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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
AIAA‐96‐37845/8/09 Aarons,Riopelle,Tanious 9
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
AIAA‐1992‐1262‐2795/8/09 Aarons,Riopelle,Tanious 10
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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