C‐17.

Tyler,JasonR.,andInstan‐Tanious

http://www.sflorg.com/aviation/av032006_01.html

HumbleRoots:theTaleofthe“Globemaster“

C‐74Globemaster

C‐124GlobemasterIIImagesfromWikipedia

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TheC‐17GlobemasterIII

•  ManufacturedbyBoeingIntegratedDefenseSystems

•  DevelopedfromMcDonnellDouglasYC‐15

•  Strategictacticalairlifter•  MajorAssemblyinLong

Beach,CAwithComponentAssemblyinMacon,GA

•  200+ActiveUSMilitary•  Winnerof1994CollierTrophy•  FirstFlightSept15,1991•  CommercialVersion

Considered(MD‐17) http://www.intplsrv.net/cdsuggs/specials/images/

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ConfigurationBasicGeometry

WingSpan 169ft9in

WingSpan(WithoutWinglets) 165ft

WingArea 3800ft2

WingMeanAerodynamicChord 25.35ft

WingSweep(quarterchord) 25°

WingAnhedral 3°

WingAspectRatio 7.2

HorizontalStabilizerArea 845ft2

Height 55ft1in

Length 174ft

AIAA‐92‐12625/8/09 Aarons,Riopelle,Tanious 4

PayloadConsiderations

CargoBox

Length(inc.Ramp)

88ft

Width 18ft

Height 12ft4in

RampLength

19ft10in

CargoCapacity:• MaximumPayloadof170,900Pounds• 65‐tonexpansiblevans• 18USAF463LPallets(12onthemainfloor,4onramp)• 140+Passengers(102Paratroopers)

AIAA‐92‐1262

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FlightControls

AIAA‐92‐1262

ControlSurfaces2Ailerons8Spoilers4ElevatorSurfacesTrimmingHorizontalStabilizer2RudderSections4Flapsand8Slats

ElectronicFlightControlSystem4FlightControlComputers2SpoilerControl/Elevator‐FeelComputers2DualAirDataComputers3Three‐AxisRateSensors3Three‐AxisAccelerometers1QuadrupleSensorperControlColumn1QuadrupleSensorperRudderPedal

•  QuadrupleRedundancy•  Hydro‐mechanicalBackupto

electricalsystems•  GlassCockpitwithdualHUDs

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FlightControlGeometryAilerons(2Surfaces)

SurfaceArea(Total) 127.34ft2

Span(SingleSurface) 21.1ft

AverageChord 3.09ft

SpanwiseLocationonWing(LocalAverageChord)

70%‐Winglet

ChordwiseLocationonWing(LocalAverageChord)

80%

Rudder(2Sections)

SurfaceArea(Total) 252ft²

Span 31.5ft

AverageChord 8ft

SpanwiseLocationonV.T.(LocalAverageChord)

0%‐85%

ChordwiseLocationonV.T.(LocalAverageChord)

64%

Spoilers(8Sections)

SurfaceArea(Total) 482ft²

Span(SingleWing) 48.2ft

AverageChord 5ft

SpanwiseLocationonWing(LocalAverageChord)

15%‐68%

ChordwiseLocationonWing(LocalAverageChord)

65.5%‐81%

Elevator(4Sections)

SurfaceArea(Total) 308.0ft²

Span(SingleHTSide) 28.5ft

AverageChord 5.4ft

ChordwiseLocationonH.T.(LocalAverageChord)

70%

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WeightsandPerformanceWeights

MaxTakeoffGrossWeight 585,000lbs

OperatingEmptyWeight 276,500lbs

MaxPayloadWeight 170,900lbs

MaxFuelWeight 180,806lbs

MaxWingLoading 161.84lb/ft2

MaxPowerLoading 3.80

Performance

CruiseSpeed(FL280) Mach0.77

AirdropSpeed 115‐250kts

ApproachSpeed 115kts

ServiceCeiling 45,000ft

LandingFieldLength(includingTRs)

3,000ft

TakeoffFieldLength 7,740ft

Range(160,000lbsPayload)

2,240nm

Range(40,000lbsPayload)

4,200nm

CruiseCL 0.55

Note:Additionaltankscanbeaddedforlongerrangeandincreasedfuelweight.

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DeepStall

•  Originally,noAngleofAttackLimitingSystem•  DeepStallPotential•  α‐LimiterDesignedandInstalledtocomplywithAirVehicleSpecification

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Propulsion(ForwardandReverse)

•  UsesfourF‐117‐PW100(PW2040usedintheB757)

•  40,400lb.thrustperengine•  5.9bypassratio•  30.8overallpressureratio•  T/W=5.7•  Speciallydesignedtobe“fully

reversible”–  CoreANDbypassexhaust

redirected

•  Usescascadestodirectthrustupandforward(toavoidFOD)

•  Enoughreversethrusttopushafullyloadedaircraftupa2°slope

ImagefromWikipedia

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AirfoilSelection

•  12%thicksupercriticalairfoil•  DevelopedbyRichardWhitcombtoreducewavedragbyproducingweakeruppersurfaceshockwaves

•  Equaldragtothinnernon‐supercriticalairfoilsallowsforhigherfuelvolume

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http://www.fas.org/man/dod‐101/sys/ac/c‐17‐1999415c17.jpg

http://www.flickr.com/photos/31864937@N00/1318527070/in/set‐72157594530625401/

Winglets

S=35.85ft2(total)

30°SweepAngle

15°declinationfromvertical

SupercriticalAirfoil

VortexGenerators

Increase“effectivespan”anddecreasewingtiplosseswhichdecreasesliftinduceddragforimprovedcruiseefficiency.

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High‐LiftSystems

•  SlottedLowering‐flapssystem

•  Externallyblownflaps–  Directlyblownbyturbofan

exhaust–  Requiresextremelystrong

materialflaps–  Cangenerateverylargenose‐

downpitchingmoments

•  Needforverylargehorizontalstabilizer

•  SlatscontrolLEflowathighanglesofattack

NASALangleyfull‐scaletunnelmodelhttp://oea.larc.nasa.gov/PAIS/Partners/C_17.html

FromAIAA‐1992‐1262‐279

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High‐LiftSystemscont’d.

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Separatedflowwouldremainattachedduetodoubleslottedflapandexternalsurfaceblowing(ESB)

CLfortakeoffandLandingaremuchhigherthanshownduetopoweredliftdevices

AlthoughweareunabletomodeltheCLcausedbyadditionofpoweredliftdevices,weestimateCL=4–5forSTOLoperation

Wingletsflattenedtoaccountforaerodynamiceffectsbuttosimplifygeometry.

Bumpnotincludedinmeanaerodynamicchordandrelatedcalculations

x

y

C‐17AerodynamicAnalysisUsingAOE4124SoftwareSuite

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WingOnly(forreference):

MeanAerodynamicChord=25.35ft

xLEmac=15.4049ftyLEmac=31.6118ft

NeutralPoint=28.247ft

TotalAircraft:

SM=‐2.45%(normw/wingmac)NeutralPoint=39.127ftCG(mintrimmeddrag)=39.75ftE=1.0513

*NeutralPointscalculatedinVLMPc*CGandEcalculatedinLAMDES

x

y

AerodynamicAnalysis

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FromLAMDES,BalancedatCGlocationforminimumtrimmeddrag

CGforMinimumTrimmedDrag

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FromLAMDES,BalancedatCGlocationforminimumtrimmeddrag

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SpecialAbilities

ShortTakeoffandLanding

ShortestTakeoffDistance 3,700ft(unloaded)

ShortestLandingDistance 2,300ft(unloaded)

UnrestrictedClimb• GetoutoftroubleFAST

AirDropCapabilities• Over100Paratroopers• Upto120,000pounds

FullThrustReversal• AircraftcanSelf‐propelup2%Slopeinreverse

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http://oea.larc.nasa.gov/PAIS/Partners/C_17.html

ReferencesChambers,Joseph.PartnersinFreedom:ContributionsoftheLangleyResearchCentertoU.S.MilitaryAircraftofthe1990’s.“BoeingC‐17

GlobemasterIII”.Oct.2003.Washington,D.C.:NationalAeronauticsandSpaceAdministration.AccessedMar.2009.<http://oea.larc.nasa.gov/PAIS/Partners/C_17.html>

Drela,Mark.XFOIL:SubsonicAirfoilDevelopmentSystem.Ver.6.96.7Apr.2008.<http://web.mit.edu/drela/Public/web/xfoil/>.

Etkin,BernardandLloydDuffReid.DynamicsofFlight:StabilityandControl.ThirdEd.NewYork,NY:Wiley,1996.

Iloputaife,Obi.DesignofDeepStallProtectionfortheC‐17A.AIAA‐96‐3784.LongBeach,CA:AmericanInstituteofAeronauticsandAstronautics,1996.

Jackson,Paul,ed.Jane'sAlltheWorld'sAircraft:2008‐2009.Coulsdon:Cambridge,2008.

Mason,W.H.“D.4‐LamDes”AppliedComputationalAerodynamics.VirginiaTech:Blacksburg,VA.January1997.<http://www.aoe.vt.edu/~mason/Mason_f/CAtxtAppD4.pdf>

NationalAeronauticAssociation.CollierTrophyWinners:Collier1990‐1999Winners.2004.Washington,D.C.:NationalAeronauticAssociation.AccessedMar.2009.<http://www.naa.aero/html/awards/index.cfm?cmsid=150>

Pratt&Whitney.F117:ExclusivePowerfortheC‐17GlobemasterIIITransport.Hartford,CT:Pratt&Whitney.AccessedMar.2009.<http://www.pw.utc.com/vgn‐ext‐templating/v/index.jsp?vgnextrefresh=1&vgnextoid=4d9f0030296eb010VgnVCM1000000881000aRCRD>

Tavernetti,L.TheC‐17:ModernAirliftTechnology.AIAA‐92‐1962.Irvine,CA:AmericanInstituteofAeronauticsandAstronautics,1992.

UnitedStatesAirForce.USAirForceFactSheet:C‐17GlobemasterIII.Oct.2008.UnitedStatesAirForce.AccessedMar.2009<http://www.af.mil/factsheets/factsheet.asp?fsID=86>.

VLMpc.Ver.2.14Nov.2002.<http://www.aoe.vt.edu/~mason/Mason_f/VLMpcv3.f>

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