldwide.Aircraftboostlocaland</p><p>globalgrowthwithitscivilanddefensesectoractivities.</p><p>Inparticular,aircraftdesignhasalsoamajorimpactonthesocietyduetoits</p><p>safetyrecordthatinspiresotherindustrialsegmentsandtechnologicalspin-off</p><p>effects.Ontheenvironmentalside,intimesofglobalwarming,efficientaircraft</p><p>willinsertconsiderablyfewerpollutantsintotheatmosphereandwillconsume</p><p>lesstripfuel.Mostaircraftdevelopmentprogramsmakeuseofextensiveand</p><p>intensiveresearchperformedbyacademyaswellaswiththehelpofinvestments</p><p>oftheprivatesectorininnovativetechnology.Fewcountriescandevelop,</p><p>certify,marketandsupportmedium-to-largecommercialairliners.This</p><p>exemplifiesthehighlevelofeffort,knowledge,andmoneyinvolvedinthe</p><p>aircraftmanufacturingindustry.Recyclingofdecommissionedaircraftand</p><p>properhandlingoftheindustrialprocessestoavoidenvironmentaldamageis</p><p>partoftheaircraftindustrynowadays.</p><p>Itisunfortunatethatintheacademicworldfewuniversitiesworldwidehavea</p><p>dedicatedchairinairplanedesign,andevenfewerinrotorcraftdesign.Most</p><p>universitiesconsideronlybasicdisciplinessuchasaerodynamics,aeronautical</p><p>structures,flightphysicsandspacetechnologiesasthefundamentalstoprovide</p><p>highereducationtoaeronauticalengineeringundergraduatestudents.They</p><p>disregardaircraftdesignasaspecificdisciplineworthyofcreatingaspecific</p><p>chair.However,aircraftdesignenablestheproperintegrationandpractical</p><p>applicationofallaeronauticaldisciplines.Theauthorsofthepresentbookhave</p><p>togetherover60yearsofexperienceworkingforoneofthelargestaircraft</p><p>manufacturersintheworld,majorairlinesandinstitutionofsuperioreducation.</p><p>Thepresentworkisnotintendedtobeorbecomeatextbook,buttobe</p><p>complementarytotheexistingoneswhilehighlightingenvironmentalaspectson</p><p>aircraftdesign.Therearealreadyseveralgoodbooksthatwerewrittenwiththis</p><p>purpose.Althoughthesebookshaveestablishedsomedesignpracticesandoffer</p><p>considerabledataandinformation,mostofthemweremainlyissuedintheyears</p><p>1980to1990.Alsoatthattime,aircraftdesignwasasequentialprocessstarting</p><p>withaerodynamics,followedbyweightbreakdown,loadcalculation,defining</p><p>wingandtailplaneareasandcheckingstabilityandcontrollability.Someofthe</p><p>methodologyofthesebooksissimpleduetothelackofcomputerpowerinthe</p><p>past.However,aircraftdesignintheaircraftindustryevolvedfromasequential</p><p>processinthepasttothecurrentutilizationofhigh-fidelitymulti-disciplinary</p><p>designandoptimizationframeworks,wherealldisciplinesareconsidered</p><p>simultaneouslyandwhereeverythingdependsuponeverything.Therefore,today</p><p>´saircraftmanufacturersareawareofthefactthatmodernengineersneedto</p><p>understandthewholeaircraftasonecomplexsystem.Thereisanecessityfor</p><p>understandingthemulti-disciplinaryaspectsofaircraftdesignalsoconsidering</p><p>environmentalaspects.Aircraftdesigndisciplinesarethebestwayto</p><p>incorporatethisphilosophy.Bookswritteninthepastwereunawareofthese</p><p>aspects.Inthemeantime,aircraftsystemshaveevolvedconsiderably.For</p><p>instance,fly-by-wiresystemshavechangedthewaycommercialandmilitary</p><p>aircraftaredesignedandflown.Aircraftwithfly-by-wiresystemsaresafer,</p><p>morereliable,easiertofly,moremaneuverableandfuelefficientwithreduced</p><p>maintenancecosts.Afly-by-wirecommandandcontrolsystemisalready</p><p>presentin9-seatbusinessjetairplanes.Allthesenewsystemsmustbetakeninto</p><p>considerationduringthe</p><p>conceptualdesignphase,wheretheaircraftsizingiscarriedoutaswellasother</p><p>importanttasks.</p><p>Theproperunderstandingoftheaviationandmanufacturingbusinessisvery</p><p>importantforengineers.Inthiscontext,thepresentworkprovidestheprocess</p><p>andinformationfortheelaborationofabusinessplanforatransportairplane</p><p>projectthatincludesinformationonhowtoconductamarketsurvey,undertake</p><p>technologicalassessmentsaswellasfinancialandriskanalysis,andshows</p><p>establishmentofrequirements.Itisveryimportantthattheaeronautical</p><p>consistingof</p><p>aDaimler-BenzDB605pair.Themodificationaimedreliabilityandprevention</p><p>ofenginefires.TheintroductionoftheDB610broughtsomenecessary</p><p>modifications,includingthelengtheningoftheenginemountingsby20cm,the</p><p>repositioningoftheengineoiltank,thecompleteredesignoftheexhaustsystem,</p><p>andthesettingofapowerlimitationontheengineswhichresultedingreater</p><p>reliability[38].Thesemajorandminormodifications,weresuccessfulin</p><p>eliminatingenginefires,butotherminorproblemsremained,involvingthe</p><p>transfergearboxbetweenthetwocomponentenginesofeach“powersystem”</p><p>andtheirsharedpropeller.</p><p>CargoAirplanes</p><p>Twocharacteristicscargoairplanesofthepre-warandwarperiodarethe</p><p>MesserschmittMe263GigantandtheAradoAr232,bothhigh-wing</p><p>configurations.</p><p>JunkersandMesserschmittcompetedin1940forthedesignofalargetransport</p><p>glider,abletocarryheavyequipmentandsoldiers[39,40].Junkersproposedthe</p><p>Ju322Mammut,whichpresentedawingspanofincredible62mandwould</p><p>haveaccommodatedmorethan100fullyequippedtroops[39].However,the</p><p>typerevealedtobeunstableandwascancelledbytheRLM.Meanwhile,</p><p>MesserschmitMe321wasasuccessfulgliderofbracedhigh-wingconfiguration</p><p>constructedwithwood,fabric,andwelded-steeltubes[39].Accesstothemain</p><p>cabinwasvialargeclamshelldoorsinthenoseoftheaircraftorbydoorson</p><p>eachsideoftherearfuselage.</p><p>TheMe323wasineffectapoweredandstrengthenedvariantofMessserschmitt</p><p>Me321.FrenchGnome-Rhôneengineswereemployedforthelargecargo</p><p>transport,fouroriginallyandsixinsubsequentprototypesandproduction</p><p>aircraft.TheMe323wasnoteasytohandleandincertaincirc*mstancesthey</p><p>neededrockettoassisttheirtakeofforsimplyrequiredatobetowed.Cruise</p><p>speedoftheEversionwas218km/h[39].</p><p>Inearly1940,workbeganonthedesignofatransportaircrafttoreplacethe</p><p>venerablethree-engineJunkersJu52/3m,ofwhichmorethan500hadbeenin</p><p>serviceonSeptember1st,1939[40].Aradoproposedanewhigh-wingtransport,</p><p>whichfeaturedanunusuallandinggearwithanadditionalsetoftensmaller,</p><p>non-retractabletwinnedwheelsperside,whichsupportedtheaircraftwhen</p><p>landingonunpreparedairfields.Thisdesignintegratedalmostallthefeatures</p><p>nowconsideredtobestandardinmoderncargotransportaircraft,includinga</p><p>box-likefuselageslungbeneathahighwing;arearcargoramp(thathadfirst</p><p>appearedontheDecember1939-flownJunkersJu90V5fifthprototypefour-</p><p>enginedtransport);ahightailforeasyaccesstothehold;andvariousfeatures</p><p>foroperatingfromroughfields[40].AlthoughtheLuftwaffewasinterestedin</p><p>replacingorsupplementingitsfleetofoutdatedJunkersJu52/3mtransports,it</p><p>hadanabundanceoftypesinproductionatthetimeanddidnotpurchaselarge</p><p>numbersoftheAr232.</p><p>Theverticalstabilizersweremountedontheendofalongboomtokeepthearea</p><p>behindthedoorsclearsotruckscoulddriverightuptotheramp,muchlikethe</p><p>1944-eraAmericanFairchildC-82Packetofadifferingtwinboomfuselage</p><p>configuration.Thehigh-settailonits“pod-and-boom”configurationfuselage</p><p>allowedtheAr232tobeloadedandunloadedfasterthanotherdesigns.</p><p>Aradoalsopioneeredaboundary-layercontrolsystem(BLC).TheGerman</p><p>companyintendedtoapplytheconcepttoimprovethefieldperformanceofthe</p><p>Ar232transportairplane.TheconceptisknownasAradoBLCsystem,which</p><p>increasedliftbydelayingairfoilstallthankstoacombinationofsuckingthenear</p><p>separationboundarylayerintheinboardwingflaparea,andthenbyblowing</p><p>energizedfreestreamairoversymmetricdownwarddeflectedailerons(actuating</p><p>thereforeasflaperons)andontheoutboardflaps.Fig.(2.24)displaystheeffect</p><p>onboundarylayervelocityprofilesduetoblowingandsuctiontechniques.</p><p>CessnainconjunctionwithsomeNorthAmericanuniversitiesconductedsome</p><p>researchonAradoboundary-layercontrolsystemwithamodifiedCessna170</p><p>airplane[41].ITA’sAircraftDesignDepartmentalsostudiedtheoreticallythe</p><p>subjectin1957(Fig.2.25).Theimpactonmaximumliftcoefficientduethe</p><p>utilizationofthesuctiontechniquesonflapsisshowninFig.(2.26).</p><p>ThereisaJapanesecompanythatmanufacturersanamphibianairplanewith</p><p>impressiveSTOLcharacteristics.TheShinMaywaUS-2(Fig.2.27)iscapableof</p><p>takeoffinseastatefeaturing3-mheightwaves[42].Asignificantcharacteristic</p><p>oftheUS-2istheBLCsystemthatprovidestheaircraftwithitsoutstanding</p><p>takeoffcapabilities.TheaircrafthasadedicatedanadaptedLHTECT800</p><p>helicopterturboshaftthatprovidesflowthroughasystemofpipesandducts.The</p><p>momentumthatisintroducedintheblownflapsandhigh-liftsurfaceskeepsthe</p><p>boundarylayerattachedanddivertstheflowdownwardsthusprovidingliftin</p><p>speedswherenormallythewingwouldstall.</p><p>Fig.(2.24))</p><p>Effectofblowingandsuctionontheboundarylayervelocityprofiles.</p><p>Fig.(2.25))</p><p>PartialapplicationofArado’sblownsystemtoamodifiedCessna170(Adapted</p><p>fromITA,AircraftDesignDepartment,Drawingno.727,Fig.II–87,</p><p>September1957).</p><p>Fig.(2.26))</p><p>Impactofsuctionontheliftcurveofairfoils.Thebasicconfigurationofthe</p><p>FieselerFi156airplanewasusedasreference(ITA,AircraftDesign</p><p>Department,Drawingno.727,Fig.II–88,September1957).</p><p>Fig.(2.27))</p><p>ShinMaywaUS-2(Photo:[Mamo],releasedtopublicdomain.Obtainedvia</p><p>WikimediaCommons).</p><p>TheJetEngine</p><p>ThejetenginerapidlyevolvedduringtheWorldwarII.Thisisoneoftop</p><p>technologicalachievementsofthatwar.Itwasindependentlybroughttofruition</p><p>ataboutthesametimeinGermanyandEngland[43].InGreatBritain,aRoyal</p><p>AirForceofficer,FrankWhittle,inventedthegas-turbineenginethatpowered</p><p>thefirstBritishjet,theGlosterE.28/39,whichperformeditsfirstflightonMay</p><p>15,1941.InGermany,HansJoachimPabstvonOhainworkedontheproblemof</p><p>gas-turbineengineswithoutanyknowledgeofWhittle’sefforts.VonOhain</p><p>foundsupportfromtheaviationindustrialistErnstHeinkel,whosoughtan</p><p>engine-manufacturingcapabilitytocomplementhisaircraftcompany.Work</p><p>proceededswiftly,andonAugust27,1939,vonOhain’sHeS.3Bengineenabled</p><p>testpilotErichWarsitztomaketheworld’sfirstsuccessfulturbojet-powered</p><p>flightinhistoryinthesingle-enginehigh-wingHeinkelHe178.TheGermans</p><p>alsodesignedandbuiltsomeoperationaljetaircraftduringWorldWarII.The</p><p>AradoAr234reconnaissanceandbomberairplane(Fig.2.28)andthe</p><p>MesserschmittMe262twinjetaretwoairplanesthatcountamongsuccessful</p><p>designs.Prof.TankfromFocke-Wulfwasworkingonasingle-enginejetfighter</p><p>Ta153.Afterthewar,Prof.TankhelpedArgentinatodevelopthePulquiIIjet</p><p>airplane,whichwasbasedonhisTa153.PulquiIIperformeditsfirstflightin</p><p>June1950.PulquiI,anotherArgentinianjetfighter,wasflownin1947andit</p><p>wasdesignedbytheFrenchmanÉmileDewoitine.</p><p>Fig.(2.28))</p><p>TheAradoAr234jetairplaneperformedreconnaissanceandbombermissions</p><p>duringWorldWarII.Above,atwin-engineversionfittedwithwheeledlanding</p><p>gear.(Photo:RoyalAirForceofficialphotographer,publicdomain,via</p><p>WikimediaCommons).</p><p>TheAradoAr234high-wingairplanewasthefirstjet-poweredbomber,also</p><p>performingstrategicreconnaissancemissionsinfrommidtolate1944[44].</p><p>ThesemissionswereflownoverWesternEuropeandEngland,areaswhichwere</p><p>virtuallyimpenetrablebypiston-poweredGermanaircraft.Someoftheseflights</p><p>involvedcalibrationsortiesfortheV-2(A4)rocket.Therewerealsoflights</p><p>conductedoverNorthernItalyafterfindingsfromtheGermanforcesrevealed</p><p>thattherewasinsufficientinformationaboutAlliedtroopmovementsthere.The</p><p>totalnumberofAr234builtamountedto210productionunits[44]and33</p><p>prototypes[44].</p><p>Someprototypesandpre-productionaircraftwerenotfitted</p><p>withpressurizedcabinsorejectionsseats,someofthemalsotestedathree-axis</p><p>autopilot.Theyweredeliveredtothetestfacilities(Erprobungsstelle)ofthe</p><p>ReichLuftMinisteriumthatwereinRechlin.Firstprototypesreceiveda</p><p>jettisionabletake-offtrolley,laterreplacedbyanosewheelandmainlanding</p><p>gearconfiguration[45],alsoadoptedforoperationalairplanes.</p><p>TheAr234B-1wasemployedasreconnaissanceaircraftandtheAr234B-2</p><p>bomberhadamaximumpayloadof2,000kg,withbombracksbeneaththe</p><p>enginenacelles.TheC-3was56km/hfasterthantheB-2version,couldclimbto</p><p>40,000ft(~12,200m)andofferedexcellenthandlingqualities[45].Theywere</p><p>equippedwithathree-axesautopilotwithoverridingcontrol,enablingthepilot</p><p>tomovethecontrolcolumntoatachometricbombsightbeusedforthebomber</p><p>versions.Acomputeraidedbombingsystemwasusedinconjunctionwitha</p><p>sightperiscopeforshallowdive-bombing.</p><p>ThedevelopmentofAr234Cemployedtwoprototypesbeingflownwith</p><p>alternativearrangementforthefourenginenacelles,bothpairedandseparate</p><p>fromeachother,theformerconsideredtobemoreefficient.TheprototypeV19</p><p>provedtobethefirsttrueAr234Cseriesaircraft[45],havingfour798-kgthrust</p><p>BMW109-003A-1turbojetsinpairednacellesbeneatheachwing.This</p><p>prototypewasemployedforpressurizedcabinandicingtests[45].</p><p>TheGermansdesignatedmanyadvancedaircraftthatnotbecamereadyforwar</p><p>operations.Plentyofthemfeaturedtheutilizationofjetengines[46,47].Oneof</p><p>themwastheHorten229bomber.In1943,MinistryofAeronautics</p><p>(Luftfahrtministerium)issuedarequestfordesignproposalstoproducea</p><p>bomberthatcouldcarrya1,000-kgbombloadover1,000km,flyingat1,000</p><p>km/h.Thisrequestwascalledthe3×1000project.ConventionalGerman</p><p>bombersattackingGreatBritainweresufferingdevastatinglossesbyAllied</p><p>fighters.Ahigh-speedbomberairplanewouldbethenhardtointercept.Atthe</p><p>time,therewasnowaytofulfiltherequirementsissuedbyRLMbecausethe</p><p>highfuelconsumptionofjetengines,liketheJunkersJumo004B,compromised</p><p>theairplanedesiredrange.Thus,Hortenintendedtoemployalow-drag</p><p>configurationtocomplywiththerangerequirement.PerHorten,thatwouldbea</p><p>low-dragflyingwingconfiguration.Inaddition,therequiredhigh-altitudecruise</p><p>thrust,alsoabigissueatthattime,couldbelowerediftheaircraftcouldpresent</p><p>ahigherlift-to-dragratio,somethingthataflyingwingcoulddeliver.</p><p>Hortenmovedforwardwithaprivateproject,theH.IX,asthebasisforthe</p><p>bomber.TheRLMapprovedtheHortenproposal,butorderedtheincorporation</p><p>oftwo30-mmcannons,astheGermanofficialsconsideredthattheaircraft</p><p>wouldalsobeemployedasafighterthankstoitsestimatedtopspeedbeing</p><p>significantlyhigherthanthatofanyAlliedaircraft.TheHortenIX(Fig.2.29)</p><p>wasofmixedconstruction,withthecenterpodmadefromweldedsteeltubing</p><p>andwingsparsbuiltfromwood.Thewingsweremadefromtwothin,carbon-</p><p>impregnatedplywoodpanelsgluedtogetherwithacharcoalandsawdustmixture</p><p>[48].Thewinghadasinglemainspar,penetratedbythejetengineinlets,anda</p><p>secondarysparusedforattachingtheelevons.Itwasdesignedwitha7gload</p><p>factoranda1.8×safetyrating.Thewingairfoilsmaximumthicknesstochord</p><p>ratiorangedfrom15%attherootsectionto8%atthewingtip.Theaircraft</p><p>utilizedretractabletricyclelandinggear,withthenosegearonthefirsttwo</p><p>prototypestakenfromaHeinkelHe177'stail-wheelsystem.Theaircraftwas</p><p>originallydesignedfortheBMW003jetengine,butthatenginewasnotquite</p><p>ready,andtheJunkersJumo004enginewasemployedinstead.Afterthewar,</p><p>ReimarHortensaidhemixedcharcoaldustinwiththewoodgluetoabsorb</p><p>electromagneticwaves(radar),whichhebelievedcouldshieldtheaircraftfrom</p><p>detectionbyBritishearly-warningground-basedradarthatoperatedat20to30</p><p>MHz(topendoftheHFband),knownasChainHome.TheonlysurvivingHo</p><p>229airframehasbeenrestoredattheNationalAirandSpaceMuseum’sGarber</p><p>RestorationFacility.</p><p>Fig.(2.29))</p><p>HortenIX(Photo:NationalAirandSpaceMuseum,SmithsonianInstitution,</p><p>releasedintothepublicdomain.ViaWikimediaCommons).</p><p>High-SpeedFlight</p><p>TheGermansalsowereattheleadingedgeofhigh-speedflightduetoresearch</p><p>carriedoutatsomeuniversities,noticeablyGöttingenUniversity.Researchon</p><p>highspeedflowledtostudywingsweepbacktoimproveaircraftperformanceat</p><p>higherspeeds.TheAmericansgainedknowledgeonhigh-speedflightbyreading</p><p>Germanreportsavailableaswarmaterial[32].Thefirstmentionandpublication</p><p>oftheconceptofwingsweepcomesfromtheaerodynamicistAdolfBusemann</p><p>inyear1935[49,50].HewasthenprofessorattheTechnischeHoschule</p><p>Dresdenandgavealectureentitledaerodynamicliftatsupersonicspeedsatthe</p><p>5thInternationalVoltaMeetinginRome[49].Followingarecommendationof</p><p>AlbertBetz,aLudwigPrandtlcolleagueatAerodynamicResearchInstitutein</p><p>Göttingen,H.StraβlandHubertLudwiegconductsystematicwind-tunneltests</p><p>withsweep-wingconfigurations[51].UponrequestfromtheMesserschmitt</p><p>aircraftmanufacturerexperimentswithrealisticaircraftconfigurationswerealso</p><p>carriedout.Theresultsandconclusionsoftheexperimentation,rangingfrom</p><p>Machnumber0.5to1.2,recommendedtheutilizationofsweep-wing</p><p>configurationstoimprovehigh-speedperformance.Theresearchers</p><p>communicatedtheirachievementsinthemeetingHigh-speedoftheGeneral</p><p>CommitteeforFluidDynamicsResearch,whichtookplacein1940[52].Fig.</p><p>2.30showsthetopviewofseveralsweep-wingcombataircraftconceiveduntil</p><p>theendofWorldWarIIinMay1945.</p><p>Fig.(2.30))</p><p>SomeGermanaircraftconceptswithsweepwingsuntil1945.</p><p>Thearearuleisanaerodynamicformulationthataddressesthegenerationof</p><p>wavedrag.Theformulationstatesverysimplythatthetransonicwavedragofan</p><p>aircraftisessentiallythesameasthewavedragofanequivalentbodyof</p><p>revolutionhavingthesamecross-sectionalareadistributionastheaircraft.This</p><p>fact,allowthedesignerstoshapetheairplaneinsuchwaythatthatitminimizes</p><p>drag.</p><p>ThearearulewasdiscoveredbyOttoFrenzlwhencomparingasweptwingwith</p><p>aw-wingwithextremehighwavedrag[49]whileworkingonatransonicwind</p><p>tunnelatJunkersFlugzeugbauinGermanysometimebetween1943and1945.</p><p>HewroteareportonDecember17th,1943entitledArrangementof</p><p>DisplacementBodiesinHigh-SpeedFlight[53].Thiswasusedinapatentissued</p><p>bytheGermanofficein1955butvalidfrom1944[54].Theresultsofthis</p><p>researchwerewidelydivulgedinMarch1944byTheodorZobelattheDeutsche</p><p>AkademiederLuftfahrtforschunginthelectureFundamentallyNewWaysto</p><p>IncreasePerformanceofHigh-speedAircraft[55].</p><p>SomeGermanaircraftdesignduringWarWorldIIincorporatedtheknow-how</p><p>broughtbyFrenzl,evidentintheslenderfuselageofaircraftsuchas:</p><p>MesserschmittP.1111Wespe-TheMesserschmittP.1111wasan8.92-mlong</p><p>taillessairplanewithnearlydelta-shaped45o-sweepbackwingsItwasequipped</p><p>withapressurizedco*ckpitforasinglepilot[56].Fuselagepracticallyblended</p><p>withthewings.P.1112wasafurtherdevelopmentofP.1111.</p><p>MesserschmittP.1106–ThisconceptwasintendedasanimprovementtotheMe</p><p>P.1101.Itwasredesignedseveraltimes.Fuselagesectionwasreducedinthe</p><p>wing-fuselagejunctionregion.</p><p>Focke-Wulf1000x1000x1000Along-rangebomberthatshouldbepoweredbya</p><p>pairofjetHeS011engines.ThetypewasconceivedtocruiseatMachnumber</p><p>of0.90at13,500maltitudeandthereforethefuselagecross-sectionsinthe</p><p>wing-fuselagejunctionareawasreduced.</p><p>Variable-sweepwingsarealsoawaytoapplythearea-ruleforimprovehigh-</p><p>speedperformance.Several</p><p>GermanairplaneconceptsemergedduringWorld</p><p>WarII:MesserschmittP.1102,MeP.1109,andBlohmundVossBVP.202count</p><p>amongthem.</p><p>Severalotherresearcherscameclosetodevelopingasimilartheory,notably</p><p>DietrichKüchemannwhodesignedataperedfighterthatwasdubbedthe</p><p>“Küchemannco*keBottle”whenitwasdiscoveredbyUSforcesin1946.Inthis</p><p>caseKüchemannarrivedatthesolutionbystudyingairflow,notablyspanwise</p><p>flow,overasweptwing.Thesweptwingisalreadyanindirectapplicationofthe</p><p>arearule.</p><p>WallaceD.Hayes,apioneerofsupersonicflight,developedthetransonicarea</p><p>ruleinpublicationsbeginningin1947withhisPh.D.thesisattheCalifornia</p><p>InstituteofTechnology.RichardT.Whitcomb,afterwhomtheruleisnamed,</p><p>independentlydiscoveredthisrulein1952,whileworkingattheNACA.</p><p>Thearearulewasimmediatelyappliedtoseveraldevelopmenteffortsinthe</p><p>UnitedStates.OneofthemostfamouswasWhitcomb'spersonalworkonthere-</p><p>designoftheConvairF-102DeltaDagger(Fig.2.31),aU.S.AirForcejet</p><p>fighterwithdisappointingperformance[57].Byindentingthefuselagebeside</p><p>thewings,and(paradoxically)addingmorevolumetotherearoftheplane,</p><p>transonicdragwasconsiderablyreduced,andtheintendedMach1.2design</p><p>speedwasreached.TheculminatingdesignofthisresearchwastheConvairF-</p><p>106DeltaDart,anaircraftwhichformanyyearswastheUSAF'sprimaryall-</p><p>weatherinterceptor.</p><p>Fig.(2.31))</p><p>ConvairYF-102beforeandaftermodifications(Photos:CourtesyNASAvia</p><p>WikimediaCommons).</p><p>THEJETAGES</p><p>FromWartoPeaceII</p><p>InthewakeofWorldWarII,theaviationexperiencedaneraofexperimentation</p><p>andcreativitywithfatbudgetsmadeavailablefor.Noideaorconceptseemed</p><p>impossibletoconsider,andanythingseemedpossible.TheKoreanWarsignaled</p><p>theendofthepropeller-poweredfighterandtheWorldWarIIB-29bomber</p><p>sufferedheavylosses.Thejetfightertacticsusedtodayweredevelopedduring</p><p>dogfightsbetweenNorthAmericanF-86sandMiG-15soverKorea(Fig.2.32).</p><p>Fig.(2.32))</p><p>MikoyanMig-15andNorthAmericanF-86Sabre,veteransofKoreanWarin</p><p>staticdisplayatKoreanWarGalleryattheNationalMuseumoftheUnited</p><p>StatesAirForce(Photo:U.S.AirForce,publicdomain).</p><p>Aseriesofnewaircraft,consistingofbothtransonicandsupersonicfighters</p><p>arose(Table2.2).Strategictransonicandsupersonicbombersalsowere</p><p>developedhavinginmindtheneedforlong-rangebombersthatcouldcarry</p><p>nuclearweapons.ThisfirstledtotheB-47andthentotheB-52andultimatelyto</p><p>theConvairB-58Hustler,whichwasdelta-wingsupersonicbomberthatentered</p><p>operationsin1960.Theideabehindthisaircraftwastoavoidinterceptionby</p><p>Sovietfightersflyingsupersonicallyathighaltitudes.</p><p>Table2.2SomeColdWarfightersfromthe1950sandearly1960s(Source:</p><p>Wikipedia).</p><p>Type YearofIntroduction Max.LevelSpeed(MachNumber)</p><p>LockheedF-94Starfire 1950 0.84</p><p>VoughtF7UCutlass 1951 0.92@sealevel</p><p>DouglasF3DSkynight 1951 0.80</p><p>Mikoyan-GurevichMiG-17 1952 0.97</p><p>GrummanF9F/F-9Cougar 1952 0.99</p><p>WestlandWywern(turboprop) 1953 0.52@3,000m</p><p>NorthAmericanSuperSabre 1954 1.3</p><p>NorthAmericanFJ-2Fury 1954 0.89</p><p>HawkerHunter 1954 0.94@sealevel</p><p>RepublicThunderstreak 1954 0.91@sealevel</p><p>Mikoyan-GurevichMiG-19 1955 1.35</p><p>YakovlevYak-25 1955 1.0</p><p>NorthAmericanFJ-4Fury 1955 0.89</p><p>DouglasA-4Skyhawk 1956 1.0</p><p>DouglasF-4DSkyray 1956 1.09</p><p>GrummanF-11Tiger 1956 1.1</p><p>GlosterJavelin 1956 0.93@sealevel</p><p>SAABJ-32Lansen 1956 0.91</p><p>McDonnelF3HDemon 1956 0.97</p><p>ConvairF-102DeltaDagger 1956 1.25</p><p>Chance-VoughtCrusader 1957 1.86</p><p>McDonnelF-101Vodooo 1957 1.72</p><p>EnglishElectricLightning 1957 2.0</p><p>SupermarineScimitar 1957 0.97@sealevel</p><p>LockheedF-104 1958 2.0</p><p>RepublicF-105Thunderchief 1958 2.08</p><p>ConvairF-106DeltaDart 1959 2.3</p><p>MikoyanMig-21 1959 2.0</p><p>SukhoiSu-9 1959 2.0</p><p>SAABDraken 1960 2.2</p><p>McDonnelF-4PhantomII 1960 2.23</p><p>YakovlevYak-28 1960 1.73</p><p>DassaultMirageIII 1961 2.0</p><p>Grandtotal 59,507</p><p>NewcivilconceptsandconsolidatedinnovativeideasfromtheWorldWarIIalso</p><p>emergedintheperiod1945–1960.Amongsuccessfulconcepts,therewasthejet-</p><p>andturboprop-poweredtransport.Thejettransportwasconceivedforspeed,to</p><p>shortentimetraveloflong-distanceflights.BoeingandDouglaspioneeredthe</p><p>civilianjetagethattookplaceinthelate1950s.Convairarrivedlateinthe</p><p>disputewithits880.In1951,theBoeingB-47strategicbomberenteredservice.</p><p>Thisbomberfeaturingwingswithhighsweephadaspin-offeffectonthefour-</p><p>engineBoeing707passengertransport.</p><p>High-CapacityTurbopropAirliners</p><p>Afterthewar,anewgenerationofpassengertransportersbegantobedeveloped.</p><p>Turbopropairlinerswereonthehorizon.Asaresultofspecificationsfromthe</p><p>BritishBrarbazonCommittee,theturboprop-poweredVickersViscountfirstflew</p><p>in1948[58].Thefour-engineVickersViscountwasthefirstturbopropairlinerto</p><p>enterregularservice,whichtookplacein1953.Initially,theVickersVanguard</p><p>wasconceivedtofulfilBEArequirementsforanairplanewith1600-kmrange</p><p>[59].Theairframealsoexperiencedsomeredesigns:Vanguardfuselagewas</p><p>initiallyconceivedtobethesameasthatofViscount,howeverwiththeintention</p><p>toprovidearoomierpassengercabin;anewdouble-bubblelayoutwas</p><p>introducedtotheVanguard.Asaresult,Vanguardenteredoperationsonlyin</p><p>1960,facingdirectcompetitionwithjetairliners.Consequently,only44</p><p>exemplarswereproduced.</p><p>TheBristolBritanniawasamedium-rangeairlinerwhosedevelopmentbythe</p><p>BristolAeroplaneCompanybeganin1952.Threeprototypeswereorderedas</p><p>Mk1(piston-engineCentaurus662),withthesecondandthirdprototypes</p><p>designatedMk2(intendedtobereplacedbyBristolProteusturboprops,then</p><p>underdevelopment).DuringthedevelopmentofBritannia,twoprototypeswere</p><p>lost,andtheturbopropenginessufferedfrominleticingproblems,thusdelaying</p><p>entryintoservicewhilesolutionsweresought.TheBritanniaModel102began</p><p>scheduledserviceonFebruary1st,1957withBOAC,flyingfromLondonto</p><p>Johannesburg[60].</p><p>Afteracommercialsuccessofthepiston-poweredConstellationairplane,the</p><p>North-AmericanaircraftmanufacturerLockheedofferedairlinesaseriesof</p><p>conceptsthatweresuccessivelyrejected.Finally,thecompanyattractedinterest</p><p>fromEasternAirLinesforaconceptwithincreasedcapacityin1955[61].The</p><p>typebecamethefour-engineLockheedElectraIIturbopropairliner(Fig.2.33),</p><p>whichwasintroducedin1959withEasternAirLines.ElectraIIutilizedthe</p><p>sameAllison501enginesofthemilitarytransportC-130.</p><p>ThreeElectraIIairplanessufferedfatalaccidentsbetweenFebruary1959and</p><p>March1960,allwiththeairplanesbreakingapartintosmallpieces[61].After</p><p>thethirdaccident,theFederalAdministrationAgency(FAA)constrainedthe</p><p>speedofElectrauntilthecausethatledtothecrashescouldbedetermined.</p><p>Accordingtoanextensiveinvestigation,enginemountingwasdeterminantfor</p><p>twoofthecrashes.Theywerenotstrongenoughtodampthevibrationsthat</p><p>resultedintoawhirlflutterattheoutboardenginestations.Whirlflutterisa</p><p>precessiontypeinstabilitythatcanoccuronaflexiblymountedaircraft-engine-</p><p>propellercombination[62].Whenadeterminedpropellerfrequencywas</p><p>transmittedtothewings,itwasresonantwiththevibrationmodesoftheouter</p><p>wingpanels,leadingtoacatastrophicfailure.Lockheedintroduced</p><p>modificationstofixtheflutterproblemandElectraIIreturnedtocivil</p><p>operations.In1957,theUnitedStatesNavyissuedarequirementforan</p><p>advancedmaritimepatrolaircraft.Lockheedproposedthedevelopmentofthe</p><p>ElectrathatwaslaterplacedintoproductionastheP-3Orion(Fig.2.34).The</p><p>Orionhasbeenincontinualfront-lineserviceformorethan50years.</p><p>Fig.(2.33))</p><p>VARIGoperated</p><p>theLockheedElectraIIintheshuttleservicebetweenRiode</p><p>JaneiroandSãoPauloformanyyears(Photo:©1985BentoMattos).</p><p>Fig.(2.34))</p><p>P3OrionoftheBrazilianAirForce(Photo:©2016BentoMattos).</p><p>Thejetlinersreplacedthehigh-capacityturboprops,leavingthemarkettothis</p><p>kindofairplaneforthesegmentbelow80seats.Inthe1990s,theERJ145and</p><p>CanadairCRJ-100hitturboprop-poweredairplanesagain,restrictingtheir</p><p>marketpenetrationevenfurther.</p><p>Inception</p><p>TheBoeing707(Fig.2.35)wingsweredesignedwithasweepbackof35</p><p>degreestolowerdragathigherspeedsandtheywereinheritedinsomeextentof</p><p>theB-47bomber.Forthisreason,likeallswept-wingaircraft,displayedan</p><p>undesirableDutchrollflyingcharacteristicthatmanifesteditselfasan</p><p>alternatingyawingandrollingmotion(thewingtipdescribesanellipse)[63].</p><p>Dutchrollisatypeofaircraftdynamicmotioncausedbyexcessofrollstability</p><p>regardingyawstability.Stabilityinrollisaffectedbymanyfactors,including</p><p>wingdihedral,sweepbackangle,andverticaltailarmtocenterofgravity;the</p><p>yawstabilityisensuredprimarilybyverticalstabilizer.Ifthewingisswept</p><p>back,thisisequivalenttoprovidethatwingsomeadditionalupwarddihedral</p><p>angleleadingtheairplaneconfigurationpronetoDucthroll.Thisyaw-roll</p><p>couplingisoneofthebasicflightdynamicmodes(othersincludephugoid,brief</p><p>period,andspiraldivergence).Boeingalreadyhadconsiderableexperiencewith</p><p>thisphenomenonontheB-47StratojetandB-52bombers,andthecompanyhad</p><p>developedtheyawdampersystemontheB-47thatwouldbeappliedtolater</p><p>sweptwingconfigurationslikethe707[63].</p><p>Fig.(2.35))</p><p>Artisticviewofthefour-engineBoeing707airliner.</p><p>Yawdampersrequireyawratesensors(and,dependingonthecontroladopted,</p><p>rollratesensors)andaprocessorthatprovidesasignaltoanactuatorconnected</p><p>totherudder.Theuseofayawdamperhelpstoprovideabetterridefor</p><p>passengers,andonsomeaircrafttheyawdamperisarequiredpieceof</p><p>equipmenttoensurethattheaircraftstabilitycomplainswithcertificationrules.</p><p>Manynew707pilotshadnoexperiencewiththeadverseflightbehaviorcaused</p><p>byDutchroll,becausetheyweretransitioningfromstraight-wingpropeller-</p><p>drivenaircraftsuchastheDouglasDC-7andLockheedConstellation.</p><p>Ononecustomeracceptanceflight,wheretheyawdamperwasturnedoffto</p><p>familiarizethenewpilotswithflyingtechniques,atraineepilot'sactions</p><p>violentlyexacerbatedtheDutchrollmotionandcausedthreeofthefourengines</p><p>tobetornfromthewings.Theplane,abrandnew707-227,N7071,destinedfor</p><p>Braniff,crash-landedonariverbednorthofSeattleatArlington,Washington,</p><p>killingfouroftheeightoccupants[64].</p><p>TestpilotTexJohnstonwroteanautobiographywherehedescribedaDutchroll</p><p>incidentexperiencedbyhimasapassengeronanearlycommercial707flight</p><p>[65].Astheaircraft'soscillationsdidnotceaseandthereforemostofthe</p><p>passengersbecameuncomfortableandnauseated,hesuspectedamisriggingof</p><p>thedirectionalautopilot(yawdamper).Hewenttotheco*ckpitandfoundthe</p><p>crewunabletounderstandandresolvethesituation.Heintroducedhimselfand</p><p>replacedthecaptainwhoimmediatelylefttheco*ckpitfeelingill.Johnston</p><p>disconnectedthefaultyautopilotandmanuallystabilizedtheplane“withtwo</p><p>slightcontrolmovements[65].”</p><p>DouglasAircraftCo.developedasimilarairplanetotheBoeing707,thefour-</p><p>engineDC-8.Pan-Am,theairlinethatwillbealwaysassociatedwiththe707,</p><p>ordered20707sand,attheverysametime,25DC-8s.Boeingwasinsome</p><p>disadvantageduethefactthatthe707wasnarrowerandslightlysmallerthanthe</p><p>DC-8.WhenWilliamAllen,Boeing’spresidentofferedAmericanAirlinesan</p><p>extrahalf-inchinwidthovertheDC-8,hewonanorderforfifty707s[66].From</p><p>thatmoment,thesalessuccessoftheBoeingwasassured.Boeingbuilt1,010</p><p>707sforcommercialairlinesbetween1958and1978,andafurther800forthe</p><p>militaryupuntil1991,whileDouglasassembled556DC-8sbetween1958and</p><p>1972[66].</p><p>Sud-AviationCaravelle</p><p>Thefirstairlinerswithturbojetpropulsionwereexperimentalconversionsofthe</p><p>AvroLancastrianpiston-poweredairliner,whichwereflownwithseveraltypes</p><p>ofearlyjetengine,includingtheDeHavillandGhostandtheRolls-RoyceNene</p><p>[67].These,however,retainedthetwoinboardpistonengines,thejetsbeing</p><p>housedintheoutboardnacelles,andtheseaircraftwerethereforeof“mixed”</p><p>propulsion.ThefirstairlinerwithfulljetpowerwastheNene-poweredVickers</p><p>VC.1VikingG-AJPH,whichfirstflewon6April1948.Thefirstpurpose-built</p><p>jetairlinerwastheBritishDeHavillandCometwhichfirstflewin1949and</p><p>enteredservicein1952.TheAvroCanadaJetlinerwasalsodevelopedin1949,</p><p>andalthoughitneverreachedproduction,thetermjetlinercaughtonasageneric</p><p>termforallpassengerjetaircraft.</p><p>Caravelle210(Fig.2.36)wasthefirstcommercialjetaircraftofshort/medium</p><p>routes.ItwasdesignedandmanufacturedbytheFrenchcompanySud-Aviation,</p><p>withproductionstartingin1955(whenitwasstillknownbytheacronymof</p><p>SNCASEandreceivedanacronyman“SE”).TheCaravellewasthefirstjetto</p><p>enterserviceinBrazil,beginningthejeterainthatcountry,CruzeirodoSul,</p><p>VARIGandPanairweretheairlinesthatoperatedCaravelleinBrazil.</p><p>Fig.(2.36))</p><p>Sud-AviationCaravelle,thefirstjetlinerwithrear-mountedengines.</p><p>TheCaravelleisgenerallyconsideredthefirstcommercialjetsuccesssinceits</p><p>predecessor,theDeHavillandComet,sufferedaseriesofaccidentsthatforced</p><p>hisprematuredecommissioning.Forseveralyears,theCaravellewasusedin</p><p>EuropeandtheUnitedStates.Historically,theCaravellewasimportantforbeing</p><p>thefirstaircraftwiththeenginesmountedatrearfuselage,leavingthewingfree</p><p>fromdisturbancescausedbyburiedengines(buried)astheCometorunderwing</p><p>configurationliketheB-52bomberandthequadrijet707.Thisarrangementof</p><p>motorswasthenadoptedbymanyotheraircraft,includingtheDC-9andBAC</p><p>111airliners.</p><p>Becauseofexperiencewiththeconstructionandoperationofthefour-engine</p><p>piston-poweredArmagnac,SudAviationdecidedtomakeuseofresistance</p><p>weldingtobuildtheCaravelletwinjet.TheArmagnacemployedover150</p><p>thousandpointsandweldingalthoughweldingmachinesusedwererelatively</p><p>oldconcept,theresultsobtainedwiththistypeofmanufacturehaveprovedtobe</p><p>eminentlysatisfactory.InatleastoneaccidentArmagnac,itwasdemonstrated</p><p>thatwhiletherivetlineshavefailed,theconstructionspotweldinghadremained</p><p>good,demonstratingboththesafetyandweldstrengthinaircraftconstruction.</p><p>SudAviationexaminedtheweldingusetheCaravelleandfoundthat[68]:</p><p>Thespotweldingenablesahermeticstructurerequiredforthepressurized</p><p>fuselage.</p><p>Thespotweldqualitydidnotaffecttheaerodynamicsoftheaircraftfuselage,</p><p>i.e.thesurfacesmoothnesswasnotaffectedbywelding.</p><p>WeightReduction-thespotweldingallowshigherdensityofribsthanthe</p><p>rivetingduetoabsenceofholes.</p><p>Theprocessofspotweldingallowsrapidmanufacturing,iseasytoperformand</p><p>cheaperthanriveting.</p><p>AstheadvantagesofspotweldingseemedtobeverypronouncedforSud-</p><p>Aviation,theCaravellewasdesignedtomakeextensiveuseoftheresistance</p><p>weldingtechnique.Theweldingwasusedthroughouttheaircraft,exceptinareas</p><p>suchasthecentralwing,andallfuselagereinforcements,panels,flooring,the</p><p>tailend,doors,enginecowlingandopeningreinforcementsareinplacewelded</p><p>(Fig.2.37).TheCaravellecontainedover300,000pointsofwelding[68].</p><p>Fig.(2.37))</p><p>WeldedpartsofCaravelle(inred).</p><p>SeveralCaravelleversionswereproducedduringthelifetimeofitsserial</p><p>production,asthethrustoftheenginesincreasedandenabledhigher</p><p>takeoff</p><p>weights.Atacertaintime,theSudAviation'sdesignbureauturneditseffortsto</p><p>theconceptualdesignofasupersonictransportwithrangelikethatofthe</p><p>Concorde.SudAviationnameditSuper-Caravelle[69].However,thisdesign</p><p>endeavorwouldlaterbemergedwithsimilarworkatBritain'sBristolairplane</p><p>companytoproducetheConcordesupersonicairliner.Insomeconfigurations,</p><p>Super-Caravellewouldhaveseveralrearward-facingpassengerseats,an</p><p>uncommonarrangementforcivilaircraft[70].</p><p>TheSuper-CaravelleseemedtobeasmallerversionofConcorde:itswing</p><p>planformalsopresentedanogiveconfigurationlikeConcorde;otherwiseitwas</p><p>similarinshapeandlayoutexceptforthenosearea,whichwasconventionaland</p><p>onlytheoutermostsectionovertheradarfeaturedadroopmechanismfor</p><p>visibilityontakeoffandlanding.Thebaselineconfigurationwasconceivedto</p><p>accommodate70passengersforarangefrom2,000to3,000km[70].TheSuper</p><p>CaravelleshouldattainacruisespeedofMachnumberof2.</p><p>TheFirstJetAge</p><p>Withtheadventofturbojet,altitudebecameacriticalfactorinflightefficiency</p><p>andperformance.Highercruisealtitudewasthenadoptedforbetterfuelburn</p><p>andimprovedperformance,basicallyspeedandrange.Furthercruisealtitude</p><p>increasecamewithimprovementsoftheturbojetengine.Thisposednew</p><p>challengestodesignersinregardcabinpressurizationbecausethisledtoa</p><p>heavierstructure,which,inturn,degradesairplaneperformanceandraisesits</p><p>costs.TheBoeing307Stratolinerwasthefirstpressurizedoperationalcivil</p><p>airplane.Thisairlinerperformeditsfirstflightin1938.Aftertestswiththe</p><p>Focke-Wulf190,theGermansintroducedapressurizedcabinintoaserial</p><p>producednightfighter,theHeinkel219Uhu,whichwasalsofittedwithejection</p><p>seats.TheDeHavillandDH106Cometwasthefirstproductioncommercialjet.</p><p>DevelopedandmanufacturedbyDeHavilland,theComet1prototypefirstflew</p><p>onJuly27,1949.Fig.2.38showssomeconceptsconsideredforits</p><p>configuration.ItfeaturedanaerodynamicallycleandesignwithfourDe</p><p>HavillandGhostturbojetenginesburiedintheinboardwing,apressurized</p><p>fuselage,andlargesquarewindows.Fortheera,itofferedarelativelyquiet,</p><p>comfortablepassengercabinandshowedsignsofbeingacommercialsuccessat</p><p>its1952debut.Turbojetenginespresenthigherspecificfuelconsumptionwhen</p><p>comparedwithpiston-poweredonesthatwereusedinairlinersofprevious</p><p>generations.Tokeepfuelconsumptionandperformanceintoacceptablelevels,</p><p>jetairplanesflyhigherthanpiston-poweredandturbopropones[71].Thisin</p><p>turnrequiresapressurizedcabintokeeppassengersaliveandcomfortable.</p><p>Duringthedescentpath,cabinpressurewouldhavetobebledoffa*gain.Each</p><p>cyclecausesenormousstressontheairplane’sstructure;thetubularcabin</p><p>stretchesslightlywhenpressurized,thencontractaspressureisreleased.</p><p>Fig.(2.38))</p><p>DesignstudiesfortheCometairliner(AuthorBzuk,releasedtothepublic</p><p>domainviaWikimediaCommons).</p><p>Ayearafterenteringcommercialservice,theCometairlinersstartedtosuffer</p><p>problems,withthreeofthembreakingupduringmid-flightinwell-publicized</p><p>accidents.Thiswaslaterfoundtobeduetocatastrophicairframemetalfatigue.</p><p>Noonehadtakenintoconsiderationthepressurizingcyclesonthefuselagefora</p><p>giventimespan,whichwerefasterthantheequivalentcyclesintheslower,</p><p>propeller-drivenairplanes[71].Britainauthoritieslastedtoreactbutlateran</p><p>entireCometfuselagewasplacedinagiantwatertank,anditssealedinterior</p><p>filledwithwatertoevaluatetheeffectsofpressurizationcyclesonitsstructure.</p><p>Tosimulatecabin-pressurechangesinanaircraftclimbingto10,700mandthen</p><p>descendingagain,interiorpressurewasincreasedanddecreasedatthree-minute</p><p>intervals.Around-the-clocktestingagedtheCometnearly40timesfasterthanit</p><p>wouldhaveperformedinactualservice.Inthemeantime,autopsyreportsfrom</p><p>theItalianpathologistwhoexaminedthebodiesofvictimsofoneofthecrashes</p><p>indicatedtheyhaddiedbyviolentmovementandexplosivedecompression.</p><p>Evidencepointedtothecatastrophicfailureofthefuselage.Thefinalclue,</p><p>revealingtheweaknessintheComet’sstructure,turneduponJune24inthetank</p><p>atFarnborough,wheretheimmersedtestComethadbeensubjectedtothe</p><p>equivalentof9,000flyinghours.Instrumentsshowedasuddendropincabin</p><p>pressure,indicatingthatsomethinghadhappenedinthetank.Althoughsales</p><p>neverfullyrecovered,theimprovedComet2andtheprototypeComet3</p><p>culminatedintheredesignedComet4serieswhichdebutedin1958andhada</p><p>productivecareerofover30years[72].TheCometwasadaptedforavarietyof</p><p>militaryrolessuchasVIP,medicalandpassengertransport,aswellas</p><p>surveillance[72].Themostextensivemodificationresultedinaspecialized</p><p>maritimepatrolaircraftvariant,theHawkerSiddeleyNimrod.</p><p>Francesucceededwithitsfirsteffortatajetairliner,creatingtheSud-Est(later</p><p>Aérospatiale)SE210Caravelle,amedium-rangeturbojetintendedprimarilyfor</p><p>thecontinentalEuropeanmarket.FirstflownonMay27,1955,theCaravelle</p><p>achievedsalesof282aircraft,andaturbofan-poweredvariantwasusedfor</p><p>domesticroutesbyairlinesintheUnitedStates.TheCaravellewastheworld’s</p><p>firstairlinertohaverear-mountedengines,adesignfeaturethatwasadoptedfor</p><p>someusesbyallothermajormanufacturers.Thetypewasoperatedbythe</p><p>BrazilianairlineVARIG.Someyearlater,theBoeing707designproved</p><p>successfulandhasbeenadoptedforjetlinersalmostuniversallysincethe1960s</p><p>[73].Later,inthe1990s,EMBRAERandCanadairbroughtthejetrevolutionto</p><p>theregionalmarket,withtheERJ145(Fig.2.39)andCRJ-100twinjets,</p><p>respectively.</p><p>Fig.(2.39))</p><p>Top-EMBRAERERJ145LRatSãoJosédosCamposAirport(Photo:©2002</p><p>BentoMattos).</p><p>TheSecondJetAge</p><p>TheCanadairChallenger600businessjetenteredinoperationin1980.Its</p><p>configurationfeaturedawiderfuselagecross-sectionthanpreviousbusinessjets</p><p>initscategory.TheChallengerwasalsooneofthefirstbizjetsdesignedwitha</p><p>supercriticalwingandpoweredbyturbofanengines.Thistechnological</p><p>combinationgavehimatruecompetitiveleap.Canadairconsideredthata</p><p>regionaljetcouldbedevelopedfromtheChallenger610Eseating24passengers.</p><p>Thisideadidnotmoveforwardbutstudiesfora50-seatregionaljetemergedin</p><p>1987.CanadairformallylaunchedtheCRJprogramin1989.TheCL-600design</p><p>wasstretched5.92meterstocreatetheCRJ-100,withfuselageplugsforeandaft</p><p>ofthewing,twomoreemergencyexitdoors,plusareinforcedandmodified</p><p>wing.TheCRJhigh-speedadvantageregardingturbopropairplanesofsimilar</p><p>capacityshouldtranslateinahigherdailyutilizationrateandoffering</p><p>competitivedirectoperatingcosts.Theconceptofastretchedairlinerderivative</p><p>oftheChallengerisnotnew,Canadair(purchasedbyBombardierAerospace)</p><p>originallystudieda24-seatstretcheddevelopmentoftheCL-600upto1981.</p><p>Designstudiesforastretchedairlinerbasedonthe601howeverwerefirst</p><p>undertakenin1987,leadingCanadairtolaunchtheRegionalJetprogramon</p><p>March31,1989.Thefirstprototype,ofatotalofthreeaircraft,tooktotheskies</p><p>forthefirsttimeonMay10,1991.TransportCanadacertificationwasawarded</p><p>onJuly31,1992,allowingthefirstcustomerdeliverytoLufthansathatOctober.</p><p>MajorchangesovertheChallengerapartfromthestretchedfuselageincludea</p><p>newadvancedwingoptimizedforairlineoperations,higherdesignweights,</p><p>EFISflightdeckwithCollinsPro-Line4avionicssuite,newundercarriage,</p><p>additionalfuelcapacityandslightlymorepowerfulCF-34engines.Theoriginal</p><p>CRJ-100series-the100,100ERand100LR-wasaugmentedbythe200series</p><p>(withmoreefficientengines)in1995.TheSeries200</p><p>isavailableinstandard</p><p>200,longrange200LRwithoptionalgreaterfuelcapacity,andtheextended</p><p>rangeSeries200LR(allthreeareofferedinBformwithCF34-3B1sfor</p><p>improvedhotandhighperformance).</p><p>Inthelate1980s,theregionalaviationmarketwasdominatedbyturboprop</p><p>airplanes.Someairlineswereanalyzingwhethertheintroductionofsmalljet</p><p>airplaneintoregularservicewouldbeviableornot.Favoringthejets,their</p><p>higherspeedsallowforhigherutilizationratebyairlines;jetaircraftalsoprovide</p><p>greaterpassengercomfortbecausetheyarequieter,faster,andpresentlower</p><p>vibrationlevelsinflight.Despitethemarketsignalsandmarketingdifficulties</p><p>thatEMBRAERwasexperiencingwiththetwin-turbopropCBA-123,which</p><p>shouldoffer350ktscruisespeedandaquietercabin,theSwedishcompany</p><p>SAABstillbetonthehigh-performanceturbopropairplaneafterthecommercial</p><p>successofitsSAAB340for34passengers.SAABbegandevelopmentofthe</p><p>twin-engine50-seaterSAAB2000inDecember1988.Toattacha400kts</p><p>promisedcruisespeed,thetypewasequippedwithtwo4,152shpAllisionAE</p><p>2100Aengines.Toreducethediscomfortcausedbynoiseoriginatedfrom</p><p>propellers,theSAAB2000incorporatedanactivenoisereductionsysteminthe</p><p>passengercabin,whichincluded72microphonesand36speakers.TheSAAB</p><p>2000twinturbopropbeganoperationwiththelaunchcustomerCrossairin1994</p><p>anditscommercialfailureledSAABtoleavethecivilaviationmarket.Atotal</p><p>of63exemplarsweresoldthelastaircraftwasdeliveredtoCrossairinApril</p><p>1999.UnlikeSAAB,EMBRAERbegandevelopmentofaregionaljet45seats</p><p>(later,thecapacitywasincreasedto50seats)aftersuggestionmadebythe</p><p>presidentoftheairlineAmericanAirlines,Mr.RobertCrandallin1989.The</p><p>unusualfirstconfigurationofthecalledEMB145wascharacterizedbyan</p><p>overwingengineconfiguration,aimingtoreducecostsbytakingadvantageof</p><p>theEMB120Brasiliawingandthefuselage.Thisconfigurationwasabandoned</p><p>becauseitwasunabletodeliveranyreasonableperformance.EMBRAERthen</p><p>consideredanunderwingconfiguration(Fig.2.40)fortheEMB-145butit</p><p>demandedevacuationslidesandwasalsoabandoned.</p><p>Fig.(2.40))</p><p>SecondconfigurationconsideredfortheEMB-145twinjetNotethewinglets,</p><p>whichwereremovedfromtheERJ145ERandLRversions(onlytheXR</p><p>featureswingletsinitsconfiguration).</p><p>Inthefirsthalfofthe1990s,acrisiscausedbytheFirstGulfWarplaguedthe</p><p>aviationindustry.Inaddition,EMBRAERwasexperiencinganothercrisis</p><p>becausetheoftheill-fatedCBA-123twinturbopropprogram.Thus,theEMB-</p><p>145programwassubstantiallydelayed.</p><p>TheEMB-145finallywasredesignedandtheengineswereplacedattherear</p><p>fuselage.Thetypeenteredoperationinearly1997withContinentalExpress.</p><p>Later,EMBRAERrenamedits50-seattwinjetERJ145.</p><p>Inthe2000s,EMBRAERportfoliogrewsignificantly.Itscommercialaviation</p><p>armexperiencedalargeexpansionwiththeintroductionofthesuccessful</p><p>EMBRAER170/175/190/195airliners,knownasE-Jetswhichpresentahigh</p><p>degreeofcommunalityamongtheairplanes.Thefirstproductofthefamilywas</p><p>theE170,whichenteredservicein2004withLOT,aPolishairline.EMBRAER</p><p>E175(Fig.2.41)isastretchoftheE170anditcanaccommodate88passengers</p><p>inasingleclasswithaseatpitchof29inches.</p><p>However,bothEMBRAERERJ145andCRJ-100/200werenotthefirstintheir</p><p>class.TheywereprecededbytheYak-40(Fig.2.42)andVFW-614.The</p><p>YakovlevYak-40,asmall,three-engineairliner,istheworld'sfirstcommuterjet</p><p>airplane.MaidenflightofYak-40wasperformedin1966.Introducedin</p><p>September1968,theYak-40wasexportedsince1970.Bythetimeproduction</p><p>endedinNovember1981,thefactoryatSaratovhadproducedoveronethousand</p><p>aircraft.</p><p>Fig.(2.41))</p><p>EMBRAERE175atSantosDumontAirportinRiodeJaneiro(Photo:©2013</p><p>BentoMattos).</p><p>Fig.(2.42))</p><p>Yak-40(Photo:Arpingstone,releasedtothepublicdomain).</p><p>TheVFW-Fokker614(alsoVFW614)wasatwin-enginejetairlinerdesigned</p><p>andbuiltinformerWestGermany.ItwasproducedinsmallnumbersbyVFW-</p><p>Fokkerinearly-tomid-1970s.ItwasoriginallyintendedasDC-3replacement.</p><p>Itsmostdistinctivefeaturewasthatit*enginesweremountedonpylonsabove</p><p>thewing.Thetypewaseclipsedbytheoilcrisesof1973.</p><p>AlthoughtheYak-40wassuccessfulintheformerSovietUnion,thisairplane</p><p>wouldbenotsuccessfulinamarket-orientedeconomydueitsthree-engine</p><p>configurationthatdoesnotenableaprofitableoperation.ThankstotheAirline</p><p>DeregulationAct,whichboostedregionalaviation,theEMBRAERand</p><p>Bombardierplanesmodifiedtheaviationlandscape.AirplanessuchasDouglas</p><p>DC-8andEMBRAERE-Jetsalsoperformedakeyroleinfirstandsecondjet</p><p>revolution,respectively.</p><p>NeedforSpeed</p><p>Thejettransportboostedtheairtravelbecausepeoplefeltstimulatedbyone-day</p><p>travels.Sincelargejetlinerscouldalsocarrymorepassengersthanpiston-</p><p>poweredairliners,airfaresalsodeclined.</p><p>Thepricetoflyinthehightransonicregimeoratsupersonicspeedsistheneed</p><p>toburnmorefuelbecause,amongotherreasons,therequiredthrustincreasesif</p><p>speedgoesup.Aircraftstructurebecomesheavierduetoneedtoresisthigher</p><p>loadsaswell,whichinturnrequiresenginesthataremorepowerful.Tokeep</p><p>fuelconsumptionwithinreasonablefigures,speedieraircraftcruisesathigher</p><p>altitudes.Thequestforevenfasterairplanesismotivatedtoprovidepassengers</p><p>shortertravelsandairlinesnewbusinessopportunities.However,economicsand</p><p>environmentalimpactshavehinderedtheprogresstowardssupersonicairliners.</p><p>AfterWorldWarII,therewasatrendtodevelopfasterairliners.Adolph</p><p>Busemann,aGermanaerospaceengineer,pioneeredtheconceptofsweptwings</p><p>in1935[50].Despitethis,BellX-1,anexperimentalaircraftwithstraightwings,</p><p>performedthefirstsupersonicflightinhistoryin1947[74].</p><p>In1958,Convair,acompanythatwassuccessfulmanufacturingpiston-powered</p><p>passengertransports,begandevelopmentofConvair990Coronado[75],which</p><p>wassupposedtobefasterthanthecompetition.Topspeedofimprovedversion</p><p>Coronado990Awas621mph,whichtranslatesintoMachnumberof0.925ata</p><p>cruisingaltitudeof41,000ft.Theconfigurationwasafasterandelongated</p><p>versionofConvair600[75].ThetypewaslaterredesignatedConvair990to</p><p>avoidtheinferencethatitwasanearlierversionofConvair880[75].Toincrease</p><p>thecriticalMachnumberandreducetransonicdrag,Coronadosufferedsome</p><p>redesignthatincorporatedfull-spanKrügerflapsatwingleadingedge,</p><p>Küchemannbodiesontheuppertrailingedgeofthewings(Fig.2.43),and</p><p>shorteroutboardenginepylons[75].Theaircraftneverliveduptoitspromiseof</p><p>coast-to-coastnonstopcapabilityfromJFKtoLAXandlaunchcustomer</p><p>AmericanAirlinesbegantodisposeoftheir990Asin1967[76].Only37</p><p>Coronadoswereproduced,bringingtheentireproductionofcommercialjet</p><p>airlinersbyConvairto102airframes.TheairlinerejectionofConvair880and</p><p>990ledtheConvairCompanytosufferwhatatthetimewasoneofthelargest</p><p>corporatelossesinhistory.</p><p>Fig.(2.43))</p><p>Convair990A.NotetheKüchmannbodiesoverthewingupperside,whichhad</p><p>onlyaerodynamicfunction(Photo:CourtesyNASA,publicdomain).</p><p>TheConvair990Aisstillthefastestnon-supersoniccommercialtransportto</p><p>haveeverbeenproduced.DuringMayof1961oneofthepre-production990</p><p>prototypeaircraftsetarecordof.97Machinlevelflightatanaltitudeof22,500</p><p>ft.,equivalenttoatrueairspeedof675mph[76].</p><p>TheConvairCoronadoairlinerwasconsiderablyfasterthanthecompetition,but</p><p>theEuropeansintendedtoflyevenfaster.TheBritishteamedwiththeFrench</p><p>andfoundedtheConcordeconsortiumtodesignandmanufactureasupersonic</p><p>airliner.Bothcountrieshad</p><p>beenworkingonownconceptssinceacoupleof</p><p>years.Aslender-delta-wingedconfigurationemergedfromtheinter-company</p><p>discussions.Thelong-andmediumrangeversionssharedthesameexternal</p><p>dimensions,buttheyhaddifferentinternallayouts.Themedium-rangeaircraft</p><p>couldaccommodate100passengersanditwouldhavea100-tonmaximum</p><p>takeoffweight;thelong-rangeversionhadacapacityof90passengersandanall</p><p>upweightof119tons.</p><p>Areviewwasmadeofthedesign,productionandresearchfacilitiesavailablefor</p><p>thejointproject,andgeneralagreementwasreachedontheallocationof</p><p>responsibilitiesbetweentheBritishAircraftCorporationandSudAviation.At</p><p>last,onNovember29,1962,anagreementwassignedinLondonbyJulian</p><p>Amery,MinisterofSupply,andGeoffroydeCourcel,theFrenchAmbassadorto</p><p>Britain,bywhichthetwogovernmentsundertooktofinancethedevelopment</p><p>andbuildingofasupersonicairliner[77].Everythingwouldbeshared-costs,</p><p>work,andproceedsofsales[77].Theairframeworkwasdivided60-40infavor</p><p>ofFrancebecausethebalanceofworkontheenginewasweightedinfavorof</p><p>Britain.ByNovember1962,theengineselectedfortheConcorde,the</p><p>supersonicversionoftheBristol-SiddeleyOlympus,wasalreadybeing</p><p>developed.Engineswereinexistenceandrunningonthetest-bed,andwhatever</p><p>adjustmentsmightbemadeinthenewprogramtoallowjointAnglo-French</p><p>developmentoftheOlympus593,theBritishworkcontentwouldbegreater</p><p>thantheFrench.</p><p>EarlyconsiderationsforConcorde’sconfigurationenvisagedtheuseoflow</p><p>aspectratiotrapezoidalwings.However,DietrichKüchemannattheRoyal</p><p>AircraftEstablishment(RAE)publishedaseriesofreportsonanewwing</p><p>planform,knownastheslenderdeltaconcept.Küchemann'steamworkedwith</p><p>thefactthatdeltawingscanproducestrongvorticesontheiruppersurfacesat</p><p>highanglesofattack.Thevortexcausesaconsiderablypressuredrop,raisingthe</p><p>liftcoefficient.Küchemann'spaperschangedtheentirenatureofsupersonic</p><p>designalmostovernight[78-80].Küchemannpresentedtheideaatameeting</p><p>whereMorienMorgan,directorofRAE,waspresent.Morganimmediately</p><p>backedthedeltawingasthesolutiontotheSSTproblemandthusConcorde</p><p>projectgainedmomentumanditwaslaunchedin1962.Anogivaldeltawing</p><p>configurationwasadoptedforConcorde(Fig.2.44).</p><p>DuetothehighspeedsatwhichConcordetravelled,largeforceswereappliedto</p><p>theaircraft'sstructureduringbanksandturns.Theresultingstressestwistand</p><p>distorttheaircraft’sstructure.Inaddition,therewereconcernsovermaintaining</p><p>precisecontrolatsupersonicspeeds.Allandotherissuesweredeeplystudied.A</p><p>scaledmodeloftheaircraftstructure(Fig.2.45)wasconstructedinFranceto</p><p>studystructuralvibrations.ThismodelwaslaterdonatedtoISAE(Institut</p><p>Supérieurdel'Aéronautiqueetdel'Espace).</p><p>TheConcordesupersonictransport(SST)airlinerneverfoundcommercial</p><p>successinregularflights.ItsserviceentrytookplaceinJanuary1976.After</p><p>decadesofregularservice,afatalcrashnearParisinJuly2000andotherfactors</p><p>eventuallycausedConcordeflightstobediscontinuedin2003.Thiswasthe</p><p>onlylossofanSSTinscheduledflight.Therewasfiercepublicoppositiontothe</p><p>operationofsupersonicairliners,noticeablyofConcorde.TheAnti-Concorde</p><p>Project,foundedbyRichardWiggs,challengedtheideaofviablesupersonic</p><p>passengertransport,andhelpedbringaboutare-evaluationofConcorde'slong-</p><p>termcommercialfuture[81,82].Thesupersonicairlinerwasdevelopedbased</p><p>ontheassumptionthatthesonicboomwouldposenoproblemandthat</p><p>populationwouldgetusedwiththenoise.</p><p>Fig.(2.44))</p><p>Concordesupersonicairliner(Photo:AdrianPingstone,releasedintothepublic</p><p>domain.ViaWikimediaCommons).</p><p>Tobetterunderstandthenoiseeffectsgeneratedbysupersonicairplanes,the</p><p>UnitedStatescarriedoutflighttestswithmilitaryairplanes.Theflightsrevealed</p><p>thatthesonicboomeffectsonpopulationarenotacceptable[82].Infact,</p><p>between1961and1962,150flightswereperformedoverStLouis,Missouri;in</p><p>1964,OklahomaCitywassubjectedto5monthsofsupersonicover-flights;in</p><p>1965,therewasfurthertestingoverChicago,Milwaukee,andPittsburgh;andin</p><p>1966–67atEdwardsAirForceBaseinCalifornia.Theflighttestsrevealedthat</p><p>sonicboomscouldbreakwindows,crackplaster,tileandbrick.Therewere</p><p>claimsforhundredsofthousandsofdollarsindamages.Inaddition,routine</p><p>exercisesflownbyUSAF(UnitedStatesAirForce)supersonicjetscausedmuch</p><p>damageannually:£3,800,000insonicboomdamageclaimswerepresentedto</p><p>theAirForceinathree-monthperiodin1967.Similarly,therewerecomplaints</p><p>andcompensationsforflightsclosetoOklahomaCityin1964[83].InJuly</p><p>1967,theUKMinistryofTechnologystagedaseriesofsupersonictestsover</p><p>SouthernEngland(usingLightningfighteraircraft),totalingelevenflights.No</p><p>officialarrangementsweremadetoinvestigatepublicreaction,butTheGuardian</p><p>newspapercommissionedapublicopinionsurvey,reportingthatpopulationof</p><p>Bristolwasfrightened[82].TheMinistryreceived12,000complaints.Between</p><p>1970and1972,whenConcordeno.2prototypeperformed20flightsoverthe</p><p>IrishSea,therewerereportsofdamageincludingcrackedandbrokenwindows,</p><p>slatesfallingfromroofs,panickingfarmanimalsandfrightenedchildrenand</p><p>adults.TheGovernmenthadtopay£40,000indamages[82].</p><p>Fig.(2.45))</p><p>A250kgmodelforvibrationstudiesofConcordestructure(Photo:©2012</p><p>BentoMattos).</p><p>BesidesConcorde,theonlyonesupersonicairlinerthatenteredserialproduction</p><p>wastheTupolevTu-144(Fig.2.46).TheSovietSSTfirstflewonDecember31,</p><p>1968nearMoscow,twomonthsbeforethefirstflightofConcorde.TheTu-144</p><p>firstsupersonicflightwasperformedonJune5,1969.OnMay26,1970,the</p><p>typebecamethefirstcommercialtransporttoexceedMachnumberof2.The</p><p>airplanestartedpassengerserviceonNovember1,1977,almosttwoyearsafter</p><p>Concorde.However,theTu-144fleetwaspermanentlydecommissionedafter55</p><p>scheduledflights.TheConcordeenteredoperationin1976andwasretiredin</p><p>2003.AirFranceandBritishAirwaysweretheonlyoperatorsofthetype.</p><p>Fig.(2.46))</p><p>TupolevTu-144L(Photo:CourtesyNASA/JimRoss).</p><p>TheUnitedStateshasinvestigatedsupersonictechnologyforciviltransportin</p><p>severalwavessincethelate1950s.Intheearly1960s,variousexecutivesof</p><p>NorthAmericanaerospacecompaniespubliclyaffirmedthattherewereno</p><p>technicalbarriersfortheintroductionofSSTsintoservice.Pressureon</p><p>congressionalrepresentativesincreasedwhentheConcordeprojectwaslaunched</p><p>in1962.CongressthenfundedaSSTprogramin1963,whichwouldbe</p><p>conductedbyFederalAviationAdministration(FAA).Inthefirstphase,</p><p>LockheedL-2000andBoeing2707conceptswereselectedamongproposals</p><p>frommanyaircraftmanufacturers.</p><p>BoeinghadstartedhisSSTsdesigneffortwithafour-engineconfiguration</p><p>featuringavariable-sweepwing,theBoeing2707-100.ByNovember1967,this</p><p>configurationhadgrownintotheBoeing2707-200.Thisairplanehada97m-</p><p>longfuselage,abletoaccommodate292passengers.</p><p>Theswing-wingdesignattemptstoexploitthehigh-liftcharacteristicsofa</p><p>primarilystraightwingwiththelow-dragcharacteristicsathighspeedsofa</p><p>sweepbackwing.Duringlandingandtakeoff,thewingswingsintoanalmost</p><p>straightposition.Duringcruise,thewingswingsintoapositionthatgivesita</p><p>highersweepangle.However,therearesomedrawbackscomingfromthe</p><p>utilizationofvariable-sweepwings,heavieraircraftandhighermaintenancecost</p><p>beingthemostsignificant.Thehingesthatenablethewingstoswingarevery</p><p>heavyandthehydraulicsystemispronetoleakage.Mainlyduetothesereasons,</p><p>Boeingdroppedoutthevariable-sweepwingin</p><p>favorofaconventionaldelta</p><p>configurationforits2707-300airplane[84].</p><p>TheaeronauticsandspaceagencyNASAwasalreadyinvolvedinresearchon</p><p>supersonicflightandhadresearchedseveralsupersonictransportconfigurations</p><p>already.NASAdesignSCAT-15F(Fig.2.47)[85]wasclosertotheBoeing2707-</p><p>300design.Thus,NASAselectedthefixed-sweepwingconfigurationfromthat</p><p>companyforcontinuedwork.OnMay1,1967,acontractforthePhase3ofthe</p><p>SSTprojectwassignedwithBoeing[86].Thecontractstipulatedthefirstflight</p><p>ofaSSTprototypein1970[86].WhenBoeingannouncedthedefinitivelayout</p><p>ofitsSST,twoversionswereofferedwithmaximumtakeoffweightofupto</p><p>360,000kg.Awide-bodyversionpresentedlowertakeoffweighttoreducethe</p><p>sonicboomoverpressureforflightsintheUnitedStates.Later,Boeingdiscarded</p><p>thenarrow-bodyversion.</p><p>Fig.(2.47))</p><p>NASASCAF-25SST(Photo:CourtesyNASAviaWikimediaCommons).</p><p>Althoughtheproductionissueshadnotbeenaddressedby1967,airlineswere</p><p>reservingpossibledelivery-linepositionsandbackingtheirorderswith</p><p>refundabledepositsofUS$750,000(1967Dollar)[86].Table2.3showsthe</p><p>BoeingSSTreservationsinNovember1967[86].PanAmevenpromoted</p><p>supersonicflightstotakeplacein1969inoneofitsadvertisem*nts.</p><p>Table2.3Boeing2707ordersbyNovember1967withrefundabledeposits[86].</p><p>Airline UnitsOrdered Airline UnitsOrdered</p><p>Aerlinte 2 ElAl 2</p><p>AirCanada 6 Iberia 3</p><p>AirFance 6 JAL 8</p><p>Air-India 3 KLM 3</p><p>Airlift 1 Lufthansa 3</p><p>Alitalia 6 Northwest 4</p><p>American 6 PanAmerican 15</p><p>Braniff 2 PIA 2</p><p>BOAC 6 Qantas 6</p><p>CPAL 3 TWA 10</p><p>Continental 3 United 6</p><p>Delta 3 World 3</p><p>Eastern 3</p><p>Total:115</p><p>Boeing2707-300wassupposedtoaccommodate320passengersandtopresenta</p><p>maximumcruisespeedclosetoMachnumberof3[84].Table2.4showsa</p><p>comparisonof2707-300characteristicswiththoseofBoeing707and747[87];</p><p>Fig.(2.48)illustratesthesizecomparisonamongtheSSTconceptsfromthe</p><p>1960s.</p><p>Table2.4MaincharacteristicsofBoeing707,747,and2707-300[84,87].</p><p>707 747-200 2707-300</p><p>MaximumOperatingMachNumber 0.84 0.90 2.70</p><p>TriptimeNewYork-Paris(h:min) 6:45 6:20 2:45</p><p>Passengercapacity 139-175 366-490 253-321</p><p>Cruisealtitude(ft) 32,000 35,000 62,000</p><p>Length(m) 46..3 70.7 90.8</p><p>Wingspan(m) 44.5 59.64 45.6</p><p>Wingaspectratio 7.1 6.96 2.66</p><p>Maximumtakeoffweight(kg) 151,300 377,840 340,200</p><p>Fig.(2.48))</p><p>ComparisonofSSTconceptsfromthe1960sanditsmaximumpassenger</p><p>capacity(samescale).</p><p>Technologicalchallengeswerenotovercome,whichdirectlyledtothe</p><p>terminationoftheSSTprogramattheendof1971.Someofthefactorsthat</p><p>playedakeyroleinthatdecisionwereconcernedfor:</p><p>highenginenoiselevels;</p><p>Pollutionofupperatmosphere,particularlyofozonelayer.</p><p>Fluttercharacteristics.Thesleekfuselageandrelativelylowpayload-to-gross</p><p>weightratiomadeadditionalstructuralweightormassbalanceparticularly</p><p>difficulttoincorporate.Theengine’scenterofgravityisfaraftofthemainwing</p><p>box.Thisisparticularlysignificantinthecaseoftheoutboardengines,which</p><p>areoutboardofthewingmidsemi-span.Thisconditionmayresultin</p><p>unfavorablewingboxbending-torsioncouplingwithattendantadverseflutter</p><p>characteristics.</p><p>Requirementsforstabilityaugmentationsystemsnotavailableatthattime.</p><p>Sonicboomoverpressure.</p><p>Lowrange/payloadcharacteristicscausedbyexcessivestructuralweight</p><p>fraction.</p><p>Highspecificfuelconsumption.</p><p>Lowlift-to-dragratio.</p><p>Economics.</p><p>In1972,Boeingcontinuedtostudyhigh-speedaircraft.Aresearchonhigh-</p><p>transonicairlinerswascarriedoutunderaNASAcontract[88].Theairplanewas</p><p>designatedHSCT,whichstandsforHighSpeedCivilTransport.Intheflight</p><p>regimestudiedbyBoeingCo.,thefreestreamMachnumberissupersonicbut</p><p>airflowinairplanevicinitiesischaracterizedformixedregions,definingthe</p><p>flowpatternastransonic.Certainly,thiswasanattempttoflyaboveMach1</p><p>withafeasibleairplane,intermsofeconomicsandenvironmentalimpacts.In</p><p>thisstudy,fivedistinctivedesignconceptswereelaboratedandcompared(Fig.</p><p>2.49),whichincluded:</p><p>Fig.(2.49))</p><p>ConfigurationsstudiedbyBoeingforaMach-1.2civiltransport[88].</p><p>Aircraftfixedsweptwing.</p><p>Aircraftwithvariable-sweepwing.</p><p>Adelta-wingairplane.</p><p>Twin-fuselageyawed-wingaircraft.</p><p>Single-fuselageyawed-wingaircraft.</p><p>TherequirementsfortheHSCTstudiedbyBoeingwere</p><p>CruiseMachnumberof1.2.</p><p>5560km(3000nm)range.</p><p>15EPNdBbelowFARPart36noiselevels.</p><p>Passengerpayloadof18,143kg(≡195passengers).</p><p>ThereportissuedbytheSeattleCompanyconcludedthataconfigurationthat</p><p>fulfilledtherequirementsposedbyNASAcouldbeachievedbythesinge</p><p>fuselageyawed-wingconfigurationwithagrossweightof226,796kg[88].A</p><p>configurationwithnegligibleboomeffectsshouldfeatureagrossweightof</p><p>211,828kg[88].Theoff-designsubsonicrangecapabilityforthisconfiguration</p><p>exceededtheMach1.2designrangebymorethan20%.Althoughwing</p><p>aeroelasticdivergencewasaprimarydesignconsiderationfortheyawed-wing</p><p>concepts,thegraphiteepoxywingsofthestudyweredesignedbycriticalgust</p><p>andmaneuverloadsratherthanbydivergencerequirements.Thetransonic</p><p>nacelledragisshowntobeverysensitivetothenacelleinstallation.Asix-</p><p>degree-of-freedomdynamicstabilityanalysisindicatedthatthecontrol</p><p>coordinationandstabilityaugmentationsystemwouldrequiremoredevelopment</p><p>thanforasymmetricalairplane,butitwouldbeentirelyfeasibleatthattime.A</p><p>three-phasedevelopmentplanwasrecommendedbyBoeingtoestablishthefull</p><p>potentialoftheyawed-wingconcept.</p><p>Tokeepongoingthesupersonicflighttechnology,theUnitedStatesstartednew</p><p>researchprogramsinthefirsthalfofthe1970s,afterthefailureoftheSST</p><p>commercialairplane.Interestonthesubjecthadalsothedevelopmentof</p><p>supersonicbombersasmotivation.Rockwellvariable-sweepB-1bomber</p><p>performeditsfirstflightin1974butstartedoperationonlymanyyearslater,in</p><p>1986.B-1AcouldreachspeedsaboveMachnumber2.</p><p>TheNationalAeronauticsandSpaceAdministrationinitiatedtheSupersonic</p><p>CruiseResearch(SCR)Programinfiscalyear1973atthedirectrequestofthe</p><p>ExecutiveOfficeofthePresidentandCongressfollowingterminationofthe</p><p>U.S.SSTprogram[89].Originally,theprogramwasentitledAdvanced</p><p>SupersonicTechnology(AST);thiswaslaterchangedtoSupersonicCruise</p><p>AircraftResearch(SCAR)and,finally,toSCR[89].FundingfortheSCR</p><p>Programendedinfiscalyear1981anditsimplementationwascarriedoutby</p><p>contractsandgrantswithindustryanduniversitiesandbyin-house</p><p>investigationsattheNASAOfficesofAeronauticsandSpaceTechnology</p><p>(NASA/OAST)[89].Thestudiesincludedsystemstudiesandfivedisciplines:</p><p>propulsion,stratosphericemissionsimpact,materialsandstructures,</p><p>aerodynamicperformance,andstabilityandcontrol.</p><p>Backtotheobliquewingconceptitcamefromstudiesfortheminimizationof</p><p>supersonicdrag.NASAAmesResearchCenterAeronauticalEngineerRobertT.</p><p>Joneselaboratedasimplifiedexpressionforminimumsupersonicdrag[90]:</p><p>(2.1)</p><p>Inthisexpression:</p><p>CD0isdezero-liftdragcoefficient;qisthedynamicpressure;Wistheaircraft</p><p>weight;M∞isthefreestreamMachnumber;bisthewingspan;Volistheoverall</p><p>volume;Sisthewingreferencearea;andlistheeffectivelengthoftheaircraft.</p><p>Fig.2.50showsacomparisonofdrag-due-to-volumeoftwodifferentwing</p><p>configurationswithsameaspectratioandsamemaximumrelativethickness</p><p>[90].</p><p>Fig.(2.50))</p><p>Volumedragfortwowingconfigurationsofsameaspectratioandsame</p><p>maximumrelativethickness[91].</p><p>IntheMachnumberrangeofFig.(2.50),thedragcoefficientoftheobliquewing</p><p>isconsiderablylowerthanthatpresentedbythehighly-sweptrectangular</p><p>wing.</p><p>Thisdragcomponentisdependentonthefourthpoweroftheeffectivelength.</p><p>Thus,consideringthattheoblique-wingconfigurationpresentsalongereffective</p><p>length,thisreflectsenormouslyonthatdragcomponent[91].Otherbasic</p><p>configuration-relatedfeaturescanbeeasilyderivedfromtheEq.2.1[91].First,</p><p>thetwowavedragtermsvaryinverselywiththelengthofthevehicle,meaning</p><p>thatalongersupersonicaircraftwilllowerthesetwocomponents.Sincetwoof</p><p>thetermsareproportionaltoqandtwoareproportionalto1/q,itisexpectedthat</p><p>theminimumdragatfixedliftwilloccuratanaltitudethatmakestheviscous</p><p>plusvolumewavedragtermsequaltothelift-dependentterms[91].Ofcourse,</p><p>aircraftusuallyflylowerthanthisaltitudeduetoReynoldsnumbereffectson</p><p>CD0,propulsionsystemperformance,andstructuralimplications(pressurization</p><p>loadsonthefuselage,forexample).</p><p>Eq.2.1indicatedthatoblique-wingconfigurationshaveapotentialfor</p><p>supersonicflight.Inaddition,windtunnelstudiescarriedoutatNASA</p><p>Amesconfirmedthatanobliquewingdesignonasupersonictransport</p><p>mightachievetwicethefueleconomyofanaircraftwithconventional</p><p>wings.Nextstepwastheinvestigationofanoblique-wingconfigurationin</p><p>flighttests.Analyzingintermsoftheoverallaerodynamicsofthe</p><p>configuration,thewavedragreductionoftheobliqueairplaneconceptis</p><p>eclipsedbythedominantvolumewavedragofthefuselage[91].Thisledto</p><p>asubsequentfocusonobliqueflyingwings.Itisworthyofmentionthatthis</p><p>conclusionwasbasedonaerodynamicconsiderationsonlyanditis</p><p>reasonablethatmulti-disciplinaryaspectsshouldbeconsideredinstead.</p><p>Anyway,NASAdesignedandbuiltaresearchairplanefortthatpurpose,</p><p>whichwasdesignatedAD-1,abbreviationofAmes-Dryden-1.Thewing</p><p>couldberotatedonitscenterpivot,sothatitcouldbesetatit*most</p><p>efficientangleforthespeedatwhichtheaircraftwasflying.Theoblique</p><p>wingontheAD-1pivotedaboutthefuselage,remainingperpendiculartoit</p><p>duringslowflightandrotatingtoanglesofupto60oasaircraftspeed</p><p>increased.AnalyticalandwindtunnelstudiesthatJonesconductedatAmes</p><p>indicatedthatatransport-sizedoblique-wingaircraftflyingatspeedsofup</p><p>toMachnumberof1.4(1.4timesthespeedofsound)wouldhave</p><p>substantiallybetteraerodynamicperformancethanaircraftwith</p><p>conventionalwings[92].TheaircraftwasdeliveredtotheDrydenFlight</p><p>ResearchCenter,Edwards,California,inMarch1979anditsfirstflightwas</p><p>onDecember21,1979.TheAD-1flewatotalof79timesduringtheresearch</p><p>program.TheAD-1programachievedallitstechnicalobjectives.However,</p><p>thevehicleexhibitedaeroelasticandpitch-roll-couplingeffectsthat</p><p>contributedtopoorhandlingatsweepanglesabove45degrees.After</p><p>completionoftheAD-1project,therewasstillaneedforatransonic</p><p>oblique-wingresearchaircrafttoassesstheeffectsofcompressibility,</p><p>evaluateamorerepresentativestructure,andanalyzeflightperformanceat</p><p>transonicspeedsoneithersideofthesoundbarrier.</p><p>NASAstudiescarriedoutin1995[93]dealtwiththedevelopmentofadatabase</p><p>ofaircraftfuelburnedandemissionsfromprojectedfleetsofhigh-speedcivil</p><p>transports(HSCTs)onahypotheticaluniversalairlinenetwork.The“Universal”</p><p>HSCTroutesystemismeanttosimulatetheoperationofHSCTsasamature</p><p>fleetinaglobalairlinenetwork.The“Universal”systemwasthesumofseveral</p><p>globalairlines,althoughitscheduledasifitisasingleairline.Inventoriesfor</p><p>500and1000HSCTfleetswereconsideredforthisstudy.Extrapolated</p><p>inventoriesfortheyear2015subsonicaircraftfleetsinservicewiththeseHSCT</p><p>fleetswerealsocalculated.Theobjectiveoftheworkwastoevaluatethe</p><p>changesingeographicaldistributionoftheHSCTemissionsasthefleetsize</p><p>grewfrom500to1000HSCTs.Forthiswork,flightswereprojectedusinga</p><p>marketpenetrationanalysisratherthanassumingequalpenetration.Emission</p><p>inventoriesonthisnetworkwerecalculatedforbothMach2.0andMach2.4</p><p>HSCTfleetswithNOxcruiseemissionindicesofapproximately5and15grams</p><p>NOx/kilogramfuel.Fuelburnedandemissionsofnitrogenoxides(NOxas</p><p>NO2),carbonmonoxide,andhydrocarbonshavebeencalculatedona1-degree</p><p>latitudex1-degreelongitudex1kilometeraltitudegrid.</p><p>TheNASAstudyconcludedthatthegeographicaldistributionofemissionsat</p><p>stratosphericcruiseissensitivetothemarketpenetrationassumptionsusedto</p><p>distributeprojectedHSCTpassengerdemand.AnincreaseinHSCTfleetsize</p><p>from500to1000unitsapproximatelydoubledemissionsatstratosphericcruise</p><p>[93].However,asthefleetgrows,emissionsindifferentgeographicalregions</p><p>growatdifferentrates.Consequently,stratosphericemissionsinnorthernmid-</p><p>latitudesarenotprojectedtodoubleasthefleetsizedoubles,whileemissionsin</p><p>thenortherntropicsandsouthernhemispheremid-latitudesareexpectedtomore</p><p>thandouble[93].ForanHSCTcombustorwithaNOxemissionindexof5,the</p><p>analysesshowedthatthetotalNOxemissionsbelow13-kilometeraltitudeare</p><p>notverysensitivetothepresenceorabsenceofanHSCTfleet[93].This</p><p>suggeststhattofirst-ordertheassessmentoftheeffectsofanHSCTfleetare</p><p>largelydecoupledfromtheassessmentofsubsonicaircrafteffects.Detailsofthe</p><p>resultsfordifferentflightsegmentsfortheMach2.0HSCTfleetsare</p><p>summarizedinTable2.5.</p><p>Table2.5Dailymileage,fuelconsumption,NOxemissions,andNOXemissions</p><p>indexfortheMach-2HSCT[93].</p><p>FlightSegment DailyMileage(nm) DailyFuel(1000lb) DailyNOx(1000lb)</p><p>Taxi 0 5,752 40</p><p>Initialclimb 87,860 36,689 297</p><p>Supersonicclimb 482,933 66,765 541</p><p>Supersoniccruise 6,079,332 367,116 1,925</p><p>Supersonicdescent 197,106 1,375 10</p><p>Subsoniccruise 562,131 32,536 214</p><p>Finaldescent 319,578 11,818 83</p><p>Taxiin 0 2,222 16</p><p>Total 7,728,940 524,273 3,125</p><p>MODERNAIRLINERS</p><p>Airlinersarecommonlysplitdownintothreecategories:long-haulairplanes,</p><p>wide-bodyjetairliners,andshort-haulcivilianpassengerairliners.Inturn,the</p><p>short-haulcivilianpassengerjetsarebothlongerandshorterrangednarrow-</p><p>bodyjetandregionaljettypes.Table2.6showssomecharacteristicsofrelevant</p><p>airlinessincetheintroductionofDC-3.</p><p>Table2.6Evolutionofairlinercharacteristicsovertime.EISmeansEntryinto</p><p>Service.</p><p>Aircraft EIS Speed(km/h) Max.Range(fullpayload,km)</p><p>DouglasDC-3 1936 346 563</p><p>DouglasDC-7 1953 555 5,810</p><p>Boeing707-120 1958 917 4,300</p><p>Boeing727-100 1963 869 5,000</p><p>Boeing747-100 1970 907 9,800</p><p>McDonnellDouglasDC-10 1971 908 7,415</p><p>AirbusA300 1974 847 3,420</p><p>Boeing767-200 1982 913 7,130</p><p>Boeing747-400 1989 912 13,450</p><p>Boeing777-200LR 1995 905 15,840</p><p>AirbusA340-500 2003 896 16,020</p><p>EMBRAERE170STD 2004 890 2,220</p><p>AirbusA380 2007 945 15,700</p><p>Boeing787-8 2011 913 13,620</p><p>Fig.(2.51)showsaphototakenataDaimler-BenzAerospaceAG(DASA)stand</p><p>duringtheInternationaleLuftfhartaustellung(ILA)in1992.Thisimagereveals</p><p>someinterestingairplaneconcepts:</p><p>Fig.(2.51))</p><p>DaimlerBenzAerospacestandatILA1992(Photo:©1992BentoMattos).</p><p>SupersonicCivilTransport(SCT).Inearly1990s,BritishAerospace,Deutsche</p><p>Airbus,Boeing,andMcDonnelDouglasteamedtoinvestigatetheviabilityofthe</p><p>introductionofa2ndgenerationsupersonicciviltransport(SCT).Thestudyfor</p><p>theSCTaddressedthesizeofthemarketandthetechnicalstandardsrequiredto</p><p>produceanenvironmentallyacceptableandcommerciallyviableairplane[94].</p><p>Regioliner.Itwasacompanyformedin1992commajorityparticipationof</p><p>DASA,theAerospatialeandAleniabeingtheremainedpartners.Theintended</p><p>todevelopandmarketairlinersrangingfrom30to120seats.AtILA1992,the</p><p>twoscaledmodelsondisplayaretheR72andR122,abletoaccommodate70</p><p>and120passengers,respectively.Regiolinertried</p><p>toestablishwithoutsuccessa</p><p>partnershipwithFokker,whichwasdeveloping70-and130-seatairlinersatthat</p><p>time.TheR72andR122programswerethenlatercancelledandotherDASA</p><p>subsidiary,DornierLuftfahrtGmBH,startedtodevelopthe70-seatairlinerin</p><p>1997,whichwasdesignated728Jet.Alargervariantof728Jetshouldfollow,the</p><p>928Jet.However,beforethefirstflightofthe728Jetcouldbeperformed,</p><p>FairchildDornierfiledforinsolvencyonApril2nd,2002,andthewhole</p><p>programcametoanend.The728Jetprototypeswerescraped.</p><p>Hydrogen-fueledaircraft.AftertheTupolevTu-155technologydemonstrator</p><p>aircraftsuccessfullyflewin1988poweredbyturbofansburningliquidhydrogen</p><p>andliquidnaturalgas,DASAsignedanaeronauticalcooperationagreement</p><p>withRussia.Thisagreementproducedasetofprojectsonalternativefuelsfor</p><p>aircraft[95]:</p><p>German/RussiafeasibilitystudyaboutacryogenicairplanebasedontheAirbus</p><p>A321airframe(1990/1993),</p><p>combustionchambertests(1992/1996),</p><p>EU/INTAStanktests(1994/1999),APUtests,</p><p>1995/98German/RussianstudiesforademonstratoraircraftbasedonDo328.</p><p>AconceptforAirbusA380.DASAA2000providesaninsightoftheovoidcross-</p><p>sectionanddouble-deckconfigurationthatwasadoptedfortheA3XXprogram.</p><p>SomeideasofDASAA2000weremergedwithothersfromtheAerospatiale</p><p>A500/600andBritishAerospaceAC14tocreatetheAirbus3Econfiguration.</p><p>TheAirbusA380resultedfromalltheseconsiderations[96].Double-deck</p><p>conceptswerealsoconsideredbybothBoeing(VLCT)andMcDonnelDouglas.</p><p>(MD-12)inthe1990s[96].</p><p>TheAirbusA380conceptevolvedintoadouble-deck,wide-body,four-engine</p><p>jetairlinermanufacturedbytheEuropeanaircraftcompanyAirbus(Fig.2.52).It</p><p>istheworld'slargestpassengerairliner,andtheairportsatwhichitoperateshave</p><p>upgradedfacilitiestoaccommodateit.ItwasinitiallynamedAirbusand</p><p>designedtochallengeBoeing'smonopolyinthelarge-aircraftmarket.TheA380</p><p>madeitsfirstflighton27April2005andenteredcommercialserviceinOctober</p><p>2007withSingaporeAirlines.</p><p>Fig.(2.52))</p><p>AirbusA380atCharlesdeGaulleAirport(Photo:©2012BentoMattos).</p><p>AccordingtoAirbus,theA380'smaininstrumentpanelincorporateseight</p><p>identicalandinterchangeableliquidcrystaldisplayUnits,providingaprimary</p><p>flightdisplay,navigationdisplay,twomulti-functiondisplays,anenginewarning</p><p>displayandasystemdisplay[97].Theirincreaseddisplaysizeprovides</p><p>improvedsituationalawarenessforpilots,andallowsforsuchenhanced</p><p>presentationmodesasaverticalsituationawarenessfunctionthatpresentsa</p><p>“verticalcut”oftheaircrafttrajectoryintegratingflightpath,terrainandweather</p><p>information[97].AkeyA380innovationistheuseofanelectroniclibraryto</p><p>avoidpaperdocumentationtobeusedbypilots.Thislibraryallowsflightand</p><p>maintenancecrewstoeasilylocateoperationalinformationinthevariousflight</p><p>manuals,listsandlogbooks,whileenablinganoptimizationofperformanceand</p><p>weight-and-balancecomputations[97].Table2.7listssometechnological</p><p>advancesinflightphysics.Someofthestructuraltechnologiesemployedin</p><p>A380are:</p><p>Glare®forpartofupperfuselage;laserbeamweldingforlowerfuselage;CFRP</p><p>forwingribs;CFRPwingbox;flaptrackfairingsinCFRP(Resintransfer</p><p>molding);CFRPforthehorizontaltailplane;CFRPrearpressurebulkhead;finite</p><p>elementanalysiswithgloballoadbehavior.</p><p>TheBoeing787airlinerisalong-range,twin-aislecommercialtransport</p><p>developedbyBoeingCommercialAirplanes(Fig.2.53).Itsvariantsseat242to</p><p>335passengersintypicalthree-classseatingconfigurations[98].Thisairplaneis</p><p>themostfuel-efficientairlinerthatBoeingeverproduced.Itisapioneering</p><p>airlinerwiththeuseofcompositematerialsastheprimarymaterialinthe</p><p>constructionofitsairframe.The787wasdesignedtobe20%morefuelefficient</p><p>thantheBoeing767,whichitwasintendedtoreplace.Boeing787wasfitted</p><p>withbleed-lessenginesandthereforeairsupplytoitsinteriorisprovidedbya</p><p>powerstationthatcompressesexternalair.TheBoeing787distinguishing</p><p>featuresincludemostlyelectricalflightsystems,rakedwingtipsfordrag</p><p>reduction,compositefuselageandwings,andnoise-reducingchevronsonits</p><p>enginenacelles.ItsharesacommontyperatingwiththelargerBoeing777to</p><p>allowpilotstobecertifiedinoperatingbothmodels[98].</p><p>Table2.7A380innovativetechnologiesinflightphysics(Source:Airbus).</p><p>Integratedwingdesign Inboardwingwithhigherloadsprovided4-tonweightsavingforaslightincreaseininduceddrag</p><p>Wake-vortexprediction Methodologyforwake-vortexpredictionwasvalidated.ItenabledtheAirbusairplanetopresentthesamesignatureofthatgeneratedbyBoeing747</p><p>Advancedloadcontrol Wingweightreductionof2.2tthankstoadditionalimprovementsinloadcontrol(fatigue/maneuver/turbulencewingloadalleviation)</p><p>Advancedenginenacelle Significant(100kg)weightreductionfortheanti-icesystem;reducedmaintenance</p><p>Optimaltailplanes Variablethicknessdistributionforthehorizontalandverticalsaved350kgandprovidedslightdragreduction</p><p>Droopedairfoils Higherlift-to-dragratioattakeoff</p><p>High-Reynoldsnumberperformanceestimationfromwind-tunneldata Betterperformancepredictionandthereforelowermarginsforperformanceguarantee</p><p>Fig.(2.53))</p><p>ArtisticviewofBoeing787.</p><p>GROUNDEFFECTAERIALVEHICLES</p><p>Manyattemptshavebeenmadetobuildaerialvehiclesbasedonwinginground</p><p>effect(WIG).Boeingreleasedaconceptinthe1990s,calledPelicanUltraLarge</p><p>TransportAircraft.IntheSovietUnionera,itwasdesignedtheso-called</p><p>Ekranoplan.TheA-90Orlyonokisoneofthemanditusesgroundeffecttoflya</p><p>coupledofmetersabovethesurface,waterorland.RussiancategorizeOrlyonok</p><p>asanEkranoplanClassB-itcanachieveanaltitudeof3,000m,placing</p><p>betweenClassA-whichislimitedtogroundeffect,andClassC,whichexploits</p><p>thegroundeffectonlyduringtake-offsandlandings[99].</p><p>ThelayoutoftheenginesontheOrlyonokwasunusualandatestamentofthe</p><p>specialneedsofsuchanunconventionalaircraft.Mountedinthetopofthetail,it</p><p>featuredamassiveKuznetsovNK-12turboprop,themostpowerfulturbopropto</p><p>findservice.Thisengineprovidestherequiredcruisepower.Twoturbofan</p><p>enginesareintheaircraftnose,withtheintakesontopofthenosetoprevent</p><p>wateringestion.Theirexhaustsareplacedsidewaysalongtheforwardfuselage</p><p>andthethrustproducedbythejetenginesarevectoredoverthewingstoproduce</p><p>increasedliftandtherequiredpropulsionattakeoff.Undercruiseconditionsand</p><p>ingroundeffect,thefrontenginescouldbeshutoffsincetheirpowerwas</p><p>unnecessarytokeeptheaircraftlifted,thisalsominimizedintakeofwater,salt</p><p>andingestionoflowflyingbirds.</p><p>SouthKoreadevelopedtheAronM50,capableofan800-kmrangeinground</p><p>effect.Themachinepresentsatopspeedof200km/handisemployedincoastal</p><p>patrolbySouthKorea.EquippedwithOptronicssystemsandasmallnaval</p><p>radar,anarmedAronM50canfiresmallanti-shipmissilesorguidedrocketsto</p><p>attacklargerships.</p><p>TheWingShipTechnologyCorporation,aSouthKoreancompany,developeda</p><p>turbopropvehiclecantransport50passengers,whichwasdesignatedWSH-500.</p><p>Ithasacatamaran-stylehullandareverse-deltawing.Cruisingat180km/h,</p><p>makesitfasterthanajetfoil,itsprincipalrival,andtheproductionversionwill</p><p>havearangeof1,000km.Table2.8comparestheWSH-500andOrlyonokwith</p><p>bigairliners[100].TheWSH-500hasaverysmallrangewithfullpayloadbut</p><p>thevehiclereaches1,000kmwithapayloadof22passengers[101].</p><p>TheSouthKoreancompanybelievesthatthereverse-deltawingiskeysolution</p><p>toturnWIGvehiclesintoviablemeanoftransportation.Thisapproachwas</p><p>devisedin</p><p>engineer</p><p>notrestricthimself/herselftohis/heredisciplinewherehe/shecarriesouthis</p><p>workbutthat,he/shecanalsounderstandthecontextoftheaeronautical</p><p>industry.</p><p>Thecontinuousincreaseincomputerspeedandcapacityhasallowedfinite-</p><p>elementmethodsforallstructurallayout,cabinconfiguration,andCFDmethods</p><p>tobeincorporatedintheconceptualdesignphasealready.Itispossibleto</p><p>integratethedifferentdesignboundaries,suchashighspeedandlow-speed</p><p>aerodynamics,andasafollow-upstep,todaythemultidisciplinarymethods</p><p>permitanaircrafttobedesignedbyintegrationofaerodynamic,structuraland</p><p>flightmechanicsdesignconstraintsandbyusingmultidisciplinaryoptimization</p><p>methodologies.Multi-disciplinarydesignandoptimizationisthemoderndesign</p><p>methodologyformanyaircraftdesignfeaturesandaspectsandnearlyallpapers</p><p>onaircraftdesignnowusesomesortofmultidisciplinaryoptimizationapproach.</p><p>Futureairplanesneedtocomplywithnewandmorestringentenvironmental</p><p>rules.Newchallengeswithregardtoperformanceandenergeticefficiencymay</p><p>reshapethetoday’sairplanesentirely.Theexplorationofnewbusiness</p><p>opportunitiesforaviation,whichmayalsoaffectairplaneconfiguration,is</p><p>addressed.Thisbookpresentsemissionandnoisemodelsthatwereemployed</p><p>foroptimaldesignairlinersofdistinctcategories.Thereisatrendtopower</p><p>groundvehicleswithelectricengines.Thiswillchangetheshareofaviationin</p><p>emissionsandthewaypublicdealswithit.</p><p>Finally,postdesigntechniquesanddevicestoimproveaircraftperformanceand</p><p>efficiencybyimprovedandrethoughtaircraftoperationsarepresented.</p><p>Mitigationofdesignflawsareanalyzedanddiscussed.</p><p>BentoS.deMattos</p><p>AircraftDesignDepartment</p><p>InstitutoTecnológicodeAeronáutica(ITA)</p><p>SãoJosédosCampos,SãoPaulo</p><p>Brazil</p><p>E-mail:greenfutureaviation@gmail.com</p><p>CONSENTFORPUBLICATION</p><p>Notapplicable.</p><p>CONFLICTOFINTEREST</p><p>Theauthorsdeclarenoconflictofinterest,financialorotherwise.</p><p>ACKNOWLEDGEMENTS</p><p>WethankFinanciadoradeEstudoseProjetos(FINEP)asupporttechnology</p><p>agencybelongingtoBrazilianfederalgovernmentfortheProjectCAPTAERII,</p><p>whichprovidedresourcesandequipmentsutilizedinthepresentwork.</p><p>NOTICE</p><p>Allrightsreserved-©2018BenthamScience.Thismaterialwaselaboratedfor</p><p>educationpurposesandismainlyintendedtothediffusionofaeronautical</p><p>knowledge.Ifsomeonebelievesthatsheorhedeservestobepartofthe</p><p>bibliographyofthiswork,pleasecontacttheeditorat</p><p>greenfutureaviation@gmail.com.</p><p>Brandnamesandproductnamesusedinthismaterialaretradenames,service</p><p>marks,trademarksorregisteredtrademarksoftheirrespectiveowners.The</p><p>editororauthorsofthepresentworkarenotvendorsortheydonotendorseany</p><p>productmentionedorusedinthechaptersofthise-Book.Theaircraft</p><p>manufacturersmentionedinthebookdidnotinfluencetheelaborationofthe</p><p>presentmaterialorhaveanydirectrelationwithitscontent.</p><p>Theauthorsandtheeditorexertnocontrolonthecontentortakeresponsibility</p><p>forpagesmaintainedbyexternalproviders.</p><p>LimitofLiability/DisclaimerofWarranty:Whiletheauthorshaveusedhisbest</p><p>effortsinpreparingthismaterial,theymakenorepresentationsorwarranties</p><p>withrespecttotheaccuracyorcompletenessofthecontentsofthisbookand</p><p>specificallydisclaimanyimpliedwarrantiesofmerchantabilityorfitnessfora</p><p>purpose.Itisdistributedontheunderstandingthattheauthorsarenotengagedin</p><p>renderingprofessionalservicesandneitherthepublishernortheyshallbeliable</p><p>fordamagesarisingherefrom.Ifprofessionaladviceorotherexpertassistanceis</p><p>required,theservicesofacompetentprofessionalshouldbehired.</p><p>MATLAB®isatrademarkofTheMathWorks,Inc.andisusedinsomepartsof</p><p>thise-Bookbylicensedandthereforelegalsoftware.Wedonotwarrantthe</p><p>accuracyofthetextorexercisesinthisbook.Thisbook’suseordiscussionof</p><p>MATLAB®softwareorrelatedproductsdoesnotconstituteendorsem*ntor</p><p>sponsorshipbyTheMathWorksofapedagogicalapproachoruseofthe</p><p>MATLAB®software.Thesameappliestoothersoftwarepackageslike</p><p>modeFrontier®andAnsys®,whichwerealsoemployedinsomecomputations</p><p>describedinthepresente-Book.</p><p>WethankinstitutionslikeNASAandUnitedStatesAirForceMuseumthat</p><p>releasetothepublicdomain,alargephotocollections.Thiskindofinitiative</p><p>contributesenormouslytowidespreadaerospaceknowledgeandhelptoinspire</p><p>younghearts.</p><p>Partofthecomputationsusedinthepresentworkwerecarriedoutwith</p><p>hardwareandsoftwarepurchasedwithsupportoftheBrazilianfederalagency</p><p>FinanciadoradeEstudoseProjetos(FINEP)throughtheprojectCAPTAERII.</p><p>AviationandtheEnvironment</p><p>BentoSilvadeMattos,JoséAlexandreT.G.Fregnani</p><p>Abstract</p><p>Thepresentchaptercontainsinformationabouttheimpactofaviationonglobal</p><p>warminganddescribestheindustrycommitmentstoreducegreenhousegas</p><p>emissions.ThischapteralsoanalysesICAO’seffortsinestablishinggoalsand</p><p>timeframe-carbonneutralby2020and50%reductionon2005baseline-to</p><p>statesandindustrytoreduceaviationpollution.Asolid“FourPillar”initiative</p><p>wassetbytheindustrywiththeobjectivetoaddresssuchatarget,considering</p><p>investmentsinoperationalprocedures,infrastructure,technologyandmarket-</p><p>basedmeasures.Accordingtotherecentstudies,operationalproceduresand</p><p>improvementsininfrastructuremaynotbesufficienttoaccomplishtheICAO</p><p>goalswithcurrenttechnologicalstateofart.Innovativetechnological</p><p>developments,mainlyrelatedtonewairframeandenginedesignsandconcepts</p><p>areindeedconsideredthemosteffectiveandpromisingmeasureswithpotential</p><p>toleadtofuelefficiencyimprovementsupto25%whencomparedwith2005</p><p>levels.Withthisperspective,fuelefficiencyisbecomingmoreandmorerelevant</p><p>inaircraftdesigntechniques.Electricalvehiclesmaybeaconsiderably,ifnot</p><p>entirely,apartofthegroundtransportationfleetincomingdecades.Astudywas</p><p>undertakeninthepresentworktoestimatethepercentageofaviationinCO2</p><p>emissionsandnoiselevelsconsideringasteadilyincreasingfleetofelectrical</p><p>vehiclesovertime.Theevidentconclusionisthatevenwhenintroducing</p><p>biofuelsinaviationoperations,theirshareinpollutioncomparedtopresent</p><p>levelswillstillsteadilyincreaseandtakeupahugepercentageofall</p><p>transportationpollution.Thiswillbeanongoingprocessuptotheyear2050</p><p>despitetheoverallemissionreductions.Inotherwords,thereisconsiderable</p><p>evidencethataviationwillbemoreandmoreinfocus(andsocial-political</p><p>pressure)throughouttheyearsregardingtheGHGemissions.Thisfact</p><p>obviouslyreinforcesthenecessityforimprovementsinaircraft/enginedesigns,</p><p>alternativemotorization,andothersourcesofenergytoempoweraircraft</p><p>systemsandimproveoperationalefficiencies.</p><p>Keywords:Aviation,Aircraftdesign,Aircraftemissions,Electriccar,</p><p>Environment,Fuelefficiency,Globalwarming.</p><p>AVIATIONANDENVIRONMENT</p><p>TheClimateChangeandAirTransport</p><p>Transportationplaysavitalroleforworldeconomy.Withinthetransportation</p><p>sector,commercialaviationhasevolvedfromthe1960stopresentdaysintothe</p><p>fastest,safestmeansoftransportandaglobaltransportationmode.Nowadays,</p><p>over3billionpeople,nearlyhalftheworld’spopulation,usetheregularair</p><p>transport,whoseindustrygeneratesonaworldwidescale56millionjobs,both</p><p>directandindirect[1].Aircraftcarryonly0.5%oftheworldtradeshipments,</p><p>whichrepresentsabout35%ofthevalueofallworldtrade.Thisproductivityis</p><p>achievedbyconsumingjust2.2%oftheworldenergy[1].</p><p>Regardlessoftheworld’sdependencyonairtransport,thepollutionitcauses</p><p>justasmuchasothermeansoftransportation,isamatterofgreatconcern,</p><p>especially</p><p>the1960sbyAlexanderLippischandHannoFischer,thelattera</p><p>designerofFanliner,anexperimentalGermanlightaircraftofthe1970s,</p><p>propelledbyapistonenginedrivingaductedfan.However,theirsingle-seater</p><p>Aerofoilboot,astheydubbedit,wasnotacommercialsuccess.However,Wing</p><p>ShipTechnologybelievestheideaofadeltawingisrevolutionary.Thedelta</p><p>wing’sgeometryamplifiesthegroundeffect,allowingthevehicletocruisefive</p><p>metersabovethewater’ssurface.Thatmeansitislesslikelytobeconfinedto</p><p>harborbyroughseas,whichwasoneoftheproblemsencounteredbyprevious</p><p>designs.Italsolaunchesitselfbydirectingsomeoftheairflowfromtheturbo</p><p>propsdownwards,tocreateatemporaryhovercrafteffectuntilitistravelling</p><p>forwardsatfulltilt.Thedifficultyofgettingairbornewasanotherbugbearof</p><p>previousdesigns.ItremainstobeseenwhetherWingShipTechnology’scraft</p><p>willbethebreakthroughthatenthusiastsofground-effectvehiclesarehoping</p><p>for.</p><p>Table2.8Wingingroundeffectvehiclescomparedwithbigairliners[100].</p><p>Orlyonok WSH-500 Boeing747-400ER</p><p>Length(m) 58 29 70.6</p><p>Wingspan(m) 31.5 28 64.4</p><p>MTOW(tones) 140 17.1 412.8</p><p>Cruisealtitude(m) 0.5-5 2-5 13,747</p><p>Cruisespeed(km/h) 370 175 900</p><p>Payload(tones) 20 4.3 112.7</p><p>Rangewithmax.payload(km) 1,000 50 14,205</p><p>Wingaspectratio 3.0 2.5 7.4</p><p>Installedpowerorthrust 2x10t1x15000hp 2x1,400hp 4x282kN</p><p>WingShipTechnologyadvocatesthattheirvehiclepresentsmoreadvantagesin</p><p>regardfuelconsumptionandCO2emissions(Table2.9).</p><p>Table2.9FuelburnandCO2emissionsofseveralmeansoftransportation[101].</p><p>MeanofTransportation CruiseSpeed[km/h] CO2Emission[g/(pax.km)]</p><p>Ferry 46 396</p><p>75-seatairliner 800 106</p><p>WSH-500WIGvehicle 180 94</p><p>TheBe-2500super-heavytransportseaplane(Fig.2.54)isaconceptaircraftof</p><p>RussianBerievtargettoperformspecializedservicetransportationon</p><p>transoceanicroutes[102].Thedesignconceptofsuper-heavyseaplaneallows</p><p>operatetheaircraftbothingroundeffectmodeabovetheoceanandusual</p><p>airplaneoperation.TheBe-2500mayalsobeusedforlandingoperations,search</p><p>andrescuemissions,aswellasthevehicleforprospectingandextraction</p><p>operationsatshelvesandarchipelagosareas[102].Thefacilitiesofexisting</p><p>majorportsmayprovidesufficientsupportforoperationandanchorageofthe</p><p>seaplane.Table2.10presentssomedataforBe-2500.</p><p>Fig.(2.54))</p><p>Beriev2500conceptcomparedtotheOrlyonokekranoplan.</p><p>Table2.10BerievBe-2500specifications(Source:BerievAircraftCompany</p><p>Website).</p><p>Wingspan 125.51m</p><p>Wingarea 3,184m²</p><p>Aircraftlength 115.5m</p><p>Aircraftheight 29.12m</p><p>Maximumtake-offweight 2,500t</p><p>Maximumpayload upto1,000t</p><p>Cruisespeed:-high-altitudeflightmode-WIGflightmode 770km/h450km/h</p><p>Maximumrange 16,000km</p><p>ALTERNATIVEFUELANDPOWER</p><p>Beforeairplanesbecametechnologicallyadvancedforanon-stopping</p><p>intercontinentalcrossing,airshipsperformedthisrole.TheGrafZeppelin(Fig.</p><p>2.55),anairshipdesignedbytheGermancompanyZeppelinLuftschiffbau,</p><p>madetheveryfirstcommercialpassengerflightacrosstheAtlantic.Theaircraft</p><p>departedfromFriedrichshafeninGermanyonOctober11,1928,andlandedat</p><p>Lakehurst,NewJersey,onOctober15,1928,afteraflightof111hoursand44</p><p>minutes[103].GrafZeppelinhadperformeditsfirstflightsometimeearlier,on</p><p>September18,1928.BythetimeofGrafZeppelin’slastflight,nineyearslater,</p><p>theairshiphadflownoveramillionmiles,on590flights,carryingthousandsof</p><p>passengersandhundredsofthousandsofpoundsoffreightandmail,withan</p><p>excellentsafetyrecord.GrafZeppelincircledtheglobewithastop-overinJapan</p><p>anditwasveryfamousthroughouttheworld.</p><p>Fig.(2.55))</p><p>LZ127GrafZeppelinoverRiodeJaneiro(Photo:BrazilianAirForceArchive,</p><p>publicdomainviaWikimediaCommons).</p><p>TheGrafZeppelinairshipincorporatedanoutstandinginnovation:theuseofthe</p><p>so-calledblaugasfuelforitsfiveengines[104].Oneofthechallengesoflighter-</p><p>than-airpoweredflighthasbeentheneedtoaccountforthelossofweightas</p><p>fuelisburned.Asgasolineordieselfuelisconsumedduringflight,theairship</p><p>becomeslighterandexpensiveliftinggasmustbereleasedtomaintainthe</p><p>aircraftbalance.TheZeppelinCompany’sinnovativesolutiontothisissuewith</p><p>theGrafZeppelinwastheuseofa*gaseousfuel,likepropane,namedblaugas</p><p>afteritsinventor,HermannBlau[104].Sinceblaugashassimilardensitytoair,</p><p>itsconsumptionduringflightdidnotsignificantlychangetheaerostaticbalance</p><p>oftheairship,andsoitisnotnecessarytoreleasehydrogentocompensatefor</p><p>blaugasburnedbytheengines.Blaugaswasalsomoreefficienttocarrythan</p><p>gasoline,andextendedtheenduranceoftheGrafZeppelinbyover30hours</p><p>[105].TheapproximatelyonemillioncubicfeetofblaugascarriedbytheGraf</p><p>Zeppelincouldpowertheairshipforoveronehundredhours,butifthatmillion</p><p>cubicfeetofblaugashadbeenreplacedbyhydrogen,theadditionalhydrogen</p><p>couldhaveliftedonlyenoughgasolinetopowertheshipfor70hoursorless.</p><p>Inearly1930s,ignitionsystemsmadelifedifficulttoradiooperators,because</p><p>theycreatedinterferencethatoftenhinderedthecommunication’sunderstanding.</p><p>Dieselenginesneednoignitionandnofireriskwasassociatedwithdieselfuel.</p><p>Dieselenginesbecamethereforehighlydesirableatthattime.Indeed,therewere</p><p>dieselenginesasaircraftengines,butofferingaweight-to-powerratioof3</p><p>kg/hp,theywerepracticallyunusable.</p><p>In1929,after20yearsofdevelopment,HugoJunkersdevelopedadieselengine</p><p>forairplanethatwascomparablewiththeusualwater-cooledpetrolengines</p><p>[106].Junkershadthendevelopedalargedieselengine,whichrequirednospark</p><p>plugandcouldstartatlowtemperatures[106].AFocke-WulfA17Möve</p><p>airplanewasemployedtoflighttesttheJunkersengineinMay1933.A500-hp</p><p>JunkersJumo205BwasinstalledintoaFwA17Cairplaneandaflighttest</p><p>campaignthenbegan.Duetonoisecausedbymanyflights,populationresident</p><p>intheareacomplainedandthetestshadtobediscontinued.Despitethis,Junkers</p><p>moveforwardwiththedevelopmentoftheengineandseveralversionswere</p><p>broughttothemarket.TheJumo205poweredearlyversionsoftheJunkersJu</p><p>86bomber,butwasfoundtoounresponsiveforcombatandliabletofailureat</p><p>maximumpower,commonsettingforcombataircraft[107].</p><p>SomeairplanesusedtheJumo205engineatextremehigh-altitudeconditions,as</p><p>withtheJu86Pand-Rversionsforhigh-altitudereconnaissanceovertheBritish</p><p>Islands.TheJumo250wasfarmoresuccessfulasapowerunitforairships,for</p><p>whichitscharacteristicswereideal,andfornon-combatapplicationssuchasthe</p><p>Blohm&VossHa139airliner.Itsmorefuel-efficientoperationlentit*elfforuse</p><p>onGermany'sfewmaritimepatrolflyingboatdesignsduringWorldWarII,such</p><p>astheBV138andsix-engineBV222flyingboat.</p><p>TheBlohm&VossBV138wasathree-engineflyingboatconceivedforlong-</p><p>rangemaritimepatrolandnavalreconnaissance.BV138sawcombatinWorld</p><p>WarIIand227unitswereproduced.Three868-hpJunkersJumo205Ddiesel</p><p>enginespoweredthefirststandardizedversion,BV138B-1[108].Diesel</p><p>enginespresentlowerspecificfuelconsumptionthanthoseburningavgas.</p><p>Thankstoitsdieselengines,theBV138airplanecouldflyover4,300kilometers</p><p>andstayairbornefor20hours[108].Rangecouldbeincreasedevenfurtherby</p><p>usingRATOpacks(RocketAssistedTakeoffs)orwhenlaunchedfromcatapults</p><p>onships.Thedieselenginesalsoenabledtheairplanetoundertakerefueling</p><p>missionstosurfacedU-boatsinremoteareasintheAtlantic.TheBV138also</p><p>hadanunusualstructuralconcept.TheBV138wingsparconsistedofa</p><p>cylindricalsteel-madetube,whichwasusedforfuelstorage[108].</p><p>Interest</p><p>indieselenginesinthepostwarperiodwasfortuitous.Lowerpower-to-</p><p>weightratioisaknowndrawbackofdieselengines,particularlywhentheyare</p><p>comparedtoturbopropones.Duetorelativecheaperavgasandkerosene,and</p><p>consideringmostfinancialsupporttoresearchonturbopropsandjetsforhigh-</p><p>speedairliners,diesel-poweredaircraftvirtuallydisappeared.Thecollapseofthe</p><p>generalaviationmarketinthe1990srecordedamassivedeclineinthe</p><p>developmentofanynewaircraftenginetypes.However,morerecently,several</p><p>factorshavechangedthispicture.First,severalnewmanufacturersofgeneral</p><p>aviation,anurseryofnewideas,emerged.Second,insomeplaceslikeEurope,</p><p>avgashasbecomeveryexpensive.Third,inseveralremotelocations,avgasis</p><p>hardertoobtainthandieselfuel.Finally,technologiesfordieselengineshave</p><p>improvedgreatlyinrecentyears,offeringhigherpower-to-weightratios,turning</p><p>themmoresuitableforaircraftapplication.</p><p>AustrianDiamondAircraft(www.diamond-air.at)hasdesignedandcertified</p><p>diesel-poweredgeneralaviationairplanes.InformationavailableatDiamond’s</p><p>Websitestatesthatfuelconsumptionofitstwin-engineDA42NGis40.5liter/h.</p><p>BoththeGrafZeppelinandBV138employedalternativefueltoimprove</p><p>performanceorthebalancingoftheaircraft.However,thereisanexperiment</p><p>withaRussianairplanethatwascarriedoutduetoconcernonoilsupply.The</p><p>TupolevTu-155wasamodifiedTu-154trijetanditwasusedasanalternative</p><p>fueltestbed.TheairplaneperformeditsfirstflightonApril15,1988.Thiswas</p><p>thefirstexperimentalaircraftintheworldoperatingonliquidhydrogen.The</p><p>trijetwasfittedwithathermally-insulated17.5m³fueltankaftofthepassenger</p><p>cabinwhichcontainedliquidhydrogenatatemperatureofminus253°C[109].</p><p>Thistankprovidedfueltoanewengine,theKuznetsovNK-88,mountedinthe</p><p>numberthreepositiononthestarboardside.Some30othersystemswere</p><p>installedintheaircraftincludingpressurizationequipment,cryogenicpumpsand</p><p>injectionmechanisms,andsafetyandmonitoringsystemstoprotectagainst</p><p>leakageandpossibleexplosion[109].Operatingteamneededtorefuelthe</p><p>aircraftonthegroundremotely.Dedicatedrigswerebuiltforthispurpose.</p><p>Althoughliquidhydrogenwasusedforthefirstfewflights,thefocusquickly</p><p>shiftedtoliquidnaturalgas,inlinewiththeSovietenergystrategyatthetime.</p><p>TheBraziliannationalethanolprogramwastriggeredbythe1973oilcrisis.It</p><p>hasbeensupportedbytheBraziliangovernmentsincethe1970s.Today,Brazil</p><p>istheworld'slargestsingleproduceroffirstgenerationbiofuels,namelyethanol.</p><p>TheBraziliangovernmenthassupportedprivateindustryinthedevelopmentof</p><p>alcohol-basedfuelsbysubsidizingresearchanddevelopment[110].The</p><p>programfordistributingthesesubsidiesisknownasPróÁlcool(National</p><p>AlcoholProgram).Sincethe1980,thesupplyofgasolineversusethanolhas</p><p>varied,asprices.Today,mostvehiclesinBrazilareflex-fuelvehicles,whichcan</p><p>runongasolineor100%ethanoloranycombinationofthetwofueltypes.</p><p>Neiva,anEMBRAERsubsidiary,consideredalcoholaviableoptiontothecrop-</p><p>dustermarketbecausethefuelisenvironmentallyfriendlyandresearchdata</p><p>indicatesitcanextendtheenginemaintenancecycle.Neivamodifiedand</p><p>certifiedanalcohol-fueledvariantoftheagriculturalairplaneIpanemaEMB-</p><p>201A(Fig.2.56).Themodificationsbasicallyincorporatedalargerinjection</p><p>nozzleandacorrosionprotectedfuelpumpabletodeliverahighermassflow.</p><p>ThenewestversionofIpanemaisEMB-203,whichpresentsalargerwingspan</p><p>thanthatofEMB-201A.</p><p>Fig.(2.56))</p><p>SomecharacteristicsofEMB201AIpanema.</p><p>Thealcohol-poweredIpanemaprojectinvolvedtheparticipationandtechnical</p><p>supportofLycoming,PrecisionandHartzell,manufacturersoftheaircraft’s</p><p>engine,thefuelinjectionsystemandthepropellergroup,respectively.Alcohol-</p><p>poweredIpanema(Fig.2.56)receivedBrazilianGeneralCommandfor</p><p>AerospaceTechnology(CTA)certificationonOctober19,2004.Produced</p><p>withoutinterruptionformorethan40years,Ipanemahasalreadysurpassed</p><p>1,300deliveredunitsin2014.</p><p>AirbusGroupdevelopedanelectricaircraftwithFrenchAeroComposite</p><p>Saintonge.Theaircraftisequippedwithon-boardlithiumbatteries,which</p><p>supplypowerfortwoelectricengines.Twooccupantsfindplaceinthecabin.A</p><p>testflightwasperformedinApril2014atMérignacAirport,France.Two</p><p>productionvariantsareplanned,atwo-seaterE-Fan2.0foruseasatrainer,and</p><p>theE-Fan4.0four-seater.Toincreaseautonomy,theE-Fan4.0willhavea</p><p>hybrid-electricsystemthatwillhaveasmallenginetochargethebattery,which</p><p>willincreasedurationfromnearlyanhourto3.5hours[111].Perinformation</p><p>postedatAirbusWebsiteonFebruary2015,AirbusGroupisinvolvedinmany</p><p>technologicalprogramswhosebreakthroughscouldeventuallyalsobeappliedto</p><p>anall-electrichelicopteranda90-seat-passengerregionalairlinerwithfully</p><p>electricorhybridpropulsion.</p><p>TheE-AircraftSystemHouseislocatedatAirbusGroupInnovationsfacilitiesin</p><p>Munichanditsdutyistocontributetothedevelopmentofelectric-powered</p><p>aircraftatAirbus.TheE-AircraftSystemHouseresultedfromcollaboration</p><p>betweenAirbusGroupandSiemens,whichsignedaMemorandumof</p><p>UnderstandingsignedwithcompanyDiamondAircraftin2013.Thesethree</p><p>partnersalreadysuccessfullyflewasecond-generationprototypeoftheDA36E-</p><p>Star2hybridaircraftinViennainJune2011.Insidethisaircraft,thereisasmall</p><p>Wankelenginewhichsuppliestheelectricitybydrivingagenerator.Theaircraft,</p><p>whichwasbasedonHK36SuperDimona,reliesonabatterytoprovidetheextra</p><p>powerneededfortakeoffandclimb,andrechargesitduringcruise.Becauseof</p><p>theairplane’slowengineoutput,DiamondstatesthatDA-36E-Starpresentsfuel</p><p>consumptionandcarbonemissionsby25percentlowerwhencomparedto</p><p>conventionalaircraft.</p><p>CONCLUDINGREMARKS</p><p>Santos-Dumontdesignedthefirstoperationalairplane,theDemoiselle,which</p><p>influenceduptoacertainextenttheBlériotXIdesign,thefirstflyingmachine</p><p>thatcrossedtheEnglishChannel.Blériotdeliveredmilitaryairplanestothe</p><p>Frencharmedforces,whichalreadywereobsoletewhenWorldWarIbegan.</p><p>WorldWarIrecordedanimpressiveincreaseinenginepowerandairplane</p><p>speed.TopspeedoftheBlériotXIwas75km/h.FokkerD.VII,anoutstanding</p><p>fighterthatsawcombatinthelastyearsofwar,couldreach200km/h.Engine</p><p>powerofBlériotXIwasamere25hpwhilethatofFokkerD.VIIwas185hp.</p><p>ZeppelinStaakenR.XVIwasaGermanheavybomberpoweredbyfourengines</p><p>inapush-pullconfiguration.Twooftheseenginescoulddeliver530hpeach,a</p><p>twenty-foldratewhencomparedwiththepowerprovidedbytheBlériotXI</p><p>engine.</p><p>Betweenthegreatwars,airshipswerethesoleflyingmachinesabletoperform</p><p>non-stoptransoceanicflightsandtheyalsoofferedauniquelevelofcomfort.</p><p>ApartfromtheHindenburgdisasterin1937,thesuccessfulnon-stopflightofthe</p><p>Focke-Wulf200CairlinerfromBerlintoNewYorkrepresentedtheendofthe</p><p>airshipera.Flyingboatsfollowedsuit,beingthenreplacedbyland-based</p><p>airplanesafterWorldWarII.Aviationalsokilledoceanliners,shipsdesignedfor</p><p>regulartransportserviceofpassengersfromaportoforigintoanestablished</p><p>destination.Theybecameobsoleteandthemaritimepassengertransportis</p><p>nowadaysexclusivelyrestrictedtotransatlanticships,whichtransportpeoplefor</p><p>leisure.</p><p>TheGrafZeppelinairshipburnedanoriginalfuel,whichwascalledBlaugas,an</p><p>artificialilluminatinggas.Thisfuelhasthesamedensityofair,avoidingthe</p><p>releaseofexpensivehydrogengasbytheairshipcrewtomaintainitscourse.</p><p>Blaugas(BlauistheGermanwordforblue)isnotblue,buthasaratherwater-</p><p>likecolor[112].</p><p>Itcanbestoredinsteelcylindersforshipmentanditsadvantage</p><p>reliesonthefactthatitpossessesthehighestspecificenergyofallartificially</p><p>producedgases.However,unlikecoalgas,Blaugasisfreeofcarbonmonoxide.</p><p>Blaugaswasalsomoreefficienttostorethangasoline,andextendedtheGraf</p><p>Zeppelin’sautonomybyover30hoursofflyingtime.</p><p>FortheNo.3airship,Santos-Dumontemployedilluminatinggasaslifting</p><p>mediuminsteadofhydrogen,whichisexpensivetoproduce,aspreviously</p><p>mentioned.Hisintentwastobuildalow-costairshipthatwouldbeaffordable</p><p>formanypeople,anattempttoturnaviationpopularathistime.Dumont</p><p>returnedtohydrogenwithhisNo.4airship.</p><p>Theintroductionofthefirstjettransportinthe1950smarkedthebeginningofa</p><p>revolutionintransportation.Thetechnologyofthejetenginedevelopedin</p><p>WorldWarIItooksometimetoestablish*tselfinthecommercialaviationsector.</p><p>ThepioneerintroductionoftheDeHavillandCometoftheearly1950's,</p><p>unfortunatelymarredbyasadhistory,ledtothehighlyefficient,safe,reliable,</p><p>andeconomicaltransportaircraftoftoday.Themodernjettransporthasaltered</p><p>foreverthetravelconceptsandhabitsofpeopleallovertheworld.Thisincludes</p><p>thesecondjetagethatwastriggeredbyEMBRAERandCanadairaircraft</p><p>manufacturerswiththeirregionaljetsintheearly1990sinthewakeofthe1978</p><p>North-AmericanDeregulationAct.Thiswasabreakthroughinair</p><p>transportation,whichthistimewasnotcausedbytechnologicaladvancebutbya</p><p>political-economicalmove.TheDeregulationchangedaviationprofoundly,</p><p>makingitpossibleforairlinestoofferjetandturboproptransporttosmalland</p><p>mediumcities,whichinturnresultedineconomicdevelopmentforthose</p><p>communities.</p><p>ThepresentChapteralsodescribesseveralattemptstodesignandmanufacture</p><p>civilsupersonicairliners.TheBritish-FrenchConcordewastheonlyairplaneto</p><p>enterserviceonaregularbasis;itsRussiancompetitor,theTu-144,wasretired</p><p>prematurelyfromserviceafteranaccidentoverParis.Concordewasnot</p><p>economicallyviabletooperate,butitremainedinregularservicethanksto</p><p>heavysubsidiesfromFranceandGreatBritain.Researchwillcontinueinthe</p><p>followingdecadestoenablecommercialsupersonicpassengerserviceata</p><p>reasonablecost.</p><p>TheConvair990wasnotcapabletoflysupersonically,butwasabletocruiseat</p><p>Machnumberof0.92.Itsimmensefuelconsumptioncausedoneofthelargest</p><p>corporatelossesinhistoryatthetime.In1994,theGeneralDynamics</p><p>CorporationsplitandsoldtheoriginalConvairDivision,alongwithother</p><p>GeneralDynamicsaerospaceunitsthathadbeenincorporatedoverthedecades.</p><p>Environmentalconcernsaboutafleetofsupersoniccommercialairplanesposea</p><p>greatbarriertothewidespreaduseofsuchairplanes,eveninashort-to-medium</p><p>timeframe.A5000-nmrange8-passengercapablesupersonicbusinessjetwill</p><p>probablypresentamaximumtakeoffweightof55tons,burning30tonsoffuel.</p><p>TheEMBRAER195ARairlinerhasamaximumtakeoffweightlikethat,52,450</p><p>kg,butcantransport124passengersfora2000-nmjourney.Theemissionlevels</p><p>perseatarefarfromacceptableforthesupersonicbusinessjet.</p><p>Despiteenvironmentalconcerns,asupersonicsmallbusinessjet(SSBJ)has</p><p>neverthelesssomeappeal.ASSBJabletocruiseaMachnumber2willcutthe</p><p>timefromLosAngelestoTokyoto3.5handonlongertripsitcouldreduce</p><p>traveltimebyhalfincludinggroundrefueling.Forthiskindofairplane,ground</p><p>refuelingisabigissuebecauseittakesconsiderabletimeduetothelarge</p><p>amountoffuelneeded.ASSBJabletoaccommodate8passengersandcapable</p><p>tocruiseatMachnumber2SSBJwouldprobablycostUS$75millionormore,</p><p>dependingontheunitsthatcouldbeputonthemarket.Certainly,therearesome</p><p>categoriesofpeopleandcorporationsthatcanaffordtopaythatpriceinbenefit</p><p>oftimetravelsaving.However,thismarketsizelacksamoreaccurateestimation</p><p>andtheenvironmenthazardposesagreatbarriertocommercialoperationsona</p><p>largescale.</p><p>Earlyin2001,theBoeingCompanyannouncedthedevelopmentofacompletely</p><p>new250-passengerhigh-speedaircraft,whichwasdesignatedSonicCruiser.The</p><p>mostimpressivefeaturesofthisnewconceptwerearangeofupto10,000nm,a</p><p>cruiseMachnumberof0.98andtheclaimofalargereductioninflighttime.</p><p>MartinEpperlefromtheGermanResearchInstituteDLRcarriedoutafeasibility</p><p>studyaboutthesoniccruiserandconcluded[113]:</p><p>“Combiningtheaerodynamicdata,thestructure/fuelmassratio,thetankvolume</p><p>andtakingthefuelconsumptionintoaccount,arangeof6,500nauticalmilesis</p><p>justreachablewhenflyingatMachnumberof0.98.Toextendtherangeto7,500</p><p>miles,theTSFCoftheenginesmustbereducedfrom0.67toabout0.55in</p><p>cruise,whichseemstobepossible.Afurtherextensionoftherangeto9,000</p><p>mileswouldrequireenginesoperatingwithaTSFCoflessthan0.55,which</p><p>seemsnottobefeasible,atleastnotwithaBPRbelow8.”</p><p>Mr.EpperledidnotaddressthepotentialoperatingcostoftheSonicCruiser,</p><p>especiallyregardingotherexistingtransportairplanesofsimilarcapacity.Infact,</p><p>thebenefitofshorterflighttimewasovershadowedbyhigheroperatingcosts.</p><p>Byanymeans,airlineslostinterestintheconceptandBoeingcancelledthe</p><p>SonicCruiserprogramin2002.Afterwards,the787programstarted.</p><p>Manyairplanesflyingin2016weredevelopedwiththetechnologylevelfrom</p><p>the1980s,as,forexample,theAirbusA320,EMBRAERERJ145,andBoeing</p><p>737-300.Transportaircraftcurrentlyinproduction,amongthemtheBoeing787</p><p>andAirbusA350,willcontinuetoleaveassemblylineformanyyearstocome.</p><p>Theywillincorporateimprovements,modifications,andadaptationstonew</p><p>routesandmarketsandwillcontinuetooperateastechnologiesevolve.</p><p>TheconceptoftheBe-2500ekranoplanstartedenvisagingmilitaryapplications,</p><p>butitcouldalsoprovideaninterestingmeanofciviltransportation.Alotof</p><p>“energy”isnecessarytoputanairplaneflyingat12,000mcruisealtitude,</p><p>specialeffortsmustbemadetokeeppassengerssafeandsoundandwelltaken</p><p>careof.Be-2500canflyat400metersabovethegroundorsea,takingadvantage</p><p>ofthegroundeffect.Inthisflightmode,itsspeedisonlyalittlebitmorethan</p><p>400km/h.Itwouldbemoreefficientintermsofdesign,ifanunpressurized</p><p>vehicleweredesignedinstead,preventingthestructurefrombeingtooheavy.A</p><p>fleetofsuchflyingvehicleswouldcausesuchanimpactonaviationthatitcould</p><p>sufferatotalrecall.Unfortunately,theinvestmentneededforthatchangeis</p><p>huge,bothforthevehicleandforchangingandestablishinganewairport</p><p>infrastructure.</p><p>Alongsideupgradedairplanedesigns,newtransportaircraftwillcertainlybe</p><p>developedinthenexttwoorthreedecadesandinnovativetechnologiesin</p><p>aerodynamics,structures,guidanceandcontrol,andpropulsionwillbe</p><p>incorporated.Laminarflow,unusualconfigurationssuchastruss-bracedwing,</p><p>compositestructures,activecontrols,andenginesofimprovedefficiencyand</p><p>reducednoiseareonlyafewofthenewkeytechnicaldevelopments.Fuel-</p><p>efficientairplanesareimportanttoreduceemissionlevels.Technological</p><p>improvementsplayakeyroleforthemitigationoftheaviationimpactonthe</p><p>environment.Newproductsmustbecontinuouslydevelopedandregularly</p><p>introducedintotheairlinefleetseverywheretoproperlyreducethe</p><p>environmentalimpactofaviation.However,significantglobalimprovementisa</p><p>lengthyprocess.Whilethecurrentandfuturegenerationofcommercialtransport</p><p>aircraftwilleventuallyburnlessthan3litersoffuelperpassenger,per100</p><p>kilometers,achievingthisaveragefuelconsumptionfortheworldwidefleetwill</p><p>takeapproximately20years.</p><p>Inadditiontoadvancesindisciplinarytechnologies,improvedmethodsfor</p><p>integratingdiscipline-baseddesignintoabettersystemarebeingdeveloped.The</p><p>fieldofmulti-disciplinarydesignoptimizationpermitsdetailedanalysesand</p><p>designmethodsinseveraldisciplinestobecombinedtothebestadvantagefor</p><p>theoverallsystem.Itisakeymethodologytodesigngreenairplaneswith</p><p>satisfactoryperformancetradeoffs.</p><p>Apartfromevolutionaryimprovementsinconventionalaircraft,revolutionary</p><p>changesarepossiblewhenthe“rules”arechanged.Thisispossiblewhenthe</p><p>configurationconceptit*elfischangedandwhennewrolesorrequirementsare</p><p>introduced.</p><p>SOMEMILESTONESINAIRCRAFTTECHNOLOGY</p><p>Aircraft Year MajorInnovations</p><p>SikorskyRusskyVityaz 1913 ●World’sfirstmulti-engineairplane●Storageroom●Passengerscouldwalkduringflightcausingnostabilityproblemtotheairplane●Dualcontrolcolumn</p><p>JunkersD-I 1919 ●Firstall-metalairplane●Cantileveredlow-wingdesign●Corrugatedduraluminskin●Variable-incidencehorizontalempennage●Advancedengineradiatordesignlayout:theradiatorwasplacedinaventralbellypositionundertheforwardfuselage</p><p>Zeppelin-StaakenE4/20 1920 ●Stressedskin●Torsion-boxspar●Wingleading-edgemountedengineswithmostpartatwinglowersideforlowdrag</p><p>DornierWal 1923 ●Transatlanticcargoandpassengerflightsbecamepossible●Semi-cantileverwing●Duraluminconstruction●Stabilizingsponsons</p><p>Westland-HillPterodactylI 1928 ●Taillessairplane●Wingtipspivotedtoactasslabelevonsprovidingcontrolinpitchandroll●Thewingwas“washedout”,havingaslighttwistwhichreducedtheangleofincidenceprogressivelytowardsthetips,providinganear-stationaryoverallcenterofpressureandensuringthattheaircraftwasstableinpitch.</p><p>GrafZeppelin 1928 ●Firstaround-the-worldflightbyanaircraftin1929●Non-stopAtlanticregularcrossings●Innovativefuelblaugaus,whichhasthesamedensityastheair</p><p>JunkersG38 1929 ●Partofpassengersseatedinthewings●Dieselengines(Laterversion)●All-metalconstruction●Blendwing-bodyconfiguration●Flaperons</p><p>HallXFH 1929 ●HallAluminum,aU.S.Company,builttheXFH,whichwasthefirstaircraftwitharivetedmetalfuselage-awatertightaluminumskinoversteeltubing.HallalsopioneeredflushrivetsandbuttjointsbetweenskinpanelsinthePHflyingboat,whichfirstflewin1929</p><p>PolikarpovI-16 1933 ●Firstlow-wingmonoplanewitharetractableundercarriage●Cantileverwingconstruction●Variable-pitchpropeller●Enclosedco*ckpit(someversions)●Aileronsactingasflaps(flaperons)</p><p>Boeing247 1933 ●Firstautopilotincivilaircraft●Firstcivilaircraftwithde-icingboots●Variable-pitchpropellers●All-metalsemi-monocoqueconstruction●Cantileverwing●NACAcowlings●Airconditioning</p><p>HeinkelHe177 1939 ●Evaporativecoolingsystemtoavoidtheutilizationofdrag-producingradiators.</p><p>Boeing307 1940 ●Firstpressurizedairliner.WorkonthisfieldbeganwithHugoJunkers,whobuiltandflewtheexperimentalairplaneJu49●Firstairplanetoincludeaflightengineerstation</p><p>MesserschmittMe262 1942 ●Firstproductionaircraftwithjetengines●Sweptwings●Tricyclelandinggear</p><p>HeinkelHe219 1943 ●Firstaircraftwithejectionseats●Pressurizedcabin●Firststeerablenosewheelofa*germanaircraft</p><p>AradoAr234 1943 ●Rocket-assistedtakeoff●Integrationofseveralnewtechnologies:●Pressurizedcabin●Autopilot●Jetengine●Ejectionseat●Bombingcomputers</p><p>Focke-AchgelisFa223 1944 ●ThankstoitsrotordesignitwasthefirstHelicopterabletoexternallytransportoutsizedcargoevenathigheraltitudes.●Somecabinequipmentcouldbethrowoutforcrewevacuationinanemergencyevent</p><p>VickersViscount 1950 ●Firstturbopropaircraftinregularservice●Pressurization</p><p>Chance-VoughtCutlass 1951 ●Firstswept-wingnavalaircraft●Firstproductionaircraftwithafterburning●Firstfightertocarryradar-guidedmissiles●High-pressurehydraulicsystem(3000psi)●Taillessconfiguration</p><p>DeHavillandComet 1952 ●Firstproductionjetliner●Pressurizedcabin●Four-wheelbogiemainlandinggear●Integralfueltanks●Redundanthydraulicsystems●Irreversiblepoweredflightcontrols●Newalloys,bothrivetedandchemicallybonded</p><p>HerculesC-130 1954 ●Firstairplanefittedwithicedetectors</p><p>MartinP6ASeamaster 1955 ●FirstamphibiousairplanetoreachMach0.90inlevelflight</p><p>Sud-AviationCaravelle 1959 ●Rear-mountedenginesconfiguration●Jettransportforshort-rangeoperations●Weldingforstructuralcomponents.●Engineelectricstart</p><p>ConvairB-58Hustler 1960 ●Firstsupersonicbomber●Ejectioncapsule●Oneofthefirstextensiveapplicationsofaluminumhoneycombpanels,whichbondedouterandinneraluminumskinstoahoneycombofaluminumandfiberglass.</p><p>SaabDraken 1960 ●Double-deltawingconfiguration●Capableofoperatingfrompublicroads●Ramairturbineprovidingemergencypower</p><p>RockwellSabreliner 1962 ●Firstbusinessjetfittedwithturbofansengines.FirstturbofansawsomedevelopmentinWWIIbytheGermans.However,duetolackoftechnologyatthattimedevelopmentstopped●Firstserialairplanewhosewingswerefittedwithsupercriticalairfoils(Series65)</p><p>LockheedSR-71 1964 ●FirstjetaircrafttoreachMach3.4●Astro-inertialnavigationsystem●Firstairplanedesignedwithstealthcapabilities●Titaniumconstruction●Coolingofstructurebycyclingfuel</p><p>Vickers_armstrongVC-10 1964 ●Autopilotenabledfully-automaticlandings●Quadruplicatedsystems</p><p>BAC-111 1965 ●Equippedwithstickshakerandpushersystems</p><p>GeneralDynamicsF-111 1967 ●Variable-sweepwing●Afterburnerforaturbofanengine●Automatedterrain-followingradarforlow-level,high-speedflight</p><p>WindeckerEagle 1969 ●TheWindeckerEaglebecamethefirstall-compositeaircrafttoreceiveFAAcertification,usingaflexible,non-wovenglassfibermaterial,“Fibaloy,”developedbyDowChemical.Carbonreplacedglassasthereinforcingfiberinsubsequentdesigns.TheEaglealsowasthefirstaircraftcertifiedunderthePart23FAAregulations,newatthattime.</p><p>SAABViggen 1972 ●Canardsurfaces●Enginefittedwithafterburnerandthrustreverser</p><p>Boeing747 1970 ●Firstwide-bodyairliner●Redundantstructuralcomponentsandhydraulicsystemsforimprovedsafety●Variablecamberflapsatleadingedgeofhoneycombconstruction</p><p>AirbusA300 1974 ●Firstmedium-rangewide-bodyairliner●Supercriticalairfoils●Structuresmadeofmetalbillets,reducingweight●Firstairlinerfittedwithwindshearprotection●Advancedautopilotscapableofflyingtheaircraftfromclimb-outtolanding●Electricallycontrolledbrakingsystem●Two-mancrewbyautomatingtheflightengineer'sfunctions,anindustryfirst●Glassco*ckpitflightinstruments●Extensiveuseofcompositesforanaircraftofitsera●Center-of-gravitycontrolbyshiftingaroundfuel●Thefirstairlinertousewingtipfencesforincreasingfluttermargins●Manufacturingemployedjust-in-timeconcept,anindustryfirst●FirstETOPScompliantaircraft</p><p>Concorde 1976 ●Ogee/Ogival-shapeddeltawing●Supercruisecapability●Variableinletramps●Thrust-by-wireengines,predecessoroftoday'sFADEC-controlledengines●Droop-nosesectionforimprovedvisibilityatlanding●Mach2.04cruisingspeed●Full-regimeautopilotandautothrottleallowing“handsoff”controloftheaircraftfromclimbouttolanding●Fullyelectricallycontrolledanaloguefly-by-wireflightcontrolssystems●Multifunctionflightcontrolsurfaces●High-pressurehydraulicsystemof28MPa(4,000lbf/in²)forlighterhydraulicsystemscomponents●Fullyelectricallycontrolledanaloguebrake-by-wiresystem●Pitchtrimbyshiftingfuelaroundthefuselageforcenter-of-gravitycontrolPartsmilledfromsinglealloybilletreducingthepart-numbercount</p><p>GeneralDynamicsF-16 1978 ●Relaxed</p><p>staticstability/fly-by-wireflightcontrolsystem●Side-mountedcontrolstick●Variablecamberwing●Reclinedseattoreduceg-forces●Blendedwingbodyconfiguration</p><p>Boeing767 1982 ●Firsttwinjettoreceiveregulatoryapprovalforextendedoverseasflights●Onethefirstairlinerstoeliminatetheflightengineerstation●Thefirsttwinjetwide-bodytypetoreach1,000aircraftdelivered</p><p>AirbusA310 1982 ●Thefirstcarbon-fiberprimarystructureinaproductioncommercialaircraftwastheverticalstabilizeroftheAirbusA310-300.ItmarkedthebeginningofincreasingcompositeuseintheEuropeanmanufacturer’sairlinersthataddedthehorizontalstabilizerwiththeA320in1987andA330/A340in1994andthecenterwing-boxandaftfuselageoftheA380in2005.</p><p>AirbusA320 1988 ●Firstcivilaircraftfittedwithdigitalfly-by-wirecontrolsystem●Side-stickcontrol●Fullglassco*ckpit</p><p>EMB202Ipanema 2004 ●Firstserial-producedaircraftpoweredbyanengineburningethanol</p><p>ShinMaywaUS-2 2007 ●Shorttakeoffandlandingamphibianairplane●Landonroughseaswithwavesheightof3m●Internalenginetoblownflapselevatorandrudder(maximumliftcoefficientapprox.7)</p><p>Bell/BoeingV-22Osprey 2007 ●FirstproductionVTOLaircraft</p><p>AirbusA380 2007 ●Skintostringerwelding●CenterwingboxinCFRP●Variable-frequencypowergeneration●GLAREutilization.GLAREisacompositelaminateconstructionofalternatinglayersofthinaluminumandlayersoffiberglassandplasticmatrixmaterial.Thefiberorientationofthefiberglasscanbetailoredtoproducedesiredstrengthandstiffness.</p><p>Boeing787 2011 ●Compositefuselageandwings●Electricwinganti-icesystem●Bleed-lessengine●Electroniccircuitbreakers</p><p>References</p><p>[1] MattosB.S..OpenSourcePhilosophyandtheDawnofAviation.J.Aerosp.Technol.Manag.20124310.5028/jatm.2012.04030812</p><p>[2] ProgressinMechanicalFlight.FlightMagazine19091213</p><p>[3] M.SantosDumont’sNewAchievements.FlightMagazine1909561</p><p>[4] SchmittG..FliegendeKisten-vonKittyHawkbisKiew.Berlin:VerlagfürVerkehrswesen,1990..</p><p>[5] Wikipedia,theFreeEncyclopediaSikorskyIliaMurometsWikipedia,082017.[Online].Available:https://en.wikipedia.org/wiki/Sikorsky_Ilya_Muromets.</p><p>[6] SikorskyI..StoryoftheWinged-S:AnAutobiographybyIgorSikorsky.NewYorkDodd,Mead&Company1938</p><p>[7] AngelucciE..Flugzeuge-1000MaschinenausallerWeltmitsämtlichenTechnischenDaten-vonErstenFluggerätbiszumÜberschalljet.StuttgartFalkenVerlagundMotorBuchVerlag1974</p><p>[8] IatrouK..100YearsofCommercialAviation1914-2014.HermesAirTransportClub2014</p><p>[9] Wikipedia,TheFreeEncyclopediaFarmanF.60GoliathWikipedia,August2017.[Online].Available:https://en.wikipedia.org/wiki/Farman_F.60_Goliath.</p><p>[10] WatkinsJ.A..AHistoryofCommercialAirliners2011https://hubpages.com/technology/A-History-of-Commercial-Airliners</p><p>[11] WingsH..TheFirstMidairAirlineDisaster2013http://fly.historicwings.com/2013/04/the-first-midair-airline-disaster/</p><p>[12] PrandtlL..ÜberFlüssigkeitsbewegungbeisehrkleinerReibung,“inIIIInternationalerMath.Krongress.Heildelberg1904</p><p>[13] Wikipedia,TheFreeEncyclopedia,"LudwigPrandtl,"Wikipedia2017https://en.wikipedia.org/wiki/Ludwig_Prandtl</p><p>[14] Wikipedia,theFreeEncyclopedia,"MixingLengthTheory,"Wikipedia2017https://en.wikipedia.org/wiki/Mixing_length_model</p><p>[15] DoshiR.M.,GillN.W..ANoteonMixingLengthTheoryofTurbulentFlowAIChE1970885888</p><p>[16] Wikipedia,TheFreeWikipedia,"JunkersD.I,"Wikipedia2017https://en.wikipedia.org/wiki/Junkers_D.I</p><p>[17] Wikipedia,TheFreeWikipedia,"JunkersF.13,"Wikipedia2017https://en.wikipedia.org/wiki/Junkers_F.13</p><p>[18] RIMOWAFLUGZEUWERKEAGALegendgrowsnewWingsRIMOWA,2017http://www.rimowa-f13.com/en/#home.</p><p>[19] NorthtropgrummanHistoryofSperryMarineNorthtropGrumman,2017.[Online].Available:http://www.sperrymarine.com/corporate-history/sperry-marine.[Accessed24August2017]..</p><p>[20] Wikipedia,TheFreeEncyclopedia"In-flightentertainment,"Wikipedia,September12017.[Online].Available:https://en.wikipedia.org/wiki/In-flight_entertainment.[Accessed4September2017]..</p><p>[21] Wikipedia,TheFreeWikipedia"CurtissT-32CondorII,"Wikipedia,2016.[Online].Available:https://en.wikipedia.org/wiki/Curtiss_T-32_Condor_II.[Accessed08April2016]..</p><p>[22] JakabP.L..WoodtoMetal:Thestructuraloriginsofmodernairplane.JournalofAircraft,November-December199910.2514/2.2551</p><p>[23] Rotachute,RotabuggyandRotatank.FlyingReviewInternational196319345</p><p>[24] ForsgrenJ..TheJunkersJu52Story.FonthillMedia2017</p><p>[25] Wikipedia,TheFreeEncyclopedia"Boeing247,"Wikipedia,28August2017.[Online].Available:https://en.wikipedia.org/wiki/Boeing_247.[Accessed2017September2017]..</p><p>[26] Wikipedia,TheFreeEncyclopedia"Boeing307Stratoliner,"Wikipedia,22July2017.[Online].Available:https://en.wikipedia.org/wiki?curid=1882449.[Accessed5September2017]..</p><p>[27] Wikipedia,TheFreeEncyclopedia"Focke-WulfFw200Condor,"Wikipedia,22August2017.[Online].Available:https://en.wikipedia.org/wiki/Focke-Wulf_Fw_200_Condor.[Accessed29August2017]..</p><p>[28] SmithJ.R..Focke-WulfFw200.ProfileBooksLtda1982</p><p>[29] Wikipedia,TheFreeEncyclopedia"MesserschmittBf109,"Wikipedia,24August2017.[Online].Available:https://en.wikipedia.org/wiki/Messerschmitt_Bf_109.[Accessed5August2017]..</p><p>[30] Wikipedia,theFreeEncyclopedia"Leading-edgeslats,"Wikipedia,TheFreeEncyclopedia,8December2015.[Online].Available:https://en.wikipedia.org/wiki/Leading-edge_slats.[Accessed17April2016]..</p><p>[31] Wikipedia,TheFreeEncyclopedia"FieselerFi156,"Wikipedia,13August2017.[Online].Available:https://en.wikipedia.org/wiki?curid=176773.[Accessed6September2017]..</p><p>[32] McDowellE.R.,WardR..NorthAmericanF-86A-LSabre.USAF&ForeignService.Canterbury,KentOspreyPublicationsLtda1970Vol.17</p><p>[33] NowarraH.J..MesserschmittBf1091936-1945.WestChesterSchifferPublishingLtd.1991</p><p>[34] SeanF..WorldWarIITechnologythatChangedWarfare-RadarandBombsightsAcademicSymposiumofUndergraduateJohnsonWales2011</p><p>[35] WikipediaTheFreeEncyclopedia"Bombsight,"Wikipedia,30May2017.[Online].Available:https://en.wikipedia.org/wiki/Bombsight.[Accessed5September2017]..</p><p>[36] WikipediaTheFreeEncyclopedia"HeinkelHe219,"Wikipedia,16August2017.[Online].Available:https://en.wikipedia.org/wiki/Heinkel_He_219.[Accessed6September2017]..</p><p>[37] GriehlM.,DresselJ..Heinkel177,277,274.ShrewsburyAirlifePublishingLtd1998</p><p>[38] Wikipedia,TheFreeWikipedia"HeinkelHe177,"Wikipedia,22august2017.[Online].Available:https://en.wikipedia.org/wiki?curid=455366.[Accessed29August2017]..</p><p>[39] GunstonB.,JacksonA.J.,MondeyD.,PassinghamM.,StroudJ.,TaylorM.J.,YoungS.H..Jane’sEncyclopediaofAviation.NewYorkCrescentBooks1996</p><p>[40] Wikipedia,TheFreeEncyclopedia"AradoAr232,"Wikipedia,19July2017.[Online].Available:https://en.wikipedia.org/wiki?curid=646085.[Accessed23July2017]..</p><p>[41] H.Clements"LeadingEdgeAeronauticalResearchonthePlains,"AirFacts-TheJournalforPersonalAirTravel,February2013.[Online].Available:http://airfactsjournal.com/2013/02/leading-edge-aeronautical-research-on-the-plains/.[Accessed24April2016]..</p><p>[42] ShinMaywaIndustries"ByLand,Sea,orAirUS-2,"ShinMaywaIndustries,2017.[Online].Available:https://www.shinmaywa.co.jp/aircraft/english/us2/index.html.[Accessed2017]..</p><p>[43] EncyclopaediaBritannica,Inc."TheJetAge,"EncyclopaediaBritannica,2017.[Online].Available:https://www.britannica.com/technology/history-of-flight/The-jet-age.[Accessed4September2017]..</p><p>[44] SmithJ.R.,CreekE.J..Arado234B.MonogramAviationPublications1983</p><p>[45] BatesonR.P..AradoAr234Blitz,Profile215.ProfilePublications1972</p><p>[46] HerwigD.,</p><p>RodeH..LuftwaffeSecretProjects-StrategicBombers1935-1945.LeicesterMidlanPublishing2000</p><p>[47] SchickW.,MeyerI..LuftwaffeSecretProjects-Fighters1939-1945.LeicesterMidlandPublishing1997</p><p>[48] Wikipedia,thefreeencyclopedia"HortenHo229,"Wikipedia,thefreeencyclopedia,13April2016.[Online].Available:https://en.wikipedia.org/wiki/Horten_Ho_229.[Accessed24April2016]..</p><p>[49] W.Heinzerling"FlügelpfeilungundFlächenregel,zweigrundlegendedeutschePatentederFlugzeugaerodynamik,"In:Beiträgedes9.KolloquiumsLuftverkehrundderneuntenAugustEuler-Preisverleihung,Darmstadt,2002..</p><p>[50] BensonR.L..QuietingtheBoom:TheShapedSonicBoomDemonstratorandtheQuestforSupersonicFlight,NASAeBookSeries,2013..</p><p>[51] StraßlH.,LudwiegH..VerringerungdesWiederstandesvonTragflügelnbeihohenGeschwinigkeitendurchPfeilform.AerodynamischenVersuchsanstaltGöttingen1939</p><p>[52] LudwiegH..PfeilflügelbeihohenGeschwindigkeiten(VersuchsErgebinisse)1940</p><p>[53] Wikipedia,TheFreeEncyclopedia"AreaRule,"Wikipedia,24August2017.[Online].Available:https://en.wikipedia.org/wiki?curid=34036.[Accessed5September2017]..</p><p>[54] HertelH.,BerreA.,FrenztlO.,HempelW.,ZiebigkD.."PatentschriftzurFlächenregel".GermanyPatent932419,1955..</p><p>[55] MeierH-U..DiePfeilflügelentwicklunginDeutschlandbis1945.Bernard&Graefe2005</p><p>[56] Wikipedia,TheFreeEncyclopedia"MesserschmittP.1111,"Wikipedia,24June2017.[Online].Available:https://en.wikipedia.org/wiki?curid=39592726.[Accessed6September2017]..</p><p>[57] D.Baals"WindTunnelsofNASA,"NASA,1981.[Online].Available:http://history.nasa.gov/SP-440/contents.htm.[Accessed17March2016]..</p><p>[58] MikeP..TheBrabazonCommitteeandBritishairliners,1945-1960.StroudTempus2007</p><p>[59] HillM.L..VickersViscountandVanguard,Ramsbury.Malborough,WiltshireCrowoodPressLtd2004</p><p>[60] Wikipedia,TheFreeEncyclopedia"BristolBritannia,"Wikipedia,2017.[Online].Available:https://en.wikipedia.org/wiki/Bristol_Britannia#cite_note-BAhis-40.[AccessedOctober2017]..</p><p>[61] Wikipedia,TheFreeEncyclopedia"LockheedL-188Electra,"Wikipedia,2017.[Online].Available:https://en.wikipedia.org/wiki/Lockheed_L-188_Electra.[AccessedOctober2017]..</p><p>[62] ReedW..ReviewofPropeller-RotorWhirlFlutter.Hampton,VANASALangley1967</p><p>[63] Wikipedia,theFreeEncyclopedia"Boeing707,"Wikipedia,22August2017.[Online].Available:https://en.wikipedia.org/wiki/Boeing_707.[Accessed22August2017]..</p><p>[64] FlightSafetyFoundation"Boeing707N7071Accident,"AviationSafetyNetwork,2015.[Online].Available:http://aviation-safety.net/database/record.php?id=19591019-0.[Accessed12March2015]..</p><p>[65] JohnstonA.M..Jet-AgeTestPilot.WashingtonSmithsonianBooks2000</p><p>[66] GlanceyJ..Boeing707:TheAirplanethatChangedtheWayWeFly2014http://www.bbc.co.uk/culture/story/20141020-the-plane-that-changed-air-travel</p><p>[67] PediaView.com"JetAirliner,"PediaView.com,2017.[Online].Available:https://pediaview.com/openpedia/Jet_airliner.[Accessed2017]..</p><p>[68] BackfilesE..ResistanceSpotWeldingintheCaravelle.Aircr.Eng.Aerosp.Technol.19628687</p><p>[69] Wikipedia,TheFreeEncyclopedia"SudAviationCaravelle,"Wikipedia,September2017.[Online].Available:https://en.wikipedia.org/wiki/Sud_Aviation_Caravelle.[AccessedSeptember2017]..</p><p>[70] OrtegaL..ReactoresComerciales1948-1994.MadridAgualarga1994</p><p>[71] R.G.Pushkar"Comet'sTale,"SmithsonianMagazine,June2002.[Online].Available:http://www.smithsonianmag.com/history/comets-tale-63573615/?no-ist=&page=2.[AccessedAugust2017]..</p><p>[72] WorldHeritageEncyclopedia"DeHavillandComet,"WorldLibrary,2017.[Online].Available:http://www.worldlibrary.org/article/whebn0000182728/de.[Accessed4September2017]..</p><p>[73] TorenbeekE..AdvancedAircraftDesign.JohnWiley&Sons201310.1002/9781118568101</p><p>[74] R.P.HallionSupersonicFlight:BreakingtheSoundBarrierandBeyond-TheStoryofBellX-1andDouglasD-558,TheMacmillianCo.inassociationwiththeSmithsonianNationalAirandSpaceMuseum,1972..</p><p>[75] MusonK..AirlinersSince1946.2ndedBlandfordPress1975167168</p><p>[76] Wikipedia,TheFreeEncyclopedia"Convair990Coronado,"Wikpedia,17August2017.[Online].Available:https://en.wikipedia.org/wiki/Convair_990_Coronado.[Accessed5September2017]..</p><p>[77] Gordon"ConcordeHistory:EarlyHistory,"June2001.[Online].Available:http://concordesst.com/history/eh1.html.[Accessed5September2017]..</p><p>[78] D.Küchemann"ABriefSurveyoftheWorkDoneinAerodynamicsDepartmentonSweptandSlenderWings,"RAETech.emoAero,1958..</p><p>[79] KüchemannD..SomeConsiderationsofAircraftShapesandtheirAerodynamicsforFlightsatSupersonicSpeeds.RAETech.MemoAero1959</p><p>[80] KüchemannD..ABriefOutlineofsomeofthePresentAerodynamicWorkonSupersonicTransportAircraft.RAETech.MemoAero1961</p><p>[81] WiggsR..Concorde:TheCaseagainstSupersonicTransport.BallantineBooks/FriendsoftheEarth1970</p><p>[82] Wikipedia"Anti-ConcordeProject,"Wikipedia,[Online].Available:https://en.wikipedia.org/wiki/Anti-Concorde_Project.[Accessed17February2015]..</p><p>[83] M.Novak"WhentheFAABlastedOklahomaCitywithSonicBoomsFor6Months,"GIZMODO,April2015.[Online].Available:https://paleofuture.gizmodo.com/when-the-faa-blasted-oklahoma-city-with-sonic-booms-for-1649589210.[AccessedSeptember2017]..</p><p>[84] TheBoeingCompanyGeneralDescriptonBoeing2707-300SupersonicTransport.SeattleBoeingCo.1969</p><p>[85] TheBoeingCompanyNASASCAT1515-FFeasibilityStudy.SeattleBoeingCo.1965</p><p>[86] FlightMagazine"CommercialAircraftSurvey,"FlightMagazine,23November1967.[Online].Available:http://www.flightglobal.com/pdfarchive/view/1967/1967-2245.html.[Accessed17032015]..</p><p>[87] TheBoeingCompany"747AirplaneCharacteristics-AirportPlanning,"May1984.[Online].Available:http://www.boeing.com/assets/pdf/commercial/airports/acaps/747_8.pdf.[AccessedJanuary2015]..</p><p>[88] M.R.Kulfen"HighTransonicSpeedTransonicAircraftStudy-FinalReport,"NASA,CR-114658,1973..</p><p>[89] S.Hoffman"BibliographyofSupersonicCruiseResearch(SCR)Programfrom1980-1983,"NASARP-1117,1984..</p><p>[90] JonesR.T..TheoreticalDeterminationoftheMinimumDragofAirfoilsatSupersonicSpeeds.J.Aeronaut.Sci.1952</p><p>[91] I.Kroo"UnconventionalConfigurationsforEfficientSupersonicFlight,"inVKILecturesSeriesonInnovativeConfigurationsandAdvancedConceptsforFutureCivilAircraft,2005..</p><p>[92] Y.Gibbs"PastProjects:AD-1ObliqueWing,"NASA,4August2017.[Online].Available:https://www.nasa.gov/centers/dryden/history/pastprojects/AD1/index.html.[Accessed6September2017]..</p><p>[93] S.BaughcumandC.S.Henderson"AircraftEmissionInventoriesProjectedinyear2015foraHighSpeedCivilTransport(HSCT)AirlineNetwork,"NASACR-4659,1995..</p><p>[94] FeildenG.B.,WickensA.H.,YatesI..PassengerAircraftAfter2000AD.LondonE&FNSpon1995</p><p>[95] R.Faaß"Cryoplane-FlugzeugemitWasserstoffantrieb,"06December2001.[Online].Available:http://www.fzt.haw-hamburg.de/pers/Scholz/dglr/hh/text_2001_12_06_Cryoplane.pdf.[Accessed25April2016]..</p><p>[96] NorrisG.,WagnerM..AirbusA380-Superjumboofthe21stCentury.St.Paul,USAZenithPress2005</p><p>[97] Airbus"A380onTheSky,"Airbus,2017.[Online].Available:http://www.aircraft.airbus.com/aircraftfamilies/passengeraircraft/a380family/innovation/.[Accessed5September2017]..</p><p>[98] Wikipedia,TheFreeEncyclopedia"Boeing787Dreamliner,"Wikipedia,18August2017.[Online].Available:https://en.wikipedia.org/wiki/Boeing_787_Dreamliner.[Accessed22August2017]..</p><p>[99] Wikipedia,TheFreeEncyclopedia"A-90Orlyonok,"Wikipedia,10August2017.[Online].Available:https://en.wikipedia.org/wiki/A-90_Orlyonok.[Accessed209August2017]..</p><p>[100] YunL.,DooJ..WIGcraftandEkranoplan.Springer201010.1007/978-1-4419-0042-5</p><p>[101]</p><p>WingshipTechnology"WSH-500ProductBrochure,"WingshipTechnology,Seul,2014..</p><p>[102] BerievAircraftCompany"Beriev2500,"BerievAircraftCompany,2017.[Online].Available:http://www.beriev.com/eng/Be-2500_e/Be-2500_e.html.[Accessed5September2017]..</p><p>[103] D.Grossman"GrafZeppelinHistory,"Airship.Net,2010.[Online].Available:http://www.airships.net/lz127-graf-zeppelin/history/.[Accessed5September2017]..</p><p>[104] TeedP.L..GasFuelsforAirships:TheManufactureofBlauGas,withDetailsofsomePossibleAlternatives.Aircr.Eng.Aerosp.Technol.19313414210.1108/eb029368</p><p>[105] D.Grossman"GrafZeppelinDesignandTechnology,"Airships.net,October2016.[Online].Available:http://www.airships.net/lz127-graf-zeppelin/graf-zeppelin-design-technology/.[Accessed29August2017]..</p><p>[106] E.SpringmannFlugzeugundHubschraubervonHeinrichFocke1912-1961,Oberhaching:AviaticVerlag,1997..</p><p>[107] Wikipedia,TheFreeEncyclopedia"JunkersJumo205,"Wikipedia,19June2017.[Online].Available:https://en.wikipedia.org/wiki?curid=638303.[Accessed5September2017]..</p><p>[108] F.KoberBV138DerFliegendeHolzschuh,Friedberg:Podzun-PallasVerlag,1973..</p><p>[109] MagazineF..SovietDesignerTupolevDescribesHydrogenFuelSafetyMeasures.FlightMagazine198916</p><p>[110] BioFuel.org.uk"NationalFuelAlcoholProgram(Proalcool),"Biofuel.org.uk,2010.[Online].Available:http://biofuel.org.uk/National-Fuel-Alcohol-Program.html.[Accessed5September2017]..</p><p>[111] Airbus"AirbusE-Fan,"Airbus,2017.[Online].Available:http://company.airbus.com/responsibility/airbus-e-fan-the-future-of-electric-aircraft.html.[Accessed5September2017]..</p><p>[112] Wikipedia,TheFreeEncyclopedia"Blaugas,"Wikipedia,21July2017.[Online].Available:https://en.wikipedia.org/wiki?curid=6474209.[Accessed6September2017]..</p><p>[113] M.Epperle"TheSonicCruiser–AConceptAnalysis,"InternationalSymposiumAviationTechnologiesoftheXXICentury:NewAircraftConceptsandFlightSimulation,2002.[Online].Available:http://www.mh-aerotools.de/company/paper_7/astec_2002.htm.[AccessedSeptember2017]..</p><p>EntropyStatisticsandClusterAnalysisAppliedtoJetAirlinerandFighter</p><p>AircraftClassification</p><p>BentoS.deMattos</p><p>Abstract</p><p>Thepresentworkdescribestheentropystatisticstheoryanditsapplicationto</p><p>analyzethecommercialaviationmarketandfighteraircraft.Airlinersare</p><p>designedtocomplywithcertificationrequirementsandtoprovideoperational</p><p>profitabilitytoairlines.Theyneedtobemoreeconomical,lighter,fasterand</p><p>betterthanitspredecessors.Understandingthetechnologicalevolutionof</p><p>aviationisextremelyusefulwhenoneisdesigningnewaircraft.Saviotti(1984)</p><p>andlater,Frenken(1997)proposedamethodofanalysisofaircrafttechnological</p><p>evolution.Thismethod,basedoninformationtheorydevelopedbyShannon</p><p>(1948),speciallytheconceptofentropystatistics,hasprovedtobeveryeffective</p><p>forproductclassification.Thus,amethodologybasedonentropystatisticswas</p><p>employedtoanalyzethejetairlinerssincethe1950sandfighteraircraftsince</p><p>WorldWarI.Theresultsshowtheimpactofnotableeventssuchasthe1978</p><p>AirlineDeregulationActontheairplanedesignsandnaturally,theworldwars.</p><p>Theairplanescanbeclassifiedintofourgroups:niche,fuzzy,scaledtrajectories</p><p>andbreakthroughdesigns.Someairplaneswerechosenforadeeperanalysisand</p><p>theentropystatisticsmethodologycouldcorrectlabelsomeairplaneslikethe</p><p>ERJ145family,theBoeing777-300,andAirbus340-500.Fighterairplaneslike</p><p>theVoughtCutlass,WestlandWyvern,andIA-54Pucaráalsocouldbe</p><p>adequatelycategorizedandrated.</p><p>Keywords:Aircraftdesign,Airliner,Airplaneevolution,Entropystatistics,</p><p>Fighteraircraft,Informationtheory.</p><p>INTRODUCTION</p><p>Objectives</p><p>Inthepresentwork,elementsofinformationtheoryaredescribedtoevaluate</p><p>keyairlinersdesigns,i.e.,airplaneconfigurationsthatplayeddecisiverolein</p><p>commercialaviationandforfighteraircraft,eitherbysuccessfullyintegrating</p><p>previoustechnologiesortransmittingtheircharacteristicstoairplanesthat</p><p>succeededthem.</p><p>Indeed,aeronauticalevolutionisdeeplyrelatedtotechnologicalevolution.As</p><p>such,likeanyotherformofevolution,itfollowscertainrulesorheuristics.</p><p>These</p><p>rulescanvaryincomplexity;fromtherelativelysimplearithmeticalprogression</p><p>tothemoreintricatebiologicalevolution.Technologyfitscloselytothecomplex</p><p>endofthatspectrum.Thisformofevolutioncanpotentiallybelucrativeifwell</p><p>understood,especiallyatacorporatelevel.Byemployingtheentropystatistics</p><p>methodology,analysesconcerningairplaneevolutionwerecarriedoutand</p><p>aircraftcouldbecategorizedregardingtheirimportanceintermsofaviation</p><p>contribution[1].However,theentropystatisticstooldoesnotjustconsider</p><p>technologyinvolvedinproductevolution.Technologyisofmajorimportancefor</p><p>improvingaircraftperformanceasitiswidelyknown,butsometimesaviation</p><p>evolvesthankstodiscoveriesofnewbusinessmodels.Forinstance,thisisthe</p><p>caseofthebusinessaviation,whichhadaconsiderableboostinthe2000sthanks</p><p>tothesharedownershipconcept.Thisinturnledtoanincreaseinnewbusiness</p><p>aircraftconfigurations.Theentropystatisticsdealingwiththeinformationand</p><p>distancebetweenthedesignscaneasilymapsuchkindofevolution.Thisisalso</p><p>validfortheeffectsthatthe1978DeregulationActexertedonairlinerdesign.</p><p>Theworkpresentedhereisanimprovedandextendedeffortregardingtheone</p><p>performedbyFrenkenandLeydesdorff[2].Here,moresuitablevariables</p><p>adequatelyrepresenttheaircraftconfigurationanditsembeddedtechnology.The</p><p>variableswerecarefullyselectedafteranextensivestudy.Bothworksalsodiffer</p><p>inrangeofapplication.Twoanalyseswereperformedtoevaluatethe</p><p>applicabilityofthemethodology.Oneisconcernedwiththeevolutionofcivil</p><p>aviationtransportationinthejetage(1955-2015)andtheotherwiththe</p><p>evolutionoffighteraircraft(from1914to2009).Afterthecreationofthe</p><p>databankcontainingaircraftcharacteristics,anumericaltoolthatwasdeveloped</p><p>takesthevariablesasinputtoevaluatetwoimportantevolutionaryindexes:</p><p>convergenceanddiffusion.Studiesanalyzingthecombinationofthediffusion</p><p>andtheconvergenceindexes,aswellasthecriticaltransitionoftheairplanes</p><p>werecarriedouthere.Basedonthisapproach,othercomputertoolscanbe</p><p>elaboratedtoassistdecision-makingprocessintheaircraftconceptualdesign</p><p>phase.</p><p>Inadditiontotheentropystatisticsclassificationoftheaircraft,clusteranalysis</p><p>forcommercialjetairlinersmadeitpossibletoaccommodatetheminto11</p><p>groups.Dendrogramplotswerealsoobtainedforthejetairlinersandfighter</p><p>aircraftandthistoolprovedtocombinetheairplanesveryefficientlyandvery</p><p>reasonably.</p><p>Anextendedutilizationofentropystatisticsandclusteranalysiscanenable</p><p>designteamstoconceivenicheairplanesortodiscoverwhatcharacteristicsof</p><p>certainaircraftmustbechangedtoturnitfromfailuretoanicheaircraftoreven</p><p>abreakthroughdesign,forexample.</p><p>HowProductsEvolve</p><p>Itcanbeeasilyobservedthatthetoolsandinstrumentsdevisedbyhumanbeings</p><p>undergoanevolutionthemselvesthatisstrangelyanalogoustoordinary</p><p>evolution,almostasiftheseartifactspropagatedthemselvesasanimalsdo.</p><p>Aircraftbeganasbirdlikeobjectsbutevolvedintofishlikeobjectsformuchthe</p><p>samehydrodynamicreasonsasthosewhichcausedfishtoevolveintofishlike</p><p>objects.Bicycleshaveevolvedandsodidmotorcars[1].</p><p>Thechallengeofunderstandingthedynamicsoftechnologicaldevelopmenthas</p><p>longbeenaconcernofeverybranchofmanufacturingenterprises.Two</p><p>approachesdominatethescene:onesuggeststhattheexternalrequirementsof</p><p>themarket[3],whiletheotherviewstheactivitiesandinternal</p><p>capabilitiesof</p><p>firmsasprimarydriversofinnovation[4].Takenseparately,eachapproach</p><p>highlightskeyaspectsoftechnologicaldevelopmentbut,asmanyhaveargued,</p><p>thegreatestinsightderivesfromtheirjointconsideration[5].</p><p>Convergencecontendsthatproductsevolveintounifieddevicesthroughlinear</p><p>evolutions;whereaswithdivergenceinnovationisspurredthroughdisruptive</p><p>revolutions.TheInternetwasadisruptivetechnologyandthesamewillcertainly</p><p>occurtotheairtransportation.Anotherwayofmovingintheatmospherewill</p><p>notbecalled“airplane”anymore.Convergencecapturestheimagination,but</p><p>divergenceistunedtothemarket.</p><p>Today,manytypesofaircraft,jetaircraft,propeller-drivenairplanes,and</p><p>helicopters,andmanytypesofautomobiles,sedans,convertibles,station</p><p>wagons,minivans,sport-utilityvehicles,areavailablebymanufacturers.</p><p>However,noflyingcarreallysucceeded,althoughmanyattemptshavebeen</p><p>madetobringthemintolife.Ries[6]asksthequestion“Whydivergenceandnot</p><p>convergence?”Perthem,thatisbecauseconvergencerequirescompromiseand</p><p>divergencesatisfiestheevolvingneedsofdifferentmarketsegments.An</p><p>automobileneedstobeheavyenoughtostayonthehighway;anairplaneneeds</p><p>tobelightenoughtotakeofffromarunwayandperformitsmissionproviding</p><p>profittoitsoperator.</p><p>Noflyingcarwilleverbeasdrivableasanautomobileoraswellflyableasan</p><p>airplane.Theautoboat,anotherconvergenceconceptthathasbeenfloating</p><p>aroundfordecades,suffersfromthesameflaws.</p><p>Thecodificationofdesignprinciplesassociatedwiththeemergenceofa</p><p>dominantdesignalsoimpliesaconvergenceofdesignprinciplesthathavebeen</p><p>developedinthepast.Thus,thecomingintoexistenceofascalingtrajectoryat</p><p>theindustrylevelisessentiallyatwo-sidedphenomenon.Itrefersbothtothe</p><p>diffusionofdesignprinciples,andtotheconvergenceofdesignprinciples.These</p><p>phenomenaaredifferent:thediffusionofdesignprinciplesdoesnotnecessarily</p><p>implyconvergenceofdesignprinciples,sinceadesigncanbescaledinvarious</p><p>andpotentiallydivergentdirections.Forexample,someaircraftfirmsmayscale</p><p>adominantdesignwithrespecttomaximumtake-offweight,otherswithrespect</p><p>tospeed,andstillotherswithrespecttorange.Hence,totestthedominant</p><p>designhypothesis,oneneedstodistinguishbetweenthediffusionofdesign</p><p>principlesthroughtimeandtheconvergenceofdesignprinciplesthatcanbe</p><p>observedinretrospect.</p><p>Atthispoint,itisworthyofmentionthedifferentmeaningsofdivergenceand</p><p>diffusion.Consideringthecomputerasexample,itcanbeeasilyperceivedthat</p><p>therearesupercomputers,networkcomputers,personalcomputers,laptop</p><p>computers,tabletcomputersandhandheldcomputers.Thatisatypical</p><p>divergencecase,afamilyofproductshavingthesamecommonancestral.</p><p>Diffusionisrelatedtovariousproductssharingcommontechnologiesor</p><p>features.Thefly-by-wireflightandcontrolsystemappearedinaWestern</p><p>commercialplaneinthesupersonicConcordeairliner.Sincethosedays,this</p><p>technologyhasspreadherlegstoalargevarietyofairplanes.Evensmallto</p><p>mediumcapacityairlinersliketheEMBRAERE170(Fig.3.1)haveadopted</p><p>suchtechnology,althoughinthiscaseisananalogiconeandnotallcontrol</p><p>surfacesareelectricallycontrolledandcommanded.EMBRAERredesignedits</p><p>largerE-Jetsandprovidedthemwithadigitalfly-by-wiresystem.Thatisa</p><p>typicalexampleofdiffusion.</p><p>Fig.(3.1))</p><p>EMBRAERE170shortbeforeitsfirstflight(Photo:©2002BentoMattos).</p><p>MODELINGTECHNOLOGICALEVOLUTION</p><p>UtterbackandAbernathy[7]haveproposedtheconceptofaproductlife-cycle</p><p>todescribetechnologicalevolutionatindustrylevel.Aproductinnovation</p><p>containsarecenttechnologyorcombinationoftechnologiesincorporatedintoit</p><p>tomeetauseroramarketneed[7].Similarwhathappensinprocess</p><p>development,abasicideaforproductinnovationisthatproductswillbe</p><p>developedovertimeinapredictablemannerwithinitialemphasisonproduct</p><p>performance,thenemphasisonproductvarietyandlateremphasisonproduct</p><p>standardizationandcosts[7].Thisconceptallowstheresearchertodistinguish</p><p>bothamongtheinnovativepatternsoffirmsinanindustryatagiventimeand</p><p>amongthoseofa*givenfirmatvarioustimesbasedondominantcompetitive</p><p>strategy[7].Thus,innovationconcentratesonprocessandincremental</p><p>improvementoftheproductregardingthedominantdesign.NelsonandWinter</p><p>[8]andDosi[4]proposedtodescribeaseriesofincrementalinnovationswithin</p><p>astabledesignframeworkasanaturaltrajectoryortechnologicaltrajectory,</p><p>respectively.Alongatrajectory,developmentisguidedandconstrainedbyaset</p><p>ofheuristicswhichmakeupatechnologicalparadigm.Thetrajectoryconcept</p><p>canbeappreciatedasthedynamicanalogueoftheconceptofadominantdesign.</p><p>NelsonandWinter[8]andSahal[9]highlightedthattrajectoriesdonotonly</p><p>concernperiodsduringwhichthebasictechnologicalprinciplesremain</p><p>unchanged,butalsoastageofincrementalscalingofdesigns.Aprimeexample</p><p>ofaseriesofscaledmodelsincivilaircrafthasbeenthepistonpropeller</p><p>Douglasairlinertrajectory.Thescalingoftheenginepower,wingspan,and</p><p>fuselagelengthhaveledtoimprovementsinspeedbyafactoroftwo,andin</p><p>maximumtake-offweightandrangebyafactoroffivefromtheintroductionof</p><p>theDC-3in1936tothatoftheDC-7in1956.</p><p>InformationtheorywasfirstmentionedbyClaudeE.Shannoninhis1948paper</p><p>entitledAMathematicalTheoryofCommunication[10].Themainpurposeof</p><p>Shannon’sworkistodealwiththeproblemoftransmittinginformationovera</p><p>noisychannel.Hecouldnotimaginethatawholenewfieldofmathematics</p><p>wouldresultfromhisproposition.Manydeepandfarreachingmathematical</p><p>theorieswerecreated,suchaschannelcapacity,source-codingandself-</p><p>information.AgreatcontributionofShannonwashisuseofentropyplayinga</p><p>vitalroleininformationtheoryasmeasuresofinformation,choiceand</p><p>uncertainty[10].</p><p>EntropyappearedasthermodynamicentropybyRudolfClausiusin1850,inhis</p><p>workonSadiCarnot’s1824thermodynamicefficiencystudy.Clausiusderiveda</p><p>proportionalrelationshipbetweenentropyandtheenergyflowbyheating(δQ)</p><p>intoasystem[11].Inasystem,thisheatenergycanbetransformedintowork,</p><p>andworkcanbetransformedintoheatthroughacyclicalprocess[12].</p><p>Clausiuswritesthat[12]:“Thealgebraicsumofallthetransformations</p><p>occurringinacyclicalprocesscanonlybelessthanzero,or,asanextremecase,</p><p>equaltonothing.”</p><p>TheamountofentropySaddedtothesystemduringthecycleisdefinedas</p><p>(3.1)</p><p>However,themoremoderndefinitionofentropyasameasureof“disorder”ina</p><p>systemwasintroducedbyLudwigBoltzmannin1877.This“disorder”entropy,</p><p>orstatisticentropy,thenbecamethecornerstoneofthetheoryofstatistical</p><p>mechanicsandwaslaterusedbyShannoninhisinformationtheory[10].Inthis</p><p>context,sometextbookserroneouslyemploythe“studentdeskincreasing</p><p>disorderwithtime”asanexampleofentropy.Thiscanbemisleadingsincethe</p><p>morepreciseexamplewouldbe,“whichsystemhashigherentropy:the</p><p>organizeddeskorthemessyone?”Theanswerwouldprobablybethemessy</p><p>one,becausetherearemanymorewaysofarrangingtheitemsinachaotic</p><p>mannerthanthereareinanorganizedone.Thisisbasicallythedefinitionof</p><p>entropyelaboratedbyShannon,andtheoneusedinthispaper.</p><p>ManyresearcherscreditShannonastheactualarchitectofentropy,sincehis</p><p>definitionofentropyisbroaderthantheoriginalthermodynamicdefinition.</p><p>Thoseresearchersclaimthatthermodynamicentropyisacategoryof</p><p>informationentropy.Howdoesthisstatisticalentropyrelatetothestudyof</p><p>technologicalevolution?Anysystemthatcontainsamacroscopic</p><p>stateruledby</p><p>manydifferentmicroscopicsystems,suchasbiologicalevolution,economic</p><p>growth,imagereconstructionandtechnologicalevolution;canbestudiedusing</p><p>entropy.</p><p>Ifacertaintechnologyhasestablisheditselfoveranextendedperiodwithoutany</p><p>majorbreakthroughs,onecanconcludethattheentropyofthateraisverylow,</p><p>sincethereisalowdegreeofuncertainty.Thismeansthatsomebreakthrough</p><p>hasoccurredinthepastandthatmostofthecompetitors,ifthereareany,have</p><p>borrowedinformationfromthatbreakthrough.Theappearanceofadominant</p><p>designusuallyprecludesalowentropyera,whileaneraofexperimentation,</p><p>withhighdiversityshowsnodominantdesigns,andthus,highentropy.</p><p>Therefore,onecanusethesefar-reachingtheoriestostudytheevolutionof</p><p>technologyinaspecificsectorofindustry,suchascivilaviation,automobiles,</p><p>computers,etc.</p><p>Inthepresentstudy,theanalysistheevolutionofciviltransportaviationofthe</p><p>jetage(1950-2017)iscarriedout.Specificpointsfrominformationtheoryand</p><p>entropystatisticswereemployedandarediscussedinthenextsection.Although</p><p>manycalculationsareperformedinthisanalysis,theresultscanonlybe</p><p>interpretedinaqualitativemanner.Entropystatisticsisbestemployed,outside</p><p>ofpureinformationtheoryandthermodynamics,asatoolforqualitativeanalysis</p><p>ofasubject.</p><p>METHODOLOGYFORAIRPLANECLASSIFICATION</p><p>Entropy</p><p>Entropycanbealsounderstoodasdedegreeofuncertaintyofatransmitted</p><p>message.Shannon,morespecificallydescribeditastheminimumnumberofbits</p><p>thatmustbecommunicatedtoasinterlocutorforhimtoknowthevalueofa</p><p>randomvariable.Consider,forexample,thatatransmissionofdataiscomposed</p><p>ofaseriesofASCIIcharacters.Ifthecharactersarerandom,theentropyofthe</p><p>messageisseventimesthenumberofcharacters(sinceeachASCIIcharacteris</p><p>composedofsevenbits,andentropyisgiveninbits).If,however,weknowin</p><p>advancethatthisseriesisarepetitionofthesamecharacter,thentheentropyis</p><p>zero,sincewe,byknowingoneofthecharacterswillknowalltheothers.Onthe</p><p>otherhand,ifthemessageiscomposedoftruetext,theentropyisnotzero,butis</p><p>notit*maximumvalue(aswasintherandomtext).Thevalueoftheentropyis</p><p>goingtobesomethinginbetween,sincewrittenlanguageallowsustoinferthe</p><p>restofamessagebyknowingonlypartsofitscontent.Writtenlanguageis,in</p><p>otherwords,redundant,whichreducesitsentropy.Englishlanguage,for</p><p>example,hasanaverageentropyof1to1,5bitspercharacter,insteadofthe7</p><p>bitspercharacterinarandommessage.</p><p>Shannon[10]proposedthattheentropyofamessageisgivenby:</p><p>(3.2)</p><p>InEq.3.2nisthesetofallpossiblemessages,whereaspiistheprobabilityof</p><p>occurrenceofthei-thpossiblevalueofthesourcesymbol.Notethatbyusingthe</p><p>logarithmicbase2theentropywillbemeasuredinbits.Hreachesitsmaximum</p><p>whenallmessageshavethesameprobabilityofoccurrence,i.e.,andhenceH=</p><p>log2n.</p><p>Asitisdefined,entropyhasasetofpropertiesthatarerelevantforthiswork:</p><p>Continuity:Themeasureofentropyisacontinuousfunction,whichallowsfor</p><p>easierconvergence.</p><p>Symmetry:Themeasureofentropyisunchangediftheorderofprobabilitypis</p><p>changed.Thisallowsdataforaircrafttobeaddedatwill,withnoregardforthe</p><p>orderinwhichitisarranged,withoutchangeintheentropyvalues.</p><p>Additivity:Entropyremainsthesameindependentlyonthewayinwhichthe</p><p>systemisdividesinsubsystems,whichinturnallowseachaircrafttobe</p><p>comparedtoothersindependently.</p><p>TheworkperformedbyFrenkenandLeydesdorff[2]providedabaseline</p><p>methodologyforthepresentstudyaboutaircraftevolutionandproduct</p><p>characterization.Thetargetedimprovementsarethechoiceofvariablesforeach</p><p>design,theavailabilityofnewerdesigndataandthefocusonregionalairliners,</p><p>whileconductingfirm-levelanalysis.Anotherexpectedconclusionforthiswork</p><p>istoascertainhowrobusttheappliedtheoryandmethodologyreallyisinthis</p><p>case.</p><p>Themosteffectivewaytonumericallyrepresentaproductistomodelitsvarious</p><p>concepts(trade-offs),whicharetheexpressionofyearsoftechnicaldevelopment</p><p>andengineeringhours.Tomodelthesetrade-offs,itisnecessarytocreateratios</p><p>betweeneverycharacteristicofaproduct.Arrangingtheseratiosinmatrixform,</p><p>amodelforthetrade-offsiscreated.Thismatrixisareasonablerepresentation</p><p>ofaproductdesign,butitisnotusefulininformationtheory.Bydividingall</p><p>theseratiosbytheirsum,aprobabilisticdistributionisthenobtained,here</p><p>denotedby(p1,p2,…,pn),wherenisthetotalnumberofratios.Thisway,a</p><p>probabilisticrepresentationforeachproductisprovided.Everyproductcontains</p><p>someinformationfrompreviousdesignsandprovidesinformationtothoseones</p><p>thatfollowedit(Fig.3.2).Usinginformationtheory,wecancalculatehowmuch</p><p>informationispassedamongdesignsusingtheformulabelow:</p><p>(3.3)</p><p>InEq.3.3,Iisameasureofdistancebetweentwoproductdesigns,withq</p><p>chronologicallyafterp.Thisisthesameastheamountofinformationpassedon</p><p>fromptoq.IfnoinformationispassedonthenparameterIisequaltozero,</p><p>becauseeverytrade-offisthesame,evenifthecharacteristicsarenotthesame.</p><p>Thiswouldbeaperfectlyscaledversionofapreviousproduct.Mathematically</p><p>thismeansthatanditslogisthenzero.InterestinglynomatterwhatIis,itwill</p><p>alwaysbepositive,thisiscalledprobabilisticentropy,anditisbecauseevery</p><p>messagethatchangehasoccurredisexpectedtocontaininformation.LowerI</p><p>meanslesschangeoccurredfromptoq,i.e.,themoresimilartheproductsare.</p><p>Fig.(3.2))</p><p>Entropyapplicationtoproductevolution.</p><p>ConvergenceandDiffusion</p><p>Forapplicationinproductevolution,inEq.3.3,pisaposterioridistributionand</p><p>qisapriorione.Fromthis,twoimportantparameterscanbederived,whichare</p><p>importantforproductcategorization.Theseparametersarecalledconvergence</p><p>anddiffusion.Convergenceisobtainedwhenweconsideranindividualpand</p><p>lookacertainperiodpastintimeandconsidersthecharacteristicsfromanother</p><p>individualqinthattimeframe.Inthecaseofdiffusionofadesignthroughtime,</p><p>theframeofreferenceisaproductdesignastheaprioriexpectationoffuture</p><p>designs[2].</p><p>ThediffusionofaproductdesigncanthenbemeasuredbyitsdistanceI</p><p>calculatedbyEq.3.3toallthemembersofthetechnologicalpopulationasa</p><p>posteriorieventsatnextmomentsintime.TheaverageofI-valuesisthen</p><p>obtainedbydividingthesumofI-valuesbythenumberofcomparisonsNduring</p><p>therespectivetimeframeofobservation[2].Table3.1summarizesthedefinition</p><p>oftheseparameters.</p><p>Table3.1Definitionoftheconvergenceanddiffusionparametersemployedin</p><p>thepresentwork.</p><p>Diffusion</p><p>Measurethepropagationofinformationcontainedineachdesignforitssuccessors</p><p>Thediffusioncoefficientiscalculatedbyaveragingthecoefficientsobtainedconsideringtheairplanesthatsucceedthereferenceproductindesiredtimewindow</p><p>AccordingtoFrenken[13],industrialproductscanbeclassifiedasfollow:</p><p>innovations;scaledtrajectories;niches;andfailures.Innovationsare</p><p>introductionofanew,redesignedorsubstantiallyimprovedgoodorservice,well</p><p>distinguishedfromitspredecessors.Innovativeproductsinfluencetheir</p><p>successorsandintroducedominantdesigns.Theyarecharacterizedbyalow</p><p>valueofdiffusionandahighvalueofconvergence.Scaledtrajectoriesare</p><p>projectsthatfollowpatternsdefinedbypreviousprojectsandinfluencetheir</p><p>successors,thescaledtrajectoriesareundertheinfluenceofdominantdesigns,</p><p>andarecharacterizedbyalowdiffusionvalueandalowconvergencevalue.</p><p>Productsthatfitintomarketnichesarethosecomplyingwithstandards</p><p>defined</p><p>bypreviousdesignsanddonotexertprofoundinfluenceondesignsthatcome</p><p>afterit.Theyarecharacterizedbyahigh-diffusionandalow-convergence</p><p>indexes.Failuresareconceptsthatdifferfromtheirpredecessorsanddonot</p><p>influencetheirsuccessors,beingcharacterizedbyahighvalueofitsdiffusion</p><p>coefficientandahighvalueoftheconvergenceindexaswell.Thiskindof</p><p>designclassificationofindustrialproductswasintroducedbyFrenken[2].Table</p><p>3.2providesacompilationofthisclassificationwiththe“failure”classification</p><p>replacedbyabetterone:“fuzzy”configurations.</p><p>ProductsthatlieintheNortheastquadrantwereclassifiedbyFrenkenasfailures.</p><p>However,wepreferthecognomen“fuzzy,”placingthemasanindistinct</p><p>product.Thisalsoconsidersthatmustbeagradationamongthequadrantsfor</p><p>theproductsthatliesclosetotheboundaries.Inaddition,theconvergenceand</p><p>diffusionindexesarehighlydependentonthetimeframeselectedfortheir</p><p>calculationandthenormalizationemployedforthevariablesthatcharacterize</p><p>theproducts.</p><p>Table3.2productclassificationaccordingtodiffusionandconvergenceindexes</p><p>Convergence HighI-values Breakthroughs Fuzzy</p><p>LowI-values DominantDesigns Niche,Monopolies</p><p>LowI-values HighI-values</p><p>Diffusion</p><p>Anevaluationoftheimpactofthetimeframeontheconvergenceanddiffusion</p><p>I-valueswascarriedoutbyVale[14].Inhiswork,analysisofthefixed-wing</p><p>businessaviationmarketwascarriedoutconsideringtimeframesof5,10,and20</p><p>years.Thesmallervalueforthetimeframeseemstofitbetterwiththeairplanes</p><p>employedinhisstudy.AMATLAB®codewaselaboratedbytheauthorsto</p><p>applytheentropystatisticstheoryforairplaneclassification,morespecifically,</p><p>jetairliners.AMicrosoftExcel®worksheetisneededforrunningthecodeand</p><p>thereforeworksheetscontainingdatafor98jetairlinersand281fighteraircraft</p><p>werecompiledtofeedthecodewithalldataitneeds.</p><p>DendrogramandCopheneticCorrelationCoefficient</p><p>Clusteranalysisisaconvenientmethodforidentifyinghom*ogenousgroupsof</p><p>objects(cases,data)[15].Besidesusefulinclusteranalysis,aDendrogramplot</p><p>isausefultooltoillustratethearrangementoftheclustersproducedby</p><p>hierarchicalclustering.ADendrogramconsistsofmanyU-shapedlinesthat</p><p>connectdatapointsinahierarchicaltree[15].TheheightofeachUrepresents</p><p>thedistancebetweenthetwodatapointsbeingconnected.Theheightofthe</p><p>verticallines,indicatesthedegreeofdifferencebetweenbranches.Thelonger</p><p>theline,thegreaterthedifference.ThehorizontalorientationofDendrograms</p><p>showsthedesignneighborhood.Instatistics,copheneticcorrelationcoefficientis</p><p>ameasureofhowcloseadendrogrampreservesthepairwisedistancesbetween</p><p>theoriginalunmodeleddatapoints[16].</p><p>ConsideringthatYisthedistancematrixandZisahierarchicaltree,the</p><p>copheneticcorrelationcoefficientisthengivenby:</p><p>Themagnitudeofthecalculatedvalueofcshouldbeverycloseto1forahigh-</p><p>qualitysolution.Thismeasurecanalsobeusedtocomparealternativecluster</p><p>solutionsobtainedusingdifferentalgorithms.</p><p>RESULTSOFAPPLICATION</p><p>Themethodologyoutlinedbeforewasappliedtostudytheevolutionofjet</p><p>airplanesandfighteraircraft.Thejetairlinerswithentryintoserviceofthe</p><p>period1950-2018wereconsidered.Theotherstudyinvolvedfighteraircraft</p><p>from1914to2009.Aconsiderableeffortwascarriedouttoconsidervariables</p><p>thatcandeliveragoodrepresentationoftheaircraft.Thejetairplanesare</p><p>describedby24variablesandthefighteraircraftbyjust19ones.</p><p>Jetliners</p><p>ThefirstcolumnoftheExcel®worksheetwasfilledwithairplanenames;the</p><p>secondonecontainstheyearofserviceentryoftheairliners.Theremained</p><p>columnscontaintheparametersemployedforairplanedescriptionandtheyare</p><p>asfollow:</p><p>1)Entryintoservice2)MTOW[kg]3)MaximumZero-FuelWeight[kg]4)Operatingemptyweight[kg]5)Fuelcapacity[kg]6)Wingreferencearea[m²]7)Wingaspectratio8)Wingtaperratio9)Wingquarter-chordsweepbackangle(Degrees)10)Verticaltailaspectratio</p><p>TheearliestdesignistheSud-AviationCaravelletwinjet.TheEmbraer190E2,</p><p>withserviceentryenvisagedfor2018,wasalsoconsideredinthecomputations.</p><p>TheConcordeandTupolevTu-144supersonicairlinersalsocomposethe</p><p>databank.</p><p>Fig.3.3displaystheMTOWandwingareaofallairplanesinthedatabank.</p><p>Thereisaconsiderablespreadofthisvariableovertheyears.</p><p>Fig.(3.3))</p><p>MTOWandwingareaoftheairplanesinthedatabankthatwereemployedto</p><p>entropystatisticscalculation.</p><p>FeaturedAircraft</p><p>Canadair(acquiredbyBombardierAerospace)isconsideredasthecreatorofthe</p><p>termregionaljetbecauseitbroughtintotheaviationmarketit*50-seatCRJ-100</p><p>twinjetin1992.However,thefirstregionaljetisthoughttobetheYakovlev</p><p>Yak-40trijet,whichwasintroducedintheSovietUnion,flyingforAeroflotin</p><p>1968.IntheWesternworld,therewereotherimportantaircraftofslightlylarger</p><p>sizesuchastheSudAviationCaravelleandtheFokkerF-28thatfitintothe</p><p>acronymregionaljet.Inaddition,theVFW-Fokker614(alsoVFW614)wasa</p><p>twin-enginejetlinerdesignedandbuiltinWestGermany.Itofferedpassenger</p><p>accommodationbetween36-40seatsandhadanunusualconfiguration,withtwo</p><p>M45Hturbofansmountedonpylonsabovethewings.VFW614wasproduced</p><p>insmallnumbersbyVFW-Fokkerintheearly-tomid-1970s.Itwasoriginally</p><p>intendedasaDC-3replacement.Embraerenteredtheregionaljetmarketin</p><p>1997,afterContinentalExpressstartedoperationswithabatchofERJ145ER</p><p>airliners.TheERJ145ERrangewasconsiderableshorterthanthecompetitionin</p><p>theformofBombardierCRJ-200airplaneandin1998Embraerwasdelivering</p><p>the1600-nmLRversion.TheERJ145XRisalaterversionandmorepowerful</p><p>versionoftheERJ145.TheERJ145XRclimbsfaster(at300kts)andburnsless</p><p>fuelthantheERJ145ER/LR.Table3.3comparessomecharacteristicsofthe</p><p>ERJ145versions.</p><p>Table3.3DataforsomeERJ145versions(Source:EMBRAER).</p><p>Version MaximumTakeoffWeight[kg] OperationalEmptyWeight[kg]</p><p>ER(MK) 19,990 12,038</p><p>LR 22,000 12,114</p><p>XR 24,100 12,591</p><p>Results</p><p>TheresultingentropyindexvariationovertimeisdisplayedinFig.(3.4).There</p><p>arethreepeaksinentropy,thelargestofthemrecordedinthe1982-1984period.</p><p>Fig.(3.4))</p><p>Entropyindexvariationovertime.</p><p>ThethreepeaksthataredisplayedinFig.(3.4)wereanalyzedandsomepossible</p><p>explanationsfortheirappearancehavebeendevelopedasfollows:</p><p>P1–The1960sarewellknownforalargediversityofnewcommercialairplane</p><p>designs-someofthemhavenevermaterialized,liketheBoeingSST.The</p><p>Boeing747-100,Boeing737-100,DC-9andmanyothersbelongtothiscreative</p><p>decadeintermsofdesignsthatmadehistory.</p><p>P2–Theturbofanengineandsupercriticalairfoiltriggeredanew-generationof</p><p>high-efficiencyairplanesthatwereneededafterthe1973oilcrisis.TheBoeing</p><p>737-200underwentadeepredesignfromwhichthe-300versionwithturbofan</p><p>enginesemerged,andconsequentlysalessoared.The1978DeregulationAct</p><p>shooktheaviationmarketandtheaircraftmanufacturerswereagileenoughto</p><p>copewiththenewworldthatappearedthereafter.Thus,theP2entropypeakisa</p><p>resultofallthesefactors:technology,theDeregulation,andtheoilcrisis.</p><p>P3–IttooksometimeaftertheDeregulationfortheintroductionofefficient</p><p>regionaljetairplanes.Inthe1980smostofthemwereturbopropairplanes.This</p><p>peakcanbeclearlycreditedtoregionaljetsofthe1990s.</p><p>TheaccumulatedentropyovertimeisshowninFig.(3.5).Itseemstobe</p><p>stagnatinginrecenttimes.Isthatasignthatanewrevolutionintechnologyis</p><p>needed?</p><p>Fig.(3.5))</p><p>Accumulatedentropyovertime.</p><p>Theclassificationofthedesignsin</p><p>inviewofincreasingglobalwarming[2]andmajorconcernsforthe</p><p>impactonpeople’shealth.Aircraft,cars,trucks,andothervehiclesoperatingat</p><p>airportscreateemissionsbecauseofthecombustionoffuel.Aircraftengines</p><p>producecarbondioxide(CO2),whichcomprisesabout70%oftheirexhaust,and</p><p>watervapor(H2O),whichcomprisesabout30%[1].Lessthan1%ofthe</p><p>exhaustiscomposedofpollutantslikenitrogenoxides(NOx),oxidesofsulfur</p><p>(SOx),carbonmonoxide(CO),partiallycombustedorunburnedhydrocarbons</p><p>(HC),particulatematter(PM),andothertracecompounds.Ingeneral,about10</p><p>percentofpollutantemissionsbyaircrafttakeplaceclosetothesurfaceofthe</p><p>earth(lessthan1000metersabovegroundlevel),theremaining90percentof</p><p>aircraftemissionsarereleasedataltitudesabove1km.ThepollutantsCOand</p><p>HCsareexceptionstothisruleastheyareproducedwhenaircraftenginesare</p><p>operatingattheirlowestcombustionefficiency(aircraftgroundswitchison),</p><p>whichmakestheirsplitabout30percentbelow1000meters,and70percent</p><p>above1000meters[1].</p><p>Significanteffortsoftheaviationandaeronauticalcommunityhavebeenmade</p><p>toloweraviation-relatedemissions.Alternativefuels,improvedairplane</p><p>designs,newaircraftconcepts,andfuel-savingoperationalproceduresare</p><p>amongthem.TheInternationalCivilAviationOrganization(ICAO)proposeda</p><p>“FourPillar”initiativetotheaviationandaeronauticalindustrywiththe</p><p>objectivetoaddresssometargetsofemissionreduction[3].Thisinitiative</p><p>considersinvestmentsaswellaseffortsonoperationalprocedures,</p><p>infrastructure,technologyandmarket-basedmeasures.</p><p>BesidesICAO,thereareseveralgovernmentsthathavebeenissuingpoliciesto</p><p>addresspollutioncausedbyaircraft.In2011,theEuropeanCommission</p><p>establishedseveralgoalsconcerningtheprotectionoftheenvironmentintended</p><p>tobeaccomplishedby2050[4].Accordingtothesetargets,technologiesand</p><p>proceduresavailableby2050aresupposedtoenablea75%reductioninCO2</p><p>emissionsperpassenger-kilometeranda90%reductioninNOxemissions;the</p><p>perceivednoiseemissionofflyingaircraftissupposedtobereducedby65%;in</p><p>addition,aircraftmovementsaresupposedtobeemission-freewhentaxiing.All</p><p>thesetargetsarerelativetothecapabilitiesoftypicalnewaircraftin2000.</p><p>However,accordingtotherecentstudies,operationalprocedures,improvements</p><p>oninfrastructure,andbiofuelsmaynotbesufficienttoaccomplishtheICAOand</p><p>EuropeanCommissiongoalswiththecurrenttechnologicalstateofart.New,</p><p>innovativeradicaldesignsmaybeneededtoaccomplishtheenvisagedemission</p><p>reductionsthatweresetbygovernmentsofseveralnations.Inaddition,aviation</p><p>shareofoverallpollutioncouldchangesignificantlyifelectricroadvehiclesgain</p><p>amorewidespreaduse.Thereareonlyfewstudiesontheimpactofelectrical</p><p>roadvehiclesintheemissionpictureonthetransportsector,andtheydisagree</p><p>significantlywitheachotherregardingtheirconclusionsonthesubject.</p><p>Electricalcarserialproductionisnotnew;anarticlefromthe1904MotorAge</p><p>Magazinepublishedaconservativeestimateoftheprobableoutputofthe</p><p>differentfactoriesforthatyear.Atotalproductionof30,000carswasestimated</p><p>thatwassupposedtobedividedroughlyasfollows:Licensedgasolinecars,</p><p>16,000;unlicensedgasolinecars,8,000;electriccars,3,000;steamcars,2,000;</p><p>miscellaneous,1,000.ColumbusElectricfromOhiowasoneoftheelectriccar</p><p>manufacturers.Its1905electriccarweighed635kgandhadarangeof75miles</p><p>beforerequiringbatteryrecharge[5].</p><p>Manyresearchersclaimthattheelectricalroadvehicleswillnotcontributeto</p><p>loweremissionlevelsinthewholechain,consideringthattheenergynecessary</p><p>toproducebatteriesandtopowerthosevehicleswillbehigherthanthecurrent</p><p>levels.However,arecentreportfromElectricPowerResearchInstitute(EPRI)</p><p>andNaturalResourcesDefenseCouncil(NDRC)affirmsthattheelectrical</p><p>vehicleemissionlevelsarefarlowerthanthepollutioncausedbyconventional</p><p>vehicles,andcouldbeevenloweriftheelectricpowersectorcleansitselfup</p><p>overthenextfewdecades[6].Inaddition,citieswillbecomecleaner,avoiding</p><p>billionsofmoneybeingspentonhealthcareofpeopleaffectedbypollution.</p><p>FortheEPRI-NRDCstudy,somepotentialscenariosfortheelectricitysectorin</p><p>thefutureandthepotentialemissionimpactofwidespreadelectrification</p><p>displacingpetroleumconsumptioninthetransportationsectorwerewell</p><p>considered.Toaddressthefirstissue,twopotentialgreenhousegasscenariosof</p><p>thefutureelectricpowersectorwereconsidered:namelythe“BaseGHG”and</p><p>“LowerGHG”scenarios.Bothrevealedthatgridemissionswilldecreaseover</p><p>time,inpartbecauseofexistingandpotentialregulationsandplausible</p><p>economicconditions.IntheLowerGHGscenario,anincreasingpriceoncarbon</p><p>issupposedtofurtherreducecarbonemissions,asitcouldresultinfaster</p><p>deploymentoflow-emissiongenerationtechnologies[6].IntheBaseGHG</p><p>scenario,thestudyestimatesthat,by2050,theelectricitysectorcouldreduce</p><p>annualgreenhousegasemissionsby1030millionmetrictonsrelativeto2015</p><p>levels,whichrepresentsa45%reduction.IntheLowerGHGscenario,thestudy</p><p>estimatesthat,by2050,theelectricitysectorcouldreduceannualgreenhouse</p><p>gasemissionsby1700millionmetrictonsrelativeto2015levels,representinga</p><p>77%reduction.</p><p>TheEPRI-NDRCreportalsoanalyzedelectricsectorandtransportationsector</p><p>emissionswithandwithoutwidespreadutilizationofelectricroadvehiclesto</p><p>determinetheeffectofelectrificationoflight-dutypersonalvehicles,some</p><p>medium-dutycommercialvehicleslikelocaldeliverytrucksandcertainnon-</p><p>roadequipment,likeforklifts.Itwasfoundthatelectrificationcoulddisplace</p><p>emissionsfromconventionalpetroleum-fueledvehiclesforeachscenario:</p><p>IntheBaseGHGscenario,carbonpollutionisreducedby430millionmetric</p><p>tonsannuallyin2050-equivalenttotheemissionsfrom80millionoftoday's</p><p>passengercars[6].</p><p>IntheLowerGHGscenario,carbonpollutionisreducedby550millionmetric</p><p>tonsannuallyin2050-equivalenttotheemissionsfrom100millionoftoday's</p><p>passengercars[6].</p><p>Independentfromtheseresults,therearegoodperspectivesthatthe</p><p>electrificationofroadvehicleswillchangetheemissionpanoramaofthe</p><p>transportationsector.Thiswillturnthecitieslesspollutedandquieter,changing</p><p>thepublicstandardforacceptablenoiseandemissionlevels.Thepresentwork</p><p>thereforeperformsananalysisoftheincreasingelectrificationofroadvehicles</p><p>ontheCO2emissionandhowthiscouldchangeaviationandredirecttheefforts</p><p>tocomplywithfutureemissionreductionpolicies.</p><p>AviationinaGlobalWarmingEnvironment</p><p>TheClimateChangeandAirTransport</p><p>Pollutiongeneratedsincetheindustrialrevolutionischangingdramaticallythe</p><p>averageglobaltemperature(Fig.1.1).Globalwarmingandclimatechangecan</p><p>bothrefertotheobservedcentury-scaleriseintheaveragetemperatureofthe</p><p>Earth'sclimatesystemanditsrelatedeffects[2].Multiplelinesofscientific</p><p>evidenceshowthattheclimatesystemiswarming[7].Morethan90%ofthe</p><p>additionalenergystoredintheclimatesystemsince1970hasgoneintoocean</p><p>warming;theremainderhasmeltedice,andwarmedthecontinentsand</p><p>atmosphere.Manyoftheobservedchangessincethe1950sareunprecedented</p><p>overdecadestomillennia[7].Despiteemissionreductionsfromautomobilesand</p><p>morefuel-efficientturbofanandturbopropengines,therapidgrowthofairtravel</p><p>registeredfromthe1978DeregulationActtothepresentcontributedtoan</p><p>increaseintotalpollutionattributabletoaviation.IntheEuropeanUnion,</p><p>greenhousegasemissionsfromaviationincreasedby87%between1990and</p><p>2006[8].</p><p>Fig.(1.1))</p><p>Atmospheric</p><p>thedatabankaccordingtoFrenken’s</p><p>criteriumisshowninFig.(3.6).Atimewindowof5yearswasutilizedforthe</p><p>calculationofbothconvergenceanddiffusionindexes.Infact,insteadofdefined</p><p>boundariesbetweenthequadrantsabetterapproachwouldbetoemployacolor</p><p>gradientfortheclassification.</p><p>Fig.(3.6))</p><p>DesignclassificationaccordingtoFrenken’scriterium.</p><p>BasedonFig.(3.6),theentropystatisticsmethodologyresultsforthethreeERJ</p><p>145versionsareanalyzedasfollows:</p><p>ERJ145ERwaslabeledas“fuzzy”design.Indeed,thisseemstobecorrectdue</p><p>toitsshortrange.TheERwasthefirstERJ145versionandenteredservicein</p><p>1997.EMBRAERsoonperceivedthisshortcomingandofferedtheLRversion</p><p>withgreaterrangealreadyin1998.</p><p>ERJ145LR.Thisversionwaslabeledasabreakthroughdesignwhichalso</p><p>seemstobecorrect.WhythenwastheCRJ100,whichenteredserviceearlierin</p><p>1992,notalsoabreakthrough?Thiscanbepossiblycreditedtoitsshorterrange</p><p>(1,305nm)andheavierMTOW(23,133kg).Probablyinthiscategory,theERJ</p><p>145LRseemstopresenttherightcharacteristicstobeclassifiedabreakthrough.</p><p>BombardierintroducedtheCRJ-200LRin1996[17],whichfeaturesan1,800-</p><p>nmrange(50PAX)andbetterairfieldperformancewhencomparedtothe</p><p>-100ERversion.AlongsidewiththeERJ-145LR,theCRJ-200LRairliner</p><p>appearsintheclassificationboxasabreakthroughconcept.</p><p>ERJ145XR.Thisairplanereallyseemstohavebeendesignedtofulfillamarket</p><p>niche.ThisversionoftheERJ145presentingimprovedperformancewas</p><p>purchasedbyExpressJetonly,asubsidiaryofContinentalAirlines.TheNewark</p><p>airportwasthemainoperationalbaseforthetype.Thankstothebetter</p><p>performancewhencomparedtotheLRversion,theERJ145XRenabled</p><p>ExpressJettoservicemoredistantcitiesfromNewark.</p><p>Otherairplaneslabeledas“fuzzy’designsaretheBoeing747-300andAirbus</p><p>A340-500,thefirstrecording56aircraftdelivered[18];thefour-engineA340-</p><p>500ofwhichonly34weredelivered[19].Thepoorrecordsalesforbothtypes</p><p>pointstobeanindicationofproductundefinitionforthemarket.</p><p>ClusterAnalysis</p><p>Classificationofsimilarcustomersandproductsintogroupsisafundamental</p><p>industrialstrategy.Clusteranalysisallowssegmentstobeformedthatarebased</p><p>ondatathatarelessdependentonsubjectivity.</p><p>Inclusteranalysis,thek-meansalgorithmcanbeusedtopartitiontheinputdata</p><p>setintokpartitions.Ausefulplotisthatthecombinetheaveragedistancein</p><p>regardthenumberofclusters.Usingthisplot,asearchisperformedfor</p><p>distinctivebreak(elbow).</p><p>UsingMATLAB®toolsaclusteranalysiswasperformedwiththedatabaseused</p><p>intheentropystatisticsstudy.Fig.(3.7)showstheaveragedEuclidiandistance</p><p>infunctionoftheclusternumber.Consideringthatall99airplanescanbe</p><p>dividedinto11groups,Fig.(3.8)displaystherelationbetweentheirMTOWand</p><p>wingarea.</p><p>Table3.4showstheclassificationoftheairlinersinto11groupscarriedoutusing</p><p>thek-meansclusteranalysis.Eachgroupreallycontainsairplanesthatpresents</p><p>similaritieswitheachother.TheBoeing777-300liesisolatedinagroup.This</p><p>mayindicatethatthetypeisafailureoranicheairplane.Inthiscontext,thereis</p><p>agoodagreementwiththeentropystatisticsanalysis,whichplacedthatBoeing</p><p>airlinerclosetotheniche-fuzzyboundary(Fig.3.6).Thisseemstoagreewith</p><p>thepoorsalesrecordoftheBoeing777-300[20].Table3.5showsdeliveriesof</p><p>thevariousversionsofBoeing777.Theextendedrangeversionofthe777</p><p>registeredanexcellentsalesrecordinstead,whatwasalsowellcapturedbythe</p><p>entropystatisticalanalysisFig.(3.6).</p><p>Fig.(3.7))</p><p>Averagedistancevariationwiththenumberofclusters.</p><p>Fig.(3.8))</p><p>Maximumtakeoffweightandwingareaforthe98jetairlinersusedinthe</p><p>clusteringanalysis.</p><p>Table3.4Classificationofairlinersinto11groupsaccordingtoclusteranalysis</p><p>carriedoutinthepresentwork.</p><p>McDonnellDouglasDC-10-10LockheedL-1011-100A330-200IlyushinIl-86IlyushinIl-96-300Boeing787-8LockheedL-1011-500</p><p>DC-10-30Boeing777-200A340-200A340-300Boeing787-9</p><p>Boeing747-200Boeing747-300Boeing747-400AirbusA340-500AirbusA340-600</p><p>CaravelleVIDC9-30/DC9-40/DC9-50MD-81/MD-82/MD-83/MD-87MD-90-30Boeing717-200737-200737-300737-400737-500737-600737-700737-800</p><p>A319-100A320-200RJ115TupolevTu-134EmbraerE190LREmbraer195LREmbraerE190E2AirbusA318Hawker-SiddeleyTrident1YakovlevYak-42BombardierC-SeriesCS300BombardierC-SeriesCS100</p><p>Table3.5Boeing777ordersanddeliveriesonFebruary28,2017(Source:</p><p>Wikipedia).</p><p>Version Orders Deliveries</p><p>777-200 88 88</p><p>777-200ER 422 422</p><p>777-200LR 59 59</p><p>777-300 60 60</p><p>777-300ER 807 709</p><p>777-F 161 129</p><p>777-X 306 –</p><p>Total 1903 1467</p><p>Usingthesamedatabankthatwasemployedintheentropystatisticsanalysisthe</p><p>Euclidiandistancebetweentheairplaneswascalculatedandadendrogramofthe</p><p>airplaneswasthengenerated(Fig.3.9).AnalyzingtheplotofFig.(3.9andTable</p><p>3.5)itcanbeinferredthatthelinkageoftheairplaneswasprecise,the</p><p>supersonicairlinersTupolevTu-144andConcordegroupedinapairaswellas</p><p>theBoeing747versionsandvariants.Thecalculatedcopheneticcorrelation</p><p>coefficientforthisdendrogramis0.90.</p><p>Fig.(3.9))</p><p>Dendrogramoftheairplanesusedintheentropystatisticsanalysis.</p><p>FighterAircraft</p><p>Thenumberaircraftinthedatabaseusedinthesimulationswasconsiderably</p><p>largerthanthatemployedfortheairlinerclassification:281insteadofthatof98.</p><p>However,just18parameterswereemployedforthefighterairplane</p><p>representation.</p><p>Thedatabasewaspopulatedwithaircraftofdifferentnature.Rocketaircraftlike</p><p>theMesserschmittMe163KometandtheYokosudaOkhaofWorldWarIIwere</p><p>included.Somebombersadaptedforthenight-fighterroleswereincludedas</p><p>well.ThisisthecaseoftheJunkersJu88G,forinstance.TheJunkersJu88(Fig.</p><p>3.10)wasanextremelyversatileairplaneanditwasemployedasabomber,</p><p>torpedobomber,divebomber,nightfighter,inthereconnaissancerole,and</p><p>heavyfighter[21].ItsawserviceevenasaflyingbombintheknownMistel</p><p>combination[22].Despitetheapproachoftakingabroadnumberofconcepts,</p><p>noseaplaneswereconsideredinthesimulations.</p><p>Thevariablesusedtodescribethefighteraircraftofthedatabasearegiven</p><p>below:</p><p>Yearofintroduction;</p><p>Enginetype:=1reciprocating;=2turboprop;=3rocket;=4jet.</p><p>Numberofengines;</p><p>Enginepower[hp]orthrust[N];</p><p>Wingspan[m];</p><p>Totallength[m];</p><p>Totalheight[m];</p><p>Wingarea(S)[m²];</p><p>Lowerwing-sweepbackangle[degrees];</p><p>Higherwing-sweepbackangle[degrees];</p><p>Emptyweight[kg];</p><p>MaximumtakeoffWeight(MTOW)[kg];</p><p>Maximumlevelspeed(VMO)[km/h];</p><p>Serviceceiling[m];</p><p>Range[km];</p><p>Fullarmamentpayloadcoefficient[kg];</p><p>Thrusttoweightratio(T/W);</p><p>Wingloading(W/S)[kg/m2].</p><p>Fig.(3.10))</p><p>JunkersJu88DattheNationalMuseumoftheUnitedStatesAirForce(Photo:</p><p>courtesyU.S.AirForce,publicdomain)</p><p>Toproperlyconsiderairplaneswithvariable-sweepwings,thevariables9and10</p><p>representthevalueofthewingsweepatthetakeoff/landingandcruise</p><p>conditions,respectively.Airplaneswithnovariable-sweepwingsarerepresented</p><p>withthesamevaluesforvariables9and10.</p><p>Thethrust(T)forairplanesfittedwithpropellerareobtainedusingthefollowing</p><p>simpleformula.UsuallyVMOisgivenatadeterminedaltitude.Toaccountthe</p><p>effectsofpowervariationofpowerwithaltitudethefollowingempiricalformula</p><p>wasused[23]:</p><p>(3.4)</p><p>WherePisenginepower,ρistheairdensityandηvistheviscousprofile</p><p>efficiency.Apisaconstant,ofwhichatypicalvalueof1.132isadopted.The</p><p>propellerefficiencyishighlydependentonthepropellertype,basicallyfixed-</p><p>pitchorconstantspeedones.FromEq.3.4itcanobserved</p><p>thatataltitude,the</p><p>totalshaftpowerislinearwithdensity.</p><p>SomeFeaturedFightersandAttackAircraft</p><p>FokkerE.I-ThismonoplanewasessentiallyanarmedversionoftheFokker</p><p>M.5Ksingle-seatreconnaissanceaircraft[24],whichwasinturnbasedonthe</p><p>FrenchMorane-SaulnierTypeHof1913,nicknamedTheBullet[24].Likewise,</p><p>Morane-Saulnier,FokkerE.Ifeaturedamid-bracedwingwithaboxsection</p><p>fuselageandfullmovablehorizontalandverticalstabilizers.Wingwarping</p><p>ensuredcontroloftherollingmotion,whichwasstandardinairplanesatthat</p><p>time[24].Externalcablesattachedtothewingrearsparhandledthewing</p><p>warping.Thefuselagestructurewasfabric-coveredwithweldedchromium-</p><p>molybdenumsteeltubing,thusaccountingforthebiggestdifferencebetweenthe</p><p>FokkerandtheMorane,whichincontrasthadanentirelywoodenframework</p><p>[24].</p><p>WestlandWyvern-Wyvernwasamulti-rolestrikeairplanefeaturingcontra-</p><p>rotatingpropellers(Fig.3.11).Itsenginewasplacedbehindtheco*ckpit,driving</p><p>apropellerinthenose,withalongshaftpassingundertheco*ckpitfloor,like</p><p>BellP-39AircobrafromWorldWarII.AllWyvernswerewithdrawnfrom</p><p>serviceby1958.Duringitsoperationalcareer,thetyperegistered68accidents,</p><p>ofwhich39werehulllosses.Thoseaccidentsareresponsiblefor13fatalities</p><p>[25].</p><p>VoughtF7UCutlass-TheVoughtF7UCutlasswasaUnitedStatesNavy</p><p>carrier-basedjetfighterandfighter-bomberoftheearlyColdWarera(Fig.3.12).</p><p>Introducedin1951,thiselegantaircraftpresentedahighlyunusual</p><p>configuration,withnoconventionalhorizontalstabilizerandalongnoselanding</p><p>gear;thelattertailoredtoprovidehigheranglesofattackforshorterrunsat</p><p>takeoff[26].AGermanengineerfromWorldWarIItookpartintheaircraft</p><p>development,whichutilizedaerodynamicdataandplanscapturedfromthe</p><p>GermanAradocompanyattheendofWorldWarII.Theco*ckpitenabledgood</p><p>visibilityforthepilotduringaircraftcarrieroperations.</p><p>Fig.(3.11))</p><p>WestlandWyvern(PublicdomainphotoviaWikimediaCommons).</p><p>Fig.(3.12))</p><p>VoughtF7UCutlass(Photo:U.S.Navy,publicdomain).</p><p>TheCutlasswasfittedwithapressurizedco*ckpitandejectionseats.Thelackof</p><p>conventionalhorizontalstabilizerledtonecessitytotheincorporationofan</p><p>automaticfueltransfersystem,tokeepthecenterofgravitywithinacceptable</p><p>margins.Besidesitsunusualconfiguration,theCutlassfighterfeaturedmany</p><p>innovations:</p><p>Firstswept-wingnavalaircraft.</p><p>Firstproductionaircraftwithafterburning.</p><p>Firstfightertocarryradar-guidedmissiles.</p><p>High-pressurehydraulicsystem(3000psi).</p><p>Taillessconfiguration.</p><p>PolikarpovI-16-Thislightmonoplaneperformeditsmaidenflighton</p><p>December31,1933.ThePolikarpovI-16wasthefirstintheworldcombining</p><p>cantilevermonoplanewingswithretractablelandinggear.Bythetimeitstarted</p><p>operations,I-16wasthefastestofitstype[1].Theairplanehadagoodcombat</p><p>recordagainstGermanaircraftduringtheSpanishCivilWar(1936to1939),and</p><p>againsttheJapaneseAirForceinManchuriain1937[27].Althoughitwasalso</p><p>highlymaneuverable,possessingexcellentclimbingspeedandrollrate,the</p><p>PolykarpovfighterairplanewassoonoutperformedbynewerGermanand</p><p>Japanesedesignsthatincorporatedsomeofitsfeatures[1].Duetoitsimportance</p><p>intermstheinnovation,thePolykarpovI-16fighterisofprimaryinterestfor</p><p>analysiswiththepresentmethodology.</p><p>DouglasA-1Skyraider-Thepiston-engineSkyraiderwasdesignedduring</p><p>WorldWarIItomeetUnitedStatesNavyrequirementsforacarrier-based,</p><p>single-seat,long-range,highperformancedive/torpedobomber,tofollow-on</p><p>fromearliertypessuchastheCurtissSB2CHelldiverandGrummanTBF</p><p>Avenger[28].TheDouglasSkyraiderattackaircraftbeganoperationsin1946</p><p>andbecameapiston-powered,propeller-drivenanachronisminthejetage[1].</p><p>InterpretationoftheResultsObtainedwiththeFighterandAttackAircraft</p><p>Database</p><p>Thisanalysiscontainsconsiderablemoreaircraftthanthatcarriedoutforjet</p><p>airliners.Thisandtheresultsofthesimulationhelptoevaluatetherobustnessof</p><p>thecodificationandmethodologyusedforairplaneclassification.Thenumberof</p><p>parameterstorepresentthefighteraircraftcharacteristicswasslightlylower,18,</p><p>thanthoseemployedforthejetairliners.Thetimeframechosenforthe</p><p>calculationoftheconvergenceanddiffusionindexeswas5years.Fig.(3.13)</p><p>containstwographsthatshowtheevolutionofthrust-to-weightratio(T/W)and</p><p>wingloading(W/S)overtheyearsfortheaircraftinthedatabase.</p><p>Fig.(3.13))</p><p>Trust-to-weightratioandwingloadingofthefightersconsideredintheentropy</p><p>statisticsstudy(piston-poweredairplanesaremarkedbydarkbluecircles;thejet</p><p>aircraftbylightblueones).</p><p>Afteracertainstabilizationintheinterwarperiod,theaverageT/Wbeginsto</p><p>dropshortbeforethestartofWorldWarII.Areasonableexplanationtothis</p><p>trendisthefactthatairplaneswerebecomingheavier,thewoodandfabric</p><p>constructionbeingprogressivelyreplacedbymetalstructures.Thiscanbeeasily</p><p>verifiedinthegraphofwingloadingevolution.Itclearlyshowsasharprisethe</p><p>W/SsomeyearsbeforetheemergenceofWorldWarII.Besidestheincreaseof</p><p>aircraftweight,wingsbecamesmallerduetoaerodynamicimprovements,more</p><p>powerfulengines,andmoreefficienthigh-liftdevices,contributingforan</p><p>increaseofW/Svalues.</p><p>Thefighteraircraftanalysisalsorevealedsomesignificantdifferencesregarding</p><p>thepreviousstudyaboutthecommercialaviation.Thefirstdifferencecanbe</p><p>seeninthediffusiongraph,showninFig.(3.14).Thedifferenceoftheeffects</p><p>thatWWI(1914-1918)andWWII(1939-1945)exertedonfighterdesignscanbe</p><p>easilyobserved.TheWorldWarItriggeredahugebatchofnewconcepts</p><p>passingontheirinnovations,ascanbeobservedbytheirlowdiffusion</p><p>coefficients.ThisstrengthinnewinnovativeconceptscontinuedthroughWorld</p><p>WarII,morepreciselyuntil1944.DuringthesecondhalfofWWII,the</p><p>innovativeconceptsquicklyspreaditscharacteristicstootheraircraft,thesenow</p><p>possessinghigh-diffusion-indexvalues,andthistrendcontinuedafterthewar.</p><p>ThisisverifiedbythehigherI-valuesingraphofFig.(3.14).Aftera</p><p>stabilizationintheaveragevalueoftheindexesintheperiod1950-1975,the</p><p>averagediffusion-indexvaluestartedtodropagainfrom1975on.</p><p>ThePolikarpovI-16presentsalowdiffusionindex,verylikeasthatofits</p><p>neighbors,indicatingthatit*preaditscharacteristicstothefollowingaircraft.</p><p>TheVoughtF7UCutlassrepresentsabreakofthediffusion-indexriseafter</p><p>WorldWarII.Itsinnovativefeaturesinfluencedfightersthatcameafterit.</p><p>Enginesfittedwithafterburnersbecameaninnatecharacteristicoffighter</p><p>airplanes.GroundattackaircraftliketheArgentinianPucará,A-10A</p><p>ThunderboltII,andCessnaT-37–thisderivedoftheT-37Asuccessfultrainer-</p><p>havehighvaluesofthediffusionindex.Thesamecanbeappliedtothenaval</p><p>strikeWyvernturbopropaircraftandthepiston-poweredDouglasSkyraider</p><p>attackaircraft.</p><p>Indeed,theverystringentrequirementsthatemergedduringbothwars</p><p>tremendouslyacceleratedaircraftdevelopment.AfterWorldWarI,aircraft</p><p>continuetoevolvewithlittleresemblancetothewartimeairplanes.Contraryto</p><p>this,someWorldWarIIaircraftpresentedasubstantialriseinI-values,</p><p>translatingintoahighdegreeofdiffusionofpreviousconceptstothem,a</p><p>distinctpatternthanthatobservedforWWIairplaneevolution.</p><p>Tables3.6and3.7containstheairplanespresentingthehighestandlowest</p><p>diffusionindexes.AlltheairplanesofTable3.6areattackaircraftandthatlisted</p><p>inTable3.7wereintroducedbeforeWorldWarII.</p><p>Fig.(3.14))</p><p>DiffusionI-valuesforFighterAircraft.</p><p>Table3.6Highestdiffusionvaluesoffighteraircraft.</p><p>Airplane</p><p>DiffusionIndex Yearofintroduction</p><p>TupolevI-4 0.037 1928</p><p>AlbatrosD.V 0.038 1917</p><p>AlbatrosD.III 0.040 1917</p><p>PfalzD.III 0.041 1917</p><p>RoyalAircraftFactoryS.E.5 0.045 1917</p><p>GrigorovitchI-2 0.046 1924</p><p>Nieuport28 0.048 1917</p><p>Table3.7Highestdiffusionvaluesoffighteraircraft.</p><p>Airplane DiffusionIndex Yearofintroduction</p><p>A-10AThunderboltII 5.91 1976</p><p>WestlandWyvern 5.21 1953</p><p>IA-54Pucará 5.1 1974</p><p>MeteorNFMark11 4.78 1950</p><p>L-59SuperAlbatros 4.75 1992</p><p>CessnaT-37C 4.63 1967</p><p>AermacchiMB-326 4.62 1962</p><p>Theconvergenceplot,asseeninFig.(3.15),showsthesameoveralltendency</p><p>seeninthediffusiongraph(Fig.3.14),withlowvaluesoftheindexduringthe</p><p>interwarperiod.However,thequantityofhigh-convergenceindexesduringand</p><p>afterWorldWarIIisnotsomassiveasthoseseeninthediffusiongraph.Apeak</p><p>duringthe1950scanalsobeverified.Theaveragevalueoftheconvergence</p><p>indexstartedtodropafter1960andafter1980itcanbeobservedadispersionof</p><p>theI-values.Table3.8containsairplanespresentingthehighestconvergenceI-</p><p>values.</p><p>Fig.(3.15))</p><p>ConvergenceI-valuesforFighterAircraft.</p><p>Table3.8Fighteraircraftpresentinghighestconvergencevalues.</p><p>Airplane ConvergenceIndex YearofIntroduction</p><p>F-86ASabre 5.185 1948</p><p>Mig-15 5.165 1948</p><p>F-104Starfighter 4.292 1960</p><p>SaabJ-29FTunnan 3.749 1958</p><p>Me262A 3.738 1944</p><p>L-39Albatros 3.702 1972</p><p>L-59SuperAlbatros 3.700 1992</p><p>WorthyofmentiontisthefactthattheconvergenceI-valuesduringWWIIare</p><p>lowerthanthediffusionones.Thisissomewhatexpectedconsideringthatwars</p><p>boosttechnologicaladvancesorimprovepreviousdesignsconsiderably.The</p><p>inventionofthejetengineduringWorldWarIIhadlongerimpactontheaircraft</p><p>development,enablingnewconceptsorotherwithimprovedperformanceasfar</p><p>thejetenginecontinuedtoimprove.</p><p>Theconvergenceanddiffusiongraphsrevealthataircraftmanufacturersofthe</p><p>belligerentcountriesofthegreatwarsdevelopedabroadrangeofdominant</p><p>designsfordistinctreasons.</p><p>ThiswasevidentduringWWI,asthepoweredheavier-than-airflightwasonly</p><p>justbeginningandthereforethedifferencesamongtheairplaneswasnotso</p><p>pronounced,mostairplanesturningintoclassicones.Beginningin1950,the</p><p>averagedI-valueofthediffusioncoefficientloweredbecauseofconstant</p><p>technologicalevolutionandtheemergenceofsomedominantdesigns.During</p><p>the1990s,therewasadropoftheI-values,revealingthepresenceofadominant</p><p>design.</p><p>Manyaircraftarecharacterizedbyalowdegreeofdiffusion(highI-value)into</p><p>subsequentdesigns.ThisisthecasefortheA-1HSkyraider,oneofthelast</p><p>piston-poweredfighter/attackaircraft,whosedevelopmentwasinitiatedin</p><p>WWII.Becauseitwasthelastoneofitskind,itdidnotdiffuseitstechnology</p><p>ontolaterdesigns.DevelopedtosatisfyaUSNavyrequirementof1944fora</p><p>single-seatcarrier-baseddivebomberandtorpedocarrier,theDouglasAD</p><p>SkyraidermaterializedtoolateforoperationalserviceinWorldWarII[28].</p><p>OrderedintoproductionalongsidetheMartinAMMauler,whichhadbeen</p><p>developedtomeetthesamespecification,itwastocontinueinproductionuntil</p><p>1957.TheSkyraiderreflectedthenavy'swartimeexperiencegainedinthe</p><p>Pacifictheatre,whereithadprovedthatthemostimportantrequirementforsuch</p><p>aircraftwastheabilitytocarryanddeliveraheavyloadofassortedweapons</p><p>[28].TheSkyraiderwasalsoemployedintheanticipatedearlywarning(AEW)</p><p>role(Fig.3.16).FacingKamikazethreatsin1944,theUnitedStatesNavystarted</p><p>thedevelopmentofanairborneradarsystemtoexpandtheradarhorizonunder</p><p>whichtheFleetwastooperateduringtheseriesofcampaignsthroughthe</p><p>PhilippinesandnorthwardstoJapan.Forthisreason,theAN/APS-20radaras</p><p>fittedtotheTBM-3WandPB-1WbecamethemainstayofAEWaircraft</p><p>developmentsfollowingWWII.WhilenotdesignedspecificallyasanAEW</p><p>aircraft,theGrummanAF-2WGuardian,whenfittedwiththeAN/APS-20,hada</p><p>secondarycapabilityendowedbythissystem.ExperiencewiththeGuardianled</p><p>tothedevelopmentofanAEWvariantofDouglasSkyraider.Onceagainthe</p><p>radarchosenwastheAN/APS-20,withalargebellyradomebeingfittedanda</p><p>crewofthree(onepilotandtwooperators)beingcarried.TheSkyraiderAEW</p><p>wasbuiltinthreeversions,theAD-3W,AD-4W,andAD-5W.AEWaircraftis</p><p>anotherexampleofdivergence.</p><p>Fig.(3.16))</p><p>Thefirstearly-warningandControl(AEW&C)aircraftofWWII.Fromleftto</p><p>right:AF-2WGuardian,GrummanTBM-3WAvengerandDouglasEA-1E</p><p>Skyraider.</p><p>Mostofthelatepropellerfighterdesignshavelowdiffusion,namelyRepublicP-</p><p>47N,F4-U5Hellcat,andNorthAmericanP-51D.Thisalsomakessensesince</p><p>theyhadnotmuchincommonwiththejetsthatwerebeingdevelopedshortly</p><p>thereafter.Anothercornerofthehigh-diffusionI-valuesispopulatedbysome</p><p>first-generationjets,suchasMeteorMk.8andYakovlevYak-15.Fighterswith</p><p>low-diffusionI-valuesandhigh-convergenceonesaretheNorthAmericanF-</p><p>86AandMig-15.Thiscanbeexplainedbythefactthatalotoftheirtechnology</p><p>waspassedontolaterdesignsandtheyhavelittleincommonwiththeir</p><p>predecessors.TheMiG-15isconsidered,alongwithotheropinionsabouttheF-</p><p>86Sabre,asthebestfighteraircraftoftheKoreanWar[29].Itcouldexpectsuch</p><p>aircraftasLockheedP-80andtheMesserschmittMe262jetfighterstobeinthis</p><p>category,butthisisnotthecasebecauseaspioneersmostoftheirdesignideas</p><p>werenotcarriedout,andthesecondgenerationisprobablytheonethatcontains</p><p>bettercharacteristics.</p><p>Fig.(3.17)displaysthecombineddiffusion/convergenceplot.Usingthesame</p><p>classificationtechniqueofTable3.2wecancategorizesomeaircraft.For</p><p>example,theMiG-15andSabreF-86areundoubtedlybreakthroughdesignsof</p><p>thesecond-generationofthemilitaryjetage.TheVoughtCutlasswasalso</p><p>labeledasabreakthrough,probablyduetoitsenginesfittedwithafterburning.</p><p>Lowconvergenceandhighdiffusionoftheseplanesplacetheminthe</p><p>breakthroughquadrantofTable3.2.SomeGlosterMeteorvariantsare</p><p>categorizedasnicheairplanes.TheMe262wascategorizedasa“fuzzy”</p><p>configuration,butitcameclosetothefuzzy/breakthroughboundary,whichisa</p><p>greyzone.Besidestheconsequencesofthepoorreliabilityofitsengines,thisjet</p><p>fightercarriedsomecharacteristicsofpreviouspiston-poweredairplanesand</p><p>probablysomeoftheirdrawbacks.Usually,thisisthepricetopayforsome</p><p>breakthroughconcepts.Althoughclassifiedasabreakthroughdesign,thisisalso</p><p>thecaseoftheVoughtCutlass,whichrecordedseveralaccidentsduringits</p><p>operationalcareer.</p><p>Fig.(3.17))</p><p>Fighteraircraftclassificationbytheentropystatisticsanalysis.</p><p>Itisalsoworthmentioningtheairplanesinthe“fuzzy”quadrant:mostareattack</p><p>aircraftderivedfromtrainerairplanes.CessnaT-37Cisavariantofthe</p><p>successfulT-37Aside-by-sidejettrainer;EmbraerSuperTucanohas</p><p>considerablymoreweightthantheEMB-312Tucano(notinproduction</p><p>anymore),ofwhichitwasbased.However,wingplanformandairfoilswere</p><p>inheritedfromthesuccessfulEmbraerturboproptrainer,whichpresents</p><p>impressiverecordsales.L-39,L-59,andMB-326attackairplaneshavealmost</p><p>thesameconfigurationofthetrainerairplanesthatservedasplatformforthem.</p><p>However,theMB-326presentsasuccessfulsalesrecordbeingpurchasedby</p><p>morethan10countriesanditwasproducedunderlicenseinAustralia,Brazil</p><p>(Fig.3.18)andSouthAfrica[30].Inmanycountries,theMB-326wasused</p><p>mainlyintheadvancedtrainerrole[31,32].</p><p>Fig.(3.18))</p><p>Fromfronttoback:EMB-326GBXavante,NeivaT-25Universal,andAerotec</p><p>T-23Uirapuru(Photo:©1979BentoMattos).</p><p>Somedominantdesigns,aretheRafaleCforthemodernfighterjet,theF8-U</p><p>CrusaderfortheColdWarfighters,theBristolBulldogforthepre-WWII</p><p>era,</p><p>andtheAlbatrossD.IIIfromWWI.DuringWWII,mostaircraftstandsoutasa</p><p>dominantdesign,becomingclassicalaircraft.</p><p>Entropypeakscanbefoundduringthegreatwarsasexpected(Fig.3.19)with</p><p>someminoronesintheinterwarperiod.WorldWarIIischaracterizedordivided</p><p>bytwoentropypeaks,indicatingtheintroductionofmanynewaircrafttypes</p><p>fromthemiddleofthatwar.Thisentropy“footprint”indicatesthatthebeginning</p><p>ofthewarsawtheintroductionofnewaircraftconceptsprobablyintegratingor</p><p>consolidatingthetechnologythatemergedfromthepreviousdecadebutthatthe</p><p>waritselftriggeredanewwaveofinnovativeconcepts.Thisiswhatthesecond</p><p>peakisindicating.</p><p>AftercalculatingtheEuclidiandistancebetweentheaircraft,aDendrogramplot</p><p>wasgeneratedwithMATLAB®(Fig.3.20).Thecalculatedcophenetic</p><p>correlationcoefficientforthisDendrogramis0.96,indicatingaverygood</p><p>correlationbetweentheelementsofthedatasample.Themaximumdistance</p><p>calculatedis10.25.Belowone-thirdofthisdistancethegroupscanbe</p><p>differentiatedbycolors.OntheleftsideoftheplotofFig.(3.20),mostofWorld</p><p>WarIfightersaregrouped.Itcanbenotedasolodesignbytheblackline</p><p>betweentheyellowandgreengroups.ThisaircraftistheF-104supersonic</p><p>fighter.ThisagreeswiththeclassificationofFig.(3.17)thatlabeleditas“fuzzy”</p><p>concept.</p><p>Fig.(3.19))</p><p>Entropyoffighteraircraftovertheyears.</p><p>Fig.(3.20))</p><p>Dendrogramobtainedforthefighteraircraftfrom1910to2013.</p><p>Aclose-upoftworegionsoftheDendrogramplotwereselectedforfurther</p><p>analysis(Figs.3.21and3.22).ThefirstregiongroupadequatelytheL-29andL-</p><p>59withtheMB-326,ground-attackairplanesderivedfromtrainerones.Fig.</p><p>(3.22)showsthatsimilaraircraftwerealsocorrectlygrouped.</p><p>Fig.(3.21))</p><p>aclose-upofpartoftheDendrogramplot.</p><p>Fig.(3.22))</p><p>aclose-upofpartoftheDendrogramplot.</p><p>CONCLUDINGREMARKS</p><p>Thecombinationofaseeminglyunconnectedmathematicaltheoryandan</p><p>empiricalstudyoftechnologicaldevelopmentaveryusefulqualitativeanalysis</p><p>toolcouldbecreated.Thiscomputationaltoolcanbeusedtoassisttechnology</p><p>assessmentoraspartofacorporatedecision-makingprocess.</p><p>Asanacademictool,itisveryinterestingtousewithavarietyofseemingly</p><p>unrelatedproductstostudytheeffectsofmajoreventsandbreakthroughsonthe</p><p>timelineoftechnologicalevolutionandtheimpactofpoliticaleventslikethe</p><p>1978DeregulationActonairplanedesigns.Ifthesameeffect,suchasarisein</p><p>diffusionorconvergenceI-values,canbeobservedforvariousproductsinthe</p><p>sametimeframe,theymighthavesomeconnection,suchaseventslikeamajor</p><p>war,oramajordiscovery.Thepossibilitiesareendlessprovidedtheproduct</p><p>characteristicsarewellchosenandorganized,andenoughdatapointsare</p><p>gathered.Thisisparticularlyimportantaswasseeninthefighterstudy.</p><p>Ifcarefullyanalyzed,itsresultscansubstantiallyimprovethefirm’sdecision-</p><p>makingprocess.Theclassificationmethoddescribedinthispaperallowsa</p><p>companytostudyhowcloseitcangettoitsdefinedgoal.Withjustthe</p><p>convergenceresults,thataremoreaccurateformoderndesigns,onecansortout</p><p>someunknownsfromtheprocess.Itissimplertothinkofadecisiontreewith</p><p>twobranchessplittingintosmallerbrancheseach.Ifastrategyisknown,saya</p><p>breakthroughisthedesiredoutcomeofafuturedesign,thenafirmmustaimfor</p><p>alowconvergencelevel.Ontheotherhand,ifthecompanycannotaffordany</p><p>riskahighdegreeofconvergingtechnologyisdesired.</p><p>Trainerairplanesadaptedtoattackmissionsfrom1960onfittedinthe“fuzzy”</p><p>quadrantoftheconvergence/diffusionplot.Thisresultdeservesfurtheranalysis</p><p>ifthiscouldindicatethatattackvariantsfromtrainerairplanescouldnotbea</p><p>goodapproach.Thisisaveryrelevantissuebecausemanyairforcesaroundthe</p><p>worldsetorareconsideringestablishrequirementsforairplaneswithadualrole</p><p>oftrainer/counter-insurgencyforbudgetaryreasons.</p><p>Estimatingtheinformationcontentonfuturecompetitors,andthereforecalculate</p><p>apreliminarydiffusionvalueisahardbutdoabletask.Subsequentlyacomplete</p><p>classificationcanbeobtained.</p><p>References</p><p>[1] BosquêA.,MattosB.S.,GirardiR.M..EntropyStatisticsAppliedtoAirplaneEvolution11thBrazilianCongressofThermalSciencesandEngineeringCuritiba,Brazil2006</p><p>[2] FrenkenK.,LeydesdorffL..ScalingTechnologiesinCivilAviation(1931-1997).Res.Policy19999331348</p><p>[3] SchmooklerJ..InventionandEconomicGrowth.Cambridge,MAHarvardUniversityPress196610.4159/harvard.9780674432833</p><p>[4] DosiG..TechnologicalParadigmsandTechnologicalTrajectories.Res.Policy19821114716210.1016/0048-7333(82)90016-6</p><p>[5] MoweryD.,RosembergN..Theinfluenceofmarketdemanduponinnovation:Acriticalreviewofsomerecentempiricalstudies.Res.Policy199322210710810.1016/0048-7333(93)90051-I</p><p>[6] RiesL..TheOriginofBrands:DiscovertheNaturalLawsofProductInnovationandBusinessSurvival.HarperBusiness2004</p><p>[7] UtterbackJ.M.,AbernathyJ.W..ADynamicModelofProcessandProductInnovation.Int.J.Manag.Sci.197536639656</p><p>[8] NelsonR.R.,WinterS.G..AnEvolucionaryTheoryofEconomicChange.Cambridge,MAHarvardUniversityPress1982</p><p>[9] SahalD..TechnologicalGuidepostsandInnovationAvenues.Res.Policy198514618210.1016/0048-7333(85)90015-0</p><p>[10] ShannonC.E..AMathematicalTheoryofCommunication.BellSyst.Tech.J.19482737942310.1002/j.1538-7305.1948.tb01338.x</p><p>[11] ClausiusR..TheMechanicalTheoryofHeat,W.R.Browne,Ed.,Cambridge,Massaschusetts:CambridgePress,1879,p.390..</p><p>[12] Wikipedia,TheFreeEncyclopedia,"ClausiusTheorem,"Wikipedia,29August2017.[Online].Available:https://en.wikipedia.org/wiki/Clausius_theorem</p><p>[13] FrenkenK.,LeydesdorffL..ScalingTrajectoriesinCivilAviation(1913-1997).Res.Policy19992933134810.1016/S0048-7333(99)00037-2</p><p>[14] ValeA.P..TeoriadaInformaçãoAplicadanaAnálisedaEvoluçãodeAeronavesExecutivas.SãoJosédosCamposInstitutoTecnológicodeAeronáutica2008</p><p>[15] MooiE.,SarstedtM..AConciseGuidetoMarketResearch.Berlin,HeidelbergSpringerVerlag201110.1007/978-3-642-12541-6</p><p>[16] SaraçliS.,DogănN.,DogănI..Comparisonofhierarchicalclusteranalysismethodsbycopheneticcorrelation.J.Inequal.Appl.2013</p><p>[17] Airfleets.netProductionList:CanadairRegionalJet2017</p><p>[18] Wikipedia,"Boeing747,"Wikipedia,12April2-17.[Online].Available:https://pt.wikipedia.org/wiki/Boeing_747</p><p>[19] Wikipedia,"AirbusA340,"Wikipedia,14April2017.[Online].Available:https://en.wikipedia.org/wiki/Airbus_A340</p><p>[20] Wikipedia,TheFreeEncyclopedia,"Boeing777,"Wikipedia,18July2017.[Online].Available:https://pt.wikipedia.org/wiki/Boeing_777</p><p>[21] Wikipedia,TheFreeEncyclopedia,"JunkersJu88,"Wikipedia,5August2017.[Online].Available:https://en.wikipedia.org/wiki/Junkers_Ju_88</p><p>[22] Wikipedia,TheFreeEncyclopedia,"Mistel,"Wikipedia,2017July2017.[Online]Available:https://en.wikipedia.org/wiki/Mistel</p><p>[23] LutzeF.H..AOE3104VehiclePerformance2017http://www.dept.aoe.vt.edu/~lutze/AOE3104/thrustmodels.pdf</p><p>[24] Wikipedia,TheFreeEncyclopedia,"FokkerE.I,"Wikipedia,9June2017.[Online]2017Available:https://en.wikipedia.org/wiki/Fokker_E.I</p><p>[25] Wikipedia,TheFreeEncyclopedia,"WestlandWyvern,"Wikipedia,3July2017.[Online]2017Available:https://en.wikipedia.org/wiki/Westland_Wyvern</p><p>[26] ThomasonT.H..U.S.NavalSuperiority:DevelopmentofShipborneJetFighters1943-1962.SpecialtyPress2008</p><p>[27] Wikipedia,TheFreeEncyclopedia,"PolykarpovI-16,"Wikiepdia,2017.[Online]Available:https://en.wikipedia.org/wiki/Polikarpov_I-16</p><p>[28] Wikipedia,TheFreeEncyclopedia,"DouglasA-1Skyraider,"Wikipedia,25August2017.[Online]2017Available:https://en.wikipedia.org/wiki/Douglas_A-1_Skyraider</p><p>[29] McDowellE.R.,WardR..NorthAmericanF-86A-LSabre.USAF&ForeignService.Canterbury,KentOspreyPublicationsLtd.1970Vol.17</p><p>[30] Wikipedia,TheFreeEncyclopedia,"AermacchiMB-326,"Wikipedia,September2017.[Online]Available:https://en.wikipedia.org/wiki/Aermacchi_MB-326</p><p>[31] GlobalSecurity.orgAT-26Xavante2013https://www.globalsecurity.org/military/world/brazil/at26.htm</p><p>[32] AlaminoA.C..EMB.326GBAT-26Xavante2017http://www.rudnei.cunha.nom.br/FAB/br/at-26.html</p><p>AircraftDesignPhases</p><p>BentoS.deMattos,PauloEduardoC.S.Magalhães</p><p>Abstract</p><p>Aircraftdesignisacomplexandfascinatingbusinessandafieldofresearchand</p><p>manygoodbookshavebeenwrittenaboutit.Theverycomplexanddynamic</p><p>natureofthesubjectmeansthatnobookcandojusticetoit.Thischapter,</p><p>therefore,willprimarilyactasanintroductiontothewholefieldofaircraft</p><p>designleadingtowardsthemainphasesofanaircraftdevelopmentprogram.It</p><p>alsoprovidesinformationaboutthewholeaircraftdesignprocesstogetherwith</p><p>descriptionsoftheaircraftdesignphases.Certificationisanimportantaspectof</p><p>aircraftdesignprocessandthereforeiscoveredinthepresentchapterwithmore</p><p>details.</p><p>Keywords:Aircraftdesignphases,Conceptualdesign,Designrequirements,</p><p>Financialanalysis.</p><p>DESIGNINGAIRPLANES</p><p>Aircraftdesignisanextremelychallengingtaskthatrequirescompromisingon</p><p>solutionsinvolvingdifferentdisciplines.Aerodynamics,structures,</p><p>aeroelasticity,landinggearandothersystems,productionandcost,propulsion</p><p>system,andstabilityaswellascontrolareonlysomeofthem.Moreover,there</p><p>maybeconflictingaspectswithinoneandthesamediscipline.Forinstance,field</p><p>andcruiseperformancedemandconflictingairfoilshapesandwingplanform.</p><p>Newchallengesposedbynewandtougherenvironmentalrequirements</p><p>contributetomakingthistaskevenmorecomplex.TheAdvisoryCouncilfor</p><p>AeronauticsResearchinEurope(ACARE),responsibleforthedefinitionofa</p><p>strategicresearchagendaforallaeronauticalresearchprogramsinEurope,</p><p>establishedin2001,atargetforreductionofemittedairplaneCO2by50%,NOx</p><p>by80%andexternalnoiseby50%bytheyear2020[1].</p><p>Aircraftserialmanufacturingisahugeinvestmentforboththebuyerandthe</p><p>manufacturer.Itisthusimperativethattheproductmeetscustomerneedsandthe</p><p>developmentprocesscostbekeptundercontrol.Indeed,itiscustomaryfor</p><p>commercialairframemanufacturerstosecurepurchasecommitmentsfrom</p><p>severalairlinesbeforedecidingtocommittotheproductionofanaircrafttype.</p><p>Basically,likeanyproduct,aircraftdesignoriginatesfromasetofrequirements</p><p>thatdrivethedevelopmentprocess.Theserequirementsmaycomefrom</p><p>completely</p><p>differentareassuchasoperation,manufacturing,maintenance,certification,etc.</p><p>Asmentionedbefore,itisvitaltolistentocustomers.Asuccessfulsalerecord</p><p>willenablethemanufacturertoimproveitsfinancialhealthandthereforetobe</p><p>abletodevelopnewaircraftorimproveexistingproducts,whilekeepingoreven</p><p>increasingitsmarketshare.Therearemanycasesofaircraftmanufacturersthat</p><p>wentoutofbusinessforofferinganinappropriateproducttothemarket.The</p><p>military,ontheotherhand,willoftencreatetheirownspecificationsintheform</p><p>ofaRequestforProposal(RFP).TheRFPinvitesmanufacturerstoproposea</p><p>designmeetingtheissuedrequirements.Eachproposalisevaluated,andoneis</p><p>usuallyselected,turningthechosenmanufacturerintothesoleproviderforthe</p><p>aircraft.</p><p>Aircraftmanufacturersregularlyconductexploratoryworkonresearch,</p><p>technology,andmarketanalysistoevaluateifaneworimprovedproductis</p><p>worthbeingdeveloped.Havingdeterminedtheprojectedmarketforaircraft,the</p><p>nextstageistoexaminetheexistingandunderdevelopmentcompetitorsinthat</p><p>market.Thiswillinfluencetheproductthatwillbedeveloped.</p><p>Beforeanewlydevelopedaircraftmodelentersoperation,itmustobtainatype</p><p>certificate(TC)fromtheaviationregulatoryagencies.Atypecertificateisissued</p><p>torecognizetheairworthinessofanaircraftmanufacturingdesign.The</p><p>certificateisissuedbyaregulatingagency,andonceitisissued,changestothe</p><p>configurationwillonlybepossibleifanew,simplifiedcertificationprocessis</p><p>followed,whichcanbeanamendmenttothetypecertificate,ifcarriedoutby</p><p>theoriginalmanufacturer,oraSupplementaryTypeCertificate(STC),whenitis</p><p>performedbyanoperatororathirdparty.ThisTypeCertificatereflectsa</p><p>determinationstipulatedbytheregulatingauthoritythattheaircraftis</p><p>manufacturedaccordingtoanexistingregulationbasis,andthatthedesign</p><p>ensurescompliancewithairworthinessrequirements.</p><p>Changesinconfigurationmaytakeplaceinthelastphasesoftheaircraft</p><p>developmentprogram,impactinginevitablythecertificationprocess[2].</p><p>Performanceandhandlingenhancementsareusuallythemajorcausesof</p><p>modifications,butoftentheyarenecessarytomeetanunanticipatedregulatory</p><p>need,anexcessdragorsomethingasmajorasasystemswitch[2].As</p><p>exemplification,fourcommercialairplaneprogramsthatsuffereddelaysor</p><p>majorredesignareanalyzedbelow:</p><p>Duringitsdevelopment,theEclipse500receivednewengines;EclipseAviation</p><p>thenswitchedfromasmallWilliamsInternationalturbofantothelargerPratt&</p><p>WhitneyCanadaPW600[2].Excessdragaccountedamongothercausesforthis</p><p>changethatalsoledtoaheavierairplane.EclipseAviationhadthereforeto</p><p>installtiptankstoattainperformancegoals[2].</p><p>Dassault’sFalcon7Xexceededtheperformancegoalsafterinstallationofa</p><p>forward-fuselagefueltank,modifiedwingletsandredesignedempennageduring</p><p>thecertificationprogram[2].Originallyconsideredtooffera5,700-nmrange,</p><p>the7Xwascertifiedwitha5,950-nmmaximumrangewithapayloadof8</p><p>passengers[2].</p><p>InMay1999,EMBRAERexpectedthego-aheadfortheERJ-170programinthe</p><p>secondquarterof1999andforecastedthattheinitialdeliveriesofitsERJ-170</p><p>wouldtakeplacein2002[3].However,thetype(laterredesignatedE-170)</p><p>enteredservicewithPolishAirlinesonlyinMay2004[4].</p><p>Theall-compositeBoeing787Dreamlinersufferedhugedelaysinits</p><p>developmentprogram[5].Softwareissues,loadrecalculation,airframe</p><p>overweight,engineblowoutduringtestingweremajorcausesofdelays[5].</p><p>Threeyearsbehindschedule,ANAreceivedthefirstDreamliner[5].Theaircraft</p><p>alsosufferedfromseveralin-serviceproblems,includingfiresonboardrelated</p><p>toitslithium-ionbatteries[6].</p><p>Theaeronauticalindustryislinkedtonationalindustrialstrategy,whichinturn</p><p>dependsoncountryinfrastructure,governmentalpolicies(notjustforordering</p><p>militaryaircraft),workforcecapabilities,academicsupportineducationand</p><p>research,andnaturalresources.Morethananyotherindustry,theaerospace</p><p>sectorislinkedtoglobaltrends.Commercialaviationisdirectlyaffectedby</p><p>recession,fuelpriceincreases,spreadofinfectiousdiseases,andinternational</p><p>politics.Inadditiontoitsimportancefornationalsecurity,themilitaryaircraft</p><p>sectorisakeyelementinseveraloftheworld’slargesteconomies.</p><p>Skilledlaborforceisessential,butitisnottheonlyrequiredconditionfor</p><p>successoftheaerospaceindustry,ifthereisnoharmonizationofactivitywith</p><p>nationalpolicies.Thebasicthreeelementsofthesystemmustprogressina</p><p>properwell-coordinatedway:industry,governmentandresearch.Becauselarge</p><p>companiesaffectregionaleconomicdevelopmentanddemandstrong</p><p>governmentalsupport,theymustsharesocio-economicresponsibilityforthe</p><p>regioninwhichtheyarelocated.</p><p>Budgetlimitations,marketrequirementsandglobalcrisissetconstraintsonthe</p><p>designprocessandcomprisethenon-technicalinfluencesonaircraftdesign</p><p>alongwithenvironmentalfactors.Competitionleadscompanies</p><p>tosearchfor</p><p>betterefficiencyintheaircraftconfigurationwithoutcompromisingperformance</p><p>andincorporatingnewtechniquesandtechnology[7].</p><p>Tokeeprisksaslowaspossible,atypicalaircraftprojectcontainsthefollowing</p><p>distinctivefeatures:</p><p>Projectisdividedintophases.</p><p>Therearescheduleddesignreviews.</p><p>Suppliersmaybecomeriskpartners.</p><p>Advancedengineeringtoolslikecomputationalfluiddynamicscodes(CFD)and</p><p>multi-disciplinarydesignandoptimization(MDO)frameworksareemployed.</p><p>Extensivemarketstudiesarecarriedout.</p><p>Alaunchercustomerissoughtand/oranexpressiveinitialordermustbe</p><p>consolidated.</p><p>Manufacturingofsomeprototypesforgroundandflighttesting.</p><p>Pioneeringandcreativeconcepts.</p><p>Lessonslearnedfrompreviousprojects.</p><p>Technologycertificationbytechnologydemonstrators,laboratories,joint</p><p>ventures,cooperativeeffortswiththeacademiccommunity.</p><p>DuringtheColdWar,astrongscientificandtechnologicalracebetweenWestern</p><p>countriesandtheformerSovietUniontookplace.Thelandingofmannedcrew</p><p>onthemoon,theInternet,theConcordesupersonicairliner,alloftheseand</p><p>muchmoreareresultsfromtheColdWar.Indeed,inthisscenario,evenabsurds</p><p>liketheveryexpensivenuclear-poweredbomberprogramwereconsidered.The</p><p>adventofIntercontinentalBallisticMissiles(ICBMs)inthe1960sgreatly</p><p>diminishedthetacticaladvantageofsuchaircraft,andrelatedprojectswere</p><p>cancelled.TheColdWarcametoanendwiththedissolutionoftheSoviet</p><p>Union.From1992on,militaryprogramssuffereddeepcuts(Fig.4.1).However,</p><p>accordingtothegraphfromFig.(4.1),globalandNorthAmericanmilitary</p><p>expendituresurpassed1988levelsin2014.Anyway,civilprogramsthatusedto</p><p>bebeneficiariesofmilitarytechnologicaldevelopmentsalsosufferedfroma</p><p>decreaseininnovationsinthewakeofbudgetcuts.Anotherconsequencewas</p><p>thatoutputandcostinfluencedatrendawayfromvolumeproductionand</p><p>towardsspecializedmanufactureoffewertypesofairlinersandmilitaryaircraft.</p><p>Theaerospaceindustryacquiredinthelasttwodecadesasetofunique</p><p>characteristicsinmanufacturinganddesign[8]:</p><p>Performancedemandsfornewsystemsrequirecontinualtechnological</p><p>advancement,whichinturninvolvesimprovedtoolsandmethodsofevaluation</p><p>ofuncertainty,risk,andeconomicalfeasibility.Forthenextdecades,abigger</p><p>challengeisposedbyenvironmentalconstraintssuchasnoiseandemissions.</p><p>Industryhasincreasinglysoughtacademytofindsolutionsforimprovingits</p><p>products.GovernmentfoundedprogramsliketheEuropeanFrameworkfor</p><p>ResearchDevelopmentseekaprominentlevelofcollaborationandintegration</p><p>betweenindustryandacademy.</p><p>Becausegovernmentsarethemaincustomer,themilitaryproductlineissubject</p><p>torevisionsonprogramlevelsoccasionedbychangingrequirementsandfunding</p><p>availabilityortheemergenceofnewthreats.</p><p>Equipmentthatchallengesthestateoftheartisnecessarilycostly,themoreso</p><p>becauserequirementsgenerallydictateshortproductionruns,negatingthe</p><p>economiesoflarge-scaleproduction.</p><p>Technologicallydemandingprogramsrequirepersonnelemphasisonhigherskill</p><p>levels.Hence,laborinputperunitofoutputissubstantiallylargerthaninother</p><p>manufacturingindustries[8].</p><p>Thecombinationoftechnologicaluncertaintyandlongproductiontime,about</p><p>7–10yearsandfrequentlylonger,betweenprogramstartandcompletion,makes</p><p>advancedestimationofcostsparticularlydifficult.Inflationandvarying</p><p>exchangeratesmakecostestimationanditscontrolwithinprogrambudgetan</p><p>evenbiggerchallenge.</p><p>Therearenowfewcustomersandrelativelyfewprograms;competitionforthe</p><p>businessopportunitiesthereforeisintense[8].</p><p>Thesecharacteristicscontributetoexceptionaldemandforindustrycapital,yet</p><p>profitsasapercentageofsalesareconsistentlywellbelowtheaverageforthe</p><p>remainingmanufacturingindustries[8].</p><p>Airplanelessorsandcompaniesthatoperatewithinfractionalownership</p><p>businessmodelsaretodaybigaircraftbuyers.Theyhaveuniquerequirements</p><p>foraircraftandmanyofthemplacebigorders,demandingbigdiscounts[8].</p><p>Fig.(4.1))</p><p>Militaryexpenditureinthe1998-2014period(2014dollar).</p><p>AIRCRAFTPROGRAMPHASES</p><p>Overview</p><p>Regardingthedesignphases,thereareseveralapproaches,whichdependon</p><p>eachmanufacturerorganization.Fig.(4.2)showsthetypicalphasesofanaircraft</p><p>developmentprogram.Table4.1describestheactivitiesandguidelinesofthe</p><p>typicalphasesofanaircraftprogram.Thefollowingparagraphsofthepresent</p><p>Sectionprovideanoverviewofthephases.</p><p>Fig.(4.2))</p><p>Classicalphasebreakdownofaircraftdevelopmentprogram.</p><p>Table4.1Phasesofanaircraftproject.</p><p>Phase Activities</p><p>Feasibilitystudy Marketanalysis;businessplan;technologyassessment</p><p>Conceptual Costs;performance;firstwind-tunneltests;CFD;MDO;layoutofaircraftsystems;partnerandsupplierselection</p><p>Preliminarydesign(JointDefinitionPhase)* Systemintegration;mitigationofcriticalengineeringproblems;</p><p>Detaileddesign Constructionofprototypes;drawings(digitalmockup);rigs;flighttests</p><p>Production Production;preparationforentryintoservice;productionplan;qualitycontrol</p><p>Operatinglifeandphaseout Certificationofmaintenanceshops;servicebulletins;fatiguelife;productimprovement</p><p>Thereareseveraldedicatedsoftwareandtoolstoassistprogrammanagement.A</p><p>Ganttchart(Fig.4.3)isatypeofbarchart,adaptedbybothKarolAdamieckiin</p><p>1896andindependentlybyHenryGanttinthe1910s,thatillustratesaproject</p><p>schedule[9].Ganttchartsillustratethestartandclosuredatesoftheterminal</p><p>elementsandsummaryelementsofaproject.Terminalelementsandsummary</p><p>elementscomprisetheworkbreakdownstructureoftheproject.ModernGantt</p><p>chartsalsoshowthedependencyrelationshipsbetweenactivitiesandcontain</p><p>importantprojectdatesandmilestones.</p><p>Fig.(4.3))</p><p>Ganttchartshowingthreekindsofscheduledependencies(inred)andpercent</p><p>completeindications(Credit:GarryL.Booker,releasedtothepublicdomain).</p><p>Anotherusefultoolforprojectmanagementisthecriticalpathmethod(CPM),</p><p>whichisanalgorithmforschedulingasetofprojectactivities.Itisastep-by-</p><p>stepprojectmanagementtechniqueforprocessplanningthatdefinescriticaland</p><p>non-criticaltaskswiththegoalofpreventtimeframeproblemsandprocess</p><p>stagnationpoints.</p><p>TheessentialtechniqueforusingCPMistoconstructamodeloftheprojectwith</p><p>thefollowingcontent:</p><p>Alistofallactivitiesrequiredtocompletetheproject.Theseactivitiesare</p><p>typicallycategorizedwithinaworkbreakdownstructure.</p><p>Thedurationthateachactivitywilltaketocomplete.</p><p>Thedependenciesbetweentheactivities.</p><p>Logicalendpointssuchasmilestonesordeliverableitems.</p><p>Identificationofthecriticalpath.</p><p>Criticalpathdiagramtorecordprojectprogress</p><p>Thelongestpathofplannedactivitiesiscalculatedcontainingthelogicalend</p><p>andstartpointsoftheproject.Inaddition,theearliestandlatestpathseach</p><p>activitycanstartandfinishwithoutmakingtheprojectlonger.Thisprocess</p><p>determineswhichactivitiesare“critical”(i.e.,onthelongestpath)andwhich</p><p>have“totalfloat”(i.e.,canbedelayedwithoutmakingtheprojectlonger).In</p><p>projectmanagement,acriticalpathisthesequenceofprojectnetworkactivities</p><p>whichadduptothelongestoverallduration,regardlessifthatlongestduration</p><p>hasfloatornot.Thisdeterminestheshortesttimepossibletocompletethe</p><p>project.Therecanbe'totalfloat'(unusedtime)withinthecriticalpath.For</p><p>example,ifaprojectistestingasolarpanelandtask'B'requires'sunrise',there</p><p>couldbeaschedulingconstraintonthetestingactivitysothatitwouldnotstart</p><p>untilthescheduledtimeforsunrise.Thismightinsertinactivetime(totalfloat)</p><p>intotheschedulefortheactivitiesonthatpathpriortothesunriseduetothe</p><p>necessarywaitforthisevent.Thispath,withtheconstraint-generatedtotalfloat</p><p>wouldmakethepathlonger,withtotalfloatbeingpartoftheshortestpossible</p><p>durationfortheoverallproject.Inotherwords,individualtasksonthecritical</p><p>pathpriortotheconstraintmightbeabletobedelayedwithoutelongatingthe</p><p>criticalpath;thisisthe'totalfloat'ofthattask.However,thetimeaddedtothe</p><p>projectdurationbytheconstraintiscriticalpathdrag,theamountbywhichthe</p><p>project'sdurationisextendedbyeachcriticalpathactivityandconstraint.</p><p>Aprojectcanhaveseveral,parallel,nearcriticalpaths;andsomeorallthetasks</p><p>couldhave'freefloat'and/or'totalfloat'.Anadditionalparallelpaththroughthe</p><p>networkwiththetotaldurationsshorterthanthecriticalpathiscalledasub-</p><p>criticalornon-criticalpath.Activitiesonsub-criticalpathshavenodrag,asthey</p><p>arenotextendingtheproject'sduration.</p><p>Althoughtheactivity-on-arrowdiagram,PERTChart(Fig.4.4)isstillusedina</p><p>fewplaces,ithasgenerallybeensupersededbytheactivity-on-nodediagram,</p><p>whereeachactivityisshownasaboxornodeandthearrowsrepresentthe</p><p>logicalrelationshipsgoingfrompredecessortosuccessorasshownhereinthe</p><p>“Activity-on-nodediagram”.</p><p>FeasibilityStudy</p><p>Thisisthephasewheretheairplaneisfirstthoughtof.Itstartswithmarket</p><p>analysisofwhataninterestingproductforthecurrentandforecastedmarketis,</p><p>typicallyfrom15to20yearsinthefuture.Businessopportunitymayalsocome</p><p>fromanairlinedirectrequest,aswasthecaseoftheEMBRAERERJ140,a</p><p>shortenedversionoftheERJ145,developedtobypassscopeclauses.Thereare</p><p>virtuallynoscopelimitstothenumberof44-seatregionaljets(RJ),whilethere</p><p>iswiththe50-seatones.BombardierAerospacealsohasa44-seatRJmodel</p><p>whichisbasicallyaCRJ-200with6seatsremovedandcertifiedastheCRJ-440.</p><p>ItwasdevelopedforDeltaAirlinesbutNorthwestorderedthisversionaswell.</p><p>Fig.(4.4))</p><p>PERTchartforaprojectwithfivemilestones(10through50)andsixactivities</p><p>(AthroughF).Theprojecthastwocriticalpaths:activitiesBandC,orA,D,and</p><p>F–givingaminimumprojecttimeof7monthswithfasttracking.ActivityEis</p><p>sub-critical,andhasafloatof1month(Credit:JeremyKemp,releasedtothe</p><p>publicdomain).</p><p>Theaircraftdevelopmentprogramusuallyconsumes5years.Financialanalysis</p><p>(Fig.4.5)iscarriedoutconcerningproductdevelopment,productionandfleet</p><p>supportinthisphase.Themanufacturerswillalsoseekmeanstofinancetheir</p><p>neworupgradedproduct.Abusinessplanisthemaindeliverableofthisphase.</p><p>Onceitisfinishedandtheaircraftprogramcouldbringatargetreturnof</p><p>investmentorthenewproductmaybestrategicforthecompany,thebusiness</p><p>planispresentedtothecompanyboardtoobtainadecisionwhethertomove</p><p>forwardwiththeprogram(“goahead”)ornot.</p><p>Fig.(4.5))</p><p>Financialanalysiswillprovideinvestmentparameters(Photo:©2015Bento</p><p>Mattos).</p><p>Marketanalysisshouldaddress:</p><p>Trendsandmarketdynamics.</p><p>Existingfleetmapping.</p><p>Marketsegmentation.</p><p>Marketpotential.</p><p>Marketshare.</p><p>Elaborationofadatabasecontainingdataandinformationaboutthecompetition</p><p>(includingothermeansoftransportation).</p><p>Competitiveadvantages.</p><p>Potentialcustomers.</p><p>Marketsurveyencompassingquestionnairesandothersourcestoobtainkey</p><p>information.</p><p>Thebusinessplanusuallycomprisesthefollowingsections:</p><p>Summary</p><p>Descriptionofthecompany</p><p>Marketanalysis</p><p>Businessfinancialparameters</p><p>Marketingstrategy</p><p>Productdevelopmentplan</p><p>Productionscheme(requiredbycertificationauthorities)</p><p>Projectmanagementplan</p><p>MasterPhasePlan</p><p>Riskassessment</p><p>Financialanalysis</p><p>Capitalamassment</p><p>ConceptualStudies</p><p>Theconceptualdesignor,formany,thestudyofconcepts,takesplaceafterthe</p><p>feasibilitystudy,whichistheinitialphasewheretheviabilityofanaircraft</p><p>programisanalyzedconclusively.Intheconceptualphase,theaircraft</p><p>configurationthatbestmeetsalltherequirementsisdefined.Requirementsare</p><p>relatedtomarket,certification,manufacturingandothersthatmaybeestablished</p><p>bytheaircraftmanufacturer.</p><p>Conceptualdesignactivitiesarecharacterizedbythedefinitionandcomparative</p><p>evaluationofnumerousalternativedesignconceptspotentiallysatisfyingan</p><p>initialstatementofdesignrequirements.Theconceptualdesignphaseisiterative</p><p>innature.Modernaircraftdesignconsidersdifferentconfigurationsthatcomply</p><p>withworldscenariosraisedbythecompany’sstrategicplanningstudies.The</p><p>objectiveistheselectionofconceptstoexploretheirmostrelevantcapabilities</p><p>andmeetthewidestrangeoffuturechallenges.</p><p>Designconceptsareevaluated(Fig.4.6),comparedtotherequirements,revised,</p><p>reevaluated,andsoonuntilconvergencetooneormoresatisfactoryconceptsis</p><p>achieved.Duringthisprocess,inconsistenciesamongtherequirementsareoften</p><p>exposed,sothattheproductsofconceptualdesignfrequentlyincludeasetof</p><p>revisedrequirements.Table4.2containsthescopeofthisphase.</p><p>Fig.(4.6))</p><p>Duringconceptualstudies,severalaircraftconfigurationsareanalyzed(Source:</p><p>ITA/IEAP).</p><p>Intheconceptualdesignphase,engineisselected,aircraftlayoutcontaining</p><p>accesspanelsisdefined,theairplaneissized,andsystemarchitecturesare</p><p>established.Preliminarysizingoftheairframeisalsoconductedinthisphase.</p><p>Table4.2Conceptualdesignscope.</p><p>Item Description</p><p>Requirementcheck Requirementsmaysufferalterationsandmustbechecked</p><p>Detailedbudget Budgetfromthepreviousphaseisanalyzedanddetailed</p><p>Configurationstudy Severalconfigurationsareproposedandoneisselectedaccordingtothebestcompliancewithrequirements.Multi-disciplinarydesignandoptimizationanddecisiontoolsareusedtochoosetheconfigurationthatwillbefurtherstudied</p><p>Sizing Sizingandintegrationofaircraftparts</p><p>Structurallayout Aircraftstructurelayoutwithaccesspanelsiselaborated.Thereisasearchforallocationofsystemcomponents</p><p>Technicaldrawings,manualsanddocuments AircraftTechnicalDescription:typicalcharacteristics,includingperformanceandsystemsdescription;usedformarketingandcustomerprospectionAircraftBasicData:detailedcharacteristics,usedfordatainterchangeamongthedifferenttechnologiesinvolvedinproductdesign</p><p>Engineselection Theengineischosenaccordingtoseveralcriteriasuchasthrust,fuelconsumption,size,bleedaircapacity,easyandcheapmaintenance,weight,etc.</p><p>Testing Somewind-tunneltestsareperformed</p><p>Aerodynamicanalysisintheconceptualphaseisusuallycarriedoutwith</p><p>numerictoolsandwind-tunneltesting.Thecomplexityoffluidflowiswell</p><p>demonstratedinmanyscientificpapersandexperiments.Mostphenomenaof</p><p>fluidflow,suchasshockwavesandflowseparation,areessentiallynonlinearin</p><p>natureandthevarietyofturbulencescalesintheflowpatternishuge.</p><p>Nowadays,computationalfluiddynamics(CFD)iswidelyemployedasakey</p><p>toolforaircraftdesign(Fig.4.7).ReynoldsAverageNavier-Stokes(RANS)</p><p>solutionsareacommontool,aswellasEulerandfullpotentialformulations.</p><p>Fig.(4.8)showsahierarchyofseveralsimplificationsoftheNavier-Stokes</p><p>equations.</p><p>Thelengthscaleofthesmallestpersistingeddiesinaturbulentflowcanbe</p><p>estimatedasoforderof1/Re3/4incomparisonwiththemacroscopiclength</p><p>scale.Thesolutionofsuchscalesforacomplexaircraftconfigurationisstill</p><p>prohibitive.Forthisreason,simplifiedformulationsareusedintheaircraft</p><p>industry.Acomputationalgridwithmillioncellsareusuallyrequiredforan</p><p>externalflowsolutionoveracompletedairplaneconfigurationemployingthe</p><p>RANSformulation.</p><p>Fig.(4.7))</p><p>SomeCFDapplicationsinaircraft</p><p>design(Source:ITA/IEAP).</p><p>Fig.(4.8))</p><p>Formulationsfornumericalflowanalysis.</p><p>AviablealternativeforMDOcomputationsistheutilizationoffullpotential</p><p>codeswithviscouscorrections.Theircostbenefitmakesthisformulationvery</p><p>attractiveforhigherfidelityaerodynamiccomputationsinaMDOprocess,</p><p>whichrequiresextensivecallsoftheflowanalysiscodesforperformance,load,</p><p>andstabilitycalculations.However,theextremesensitivenatureoftransonic</p><p>flowinregardtheairplanegeometry,inwhichvariationsintheorderof</p><p>boundary-layerthicknessorlowerleadtosignificantchangesinpressure</p><p>distribution,makesmandatorythatintegralboundary-layerroutinestobe</p><p>coupledwiththetransonicpotentialandEulercodes.Besidesdelivering</p><p>satisfactoryprofiledragvalues,theviscouscoupledcalculationshallalsobeable</p><p>tohandleshock-boundarylayerinteraction.</p><p>AcomparisonbetweenaRANScodeandafull-potentialone[10]wascarried-</p><p>outforatwinjetairlinerwithrear-mountedengines(Fig.4.9).TheRANS</p><p>simulationemployedtheSSTk-ωturbulencemodelandthehexahedralmesh</p><p>thatwascreatedforthesimulationwascomposedofapproximately2.1million</p><p>cells[11].Makinguseofanimplicitschemefortimemarching,theconvergence</p><p>wasreachedafterallresidualsdroppedtovaluesbelow1x10-4,whichconsumed</p><p>5675iterations.Eachiterationdemandedinaverage84sonadesktopcomputer</p><p>fittedwithanIntel®Core™i7-3820processor.Thefullpotentialsolutionfor</p><p>thewing-fuselagecombinationtook25secstoconvergeonthesamemachine.</p><p>Fig.(4.10)showsacomparisonbetweentheresultsfromtheRANSandthefull</p><p>potentialcodes.There,Cpdistributionsfortwowingstationsoftheairlinerof</p><p>Fig.(4.9)areshown.TheagreementbetweentherelatedCpdistributionsisvery</p><p>good.</p><p>Fig.(4.9))</p><p>StreamlinesleavingthewingfortheITA50ADVairliner(Mach=0.775,</p><p>α=1.21o,Re=15x10 ).</p><p>Fig.(4.10))</p><p>CpdistributionsobtainedwithaRANScodeandafullpotentialoneforthe</p><p>ITA50ADVairliner.Atleft,stationa22%ofsemispan;right,stationlocatedat</p><p>50%ofsemispan(Mach=0.775,α=1.21o,Re=15x10 ).</p><p>Numerouscomplexreal-lifeproblemshavebeenaddressedwithoptimization</p><p>techniques.Thisapproachhasbeenadoptedinmanyfieldssuchasengineering,</p><p>economics,andbusiness,forproblemsthatcannotbesolvedinareasonable</p><p>amountoftimeandatsametimerequiringaprecisesolution.Amongother</p><p>relevantaerospaceapplications,optimizationtechniquesareemployedto</p><p>minimizeengineemissions,noisefootprint,developmentandproductioncosts,</p><p>orrisk;andtomaximizeprofit,performance,andaerodynamicefficiency.</p><p>Indeed,aerospaceproblemsareoftenhighlynonlinearandencompassmany</p><p>disciplinesandtheyaresubjectedtocomplexconstraints.Theseconstraintsare</p><p>eitherintheformofsimpleboundssuchasflightquality,orintheformof</p><p>nonlinearrelationshipssuchasmaximumstress,maximumdeflection,minimum</p><p>noiselevels,orgeometricalconfigurationandtopology.</p><p>Manyoptimizationproblemsaresolvedbyalgorithmsbasedonmetaheuristics.</p><p>Manyfieldsincludingartificialintelligence,mathematicalprogramming,and</p><p>operationalresearchutilizemetaheuristics,whichhasbeenexperiencingahuge</p><p>developmentinthelast20years[12].Mostmetaheuristicalgorithmsareinspired</p><p>bynaturalphenomenabehaviors:</p><p>GeneticAlgorithm(GA)mimicsthenaturalevolutionprocess[13].</p><p>ParticleSwarmOptimization(PSO),proposedbyEberhartandKennedy[14],is</p><p>inspiredbysocialbehaviorofflocksofbirdssearchingforalandingspot.</p><p>Everyparticleintheuniverseattractseveryotherparticle,thisrulebasedonthe</p><p>lawofgravityandmassinteractionsistheonewhichGravitationalSearch</p><p>Algorithm(GSA)wasdeveloped[15].</p><p>DevelopedbyKaraboga,ArtificialBeeColony(ABC)modelstheforaging</p><p>behaviorofabeecolony[16].</p><p>Antcolony(AC)isanoptimizationalgorithminspiredbytheforagingbehavior</p><p>ofantcolonies[17].</p><p>CuckooSearch(CS)isanothersuccessfulmetaheuristicwhichmimicsthe</p><p>cuckoobehaviorreproductionstrategy[18].</p><p>ICAisthemathematicalmodelandthecomputersimulationofhumansocial</p><p>evolution,whilegeneticalgorithmsarebasedonthebiologicalevolutionof</p><p>species[19].</p><p>StocasthicFractalSearch(SFS)isbasedonthemathematicalconceptoffractal.</p><p>Usingthediffusionpropertyseenregularlyinrandomfractals,theparticlesin</p><p>thisalgorithmexplorethesearchspaceforanoptimalsolution[12].</p><p>Modernconceptualstudyemploysmulti-disciplinarydesignandoptimization</p><p>frameworks.Theycanhandlediversityofconfigurationsandthecomplexsetof</p><p>requirementsthatareembeddedinaircraftdesign,includingnoiseandemission</p><p>constraints.Thoseframeworksembodyseveraldisciplines,includingoperational</p><p>cost,andintegratedthemtocomplywithconstrainsandtosearchforoptimal</p><p>configurationsunderamulti-objectiveapproach(Fig.4.11).Numerical</p><p>optimizationmethodswereinitiallyappliedtothedesignofoptimallyshaped</p><p>airfoilsections.Ascomputationalcapabilitiesincreased,aerodynamiciststackled</p><p>thedesignofoptimallyshapedwings.Recentadvancesincomputerhardware</p><p>andinparallelcomputingmethodshaveplacedengineersatthethresholdof</p><p>optimizingtheshapeofanentireaircraftconfigurationwithamulti-disciplinary</p><p>approach.Theconceptofsystemengineeringandoptimizationhasresultedin</p><p>theinclusionofahostofengineeringandnon-engineeringdisciplineslike</p><p>manufacturingandprogramfinancialanalysisundertheumbrellaof</p><p>multidisciplinarydesignoptimization.</p><p>Fig.(4.11))</p><p>Multi-disciplinaryandmulti-objectiveoptimizationispartofmodernaircraft</p><p>conceptualdesignasshowninthisillustration.</p><p>Afterthisphase,aircraftmustlookroughlyaccordingtoFig.(4.12).</p><p>Fig.(4.12))</p><p>Aircraftstructurallayoutwithinitialsizing,geometry,andconfigurationare</p><p>definedaftertheconceptualdesignisfinished.</p><p>PreliminaryDesign</p><p>Duringpreliminarydesign,oneormorepromisingconceptsfromtheconceptual</p><p>designphasearesubjectedtomorerigorousanalysisandevaluationtodefine</p><p>andvalidatethedesignthatbestmeetstherequirements.Extensiveexperimental</p><p>efforts,includingwind-tunneltestingandevaluationofanyuniquematerialsor</p><p>structuralconcepts,areconductedduringpreliminarydesignsothatkeyissues</p><p>areaddressed.Allcriticalengineeringproblemsaresolved.Thefinalproductof</p><p>preliminarydesignisacompleteaircraftdesigndescriptionincludingall</p><p>systems,andsubsystemsandtheirintegration.Thefollowingitemsillustrate</p><p>someofthedeliverablesofthisphase(Figs.4.13-4.18):</p><p>GroundServicing</p><p>Fig.(4.13))</p><p>Equipmentforservicingatransportairplaneonground(Source:ITA/IEAP,</p><p>Teodoro,1971).</p><p>LandingGearRetractionandAccommodation</p><p>Fig.(4.14))</p><p>Exampleofmainlandinggeararrangement(Source:ITA/IEAP,Brandão,1957).</p><p>CommandSurfacesandHigh-liftSystem</p><p>Fig.(4.15))</p><p>Aileron,spoliler,flaps,andslatsmustbedefinedinthepreliminarydesignphase</p><p>(Source:ITA/IEAP,Teodoro,1971).</p><p>AccesstoAircraftStructureanditsSystems</p><p>Fig.(4.16))</p><p>Accesstowingstructureandengine(Source:ITA/IEAP,Teodoro,1971).</p><p>MoreDetailedAircraftStructure</p><p>Fig.(4.17))</p><p>Exampleofwingstructure(Source:ITA/IEAP).</p><p>SystemIntegration</p><p>Fig.(4.18))</p><p>Preliminarydesignisalsoconcernedwithsystemintegration(Source:ITA/IEAP,</p><p>Horley,1971).</p><p>DetailedDesign</p><p>Duringdetaileddesign,theselectedaircraftdesignistranslatedintothedetailed</p><p>engineeringdatarequiredtosupporttoolingandmanufacturingactivities.This</p><p>processmakesintensiveuseoftoolssuchasCAD(ComputerAidedDesign).</p><p>Afterfreezingtheairplaneconfiguration,manufacturersmoveontodetaileven</p><p>furtherairplanepartsandvirtuallyassemblethemusingComputerAidedDesign</p><p>andVirtualRealitytools,sothatacomplete</p><p>digitalmock-up(DMU)ofthe</p><p>airplaneisobtained.Thecreationofahighlydetailedsinglemock-upthatis</p><p>sharedbyallhelpstospeedupdevelopment,aseveryoneontheprogram–no</p><p>matterwheretheyarelocated–canworkasavirtualteam,sharingthevery</p><p>latestinformationduringeachphaseofdevelopmentandmanufacturing.The</p><p>DMU’sfunctionalityextendsthroughtosimulatingandvalidatingtheindustrial</p><p>manufacturingprocessesatanearlystageindevelopment.Itcanalsobeusedto</p><p>showairlineswhattheiraircraft’sinteriorwilllooklike,andeventotrain</p><p>maintenanceteamsinadvance.Inaddition,DMUisalsousefultoavoidspatial</p><p>mismatchbetweenelementsofaircraftsystems.(Fig.4.19)</p><p>Fig.(4.19))</p><p>Digitalmockupisusefulforidentifyingspatialmismatchbetweencomponents</p><p>ofaircraftsystems.</p><p>OthertoolssuchasVirtualRealitymaybeusedtoassistengineersfinalizethe</p><p>design(Fig.4.20).Atthisstage,partsstarttobemanufacturedandthefirst</p><p>prototypesarebuilt.Withtheprototypes,themanufacturersstarttotestthe</p><p>airplanetovalidateassumptionsandchoicesmadeduringthepreviousphases.</p><p>Theaimofrig,ground,andflight-testingistoobtainatypecertificateissuedby</p><p>certificationauthoritiessothattheairplanecanbeputintoserialproduction,</p><p>manufacturedanddeliveredtoownersandoperators.</p><p>Fig.(4.20))</p><p>Afterthedetaileddesigniscomplete,theairplanemustlooklikeshownabove.</p><p>Production</p><p>Materials</p><p>Weightisacriticalissueforaerialvehicles.Aerospacemanufacturershave</p><p>developednewtechniquesformodifyingthecharacteristicsofmaterialsthatare</p><p>employedinaerospacestructures.</p><p>Acompositematerialtypicallyconsistsofrelativelystrong,stifffibersinatough</p><p>resinmatrix.Thefibersaresetintoresintoformsheetswhicharelaidontopof</p><p>eachother,bondedandthenheatedinalargeoven,or“autoclave”.Themain</p><p>materialsusedinaerospacecompositestructuresarecarbon-andglass-fiber</p><p>reinforcedplastic.Theyhaveseveraladvantagesovertraditionalaluminum</p><p>alloys.Ascarboncompositesare,ingeneral,only60%ofthealuminumdensity</p><p>andtheyprovideamuchbetterstrength-to-weightratiothanmetals:sometimes</p><p>byasmuchas20%.Theycanalsobeformedintomorecomplexshapesthan</p><p>theirmetalliccounterparts,reducingthenumberoffuselagepartsandtheneed</p><p>forfastenersandjoints.Fig.(4.21)showsthepercentageofcompositesusedin</p><p>modernaircraft[20].Fig.(4.22)illustratesthedistributionofmaterialsthat</p><p>composethestructureofaproposed150-seatairliner(agraduatestudentconcept</p><p>study).</p><p>Fig.(4.21))</p><p>Compositepercentageemployedinmodernaircraft(BasedonPlanet</p><p>Aerospace’sdata).</p><p>Fig.(4.22))</p><p>materialsconsideredfora150-seatairlinerconcept.</p><p>Theso-calledhoneycombsandwich,whichisfarlighterthanametalplateof</p><p>comparablethicknessandhasgreaterresistancetobending,consistsofa</p><p>honeycombcore,composedofrowsofhollowhexagonalcells,bondedbetween</p><p>extremelythinmetalfacesheets.Aluminumisthemostextensivelyusedmetal</p><p>inbothcoreandfacesheets,butthetechniqueisapplicabletoalargevarietyof</p><p>metallicandnonmetallicmaterials.Sandwichconstructionisnowemployedto</p><p>somedegreeinalmosteverytypeofflightvehicle.</p><p>Thestrength/weightratioisusedasprimedriverformaterialselectionsforboth</p><p>enginesandaircraft[21].Thisisstillthefirstorderofimportance,alongside</p><p>easeofassembly.However,althoughalightweightstructureisnecessary,itis</p><p>notsufficientanymore.Designcriteriahavebecomemuchmorecomplexand</p><p>multi-disciplinaryandcompetitiveaircraftnowrequireinnovativedesign</p><p>methodsaswellasimprovedmaterialandprocessingmethods[21].</p><p>Materialsplayakeyrolenotonlyinthefabricationmethodsusedbutalsointhe</p><p>safetymeasuresemployed.Forexample,beryllium,whosecombinationoflight</p><p>weight,highstrength,andhighmeltingpointmakesitavaluablestructural</p><p>material,yieldsdustandchipsduringmachining[22].Becauseexposureto</p><p>berylliumparticlescancauseadversehealtheffects,exceptionalcareisrequired</p><p>toprecludetheircontaminationofpersonneloratmosphere[22].Polymer-matrix</p><p>compositesalsorequirespecialcontaminationprotectionbecauseofthetoxic</p><p>characteroftheresinsinvolved.Polymer-matrixcompositesarevaluedinthe</p><p>aerospaceindustryfortheirstiffness,lightness,andheatresistance.Theyare</p><p>fabricatedmaterialsinwhichcarbon,glassorKevlarfibers(andsometimes</p><p>metallicstrands,filaments,orparticles)arebondedtogetherbypolymerresinsin</p><p>eithersheetorfiber-woundform.Intheformer,individualsheetelementsare</p><p>layeredinmetal,wood,orplasticmoldsandjoinedwithadhesives.Applications</p><p>forsheetcompositesincludewingskinsandfuselagebulkheadsinaircraftand</p><p>theunderlyingsupportforsolararraysinsatellites.Infiber-woundforms,</p><p>tubularorsphericalshapesarefabricatedbywindingcontinuousfiberona</p><p>spinningmold(mandrel)withhigh-speed,computer-programmedprecision,</p><p>injectingliquidresinasthepartisformed,andthencuringtheresin.This</p><p>processisusedforformingrocketmotorcasings;sphericalcontainersforfuels,</p><p>lubricants,andgases;andductsforaircraftenvironmentalsystems.</p><p>Composites,makingforlighterandmorefuel-efficientaircraft,comprised</p><p>roughly50%oftheairframestructureofBoeing’sB787Dreamliner(byweight),</p><p>comparedtoabout5%intheoriginalBoeing747-100fromthelate1960s.</p><p>Boeingitselflistsitsmaterialsbyweightas50%composite,20%aluminum,</p><p>15%titanium,10%steel,and5%other[23].</p><p>AccordingtoBoeing,experiencewiththeBoeing777airlinerdemonstratedthat</p><p>compositestructuresrequirelessscheduledmaintenancethannon-composite</p><p>structures[23].Althoughthe777compositeverticaltailis25percentlargerthan</p><p>the767tail,whichismadefromaluminum,itrequires35percentfewer</p><p>scheduledmaintenancelaborhours[23].Thislaborhourreductionisduetothe</p><p>resultofareducedriskofcorrosionandfatigueofcompositescomparedto</p><p>metal[23].</p><p>Carbonandglassfibercomposites-and,potentiallymorecommon-ceramic</p><p>andmetalmatrixcomposites,arenowbeingappliedinanincreasingnumberof</p><p>airplaneparts,includingsecondarystructures,wingandfuselageandenginefan</p><p>blades.In2012,theglobalaerospacecompositesmarketwasestimatedat</p><p>US$10.3billionanddemandforcompositeaircraftenginestructuresaloneis</p><p>forecasttogrowby7%annuallythrough2016[24].</p><p>Batteriesareusedtopowerairplanesbeforetheauxiliarypowerunit(APU)or</p><p>enginesarestarted.Theyalsosupportgroundoperationssuchasrefuelingand</p><p>poweringbrakesystemswhenairplaneistowed.However,thekeyroleof</p><p>batteriesistoprovidebackuppowerforcriticalsystemsduringflightinthe</p><p>extremelyunlikelyeventofapowerfailure.</p><p>Lithium-ionbatteriesareusedinmanyaircrafttoday.Theypresentmany</p><p>advantagesovertraditionalNi-Cdbatteries,suchas:</p><p>Higherpowerdensity,whichistranslatedintosmallervolumeandweight(over</p><p>50%reductioncomparedtoNi-Cdbatteries).</p><p>Absenceoflithiummetal.</p><p>Absenceoftoxicmaterialslikecadmium,mercuryandlead.</p><p>Nofreeliquidsbecauseoftheuseofasolidpolymerelectrolyte.</p><p>Nogasexertingpressure.</p><p>Nothermalrunaway.Thermalrunawayreferstoasituationwhereanincreasein</p><p>temperaturechangestheconditionsinawaythatcausesafurtherincreasein</p><p>temperature,oftenleadingtoadestructiveresult.Itisakindofuncontrolled</p><p>positivefeedback.</p><p>Noproblemwhensubmittedtoincineration.Noriskofexplosionwhenbatteries</p><p>areexposedtoshortcircuits,nailpunctures,waterimmersion,overcharge,over</p><p>discharge,andhydraulicpressuresupto1500psi.</p><p>Low-levelheatgeneration.</p><p>Operationathighertemperatures.</p><p>Highervoltage.Asinglelithiumioncellgeneratesa3.7Vtension(average</p><p>value),</p><p>whichisequaltoeitherthreenickel-cadmiumornickel-metalhydride</p><p>cellsseriallyconnected.</p><p>Longlifecycle.</p><p>Nomemoryeffects.</p><p>Fastrecharge.</p><p>TheBoeingCompanyintroducedseveralinnovationsintoitsBoeing787</p><p>Dreamliner.Among787flightsystems,akeychangefromtraditionalairlinersis</p><p>theelectricalarchitecture.Bleedairandhydraulicpowersourceswerereplaced</p><p>byelectricallypoweredcompressorsandpumps,eliminatingpneumaticsand</p><p>hydraulicsfromsomesubsystems,e.g.,enginestartersorbrakes[23].However,</p><p>inthefirstyearofservice,atleastfour787aircraftsufferedfromelectrical</p><p>systemproblemsstemmingfromitslithium-ionbatteriesandthefleetwas</p><p>grounded.TheFederalAviationAdministration(FAA)decidedonApril19,</p><p>2013toallowUSDreamlinerstoreturntoserviceaftermodificationswere</p><p>incorporatedintotheirbatterysystemstobettercontainbatteryfires[25].</p><p>However,therearestillconcernsbecausetheprimarycauseofthefireswasnot</p><p>identified.</p><p>Nanotechnologyisslowlybeingincorporatedinaircraft-forexample,carbon</p><p>nano-tube-basedmaterialsornanocoatingsonelectro-chromaticwindows.</p><p>EasyJetwasamongthefirstcommercialairlinestousea“nano-coating”onits</p><p>planes-apolymercoatingusedoveraconventionalfilmthatrepelsdirtanddust</p><p>toreducedrag,cuttingfuelconsumption[24].</p><p>Manymaterialsusedinthemanufacturingprocessdonotbecomepartofthe</p><p>finalairframe.Aircraftmanufacturersmayhavetensofthousandsofindividual</p><p>productsapprovedforuseinthemanufacturing.Alargequantityandvarietyof</p><p>solventsareused,withenvironmentallydamagingvariantssuchasmethylethyl</p><p>ketoneandFreonbeingreplacedwithmoreenvironmentallyfriendlysolvents.</p><p>Chromium-andnickel-containingsteelalloysareusedintooling,andcobalt-</p><p>andtungstencarbide-containinghard-metalbitsareusedincuttingtools.Lead,</p><p>formerlyusedinmetal-formingprocesses,isnowrarelyused,havingbeen</p><p>replacedwithkirksite[20].Intotal,theaerospaceindustryusesmorethan5,000</p><p>chemicalsandmixturesofchemicalcompounds,mostfrommultiplesuppliers,</p><p>andwithmanycompoundscontainingbetweenfivetoteningredients[22].</p><p>Tooling</p><p>Aircraftmanufacturingutilizesdedicatedtoolingintheassemblyprocessto</p><p>ensuretheattainmentofassemblytolerancesandproductquality.External</p><p>surfacesaresubjectedtoaerodynamictolerances,inadditiontoassemblyones.</p><p>Thetightertheaerodynamictoleranceis,thecostlierthemanufacturingprocess</p><p>is.Dedicatedtoolingclampstheaircraftpartstobeassembledintothejigto</p><p>enableassemblybyriveting.However,increasedcompetitionintheaircraft</p><p>industryhasdriventheneedtoimproveassemblyqualitywhilereducingcost</p><p>and,inturn,theneedforinnovativesolutionstoaccomplishthis.Today,robots</p><p>areusedtoproducepartswithincreasedaccuracy.Duetothesmallproduct</p><p>volumesintheaircraftindustry,thejigsmustbeflexibletoassemblemorethan</p><p>onestructureineachjig.Moderntoolingalsousesadjustablemulti-pointtooling</p><p>technology.Thisinnovativeapproachembracesthedevelopmentofdigitally</p><p>adjustablemulti-pointtooling,theinnovationofflexiblefabricationtooling,</p><p>applicationsofdielessformingtoolingandjiglesspositioningtooling.</p><p>Assembly</p><p>Contrarytotheautomotiveindustry,whereavehicleisproducedeveryminute,</p><p>andapproximately1,000carsaremanufacturedaday,anaircraftassemblyline</p><p>withhighproductionratesproducesoneairplaneperday.Assemblybeginswith</p><p>thebuild-upofcomponentpartsintosub-assemblies.Majorsub-assemblies</p><p>includewings,stabilizers,fuselagesections,landinggear,doorsandinterior</p><p>components.Wingassemblyisparticularlyintensive,requiringmanyholestobe</p><p>preciselydrilledandcounter-sunkintheskins,throughwhichlaterrivetsare</p><p>driven.Thefinishedwingiscleanedandsealedfromtheinsidetoensurealeak-</p><p>prooffuelcompartment.Finalassemblytakesplaceinhugeassemblyhalls(Fig.</p><p>4.23),someofwhichareamongtheworld’slargestmanufacturingbuildings.</p><p>Theassemblylinecomprisesseveralsequentialpositionswheretheairframe</p><p>remainsforseveraldaystomorethanaweekwhilepredeterminedfunctionsare</p><p>performed.Numerousassemblyoperationstakeplacesimultaneouslyateach</p><p>position,creatingthepotentialforcrossexposurestochemicals.Partsandsub-</p><p>assembliesaremovedondollies,custom-builtcarriersandbyoverheadcraneto</p><p>theappropriateposition.Theairframeismovedbetweenpositionsbyoverhead</p><p>craneuntilthelandinggearsareinstalled.Subsequentmovementsaremadeby</p><p>towing.Duringfinalassembly,thefuselagesectionsarerivetedtogetheraround</p><p>asupportingstructure.Floorbeamsandstringersareinstalledandtheinterior</p><p>coatedwithacorrosion-inhibitingcompound.Foreandaftfuselagesectionsare</p><p>joinedtothewingsandwingstub(abox-likestructurethatservesasamainfuel</p><p>tankandthestructuralcenteroftheaircraft).Thefuselageinterioriscovered</p><p>withblanketsoffiberglassinsulation,electricalwiringandairductsareinstalled</p><p>andinteriorsurfacesarecoveredwithdecorativepaneling.Storagebins,</p><p>typicallywithintegratedpassengerlightsandemergencyoxygensupplies,are</p><p>theninstalled.Pre-assembledseating,galleysandlavatoriesaremovedbyhand</p><p>andsecuredtofloortracks,permittingtherapidreconfigurationofthepassenger</p><p>cabintoconformtoaircarrierneeds.Powerplantsandlandingandnosegearare</p><p>mounted,andavioniccomponentsareinstalled.Thefunctioningofall</p><p>componentsisthoroughlytestedpriortotowingthecompletedaircrafttoa</p><p>separate,well-ventilatedpainthanger,whereaprotectiveprimercoatisapplied,</p><p>followedbyadecorativetop-coatofurethaneorepoxypaint.Priortodeliveryof</p><p>theaircraft,itisputthrougharigorousseriesofgroundandflighttests.</p><p>Fig.(4.23))</p><p>AssemblyLockheedC-141Starlifteraircraftplantin1980(PhotoWilliamG.</p><p>Holder,publicdomain,viaWikimediaCommons).</p><p>Anew,emptyBoeing777weighs166,441kgandincludesabout3millionparts</p><p>[26].Boeingemploysamovingassemblylineforthe777twinjet,whichis</p><p>movedat4.1to4.6centimetersperminuteduringproduction[26].Accordingto</p><p>Boeing,amovinglineisapowerfultoolavailabletoidentifyandeliminate</p><p>wasteinaproductionsystem[26].Themanufactureralsostatesthatitalso</p><p>drivesefficiencythroughoutthesystembecauseitmakesproblemsvisibleand</p><p>createsasenseofurgencytofixtherootcausesofthoseproblems.Themoving</p><p>lineshortenedthe777finalassemblyprocess,thetimeittakesbetweenthe</p><p>arrivalofinitialfuselagesectionsintosystemsinstallationtothedaythe</p><p>completedjetlinerrollsoutthefactorydoors,from26daysto17days[26].</p><p>Airbus’finalassemblylineinToulouseforitsA350XWBairlinerwas</p><p>conceivedtopresentthelowestenvironmentalfootprintofanyfinalassembly</p><p>lineeverbuiltbyAirbus[27].The72,000-m²,L-shapedfacilityhousestheinitial</p><p>stagesoffinalassembly,involvingthejoin-upoffuselageandwings.The</p><p>assemblyprocessfortheA350XWBallowsteamstoworkinparallel,reducing</p><p>thetimefromstartoffinalassemblytoaircraftdeliveryby30percent[27].With</p><p>anewlightingsystem,roof-mountedphotovoltaicsolarpanels,translucent</p><p>panelsandglassarchedroofs,theassemblyfacilitycanproducetheequivalent</p><p>ofmorethan50percentofitsownenergy[27].Furtherincreasingitsstatusas</p><p>the“greenest”finalassemblylineeverbuiltbyAirbus,manyofthematerials</p><p>presentonthissitewererecycledduringtheconstructionwork.</p><p>Modernassemblylinesuserobotsforautomaticrivetingandpainting.Robots</p><p>arealsousedtoperformwaterproofingandpressurizationtestsonfuselages,</p><p>doorsandwindows–ameticulousprocessthatistaxingonthehumanbody.The</p><p>robottrackstheentireperimeterofthepart,centimeterbycentimeter,</p><p>CO2concentrationandglobalairsurfacetemperature(Source:</p><p>NASAGoddardInstituteforSpaceStudies,Graphreleasedtopublicdomain).</p><p>Icecoresprovideevidenceforgreenhousegasconcentrationvariationsoverthe</p><p>past800,000years.BothCO2andCH4varybetweenglacialandinterglacial</p><p>phases,andconcentrationsofthesegasescorrelatestronglywithtemperature</p><p>(Fig.1.2)[9-11].Directdatadoesnotexistforperiodsearlierthanthose</p><p>representedintheicecorerecordbecausetheearthinternalheatmeltstheice.</p><p>DataindicatesCO2molefractionsstayedwithinarangeof180ppmto280ppm</p><p>throughoutthelast800,000years,untiltheincreaseofthelast250years.</p><p>Thepowerstationspresentedin2000thebiggercontributioninworldenergy</p><p>useandemissionsofgreenhousegases(GHGs)withthetransportsectorcoming</p><p>intothirdplace(Table1.1).In2004,transportenergyuseamountedto26%of</p><p>totalworldenergyuseandthetransportsectorwasresponsibleforabout23%of</p><p>worldenergy-relatedGHGemissions[12].The1990–2002growthrateof</p><p>energyconsumptioninthetransportsectorwashighestamongalltheend-use</p><p>sectors.Roadvehiclesaccountformorethanthree-quartersofatotalof77</p><p>exajoules(EJ)oftotaltransportenergyuse,withlight-dutyvehiclesandfreight</p><p>truckshavingthelion’sshare.Virtuallyall(95%)oftransportenergycomes</p><p>fromoil-basedfuels,largelydiesel(23.6EJ,orabout31%oftotalenergy)and</p><p>gasoline(36.4EJ,47%).Oneconsequenceofthisdependence,coupledwiththe</p><p>onlymoderatedifferencesincarboncontentofthevariousoil-basedfuels,isthat</p><p>theCO2emissionsfromthedifferenttransportsub-sectorsareapproximately</p><p>proportionaltotheirenergyuse.</p><p>Fig.(1.2))</p><p>700thousandyearsoficecoredataindicatesastrongcorrelationbetween</p><p>temperatureandCO2concentration[9,11].</p><p>Table1.1Relativefractionofman-madegreenhousegases(CO2,CH4andN2O)</p><p>comingfromeachofeightcategoriesofsources[13].</p><p>Sector PercentShareOverall</p><p>IndustrialProcesses 16.8</p><p>PowerStations 21.3</p><p>Wastedisposalandtreatment 3.4</p><p>Landuseandbiomassburning 10.0</p><p>Residentialcommercial,andothersources 10.3</p><p>Fossilfuelretrieval,processing,anddistribution 11.3</p><p>Agriculturalbyproducts 12.5</p><p>Transportationfuels 14.0</p><p>Infact,aviationcontributiontoworld’spollutioniscontroversial.Contrails</p><p>representoneofthesecontroversies.Contrailsarecloudsformedwhenwater</p><p>vaporcondensesandfreezesaroundsmallparticles(aerosols)thatexistin</p><p>aircraftexhaust(Fig.1.3).Someofthatwatervaporcomesfromtheairaround</p><p>theplane;and,someisaddedbytheexhaustoftheaircraft.Theexhaustofan</p><p>aircraftcontainsbothgas(vapor)andsolidparticles.Aircraftcontrailscan</p><p>spreadintocirrus-likecloudshighintheatmosphere.Likenaturalclouds,they</p><p>arethoughttohaveanoverallwarmingeffectontheplanet.Buttheycanalso</p><p>moderatedailytemperatureextremesbytrappingheatthatescapesfromthe</p><p>groundandreflectingsunlight[14].Thisraisesthelowestovernight</p><p>temperaturesand,toalesserdegree,reducesthehigherrecordingsduring</p><p>daylighthours.</p><p>Noisedisturbanceisacomplicatedissuetoevaluate,asitisopentosubjective</p><p>reactions.Itsimpactisnotalastingoneontheactualenvironment,butitcan</p><p>havesignificantadverseeffectsonpeoplelivingclosetoanairport,including:</p><p>interferencewithcommunication,sleepdisturbance,annoyanceresponses,</p><p>learningacquisition,performanceeffectsandcardiovascularandpsycho-</p><p>physiologicaleffects.</p><p>Fig.(1.3))</p><p>Airplanecontrails(Photo:courtesyofPauloEduardoCypriano).</p><p>TheOctober2006reportbyNicholasStern[15]statesthatthelargest</p><p>contributortohuman-inducedCO2ispowergeneration(24%),mostlyproduced</p><p>inelectricitystationsburninggasandcoal.Landusehits18%,thenagriculture,</p><p>industryandtransportat14%each(aviationcontributionisinthe2-2.5%range).</p><p>Buildings(8%),otherenergyrelatedactivities(5%)andwaste(3%)makeupthe</p><p>rest.</p><p>Carbondioxideisnottheonlygreenhousegasemittedbyaircraft,however.The</p><p>exhaustfromaircraftenginesismadeupof:7%to8%CO2andwatervapor;</p><p>around0.03%nitrogenoxides,unburnedhydrocarbons,carbonmonoxideand</p><p>Sulphuroxides;tracesofhydroxylfamilyandnitrogencompoundsandlesser</p><p>amountsofsootparticles,despiteoftheindustryhasmanagedtoeliminatesoot</p><p>emissionsoverthepastfewdecades.Between91.5%and92.5%ofaircraft</p><p>engineexhaustisnormalatmosphericoxygenandnitrogen.</p><p>TheInternationalCivilAviationOrganizationhasdefinedasetofconditionsfor</p><p>theassessmentoflocalemissions,termedLanding-Takeoff(LTO)cycle,which</p><p>coversNOX(NO+NO2),CO,UHC,andsmokeemissions.Theseconditionsare</p><p>detailedinthevolumeII(Emissions)oftheAnnex16(Environmental</p><p>Protection)totheConventiononInternationalCivilAviation[16].TheLTO</p><p>cycleconsiderstheairplaneengineoperatingatthetakeoff,climb,approachand</p><p>taxi(idle)settings.Thesesettingsaredefinedasapercentageoftheratedengine</p><p>thrust(F∞):100%F∞(takeoff),85%F∞(climb),30%F∞(approach)and7%</p><p>F∞(idle).Theengineissupposedtooperateateachsettingforadefinitetimeas</p><p>follows:42s(takeoff),132s(climb),240s(approach)and1,560s(idle/taxi).</p><p>Fig.(1.4)showstheschemeoftheLTOcycle.</p><p>Fig.(1.4))</p><p>LTO-cycleforevaluationofengineemissions.</p><p>BasedontheLTOcycle,theICAOCommitteeonAviationEnvironmental</p><p>Protection(CAEP)setsforththelimitsforenginecertification[16].Theselimits</p><p>considerthetotalpollutantemissionparameterizedbythetotalreferenceengine</p><p>thrust(F∞)whichenablesthecomparisonofenginesofvariedsizes.Table(1.1)</p><p>providesvaluesofemissionsandfuelusedintheLTOphaseforaircrafttypes</p><p>frequentlyoperatedfordomesticandinternationalroutes[16].Concordefigures</p><p>layswellabovethoseoftheotherairplanes.ThevaluesforCO2andNOx</p><p>emissionsperpassengerfortheaircraftofTable(1.2)aredisplayedinTable</p><p>(1.3).</p><p>TheimpactofNOxemissionsfromaircraft,which,althoughrepresentingonly</p><p>1–2%ofthetotalemissionsofNOxfromhumanandnaturalsourcesintheearly</p><p>1990s[17]mayhaveapronouncedimpactonthechemicalcompositionofthe</p><p>atmosphere.Numerousstudieshavefocusedonthedifferentimplicationsof</p><p>NOxemissionsfromaircraft[18-22].Mostimportantly,NOxemissionsfrom</p><p>aircraftareexpectedtoincreaseozoneintheuppertroposphereandlower</p><p>stratosphereregion[22].</p><p>Table1.2DefaultfuelandemissionfactorsforsomeaircrafttypesinLTOcycle</p><p>(kg/LTO)[16].</p><p>Aircraft CO2 CH4</p><p>A300 5470 1.0</p><p>A320 2560 0.04</p><p>BAe146 1800 0.16</p><p>Boeing707 5880 9.8</p><p>Boeing727 4455 0.3</p><p>Boeing737-300 2905 0.2</p><p>Boeing747-200 10680 3.6</p><p>Boeing747-400 10710 1.2</p><p>Boeing757 4110 0.1</p><p>Boeing767-300 5405 0.4</p><p>Boeing777-200ER 7346 -</p><p>Fokker100 2340 0.2</p><p>SAAB340 945 1.4</p><p>Concorde 20290 10.7</p><p>*TheSulphurcontentofthefuelwasassumedtobe0.05%.</p><p>Table1.3CO2,NOx,andfuelperpassengerfortheLTOcycle(kgofLTO/PAX)</p><p>[16].</p><p>Airplane Paxcapacity(singleclass) CO2/PAX Fuel/PAX</p><p>A300 345 15.85 5.01</p><p>A320 180 14.22 4.50</p><p>BAe146 112 16.07 5.08</p><p>Boeing707 189 31.11 9.84</p><p>Boeing727 189 23.57 7.46</p><p>Boeing737-300 140 20.75 6.57</p><p>Boeing747-200 480 22.25 7.04</p><p>Boeing747-400 565 18.96 6.00</p><p>Boeing757 239 17.19 5.44</p><p>Boeing767-300 290 18.63 5.90</p><p>Boeing777-200ER 440 16.69 5.30</p><p>Fokker100 107 21.87 6.92</p><p>SAAB340 34 27.79 8.82</p><p>Concorde 120 169.08 53.5</p><p>EmissionControlPolicy</p><p>Themitigationofenvironmentalimpactisoneofthekeychallengesforaviation</p><p>andamaindriverforresearchandtechnologyinthesector.Whilethefocusin</p><p>thepastwasonnoiseandpollutantemissions,aviationgreenhousegasemissions</p><p>havebecomethepredominantenvironmentaltopicfortheaviationcommunityin</p><p>thelastyears.Modernairlinersarepoweredbyturbofanorturbopropengines</p><p>burning</p><p>recording</p><p>andlisteningfornoisethatwouldindicatealeakorholeintheairframe.</p><p>AircraftDelivery</p><p>Fortheoperatorandownerofanewaircraft,itisveryimportantthattheaircraft</p><p>isinspectedandcheckedduringtheassemblyandacceptancephases.Thereare</p><p>manystepsafutureownershouldtakepriortotakingdeliveryofanairplane,</p><p>fromsigningupforpost-deliveryproductsupportprogramstocoordinatingwith</p><p>certificationauthoritiestoensureReducedVerticalSeparationMinima(RVSM)</p><p>approval.</p><p>Deliveryisaveryimportanttaskinaircraftproductionprocess.Beforetaking</p><p>deliveryofanaircraftandsigningthetransferofthetitle,thecustomerairline</p><p>carriesoutacompleteanddetailedcheck.Itisrepresentedbyateamofexperts</p><p>whoseassignmentistochecktheconformityoftheaircraftwiththecontractual</p><p>specification.Thedeliveryphaseisusuallyspreadoverfourorfivedayson</p><p>average,dependentuponaircraftsizeandcharacteristics.Astandarddelivery</p><p>proceduretakesplaceasfollows:</p><p>1stround:groundchecks:externalsurfaces,baysandcabinvisualinspection,</p><p>staticaircraftsystemandco*ckpitchecks,enginetests.</p><p>2ndround:acceptanceflight:checksduringflightofallaircraftsystems</p><p>(includingcabinsystems)andaircraftbehaviorinthewholeflightenvelope.The</p><p>aircraftevaluationflightisknownasproductionflight.</p><p>3rdround:physicalreworkorprovisionofsolutionsforalltechnicalandquality</p><p>issuesopenindelivery.</p><p>4thround:completionoftechnicalacceptance.Technicalclosureoftheaircraft</p><p>andallassociateddocumentsattestingtheaircraft’scompliancetothetype</p><p>certificateandconformitytothetechnicalspecificationallowingtheissuanceof</p><p>theCertificateofAirworthiness.</p><p>5thround:transferoftheaircraft'stitledeedstothecustomerairline:theaircraft</p><p>changesowner.Preparationoftheaircraftfortheferryflighttoitshomebase.</p><p>CERTIFICATIONPROCESS</p><p>Overview</p><p>Theaircraftmanufacturermustpresenttheprojectunderconsiderationtothe</p><p>certificationauthority.Anapplicant'sformalapplicationforaTypeCertificate</p><p>includesanairplanedescriptionwithathree-viewdrawing.Afterreachinga</p><p>sufficientdegreeofmaturity,thecertificationteamsetrulesthatareapplicableto</p><p>thecertificationofthisspecificaircrafttype(Certificationbasis).The</p><p>certificationauthorityandthemanufacturerdefineandagreeonthemeansto</p><p>demonstratecomplianceoftheaircrafttypewitheachrequirementofthe</p><p>CertificationBasis.</p><p>TheCertificationProgramPlan(CPP)isakeydocument.Itcontainsthe</p><p>proposedcertificationbasis,includingnoiseandemissionrequirements.The</p><p>planalsocontemplatesspecialconditions,exemptions,andequivalentlevelof</p><p>safetyfindings.Theuseofdelegations/designeesisalsoplanned.</p><p>Theaircraftmanufacturermustdemonstratecomplianceofitsproductwith</p><p>regulatoryrequirements:thestructure,engines,controlsystems,electrical</p><p>systemsandtheflightperformanceandhandlingqualitiesareanalyzed</p><p>accordingtothecertificationbasis.Thiscompliancedemonstrationiscarriedout</p><p>byanalysesduringgroundtesting,suchastestsonthestructuretowithstandbird</p><p>strikes,fatiguetestsandgroundvibrationtests(GVT).Inaddition,thereisan</p><p>extensiveandexpensiveflighttestcampaign.Expertsfromthecertification</p><p>authorityperformadetailedexaminationofthiscompliancedemonstration,by</p><p>meansofdocumentreviewsintheirofficesandbyattendingsomeofthese</p><p>compliancedemonstrations(testwitnessing).Thisisthelongestandprobably</p><p>themostdemandingphaseofthecertificationprocess.Inthecaseoflarge</p><p>aircraft,theperiodtocompletethecompliancedemonstrationissetatfiveyears,</p><p>whichmaybeextended,ifnecessary.</p><p>TheTCdatasheetispartoftheTCanditdocumentconditionsandlimitationsto</p><p>meetcertificationrequirements.Iftechnicallysatisfiedwiththecompliance</p><p>demonstrationbythemanufacturer,thecertificationauthorityclosesthe</p><p>investigationandissuestheTC.ThepostcertificationactivitiesincludetheType</p><p>InspectionReport(TIR),CertificationSummaryReport(CSR),andPost</p><p>CertificationEvaluation.Fig.(4.24)providesasummaryofthecertification</p><p>phases.</p><p>Fig.(4.24))</p><p>Phasesofcertificationprocess.</p><p>CertificationRequirements</p><p>Eachaviationauthoritydefinesitsownsetofrequirements,whichisorganized</p><p>intosubsetscoveringthevariousaspectsofaviation-relatedactivities.Oneofthe</p><p>mostcomprehensiveandwell-organizedsetofrequirementsisthatofthe</p><p>FederalAviationAdministration(USA),whichisexplainedinthefollowing</p><p>paragraphsasanexample.</p><p>Title14oftheCodeofFederalRegulations(14CFR)dealswithaviation</p><p>requirements[28].FormerlyknownasFederalAviationRegulations,orFARs,</p><p>theserulesprescribedbytheFederalAviationAdministration(FAA)governall</p><p>aviationactivitiesintheUnitedStates.Awidevarietyofactivitiesareregulated,</p><p>suchasaircraftdesignandmaintenance,typicalairlineflights,pilottraining</p><p>activities,hot-airballooning,lighter-than-airaircraft,man-madestructure</p><p>heights,obstructionlightingandmarking,andevenmodelrocketlaunches,as</p><p>wellasmodelaircraftoperation,andkiteflying.Theserulesaredesignedto</p><p>promotesafeaviation,protectingpilots,flightattendants,passengersandthe</p><p>publicfromunnecessaryrisk.TheFARsareorganizedintosections,calledParts,</p><p>duetotheirorganizationwithintheCFR(Table4.3).Eachpartdealswitha</p><p>specifictypeofactivity.Forexample,14CFRPart141containsrulesforpilot</p><p>trainingschools.ThesectionsmostrelevanttoaircraftpilotsandAMTs</p><p>(AviationMaintenanceTechnicians)arelistedinTable4.3[29].Manypartsof</p><p>theFARsaredesignedtoregulatecertificationofpilots,schools,oraircraft</p><p>ratherthantheoperationofairplanes[29].Onceanairplanedesigniscertified</p><p>byusingsomepartsoftheseregulations,itiscertifiedregardlessofanyfuture</p><p>regulationchanges.Forthatreason,newerplanesarecertifiedusingnewer</p><p>versionsoftheFARsandinmanyaspects,maybethusconsideredsaferdesigns.</p><p>Table4.3FARParts[29].</p><p>Part1–DefinitionsandAbbreviationsPart13–InvestigationandEnforcementProceduresPart21–CertificationProceduresforProductsandPartsPart23–AirworthinessStandards:Normal,Utility,AcrobaticandCommuterAirplanesPart25–AirworthinessStandards:TransportCategoryAirplanesPart27–AirworthinessStandards:NormalCategoryRotorcraftPart29–AirworthinessStandards:TransportCategoryRotorcraftPart33–AirworthinessStandards:AircraftEnginesPart34–FuelVentingandExhaustEmissionRequirementsforTurbineEnginePoweredAirplanesPart35–AirworthinessStandards:PropellersPart39–AirworthinessDirectivesPart43–Maintenance,PreventiveMaintenance,Rebuilding,andAlterationPart45–IdentificationandRegistrationMarkingPart47–AircraftRegistrationPart61–Certification:Pilots,FlightInstructors,andGroundInstructorsPart65–Certification:AirmenOtherThanFlightCrewmembersPart67–MedicalStandardsandCertificationPart71–DesignationofClassA,ClassB,ClassC,ClassD,andClassEAirspaceAreas;Airways;Routes;andReportingPointsPart73–SpecialUseAirspacePart91–GeneralOperatingandFlightRulesPart97–StandardInstrumentApproachProceduresPart101–MooredBalloons,Kites,UnmannedRocketsandUnmannedFreeBalloonsPart103–UltralightVehiclesPart105–ParachuteOperationsPart119–Certification:AirCarriersandCommercialOperatorsPart121–OperatingRequirements:Domestic,Flag,andSupplementalOperationsPart125–CertificationandOperations:AirplanesHavingaSeatingCapacityof20orMorePassengersoraPayloadCapacityof6,000lborMorePart129–isaforeigncarrieroroperatorofU.S.AircraftPart133–RotorcraftExternal-LoadOperationsPart</p><p>kerosene,whichisamixtureofhydrocarbonsandcontainsalarge</p><p>varietyofcarbonchainmolecules,generallywithchainlengthsofnineto</p><p>sixteenatoms.ThisisthecasewithJETA-1,fuelproducedaccordingto</p><p>internationalstandardspecificationsforuseincivilaviation.Engineemissions</p><p>canbedividedintotwobasicgroups:thoseproportionaltoenginefuelburnand</p><p>thoseproportionaltoenginethrustsetting.Thefuel-burnproportionalemissions</p><p>asseenbeforeareessentiallycarbondioxide(CO2),watervapor(H2O),and</p><p>sulfuroxides(SOX),whereasthoseproportionaltothrustsettingcomprise</p><p>carbonmonoxide(CO),unburnthydrocarbons(UHC),nitrogenoxides(NOX),</p><p>soot,andsmoke.Fromallthesecombustionproducts,carbondioxide(CO2)is</p><p>themaingreenhousegasthatoccursnaturallyintheenvironmentandthesingle</p><p>mostimportantwasteproductofindustrializedeconomies.Itisproducedinthe</p><p>engineatarateofapproximately3.15gramsperkilogramoffuelburntinthe</p><p>engine.Itisrelativelyabundantandhasaverylonglifeintheatmosphere,</p><p>having,therefore,aleadingimportanceintheglobalclimatesystem.Per</p><p>IntergovernmentalPanelonClimateChange(IPCC)in2007[23],theCO2</p><p>emissionsfromglobalaviationwereincreasedbyafactorofabout1.5,from330</p><p>MtCO2/yearin1990to480MtCO2/yearin2000,andaccountedforabout2%of</p><p>totalanthropogenicCO2emissions.Consideringalsootherrelevantexhaust</p><p>emissionsfromaircraftenginesincludingcontrailsandcirrus,thecontributionof</p><p>airtransporttothetotalanthropogenicgreenhouseeffecthasbeenestimatedat</p><p>around3%.IPCC[23]alsoconcludedthat,intheabsenceofadditional</p><p>measures,projectedannualimprovementsinaircraftfuelefficiencyoftheorder</p><p>of1–2%arelikelytobeoverlappedbytrafficgrowthofaround5%eachyear,</p><p>despiteofpoliticalandeconomicturmoil,leadingtoaprojectedincreasein</p><p>emissionsof3–4%peryear.IPCCalsoforecaststhatby2050aviation</p><p>contributiontoglobalanthropogeniccarbonemissionscouldgrowto3%,</p><p>representing5%ofthetotalgreenhouseeffect[23].Whileaviationisarelatively</p><p>smallcontributorofgreenhousesgases,thescientificfindingsoftheIPCC[24]</p><p>indicateaclearurgencyforactionfromallsectorstoachievetheirmediumand</p><p>long-termobjectives.Therefore,emissionsreductionmeasureswereperceived</p><p>bytheindustryasarealneedforcompensationoftheeffectofthetrafficgrowth</p><p>forecasted.</p><p>TheAviationIndustryInitiatives</p><p>Consideringtheabovescenario,attheUnitedNationsClimateConferencein</p><p>Copenhagenin2009(twoyearsaftertheIPCCreport),theaeronauticaland</p><p>aviationindustry(airlines,manufacturers,airportsandairnavigationservice</p><p>providers)finallyannounceditscommitmenttoaglobalapproachtomitigating</p><p>aviationgreenhousegasemissions,settingthefollowingobjectives[25]:</p><p>Improvementinfuelefficiencyof1.5%peryearfrom2009to2020(measures</p><p>underindustrycontrol,linkedtooperationalproceduresandbasicinfrastructure</p><p>improvements).</p><p>Carbon-neutralgrowthat2020(fuelCO2emissionsareneutralized).</p><p>ReductioninCO2emissionsto50%of2005levelsby2050.</p><p>Itwasnoticeablethatthisisaveryambitiousroadmapwheretheaviation</p><p>industrywouldinvesthardandcontinuouslyoninnovativetechnologies.Focus</p><p>onfuelefficiencyturnedthereforethemaingoalfortheindustry,notonlydriven</p><p>byfuelprices,butnowintheenvironmentalimpact.Opportunitiescontinueto</p><p>existforaddressingaviationemissionsthroughfurtherairtrafficmanagement</p><p>andoperationalmeasures,butclearlynotsufficienttopushtheambitious50%</p><p>reductionby2050.FromFig.(1.5)itiswidelyperceivedbytheaviationindustry</p><p>hasandmustcontinuetopursuearangeofopportunitiesinnewareas[26].</p><p>Fig.(1.5))</p><p>Emissionsreductionroadmap.</p><p>Advancesonnewaircraftdesigntechnologiesaswellasthedevelopmentof</p><p>“drop-in”biofuelstoreplacefossil-basedfuelscouldofferfurthergainsinthe</p><p>futuretoreachthetargets.Inaddition,arangeofmarket-basedmeasures</p><p>(MBM),includingpurchaseofoffsetsfromothersectorscouldfurthermitigate</p><p>theclimateimpactofCO2emissionsfrominternationalcivilaviation.Basedon</p><p>thisindustrycommitment,toachievetheabovehigh-levelgoals,theaviation</p><p>industry,ledbytheInternationalAirTransportAssociation(IATA),announced</p><p>theso-called“Four-pillarStrategy”[26]withtheobjectivetocommitthe</p><p>industrystakeholdersonsuchemissionsreductiongoals,whichareresumedin</p><p>Table(1.4)</p><p>Table1.4Globalstrategiesforreducingaviationfuelusesandemissions[26].</p><p>Technology Operations</p><p>Newairframeandenginetechnologies Improvedoperationalprocedures</p><p>Retrofits Moreefficientflightprocedures</p><p>Sustainableaviationfuels Weightreduction</p><p>Infact,attheThirdAviationandEnvironmentSummitinGeneva(April2008)a</p><p>globaldeclarationwassignedacrosstheairtransportindustry(ACI,CANSO,</p><p>IATA,ICCAIA,Airbus,Boeing,Bombardier,CFMInternational,EMBRAER,</p><p>GeneralElectric(GE),PrattandWhitney(PW),RollsRoyce(RR),ATAG)</p><p>whichcommittedtheindustrytoafour-pillarstrategybasedontechnological</p><p>progress,infrastructureenhancements,operationalimprovementsandsuitable</p><p>economicinstrumentstoworktowardsthevisionofzeronetcarbonemissions.</p><p>Followingsuchinitiative,atthe36thSessionoftheInternationalCivilAviation</p><p>Organization(ICAO)Assemblyin2009,ContractingStatesadoptedthe</p><p>statementofcontinuingICAOpoliciesandpracticesrelatedtoenvironmental</p><p>protection.Underthisscope,theGrouponInternationalAviationandClimate</p><p>Change(GIACC)formalizedICAOCounciltheseinitiativesfromtheindustry</p><p>commitmentandrecommendations,mostlybasedontheFourPillarsproposal.</p><p>GIACCwasthereforetaskedwithdevelopingandrecommendingtotheCouncil</p><p>anaggressiveprogramofActiononInternationalAviationandClimateChange</p><p>andacommonstrategytolimitorreducegreenhousegasemissionsattributable</p><p>tointernationalcivilaviation.Thegrouphasrecommendedthefollowing</p><p>potentialareasofdevelopmentandinvestmentstoContractingStatesdefinedas</p><p>follows[27]:</p><p>Investmentininnovativetechnologies:Measuresinthiscategorymay</p><p>includepurchaseofnewaircraft,retrofittingandupgradeimprovementson</p><p>existingaircraft,innovativedesignsinaircraft/engines,fuelefficiency</p><p>standardsandalternativefuels.Someofthesemeasureshavethepotential</p><p>forveryhighgainsinfuelefficiency/emissionsreductionbutthecostsare</p><p>likelytobehighwithalongtimeframeforimplementation.</p><p>Developmentofefficientoperations:Thesemeasuresincludeminimizing</p><p>weight,improvingloadfactors,reducingspeed,optimizingmaintenance</p><p>schedules,andtailoringaircraftselectiontouseonroutesorservices.This</p><p>areaisessentiallyamatterforaircraftoperatorswhowillmaketheir</p><p>decisionsbasedoncommercialfactorsintheiroperationalscenarios.</p><p>Investmentoneffectiveinfrastructure:Thesemeasuresmeanmoreefficient</p><p>airtrafficmanagementplanning,groundoperations,terminaloperations</p><p>(departureandarrivals),en-routeoperations,airspacedesignandusage,</p><p>andairnavigationcapabilitiesaremeasureswithpotentialforrelatively</p><p>shorttomedium-termgainsalthoughthescaleofpotentialrelativegainsis</p><p>lowtomedium.Inaddition,moreefficientplanninganduseofairport</p><p>capacities,constructionofadditionalrunwaysandenhancedterminal</p><p>facilities,andcleanfueloperatedgroundsupportequipmenttobe</p><p>implementedintheshorttomedium-term,butpotentialemissionreduction</p><p>gainsarelikelytobelow.Increasedairportcapacitymayalsoencourage</p><p>increasedemissionsfromaircraftunlessappropriateactionsaretakento</p><p>addresstheemissions.</p><p>Positiveeconomicmeasures:Thesemeasuresincludevoluntarycarbon</p><p>offsetting,emissionstradingschemes(MBM,MarketBasedMeasures),</p><p>emissionschargesandpositive</p><p>economicincentives.Measuresinthis</p><p>categoryhavepotentialforachievinggainsintermofreductionsinnet</p><p>emissions.</p><p>Regulatoryandothers:Measuresthatincluderegulatoryenforcementson</p><p>carbonemissionsreduction(i.e.aircraftmovementcaps/slotmanagement)</p><p>andotherinitiativessuchasenhancedweatherforecasting,transparent</p><p>carbonreportingandeducation/trainingprograms.</p><p>Finally,thegovernmentalmeetingatICAOinitsClimateChangeResolution</p><p>17/2atthe37thGeneralAssemblyinOctober2010setoutafuelefficiencygoal</p><p>to2%peryear(fromformer1.5%)andreinforcedthecarbon-neutralgrowthto</p><p>the2020goal,whichrepresentsarealchallengefortheaviationindustry.This</p><p>newgoalnowconsiderscomprehensivegovernmentcontrolledmeasuresatState</p><p>Level,suchthedevelopmentofAirTrafficManagementprograms,mainly</p><p>focusedonPerformanceBasedNavigation(PBN)implementation.Inthis</p><p>session,theAssemblyalsodecidedtodevelopanICAOaircraftcertification</p><p>standardforCO2emissions,liketheexistingstandardsfornoiseandengine</p><p>emissions(nitrogenoxides,carbonmonoxide,unburnedhydrocarbonsand</p><p>smoke).WiththisICAOwouldfosterdevelopmentanduseoffuel-efficient</p><p>technologiesanddesignsbyaircraftandenginemanufacturers.WithICAO’s</p><p>engagement,alllevelsoftheindustryandStateswerefinallycommittedwiththe</p><p>newemissionsreductionstargetsthefocusturnedsignificantlytofuelefficiency</p><p>programs.</p><p>Historically,thedevelopmentofaviationhasalwaysbeendrivenbyfuel</p><p>efficiency(fuelburnperseat),andoverthelast50yearsthefuelburn(andthe</p><p>carbonemissions)perpassengerkilometerhasbeenreducedbyover70%.Fuel</p><p>isthemostimportantsinglecostelementforairlineoperators;andthehighand</p><p>stronglyvolatileoilpricesofthelastyearshaveevenmoreincreasedtheirneed</p><p>formorefuel-efficientaircraft.Inaddition,anaircraftcertificationstandard</p><p>limitingcarbonemissionsiscurrentlybeingdevelopedunderICAO,whichis</p><p>intendedtodriveforwardthedevelopmentandencouragetheuseofmorelow-</p><p>emissionsaircraft.</p><p>Thefuelefficiencyofcivilaviationcanbeimprovedbyavarietyofmeans</p><p>includingtheincorporationintoairplanesofinnovativetechnologies,operations</p><p>techniquesandairtrafficmanagement.PerIPCC[24],technologydevelopments</p><p>mightoffera20%improvementinfuelefficiencyover1997levels.Byusing</p><p>datafromRef[28],agraphcontainingfuelefficientoftransportairplaneswas</p><p>elaborated(Fig.1.6).Thisgraphcontainssomeairplanesduetoenterservicein</p><p>thenextcomingyearsliketheBoeing737MAX.Itisnoticeablethatoverthe</p><p>past40years,sincethefirstgenerationofjettransportaircraft,fuelefficiency</p><p>hasimprovedconsiderably,consideringthe4thgenerationofjetenginesand</p><p>airplanesmadeofCFRP(Carbon-fiberReinforcedPolymer).</p><p>Thedevelopmentofnewoperationalproceduresandtechniquesarerelevant,but</p><p>limitedtothecurrenttechnologicallimitations.Fuelconservationprogramsare</p><p>widelysebyairlinesandimprovementsaresetobservedonthemagnitudeof5%</p><p>to10%atmost.Thisrepresentsasignificantimprovementwithrelativelylesser</p><p>amountsofinvestmentsandairlinesareconstantlyencouragedtooptimizetheir</p><p>operationsonFuelConservationinitiatives.</p><p>However,thefirstofthefourpillars(innovativetechnologies)isconsidered</p><p>nowadaysasthemainpotentialcontributorforachievingthedesiredICAO</p><p>objectivesinemissionreduction.Itsachievementstronglydependsonthe</p><p>developmentandimplementationofinnovativetechnologiesbyaircraft,engine</p><p>andequipmentmanufacturers,usinghigherfidelityaircraftdesigntools.The</p><p>principalareashavedirectimpactonfuelefficiencyareenvisionedtobe</p><p>airframe(aerodynamics,structures,equipmentsystemsandnewconfigurations)</p><p>andenginestechnologies.Nowadays,manyindividualtechnologiesareunder</p><p>considerationforimplementationinfutureaircraftandengines.Forexample,a</p><p>studyconductedin2013byIATA[26],theGermanAerospaceCenter(DLR)</p><p>andtheAircraftSystemandDesignLaboratory(ASDL)oftheGeorgiaInstitute</p><p>ofTechnologylaunchedtheTechnologyRoadmapforEnvironmentally</p><p>SustainableAviation(TERESA)[27].Theobjectivewastoquantifythe</p><p>expectedbenefitsoftheimplementationofindividualtechnologiesinan</p><p>operationalframework,consideringatypicalworldfleet.CurrentNASA's</p><p>readinesslevels[29]areconsideredtoestimatetheavailabilityofeachproposed</p><p>technology.Tables(1.5)and1.6)containthelistofproposedtechnological</p><p>improvements(airframeandenginesrelated)andtheirassociatedfuelefficiency</p><p>reduction.Itisnoticeablethatupto30%reductionon2005levelsonfuel</p><p>efficiencymaybeachievableafter2020,mostofthemrelatedtoengines</p><p>technologies.</p><p>Fig.(1.6))</p><p>Fuelefficiencygainsincetheearlyjetage[28].</p><p>Finally,itisvaluabletomentionthatenvironmentalbenefitsofinnovative</p><p>technologies(throughabetterfuelefficiencyandthuslowercarbonemissions)</p><p>willbecomeeffectivethroughairlinefleetmodernizationand,toaminordegree,</p><p>retrofitstoin-serviceaircraft.Thereisanunderlyingchallengetoselectthe</p><p>appropriatetechnologiesasthisselectionaredrivenbyuncertainfactorssuchas</p><p>theircurrentdevelopmentstatus,benefits,riskandtheirresearchand</p><p>developmentcosts.</p><p>Table1.5Airframetechnologiesdevelopmentimpactandexpectedavailability</p><p>forintroduction.TRLmeansTechnologyReadinessLevel[29].</p><p>Group Concept Technology</p><p>AircraftConfiguration Trussbracedwing After2020</p><p>Hybridwing-body After2020 10to15%</p><p>Cruiseefficientstall After2020 <1%</p><p>Flyingwithoutlandinggear After2030 10%to20%</p><p>Aerodynamics AdvancedWingtip Wingtipfence</p><p>Blendedwinglet/Sharklets Retrofit 3%to6%</p><p>Rackedwingtip Retrofit 3%to6%</p><p>Splitwinglets(scimitartips) Retrofit 2%to6%</p><p>Spiroidwingtip After2020 2%to6%</p><p>HighLiftDevices Highlift/LowNoise After2020</p><p>VariableCamberTrailingEdge Before2020 1%to2%</p><p>Droppedspoiler Before2020 1%to2%</p><p>Hingelessflap After2030 1%to2%</p><p>Dragreduction Dragcoating Retrofit</p><p>Turbulentflowcoating(riblets) Retrofit 1%</p><p>GraphicFilms Retrofit 1%</p><p>NaturalLaminarFlow After2020 5%to10%</p><p>HybridLaminarFlow After2020 10%to15%</p><p>VariableCamber Before2020 1%to3%</p><p>VariableCamberwithnewcontrolsurfaces After2020 1%to5%</p><p>Structures ActiveLoadAlleviation Before2020</p><p>CompositePrimaryStructures Before2020 1%to3%</p><p>Smartwing/actuators After2020 <1%</p><p>Morphingwings After2030 2%to8%</p><p>Table1.6Enginetechnologiesdevelopmentimpactandexpectedavailabilityfor</p><p>introduction.TRLmeansTechnologyReadinessLevel[29].</p><p>Group Concept Technology</p><p>NewEngineArchitecture GearedTurbofans Before2020</p><p>AdvancedTurbofans Before2020 10%-15%</p><p>Counterrotatingfan After2020 15%-20%</p><p>OpenRotor After2020 15%-20%</p><p>Newenginecoreconcepts After2030 25%-30%</p><p>EmbeddedDistributedFan After2030 Lessthan1%</p><p>AdvancedConcepts Fan ComponentImprovements</p><p>ZeroHub Before2020 2%-4%</p><p>HighBPR Before2020 2%-6%</p><p>VariableNozzle After2020 1%-2%</p><p>Combustor VariableFlowSplits After2020</p><p>Ultracompactlowemission Before2020 1%-2%</p><p>Advanced Before2020 5%-10%</p><p>Compressor Blingconcept After2030</p><p>BiskConcept After2020 1%-3%</p><p>VariableGeometryChevron After2020 Lessthan1%</p><p>NacellesandInstallation Buriedengines After2020</p><p>Reducednacelleweight Before2020 1%-3%</p><p>EnginesCycles AdaptiveCycles After2030</p><p>PulseDetonation After2030 5%-15%</p><p>Others BoundaryLayerIngestionInlet After2020</p><p>UbiquitousComposites After2020 10%-15%</p><p>Adaptiveflowcontrol After2020 10%-20%</p><p>Insummary,aircraftdesigntechniquesundertheenvironmentalperspective</p><p>becamesignificantlyrelevantthroughoutthelastdecade,drivenbytheindustry</p><p>commitmentonemissionsreductionssetbyICAOgoals.Theinclusionoffuel</p><p>efficiencyfocusonthedesignframeworkisa</p><p>keyparameteronthenextaircraft</p><p>generations.</p><p>AERONAUTICALINDUSTRYFACINGTHEENVIRONMENTAL</p><p>CHALLENGES</p><p>TheCleanSkyProject</p><p>WithinEurope,publicandgovernmentalpositionsincreasinglypointtowardsa</p><p>desiretoregulatetheclimateimpactscausedbyaircraft.ThereportbytheUK</p><p>RoyalCommissiononEnvironmentalProtection(RCEP)notedthatwithout</p><p>regulatorycontrol,therapidgrowthofairtransportwouldproceedin</p><p>fundamentalcontradictiontotheBritishgovernment’sstatedgoalofsustainable</p><p>development[30].Europeanshaveagreatconcernwithsustainablegrowth.The</p><p>UKpositiononclimateregulationissharedwithmanyothersEuropean</p><p>countries.In2001,thereportoftheGroupofPersonalities“European</p><p>Aeronautics:Avisionfor2020”pioneeredanintegratedvisionoftheEuropean</p><p>AirTransportSystemforthenext20years.Itestablished,asitstop-level</p><p>objectives,theneedtorespondtosocietyneedsandtosecureEuropean</p><p>leadershipintheaeronautics,encompassingsignificantreductionsinpollution</p><p>andnoiseemissionlevels.Thereportalsorecommendedthecreationofthe</p><p>AdvisoryCouncilforAeronauticsResearchinEurope(ACARE).</p><p>ACAREisthefirstEuropeantechnologyplatform,whichproducedasetof</p><p>strategicresearchobjectives(SRA1)in2002andasecondupdatededition</p><p>(SRA-2)in2004.SRA-1isbuiltaroundfivechallengesfortechnology</p><p>development.Ithasbeenusedasareferenceguideforseveralnationaland</p><p>institutionalbodiesforestablishingtheirresearchprograms.SRA-2describessix</p><p>high-leveltargetconcepts(HLTCs)andtheirassociatedtechnologieswith</p><p>respecttodifferentsocio-economicscenario.EachHLTCstressesanaspectof</p><p>theAirTransportSystem.TheCleanSkyprojectwascreatedtoaddressof</p><p>ACAREHLTCs.Infact,CleanSkyisoneofthemostambitiousaeronautical</p><p>researchprogrameverlaunchedinEurope.Itsmissionistodevelop</p><p>breakthroughtechnologiestoreduceenvironmentalimpactsofaircraftandaerial</p><p>vehiclesdevelopingaircraftthatarequieterandmorefuel-efficient.CS1was</p><p>createdasapublic-privatepartnership.CleanSky1(CS1)startedin2008.Clean</p><p>Sky2(CS2)willenableanaturalcontinuationtotheprogressachievedinthe</p><p>firstCleanSkyProgramlaunchedundertheEU’s7thFrameworkProgramfor</p><p>ResearchandTechnologicalDevelopment(FP7),whichwillendin2017.CS2</p><p>extendsthepublic-privatepartnershipto2024,andexpandsittoencompass</p><p>large-scalehigh-bypasspropulsion,hybridlaminarflowcontrol,integratedcabin</p><p>systemsandstructures,andnext-generationco*ckpits.Theprogramwillflyboth</p><p>compoundandtiltrotorhigh-speedrotorcraft,andshowtechnologiesfora90-</p><p>seatturbopropanda19-seattransport.</p><p>TheCleanSkyprojectintendstoinvestigatekeyaircrafttechnologies:</p><p>LargePassengerAircraft:ThisCleanSkycomponentincludesnew</p><p>propulsionsystemsandtheirintegrationinfutureaircraft;advanced</p><p>fuselageandaircraftsystemsconceptsforpossiblenextgenerationcabin</p><p>architectures;andinnovativeco*ckpits.Large-scaledemonstrators,testrigs</p><p>andflighttestdemonstrationareplannedactivities.</p><p>TheGreenRegionalAircraft(GRA):Thefuturegreenregionalaircraft</p><p>featuresconsiderablylessemptyweight,moreenergyefficiency,lowerdrag,</p><p>andhigherlevelofoperativeperformance.Allthismustbeinpacewith</p><p>reducedpollutantemissionsandlowernoisesignature.</p><p>TheFastRotorcraftinitiative:consistsoftwoseparatedemonstrators,the</p><p>NextGenCTRtilt-rotorandtheLifeRCraftcompoundhelicopter.Thesetwo</p><p>fastrotorcraftconceptsaimtodeliversuperiorvehicleproductivityand</p><p>performance.</p><p>Airframe:Investigationofadvancedandinnovativeairframestructureslike</p><p>amoreefficientwingwithnaturallaminarflow,optimizedcontrolsurfaces,</p><p>controlsystemsandembeddedsystemshighlyintegratedinmetallicand</p><p>advancedcompositesstructures.Itwillalsotestnovelengineintegration</p><p>strategiesandinvestigateinnovativefuselagestructures.</p><p>Engines:CleanSkywillbuildontheworkdoneintheSustainableand</p><p>GreenEnginesactivitytovalidatemoreradicalenginearchitectures.</p><p>Systemsandequipmentarecrucialforaircraftoperation,flightoptimizationand</p><p>airtransportsafety.Thus,theCleanSkyprojectwillinvestigateinnovative</p><p>aircraftarchitectures,suchasmoreelectricalaircraftandbleed-lessenginesrely</p><p>onnewsystemtechnologiestoimproveglobalaircraftperformance.</p><p>TheSmallAirtransportrepresentstheresearchandtechnologyforsmallaircraft</p><p>inthe19-passengercategoryorforfreighttransport.ThiscomponentofClean</p><p>skyprojectaimstodevelop,validateandintegratekeytechnologieson</p><p>demonstratorsthatcanrevitalizeanimportantsegmentoftheaeronauticssector</p><p>thatcanbringkeynewmobilitysolutions.</p><p>Eco-Designwillcoordinateresearchgearedtowardshigheco-complianceinair</p><p>vehiclesovertheirproductlife.ItwillheightenthestewardshipinintelligentRe-</p><p>use,Recyclingandadvancedservices.Thisactivityiscriticaltoobtain</p><p>excellenceinmaterials,processesandresources;supportingthemanufacturing</p><p>baseandsupplychaincompetitivenessandsustainability.</p><p>TheERAinitiative</p><p>TheUnitedStateshasalsoestablishedapolicyforimprovementofairplanes</p><p>consideringenvironmentalaspects.Createdin2009,aspartofNASA's</p><p>AeronauticsResearchMissionDirectorate'sIntegratedSystemsResearch</p><p>Program,theEnvironmentallyResponsibleAviation(ERA)Projectexploresand</p><p>documentsthefeasibility,benefitsandtechnicalriskofvehicleconceptsand</p><p>enablingtechnologiestoreduceaviation’simpactontheenvironment.ERAs</p><p>goalsincludeslashingaircraftlevelfuelburnby50%,dragby8%,weightby</p><p>10%,emissionsbyatleast70%andnoisebyupto42EPNdB.Themain</p><p>groundsforstartingERAare[31]:</p><p>FuelEfficiency</p><p>In2008,NorthAmericanmajorcarriersburned19.6billiongallonsofjetfuel.</p><p>DepartmentofDefensealoneburned4.6billiongallons.Consideringanaverage</p><p>priceofUS$3.00/gallon,fuelcostamountedUS$73billion.Evensmall</p><p>reductionsinfuelburnwouldresultinsignificantlessermoneyspending.</p><p>Emissions</p><p>MajorityofU.S.airportsareinnon-attainmentareasthatdonotmeet</p><p>EnvironmentProtectionAgency(EPA)localairqualitystandardsforparticulate</p><p>matterandozone.</p><p>ThefuelconsumedbyU.S.commercialcarriersandDepartmentofDefense</p><p>releasesmoreythan250milliontonsofCO2intotheatmosphereeachyear.</p><p>Noise</p><p>Aircraftnoisecontinuestoberegardedasthemostsignificanthindranceto</p><p>airspacecapacitygrowth.</p><p>FAAmadeseveralattemptstoreconfigureNewYorkairspace,whichresultedin</p><p>14lawsuitsby2010.</p><p>Since1980,FAAhasinvestedoverUS$5billioninairportnoisereduction</p><p>programs.</p><p>MarketoutlookfromairplanemanufacturersandforecastsfromU.S.</p><p>governmentalagenciespredictthattheairtransportationsystemwillexpand</p><p>significantlywithinthenextdecades.Consideringthatsuchanexpansionwill</p><p>bringnegativeenvironmentalimpacts,itmakesimperativeneutralizeorreduce</p><p>them.ThisisthegoaloftheERAProjectanditsfocusedresearch.Theprojectis</p><p>organizedto[31]:</p><p>Maturepromisingtechnologyandadvancedaircraftconfigurationsthatmeet</p><p>mid-termgoalsforcommunitynoise,fuelburnandnitrogenoxides(NOx)</p><p>emissionsasdescribedintheNationalAeronauticsResearchandDevelopment</p><p>Planand;</p><p>determinethepotentialimpactoftheseadvancedaircraftdesignsand</p><p>technologiesifsuccessfullyimplementedintotheairtransportationsystem.</p><p>TomaturetechnologiesandstudyvehicleconceptsERAProjectisworkingon</p><p>technologiesintheseresearchareas,calledintegratedtechnologydemonstrations</p><p>(ITC):</p><p>InnovateFlowControlConceptsforDragReduction.</p><p>AdvanceCompositesforWeightReduction.</p><p>AdvanceUHBEngineDesignsforSpecificFuelConsumptionandNoise</p><p>Reduction.</p><p>AdvanceCombustorDesignsforOxidesofNitrogenReduction.</p><p>AdvanceAirframeand</p><p>EngineIntegrationConceptsforCommunityNoiseand</p><p>FuelBurnReduction.</p><p>TheERAProjectiscomprisedofthreesubprojects:AirframeTechnology,</p><p>PropulsionTechnologyandVehicleSystemsIntegration.Workwithintheproject</p><p>iscoordinatedwithresearchperformedbyotherprogramswithinNASA's</p><p>AeronauticsResearchMissionDirectorateaswellasotherfederalgovernment</p><p>agencies.NASAhasalsoputmechanismsinplacetoengageacademiaand</p><p>industry,includingworkinggroupsandtechnicalinterchangemeetings;Space</p><p>ActAgreementsforcooperativepartnerships;andtheNASAResearch</p><p>Announcementprocessthatprovidesforfullandopencompetitionforthebest</p><p>andmostpromisingresearchideas.TheERAProjectdisseminatesallits</p><p>researchresultstothewidestpracticalextent.TeamsfromTheBoeingCompany</p><p>inHuntingtonBeach,Calif.,LockheedMartininPalmdale,Calif.,andNorthrop</p><p>GrummaninElSegundo,Calif.,havespenttimeandeffortstudyinghowto</p><p>meetNASAgoalstodeveloptechnologytomeetERA’atargets(Fig.1.7).</p><p>Amodified757isbeingemployedastechnologydemonstratorbyBoeingto</p><p>investigateAFC.TheairplaneiscalledecoDemonstrator.Theairplanewasfitted</p><p>withdevicesthatwillblowjetsofairontheverticaltail(VT)andtheother</p><p>involvesnon-stickcoatingstohelprepelbugsfromtheleadingedgeofwings.</p><p>ThefirsttechnologythatwastestediscalledtheActiveFlowControlEnhanced</p><p>VerticalTailFlightExperiment.NASAworkedwithBoeingtoinstall31tinyjets</p><p>calledsweepingjetactuatorsthatcanmanipulate,ondemand,theairthatflows</p><p>overtheecoDemonstrator757'sverticaltailandruddersurfaces[32].An</p><p>aircraft’sverticaltailisprimarilyusedtoaddstabilityanddirectionalcontrol</p><p>duringtakeoffandlanding,especiallyintheeventofanenginefailure.Butwhen</p><p>theaircraftiscruisingataltitudethesamelarge,heavytailislessutilized.Ifthe</p><p>sizeoftheVTthesizeoftheverticaltailbyusingthesweepingjetstogenerate</p><p>thesamesideforceduringtakeoffandlandingthatalargertaildoes.Thatwould</p><p>reducetheweightanddragoftheairplaneanddecreaseitsfuelconsumption.</p><p>Fig.(1.7))</p><p>UnusualconfigurationsproposedbyBoeing(Blendedwingbodyatright),</p><p>Lockheed-Martin(joinedwingstwinjet),andNorthrop-GrummanfortheERA</p><p>Project(Illustration:CourtesyNASA).</p><p>ELECTRICVEHICLESANDAVIATION</p><p>ElectricalAutomobiles</p><p>Thetrendofreplacinghydraulic,pneumatic,mechanicalsystemsandsub-</p><p>systemswithelectricequivalents,coupledwithacallforhighpassengercomfort</p><p>andin-flightentertainmentsystemshasresultedinanever-increasingdemandon</p><p>anaircraft'spowerrequirements.Thismoverequiresadvancesintheareasof</p><p>powerelectronics,necessarytoprovidethetechnologytoimproveefficiencyand</p><p>safetyofaircraftsystemsoperation.Atthesametime,anincreaseduseof</p><p>electromechanicalandelectrohydrostaticalactuationrequirestheevolutionof</p><p>theelectricalpowerdistributionsystem.</p><p>Below,someadvantagesofelectricalroadvehiclesarelisted:</p><p>Highertorque</p><p>Increasedpropulsionefficiency</p><p>Quieterthanvehiclespoweredbyinternalcombustionengines</p><p>Greatersimplicity</p><p>Greaterreliability</p><p>Usesregenerativebrake</p><p>Inuse,donotpollutetheenvironment</p><p>Lessmaintenance</p><p>Whenstoppedandinuse,donotconsumefuel</p><p>Canbeusedforenergystorage</p><p>Flexibilityinrelationtopowersupplysources</p><p>Morepowerperweightunitorvolumeunit</p><p>Theautomotiveindustryhasmadeconsiderableprogresstowardselectricalcars.</p><p>TeslaandGeneralMotorsstandoutamongautomakers.Hence,adeepanalysis</p><p>theTeslaModelS(Fig.1.8)andChevroletVoltiscarriedoutinthissection.</p><p>TheChevroletVoltisaplug-inhybridelectricvehiclemanufacturedbyGeneral</p><p>Motors.TheVoltoperatesasapurebatteryelectricvehicleuntilitsplug-in</p><p>batterycapacitydropstoapredeterminedthresholdfromfullcharge[33].From</p><p>thereitsinternalcombustionenginepowersanelectricgeneratortoextendthe</p><p>vehicle'srangeasneeded.Whentheengineisrunningitmaybeperiodically</p><p>mechanicallylinked(byaclutch)toaplanetarygearset,andhencetheoutput</p><p>driveaxle,toimproveenergyefficiency.TheVolt'sregenerativebrakingalso</p><p>contributestotheon-boardelectricitygeneration.UndertheUnitedStates</p><p>EnvironmentalProtectionAgency(EPA)cycle,the2013/14modelyearVoltall-</p><p>electricrangeis38mi(61km),withacombinedelectricmode/gasoline-only</p><p>ratingof62mpg-US(3.8L/100km;74mpg-imp)equivalent(MPG-equivalent).</p><p>TheTeslaModelSisafull-sizedelectricfive-door,luxuryliftback,producedby</p><p>TeslaMotors[34].Theall-wheeldrivesystemofModelSemploystwomotors</p><p>forthefrontandrearwheelswithadigital-independentcontroltorque,resulting</p><p>inanunparalleledtractioncontrolinallconditions.InJuly2017,Teslastarted</p><p>deliveryofitsmoreaffordableelectriccartheModel3.Thecompanyintendsto</p><p>reachthegoalofmaking500,000in2018.Fourteen-year-oldTeslahasnever</p><p>mademorethan100,000carsinayear.Thus,theenvisagedproductionlevelisa</p><p>verychallengetask.</p><p>Fig.(1.8))</p><p>TeslaModelS(Photo:©2016BentoMattos).</p><p>Whattheaeronauticalindustryisdoingtowardsmoreelectricairplanes?Apoint</p><p>toremember:ifcarsgoelectric,theaviationshareofgreenhousegases</p><p>generationwillrisesharply.TheElectricVehiclesInitiative(EVI)isamulti-</p><p>governmentpolicyforumdedicatedtoacceleratingtheintroductionandadoption</p><p>ofelectricvehicles(EVs)worldwide[35].EVIisoneofseveralinitiatives</p><p>launchedin2010undertheCleanEnergyMinisterial,ahigh-leveldialogue</p><p>amongenergyministersfromtheworld’smajoreconomies.EVIcurrently</p><p>includes15governmentalmembersfromAfrica,Asia,Europe,andNorth</p><p>America,aswellasparticipationfromtheInternationalEnergyAgency(IEA)</p><p>[36].Theinitiativeseekstofacilitatetheglobaldeploymentof20millionEVs,</p><p>includingplug-inhybridelectricvehiclesandfuelcellvehicles,by2020.</p><p>EVIwillenableprogresstowardthisgoalby:</p><p>Encouragingthedevelopmentofnationaldeploymentgoals,aswellasbest</p><p>practicesandpoliciestoachievethosegoals;</p><p>Leadinganetworkofcitiestoshareexperiencesandlessonslearnedfromearly</p><p>EVdeploymentinurbanareasandregions;</p><p>Sharinginformationonpublicinvestmentinresearch,development,and</p><p>demonstration(RD&D)programstoensurethatthemostcrucialglobalgapsin</p><p>vehicletechnologydevelopmentarebeingaddressed;and</p><p>Engagingprivate-sectorstakeholderstobetteralignexpectations,discussthe</p><p>respectiverolesofindustryandgovernment,andfocusonthebenefitsof</p><p>continuedinvestmentinEVtechnologyinnovationandEVprocurementfor</p><p>fleets.</p><p>Figs.(1.9and1.10)showcumulativesalesandstocktargetsforthe9outofthe</p><p>15EVImembersthathaveofficialtargets.</p><p>Fig.(1.9))</p><p>ElectricvehiclessalestargetestablishedbyElectricVehiclesInitiative(Source</p><p>EVI).</p><p>Togetherthesetargetsaddupto5.9millioninsalesand20millionofstockby</p><p>2020.ThereareothercountriesoutsideoftheEVImembergroupthathave</p><p>officialtargets,butthebulkofEVsalesuntil2020willlikelytakeplaceinEVI</p><p>membercountries,whichcanthereforebeconsideredausefulbenchmarkforEV</p><p>deploymentinthenearterm.</p><p>Nationalsalesandstocktargetsarenotmeanttobeforecasts,buttheycanbe</p><p>usedforcreatingnationalroadmapsthatoutlinestepstobetakentoachievethe</p><p>goalswhilealsotrackingprogress.</p><p>Attheendof2012,totalworldwideelectricvehiclestocknumberedover</p><p>180,000,withover90%ofthisstockintheEVImembershipgroup.Thelargest</p><p>non-EVIstockcanbefoundinNorway,whichnumbersabout10,000.</p><p>Fig.(1.10))</p><p>ElectricvehiclesstockstargetestablishedbyElectricVehiclesInitiative(Source</p><p>EVI).</p><p>TheFutureoftheAirlinerswillbeMoreElectric?</p><p>Fig.(1.11)containsagraphthatplotsairplaneenergeticefficiency</p>