NASA Technical Reports Server (NTRS) 20140006948: A Mission-Adaptive Variable Camber Flap Control System to Optimize High Lift and Cruise Lift-to-Drag Ratios of Future N+3 Transport Aircraft

1.3 MB·English

by  NASA Technical Reports Server (NTRS)

A Mission-Adaptive Variable Camber Flap Control System to
Optimize High Lift and Cruise Lift-to-Drag Ratios of Future
N+3 Transport Aircraft
∗
JamesUrnes,Sr.
BoeingResearch&Technology,St. Louis,MO63134
NhanNguyen†,CoreyIppolito‡,JosephTotah§
NASAAmesResearchCenter,MoffettField,CA94035
KhanhTrinh¶,EricTing(cid:3)
StingerGhaffarianTechnologies,Inc. /NASAAmesResearchCenter,MoffettField,CA94035
Boeing and NASA are conducting a joint study program to design a wing flap system that will provide
mission-adaptiveliftanddragperformanceforfuturetransportaircrafthavinglight-weight, flexiblewings.
ThisVariableCamberContinuousTrailingEdgeFlap(VCCTEF)systemoffersalighter-weightliftcontrol
systemhavingtwoperformanceobjectives:(1)anefficienthighliftcapabilityfortake-offandlanding,and(2)
reductionincruisedragthroughcontrolofthetwistshapeoftheflexiblewing. Thiscontrolsystemduring
cruisewillcommandvaryingflapsettingsalongthespanofthewinginordertoestablishanoptimumwing
twist for the current gross weight and cruise flight condition, and continue to change the wing twist as the
aircraftchangesgrossweightandcruiseconditionsforeachmissionsegment.Designweightoftheflapcontrol
systemisbeingminimizedthroughuseoflight-weightshapememoryalloy(SMA)actuationaugmentedwith
electric actuators. The VCCTEF program is developing better lift and drag performance of flexible wing
transportswiththefurtherbenefitsoflighter-weightactuationandlessdragusingthevariablecambershape
oftheflap.
I. Introduction
Theaircraftindustryhasbeenrespondingtotheneedforenergy-efficientaircraftbyredesigningairframestobe
aerodynamically efficient, employing light-weight materials for aircraft structures and incorporating more energy-
efficient aircraft engines. Reducing airframe operational empty weight (OEW) using advanced composite materials
is one of the major considerations for improving energy efficiency. Modern light-weight materials can provide less
structural rigidity while maintaining sufficient load-carrying capacity. As structural flexibility increases, aeroelastic
interactions with aerodynamic forces and moments can alter aircraft aerodynamics significantly, thereby potentially
degradingaerodynamicefficiency.
UndertheFundamentalAeronauticsProgramattheNASAAeronauticsResearchMissionDirectorate,theFixed
Wing(FW)projectisconductingdiscipline-basedandmultidisciplinaryfoundationalresearchtoinvestigateadvanced
conceptsandtechnologiesforfutureaircraftsystems.
ANASAstudyentitled“ElasticallyShapeFutureAirVehicleConcept”wasconductedin20101 toexaminenew
conceptsthatcanenableactivecontrolofwingaeroelasticitytoachievedragreduction. Thisstudyshowedthathighly
flexible wing aerodynamic surfaces can be elastically shaped in-flight by active control of wing twist and vertical
deflectioninordertooptimizethelocalangleofattackofwingsectionstoimproveaerodynamicefficiencythrough
dragreductionduringcruiseandenhancedliftperformanceduringtake-offandlanding.
∗ProgramManager,PlatformSystems/SubsystemsTechnology,[email protected],[phone]
†AssociateFellowAIAA,IntelligentSystemsDivision,[email protected],[phone]
‡IntelligentSystemsDivision,[email protected],[phone]
§AssociateFellowAIAA,IntelligentSystemsDivision,[email protected],[phone]
¶IntelligentSystemsDivision,[email protected],[phone]
(cid:3)IntelligentSystemsDivision,[email protected]
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Thestudyshowsthatactiveaeroelasticwingshapingcontrolcanhaveapotentialdragreductionbenefit. Conven-
tionalflapandslatdevicesinherentlygeneratedragastheyincreaselift. Thestudyshowsthatconventionalflapand
slatsystemsarenotaerodynamicallyefficientforuseinactiveaeroelasticwingshapingcontrolfordragreduction. A
newflapconcept,referredtoasVariableCamberContinuousTrailingEdgeFlap(VCCTEF)system,wasdevelopedto
addressthisneed. InitialresultsindicatethattheVCCTEFsystemmayofferapotentialpay-offfordragreductionthat
will result in significant fuel savings. In order to realize the potential benefit of drag reduction by active aeroelastic
wingshapingcontrol,configurationchangesinhigh-liftdeviceshavetobeapartofthewingshapingcontrolstrategy.
Asecondstudywasawardedin2011undertheNASASubsonicFixedWing(SFW)project,entitled“Development
ofVariableCamberContinuousTrailingEdgeFlapSystem”.2 ThisstudybuiltuponthedevelopmentoftheVCCTEF
system for NASA Generic Transport Model (GTM) which is essentially based on the B757 airframe,3 employing
light-weightshapedmemoryalloy(SMA)technologyforactuationandthreeseparatechordwisesegmentsshapedto
provideavariablecambertotheflap.Thiscamberedflaphaspotentialfordragreductionascomparedtoaconventional
straight,plainflap. Theflapisalsomadeupofindividual2-footspanwisesectionswhichenabledifferentflapsetting
ateachflapspanwiseposition.Thisresultsintheabilitytocontrolthewingtwistshapeasafunctionofspan,resulting
in a change to the wing twist to establish the best lift-to-drag ratio (L/D) at any aircraft gross weight or mission
segment. Currentwingtwistoncommercialtransportsispermanentlysetforonecruiseconfiguration, usuallyfora
50% loading or mid-point on the gross weight schedule. The VCCTEF offers different wing twist settings for each
grossweightconditionandalsodifferentsettingsforclimb,cruiseanddescent,amajorfactorinobtainingbestL/D
conditions.
The second feature of VCCTEF is a continuous trailing edge flap. The individual 2-foot spanwise flap sections
areconnectedwithaflexiblecovering,sonobreakscanoccurintheflapplatforms,thusreducingdragbyeliminating
these breaks in the flap continuity which otherwise would generate vorticity that results in a drag increase and also
contributestoairframenoise. Thiscontinuoustrailingedgeflapdesigncombinedwiththeflapcamberresultinlower
dragincreaseduringflapdeflections. Inaddition,italsooffersapotentialnoisereductionbenefit.
TheVCCTEFprojecthasfourobjectives:
1. UsetheVCCTEFtotwisttheflexiblewingtoobtainchangesinlift-to-dragratiosthatwillreducecruisedrag
throughouttheflightenvelope.
2. Determineaeroelasticcontrolapproachesthatwillcompensateforreducedfluttermarginsofflexiblewings.
3. Use the full span cambered flap as the primary high lift device for take-off, climb-out, let-down and final ap-
proach.
4. Use the aft section of the cambered flap as a roll control effector and as an aeroservoelastic control device of
flexiblewingstructuredynamicmodes.
II. PerformanceBenefit
Drag reduction by increasing lift-to-drag ratios through reshaping the wing twist has a significant advantage if
the wing has structural flexibility properties that will permit this change in shape. Current transport wing design
incorporates a twist profile that provides efficient lift-to-drag ratios, and the twist angle is set for an average flight
profileandatthemid-pointgrossweight. Figure1showsresultsofdragpolarsofaflexiblewingtransportforthree
fuelloadings: 80%fuelloadearlyincruise,50%fuelloadatthemid-pointcruise,and20%fuelloadtowardtheend
ofcruise.
The1-gtrimpointsshowthelowestdragatthe50%mid-pointthatisindicativeofthewingtwistdesign,witha
significantdragincreaseattheotherfuelloadingconditionsduetowingshapechangesforaflexiblewingtransport.
Using the VCCTEF, the drag polars can be changed to reduce drag, two examples are shown in Figure 1.1 The
importantfactoristomaintainthedesiredwingtwistthroughthedeflectionoftheVCCTEF,butnottolosethedrag
benefit by having too much increase in drag due to the flap deflections. Hence, the use of the variable camber flap
insteadofconventionalflapscanofferabetterdragsignature.
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0.03
80% Fuel w/ Aeroelastic Deflection
50% Fuel @ Design Condition
20% Fuel w/ Aeroelastic Deflection
0.025
VCCTE Flap Down 3.9 deg
VCCTE Flap Up −3.3 deg
0.02
D
C 1−g Trim Points
0.015
0.01
0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6
C
L
Nguyen,N.,“ElasticallyShapedFutureAirVehicleConcept,”NASAInnovationFundAward2010Report,October2010
SubmittedtoNASAInnovativePartnershipsProgram
Figure1. WingShapingControlcanChangetheLift-to-DragRatiotoMinimizeTrimDrag
III. DesignoftheVCCTEFSystem
Figure2showsawingandflaplayoutoftheVCCTEFdesignfortheGTM.
Figure2. WingConfiguredwiththeVariableCamberContinuousTrailingEdgeFlap
The flap is divided into 14 sections attached to the outer wing and 3 sections attached to the inner wing. Each
24-inchsectionhasthreecamberflapsegmentsthatcanbeindividuallycommanded. Thesecamberflapsarejoinedto
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thenextsectionbyaflexibleandsupportedmaterial(showninblue)installedwiththesameshapeasthecamberand
thusprovidingcontinuousflapsthroughoutthewingspanwithnodragproducinggaps.
Amajorgoaloftheprogramistodevelopalight-weightflapcontrolsystemthathasasignificantweightadvantage
as compared to current flap screw-jack actuators. Hydraulic, electric and Shape Memory Alloy (SMA) torque rod
actuationwereevaluatedwiththeresultthattheSMAactuationhasthebestweightadvantage,asshowninFigure3
hardwarecomparisons.
Moreover,theuseofhingelineactuationeliminatesthelargeandheavyexternalmountedactuators,andpermits
allactuatorstobeinteriortothewingandflapmoldlines,thuscontributingtotheoveralldragreductiongoal.
Figure3. ShapeMemoryAlloyActuatorsHaveaLowWeightComparedtoElectricMotorActuators
Figure4showsthreeoftheouterwingflapsections,eachhavingthreecambercomponents.
Figure4. TheVariableCamberFlapControlusesShapeMemoryAlloyTorqueRodandElectricDriveActuation
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SMAactuatorsdrivethefirstandsecondcamberflapsegmentsandafasteractingelectricactuatordrivesthethird
camberflapsegment. SMAactuatorscandeliverlargehingemoments,butgenerallymoveataslowrate. Theouter
wingflapusesthefull-spanthirdcambersegmentasarollcommandeffectorandasacontroldeviceforsuppressing
aeroelasticwingstructuraldynamicmodes,bothrequiringhighrateswhichcanbemetbyelectricactuators. Figure5
showsanSMAactuator.
Figure5. ShapeMemoryAlloyActuatorscanMeettheVCCTEFHingeMomentRequirements
IV. HighLiftConfiguration
Using the camber positioning, a full-span, low-drag, high-lift configuration can be activated that has no drag
producinggapsandalowflapnoisesignature. ThisisshowninFigure6.
Tofurtheraugmentlift,aslottedflapconfigurationisformedbyanairpassagebetweenthewingandtheinnerflap
thatservestoimproveairflowovertheflapandkeeptheflowattached. Thisairpassageappearsonlywhentheflaps
areextendedinthehighliftconfiguration.
Figure6. CruiseandHighLiftVCCTEFConfigurations
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Inthehigh-liftconfiguration,theouterwingflapusesthethirdcambersectionforrollcontrol,asshowninFigure
6. Thisprovidesrollingmomentthatisequivalenttoaileroncontrol. Itissomewhatsimilartodeflectingtheailerons
inadrooppositiontoactasflaps,acommonprocedureusedontacticalaircraftandonsometransportaircraft.
Thehigh-liftconfigurationdistributestherequiredflaphingemomentthroughoutthespanofthewingwhileusing
actuationcomponentsthatarealllocatedinteriortothewingandflap. ThiscanbeachievedbytheuseofSMAhinge
linetorquerods,sizedtomeetthehingemomentrequirementsateachspanwiselocationonthewing.Thisdistribution
ofactuatorloadpermitsefficientsizingoftheactuators,andeliminatestheneedforlargeexternalflapactuatorsand
associateddragfromtheseinstallations.
V. Vortex-LatticeFlexibleAircraftGeometryModeling
TheGTMconfiguredwiththeVCCTEFisanalyzedusingNASAvortex-latticecodeVorview.4 Thiscodeisalso
usedtooptimizelift-to-dragratiosoftheVCCTEFwings. Vorviewreadsinaircraftgeometries,flightstatesincluding
altitude, airspeed, angle of attack and aircraft weight and computes aircraft aerodynamic coefficients, stability and
control derivatives, and distributions of wing lift, drag, and pitching moment coefficients. The aircraft geometry
in Vorview is defined by a surface mesh. The optimization process involved running multiple Vorview analyses
comparing different flap settings of the VCCTEF. In the optimization process, a new mesh model was produced for
eachnewflapsettingontheflygeneratedbyanautomatedgeometrygenerationtooldevelopedinMatlab.
Figure7showsameshmodeloftheGTMwiththeVCCTEF.Themeshmodelcontains6components: fuselage,
wings, engines, pylons, horizontal tails and vertical tails. Each component is a structured mesh containing quadri-
lateral elements defining the outer mold line of the component geometry. Each component is treated as a cylinder
topologically. Non-uniform section cuts were placed along cylinder axes and non-uniform mesh nodes were placed
alongthecircumferentialdirectionofeachsectioncutstocapturetheaircraftgeometrywhilekeepingthenumberof
elementsdown. Eachcomponentwasmeshedseparately. Vorviewdoesnotrequireaconformalmeshatintersections
ofintersectingcomponents. However,Vorviewdoesrequirethegeometrytobewater-tight. Toproduceawater-tight
mesh, intersecting ends of wings, pylon, horizontal tails and vertical tails were extended so that the end nodes pro-
truded into adjacent components. The aircraft mesh has a total of 20,806 nodes and 19,908 quadrilateral elements.
Table1showsmeshsizedataforthe6components.
NumberofSections NumberofNodesperSection NumberofQuadElements
Fuselage 84 101 8300
Wings 80 115 8892
Engines 32 21 600
Pylons 4 23 44
HorizontalTails 18 81 1280
VerticalTail 20 45 792
Table1. MeshSizeDataofGeometryModel
Figure7. VorviewGTMMesh
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InmeshingtheVCCTEFwings,sectioncutswereplacedateveryflap/followerflexiblematerialboundary. This
allowsthemeshtocorrectlydefinetheVCCTEFgeometryinthewingspanwisedirection.Likewise,meshnodesalong
eachwingsectionswereplacedtocorrectlydefinetheflapgeometryinthewingchord-wisedirection. Therewere3
quadsalongthechord-wisedirectionofeachofthe3chordwiseflapsections. Foreachflapsetting,thelocationsof
the3flaphingerodsweredeterminedfirst. Thennodelocationsofthequadsdefiningeachflapwerecalculated. Thus,
thesidesoftheflapquadsfollowtheflapgeometryboundaries. Figure8showsmeshofVCCTEFwingsandmesh
sectionsfor2differentflapsettings.
Vorviewprocessesaircraftquadsurfacemeshalongwithuser-definedcontrolparameterstodefineslicesandsub
polygonsthataresubsequentlyusedintheaerodynamiccalculations.Figure8showsVorviewslicesandsub-polygons
oftheGTMwithVCCTEF,respectively.
Figure8. VorviewGTMSub-Polygons
ThevariablecamberflapismodeledwiththreechordwiseflapsegmentsasshowninFigure9.1
Nguyen,N.,“ElasticallyShapedFutureAirVehicleConcept,”NASAInnovationFundAward2010Report,October2010
SubmittedtoNASAInnovativePartnershipsProgram
Figure9. VariableCamberFlap
The variable camber flap geometry is specified by three deflection values δ , δ , and δ for the innermost,
f1 f2 f3
intermediate, and outermost flap segments, respectively. The baseline camber shape is described by a circular arc,
witheachflapsegmentdeflectedbythesameamountrelativetoeachother. Withacirculararccamber,onlyoneflap
deflectioncommandisneeded. Forexample, foracommandedflapdeflectionof12o, theinnermostflapsegmentis
deflected4o,theintermediateflapsegmentisdeflected8o,andtheoutermostflapsegmentisdeflectedby12o. Thus,
ingeneral
iδ
δ = fc (1)
fi 3
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wherei=1,2,3,andδ isthecommandedflapdeflection.
fc
Thecamberangleofthecirculararccamberflapisthedifferencebetweenbetweenδ andδ . Thus,thevariable
f3 f1
camberangleχ=2δ /3isafunctionofthecommandedflapdeflection.Acamberflapismoreeffectiveinproducing
fc
liftthanastraightuncamberedflap. Asthecamberincreases,thepressuredistributionattheaftoftheairfoilincreases
thatresultsinaliftincrease.
The variable camber flapproduces about the same downwash as a simpleplain flap deflected by the same angle
as shown in Figure 9–. However, the normal surface area of the variable camber flap exposed to the flow field is
significantlyreduced. Thus,thedragreductionbenefitofthevariablecamberflapisrealizedsincethepressuredrag
acrosstheflapsurfaceisreducedduetolessexposednormalsurfacearea.
In order to model a flexible wing aircraft, an automated geometry generation tool is developed in Matlab. This
geometry modeling uses structural deflection data computed by a finite-element model (FEM) to update the unde-
formedaircraftwinggeometrytoreflectstaticaeroelasticdeflections. Thedeformedgeometry,whichreflectsaseries
ofcoordinatetransformationsontheoutermoldlineofthejig-shapeaircraftwing, isprocessedintoageometryfile
thatcanbeuseddirectlyinvortex-latticecalculations.
WithreferencetoFigure10, thecoordinatereferenceframe(x ,y ,z )definestheBodyStation(BS),theBody
B B B
Butt Line (BBL), and the Body Water Line (BWL) of the aircraft, respectively. The coordinate reference frame
(x ,y ,z )isthetranslatedcoordinatesystemattachedtothenoseoftheaircraftsuchthatx =x −13.25ft,y =y ,
V V V V B V B
andz =z −15.8333ft. Thisreferenceframeisusedforthevortex-latticeaerodynamicmodelingandoptimization.
V B
Thestabilityreferenceframe(x,y,z)isattachedtotheCGsuchthatx=x¯ −x ,y=y −y¯ ,andz=z¯ −z ,where
V V V V V V
(x¯ ,y¯ ,z¯ )isthecoordinateoftheCGinthe(x ,y ,z )referenceframe.5
V V V V V V
Figure10. GTMCoordinateSystems
Thewingreferenceframeisdefinedbythecoordinatereferenceframe(x ,y ,z )asshowninFigure11. The
W W W
x -axisisthewingelasticaxis,they -axispointsaftalongthechorddirection,andthez -axisisthewingnormal
W W W
direction.
Figure11. WingBendingDeflectionsandTwist
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Neglecting chordwise bending deflection, the aeroelastic deflections in bending and torsion are expressed in a
vectorformas
φ =Θi −W j (2)
W x W
δ =−WsinW i +WcosW k (3)
xW x W
whereΘisthewingtwist(positivenose-down),W isthewingbendingslope(positiveslopeupward),and(i ,j ,k )
x W W W
aretheunitvectorscorrespondingto(x ,y ,z ).
W W W
Thecoordinatereferenceframe(x ,y ,z )isrelatedtothecoordinatereferenceframe(x ,y ,z )bythefollow-
W W W V V V
ingrelationship:
⎡ ⎤ ⎡ ⎤⎡ ⎤
i −sinΛcosΓ −cosΛcosΓ −sinΓ −i
⎢ W ⎥ ⎢ ⎥⎢ V ⎥
⎣ j ⎦=⎣ −cosΛ sinΛ 0 ⎦⎣ −j ⎦ (4)
W V
k sinΛsinΓ cosΛsinΓ −cosΓ −k
W V
whereΛisthesweepaxisoftheelasticaxis,Γthewingdihedralangle,and−(i ,j ,k )aretheunitvectorscorre-
V V V
spondingto(x ,y ,z ).
V V V
Thus, the aeroelastic deflections result in a wing twist expressed as an incremental angle of attack Δα (positive
nose-up),ahorizontaldeflectionΔy (positivedisplacementtowardwingtip),andaverticaldeflectionΔz (positive
V V
displacementupward)asfollows:
Δα =−ΘcosΛcosΓ−W sinΛ (5)
x
Δy =−WsinW cosΛcosΓ−WcosW cosΛsinΓ (6)
V x x
Δz =−WsinW sinΓ+WcosW cosΓ (7)
V x x
A coordinate transformation to account for wing aeroelastic deflections is performed by rotating a wing section
about its elastic axis by the incremental angle of attack Δα and then translating the resultant coordinates by the
horizontaldeflectionΔy andtheverticaldeflectionΔz accordingto
V V
x(cid:4) =x +(x −x )cosΔα−(z −z )sinΔα (8)
V ea V ea V ea
y(cid:4) =y +Δy (9)
V V v
z(cid:4) =z +Δz +(x −x )sinΔα+(z −z )cosΔα (10)
V ea V V ea V ea
wheretheprimesuperscriptdenotesthetransformedcoordinates,and(x ,y ,z )isthecoordinateoftheelasticaxis
ea ea ea
inthereferenceframe(x ,y ,z ).
V V V
VI. RollControlAnalysis
AninvestigationoftherollcontrolauthorityofferedbytheVCCTEFisconducted.Asaconcept,rollcontrolusing
theVCCTEFisaccomplishedbyutilizingsolelytheoutermostcamberflapsegmentsofthe14spanwisesectionsof
theVCCTEFonthewingportionoutboardfromtheengines. Vorviewisemployedwiththeflapmodeltoanalyzeroll
controlderivatives. Theinitialanalysisdoesnotincludetheeffectofaeroelasticdeflectionswhichgenerallydecrease
therollcontroleffectiveness.
InordertoanalyzetheasymmetricdeflectionoftherollcontrolsegmentsoftheVCCTEF,Avortex-latticeanalysis
isperformedonthreesepa(cid:8)ratecasesfo(cid:9)reachflightcondition. First,anominalbaselineisestablishedbasedonatrim
deflectionoftheVCCTEF δ ,δ ,δ whichrepresentsthedeflectionsoftheinnermost,intermediate,andoutermost
f1 f2 f3
camber segments of a VCCTEF spanwise flap section. The second and third vortex-lattice cases are then computed
for δ ±Δδ on the 14 VCCTEF spanwise flap sections, with Δδ =1o. These three cases thus provide the wing
f3 f3 f3
spanwisedistributionsofliftanddrag.
To generate a positive roll about the roll axis of the aircraft, the outermost camber segments are differentially
deflectedsuchthatΔδ >0ontheleftwingandΔδ <0negativeontherightwing. Letybethespanwiselocation
f3 f3
ofawingstationalongtheaircraftpitchaxiswherepositiveyisalongtherightwingwingandnegativeyisalongthe
leftwing. Aerodynamicdataforspanwisewingstationsarethenobtainedfromthevortex-latticesolutionsasshown
inFigure12.
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1
Nominal VCCTEF Setting
0.9 Negative −1o VCCTEF Roll Segments Deflection
0.8 Positive 1o VCCTEF Roll Segments Deflection
cl 0.7
nt
e
ci 0.6
effi
o 0.5
C
Lift 0.4
al
c
o 0.3
L
0.2
0.1
0
−80 −60 −40 −20 0 20 40 60 80
Spanwise Location y, ft
Figure12. LocalLiftDistributionwithDifferentialDeflectionofOutermostVCCTEFSegmentsforRollControl
The spanwise lift and drag distributions on the left and right wings allow the rolling moment coefficient to be
establishedintermsoftherollcontrolderivativeduetothedeflectionoftherollcontrolsegmentsoftheVCCTEF.
ˆ
1 b/2
C = [Δc (y)cosα (y)−Δc (y)sinα (y)]c(y)ydy (11)
lδf SbΔδf3 −b/2 l l d l
whereΔc andΔc aretheincrementalsectionliftanddragcoefficients, respectively, cisthesectionchord, S isthe
l d
referencewingarea,bisthewingspan,andα isthelocalangleattackdefinedas
l
α (y)=α+γ(y)+Δα(y) (12)
l
whereγ isthewingpre-twistdistribution.
Themagnitudeofthedragcontributiontotherollingmomentismuchsmallerthanthatoftheliftcontributionand
isnotincludedintheestimate.
0.34
0.32
Clδf 0.3
C, lδa 0.28
s
e
ativ 0.26 Cl Conventional Ailerons
v δ
eri 0.24 C a VCCTEF
D l
ol 0.22 δf
ntr
o 0.2
C
Roll 0.18
0.16
−2 0 2 4 6 8 10 12
α, deg
Figure13. ComparisonofRollControlDerivativesduetoVCCTEFC andConventionalAileronsC atCruise
lδf lδa
Conditions
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