1、,!ssos ac4,“,NATIONALADVISORYCOMMIEEFORAERONAUTICSTECHNICALNOTE2468INVESTIGATIONAT LOWSPEEDOF45 AND60 SWEPT13ACK,TAPERED,LOW-DRAGWINGSEQUIPPEDWITHVARIOUSTYPESOF FULL-SPAN,TRAILING-EDGEFLAPSByJohnJ. HarperGeorgiaInstituteof Technology-.,Provided by IHSNot for ResaleNo reproduction or networking permi
2、tted without license from IHS-,-,-TECHLIBRARYK.AFB,NM IlllllllllllillulllENATIONALADVISORYCOMMITTEEFORAERONAUTICS oqb5574 .=TEOHNICALNOTE2468INVESTIGATIONATLOWSPEEDTAPERED,LOW-DRAGWINCETYPESOFFULL-SPAN,OFs”AND60SWEPTBACK,EQUII+EDWITHVARIOU3a71TRAILING+DGEFLAFSByJohnJ.Harper sUMMARY .Aninvestigationw
3、asmadeintheGeorgiaInstituteofTechnologyq-footwindtunneltodeterminethelow-speedaerodynamiccharacteristicsoftwosweptback,low-drag,taperedwingsequippedwithfull-spansplitandslottedflapsandthreespecialtypesoftrailing-edgeflaps.-MOsweepanglesofhand600,measuredatthequarterchord,wereused.Althoughemphasiswas
4、placedonatmptstoobtainhighermaximumliftcwfficients,theresultsshownoappreciablegafiin for* eitherthesplitflaporthespecialflapsonthe600wing.Thesesameflapsdidproduceanincrementin CL- onthehs”model,however.Theslottedflapproducedbyfarthelargestincrease.inliftonbothmodels. -Theeffectoftheflapsondragandpit
5、chingmomntisthesameasthatindicatedotherthelargestincreaseinAllflapconfigurationstestdataavailable.Theslottedflappitchingmomentforagivendeflectionincreasedthestabilityofbothwings.causedangle.INTRODUCTIONTheuseoflargeamountsofsweepforthepurposeofdelayingcowpressibilityeffectsisnowquitecommonandwasorig
6、inallyproposedinthiscountrybyJones(reference1). Unfortunately,theuseofWplanformsincorporatinglargesweepanglesinconjunctionwiththethinairfoilsectionsnecessaryforhighcriticalMachnumbershasresulted* inwingshavingvaluesofmaximumliftconsiderablylessthanthoseofconventionalstraightwings.Thishasimposedrathe
7、rseverelimitationsuponthelandingspeedsofsuchaircraft.*Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-2 NACATN2h68Althoutheusualtra.il.ing-edge.typeg:.high-liftdevicesmaYbeemployedonswept-wings,Germandata(reference2)haveindicatedthatitheconventional-
8、splitandslottedflapsdo.notshowtheS- gainsmaximumliftcoefficientonsweptbackwings.A considerabletiountof.Germantestdata(references2and3)onflappedsweptback-wingsisavailablebutseminglylittleworkh=.beendonetowardincreasingthemaximumliftcoefficientbyeliminatingorreducingthesweepangleoftheflapitself;Inorde
9、rtodeterminewhethersuchflapswerefeasible,atestprogramelanexploratorynaturewasinstigated.Thepresentitestshavealsosupplementedtheresultsofreferences4 ands.Thisworkwasconductedatthe-GeorgiaInstituteof.Technologyunderthesponsorshipandwiththefinancial,assistanceoftheNational.AdvisoryCommitteeforAeronauti
10、cs.-.-APPARATUSANDMODEIS!17wosemispansweptbackwingmodel-ewere*stealinthe+-footwind. .*.tunnelofthe-OeorgiaInstituteofTechnology.Thisturinelisofthe single-returntypehavingaclosedcirculartestsection12feetlong.Forpaneltestingsflatflooris.installedwhichgivesa jetheightof Papproximate8feet.Speedchangesar
11、eaccomplishedbymeansofacontrollable-pitchpropeller.Thetunnelt_bulencefactoris1;7. -.Twomodelsof.hsoand60Sweepweremountedon asFigures4andSarephotographsof“thevariousflapstestedonthetwo.wings.Thevariousflaparrange-mentsonbothmodelsareshownschematicallyinfigures6and7. Thespecialflapswereobtainedbycutti
12、ngoffandrotatingtheoriginal .flaptoreducethesweepangledfthehingeaxis.Allflapswerefull-spanandwere.30“rcentofthechordmeasuredparalleltotheplaneofsymmetry.Thisresultedina“flapareaofapproximately2.26squarefeetforthesplitandslottedflaponbothmodels.ThisgavearatioofflapareatowingareaSf/Sof0.28.Thespecialf
13、lapshadaveryslightlysmallerareabecablockingcorrectionsasgiveninreference8havealsobeenapplied.Thedataobtainedatanglesofattackgreaterthan300maybelessaccurate,since,athighanglesofattack,thetipofthewingwasclosetothetunnelwallandnoadditionalcorrectionswereappliedforthiscondition.Inviewofthisfactitisbelie
14、vedthatthetunnelwallsaffectthevaluesof ACL lessthanthoseof C-; them-foretheincrementsmorequantitativelycoefficient.Nocorrectionsof c duetoflapdeflectionareconsideredcorrectthantheabsolutevaluesofthemaximumliftwereappliedtothepitching-momentdata.Provided by IHSNot for ResaleNo reproduction or network
15、ing permitted without license from IHS-,-,-6TESTSNACATN2468,Becauseoflimitatonsoftestequipmenmostofthetestsonthe600modelwererunatvadynamicpressureof25.6poundspersquarefoot,whichcorrespondstoanindicatedairspeedof100milesperhour,givinganeffectiveReynoldsnumberofabout2,900,000basedonthemeanaerodynamic.
16、chordofthewing.Split-flaprunsweremadeatanindicatedspeedof120milesperhourgivingRe=3;480,000.Alltestsontheb”wingwerernnatan indicatedairspeedof120milesperhourgivingRe=3,480joo0forallflapconfigurations.Anopen-jettestwasmadeonthe60winginordertocompare-theresultswiththoseof _theclosedjet.Theopen-jetidata
17、onlyindicatedthattheadditivewallcorrectionwerequalitativelycorrectsincetheirusegavelift-anddragcurvesfa%lingbetweenthosefortheopen-andclosed-jetdata.Theforce-testswererunthroughanangle-of-attackrangeof-12tostallinincrementsof3,exceptinearthestallwheretheincrementwasinsomeinstancesreducedto-lo.Thesma
18、llerincrementwasusedsothattheliftcum-ecouldbe”moreaccuratelyfairedatthestall.Tuftstudiesoftheuppersurfaceweremadeforboththemodelsatlow,medium,andhighanglesofattack.RESULTSANDDISCU%510Na71Theresultsofthefmrcetestsarepresentedinfigures8,to17;theincrementsofmaximumliftoefficientsagainstflapangleareshow
19、ninfigures18and19;the,dragincrementACD forthevariousflapsis*.presentedinfigures20and21;tuft-studydataareshownschematically”infigure22;andthevariationofaerodynamic-centerpositionwithisgiveninfigure23. .-.Aneffortwasmadetoevaluatewithinthelimitationsofthetestequipmenttheeffectof-Reynoldsnumber.Theresu
20、ltsofthesetestsarepresentedinfigure24andshownosystematicvariationsovertheraneoftestvebcities.ThefigurespresentingtheresultsofthetestsaregivenintableIIalongwith”alistofthe-cross-plottedresults.Plainwings.- .Ingeneral,the”aerodynamiccharacteristicsoftheplainwingsaresimilartothose.previouslyreportedinr
21、eferences3,4, .Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACATN2468 7and. Althouthemaximumltitcoefficientwasverynearlythesameforbothwings,itwasslightlylessthanthatobtainedforthesame-, wingconfigurationsinunpublisheddatafromtheLangleyAeronautica
22、lLaboratoryoftheNACA.Accordingtothesedatathemaximtiliftcoef-,ficientsobtainedat R =3 X10bwereaboutl.ohandlmo8forthe4oand600wings,respectively.Thesevaluescomparewith1.03and1.0forthehs”and600wingsreportedherein.Thedecreasein forthemax600wingisapparentlycausedbytheproximityofthetunnelwallatthestall.The
23、measuredstallanglesoftheh”and60wingswereapproxi-.matel.y27andO, respectively.Forthesamewings,stallanglesof2soand36owereobtainedaccordingtotheabovedata.Themeasuredslopesoftheliftcurveswere0.062and0.040forthe40and600wings,respectively.Thevaluesoflift-curveslopesobtaihowever,forinboardsplit-flapspansup
24、to0.5%/2themethoddescribedabovewillgive,withreasonableaccuracy,theliftcontribu-tionofthesplitflapatzeroangleofattack.Thismethodfailstogiveaccurateestimatesof ACL forflapspansgreaterthan0.b/2becausetheoutboardportionoftheflapapparentlysuffersanabnormallossineffectivenessonasweptbackwing.Asshowninfigu
25、re2Stheincrementsofliftatzeroangleofattackarelargerthanthoseatmaximumlift.TheorderofmagnitudeofthiseffectisaboutthesameasthatnotedforstraightwingsThedat;intableIII,whileonlyqualitatiw,doindicate,aspreviouslyreportedinreference10,that,thesplitflapactuallyreducestheglideangleat .CL forthe”wing,whereas
26、theglideangleismaxincreasedonthe60wing.oDeflectionofthesplitflapincreasedthenegativevaluesof cmc/bwithoutappreciablychangingtheshapeofthepitching-momentcurve,exceptforaslightnegativeincrease.Theincreaseinstabilitywas* greater,however,forthe600wing.Theliftcoefficientatwhichinstabilityoccurredwasincre
27、asedonbothwings,thusr+ucingtheaerodynamic-centershiftonbothwingsIProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACATN2468Forcomparison,theaerodynamic-centershift;-flapsdown,isplottedinfigure23. Thisfigureshowsthesomewhataterrangeof A.stabilityobtai
28、nablewithflapsdown. .ThevariationofdragincrementACD withflapdeflectionispre-sentedinfigures20and.21.Three-step.flap.-Sincetheflapeffectivenesswasthoughttobereducedprimarilybecauseof-thesweepofthehingeline,specialflapsincorporatedweredesigned.toremoveallorpartofthissweep.“Thepracticabilityofthesedevi
29、cesmaybequestionable,butthisinvesti-gationwasconcernedprimarilywiththeiraerodynamicqualitiesandnottheirstructuraladaptability.Thefull-span,three-stepflap,arrangedtodeflectinthreesegmentsabout=naxisnormaltotheplaneofsymmetryforthe4sowingandanaxisof4104lforthe600wing(figs.6and7),provedtobeof.littleval
30、ue.Asshowninfigures9and18,averyslight-gaininC!maxwasrealizedontheowingfordeflectionslessthan4s0.FiguresIhand19revealthatadecrementofliftresultedonthe600wingforflapdeflectionsgreaterthanlo.Possiblytheturbulencecreatedbythestaggeredarrangementmaybe .partiallyresponsibleforthepoorperformance.Theseresul
31、tsconfirmthedataoflowReynoldsnumbertestsofasimilarconfigurationzwported inreference2,whichshowedthistypeofflapona4”sweptbackwingtobeineffective.TheticrewntsofmaximumliftcoefficientforvariousdeflectionsasshowninfiguresI-8and19indicateanegligibleincreasein Ctionthe4s0wingandadecrementofliftonthe60wing
32、.TableIIrshowsthatthethree-steparrangementwasaboutas-effectiveastheplainsplitflapat-a=OO. Itisalsonotedthatthisflaphadaboutthesaneffectontheglideangle,decreasingitonthe4sowingandincreasingitonthe600wing.The-effecton thepitchingmomentwassimilartothatofthesplitflapinthataslightincreaseinstabiliwasnote
33、d.TheincreaseinmomentcoefficientC%/L wasnotsogreat.asthatduetothesplitflap.Theincrement-ofdragcoefficientduetotheflapis,showninfigures21and22. .Six-stepflap.-Thesix-stepflaparrangementshowninfigures6and7wasinferiortothesplitflap.Figures19and20showthatACLmx d-wasabouthalfaslargeasfortheplainsplitflap
34、onthe40wing,.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACATN2RobertC.: AerodynamicCharacteristicsofaWingwithFowlerFlapsincludingFlapLoads,Downwash,andCalculatedEffectonTake-Off.NACARep.534,1935.Pope,Alan:Wind-TunnelTest. JohnWiley; 1.08390 .72
35、795 .370100 .01.3L.E.radius:0.229T.E.radius:O.OlhProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-16TABLEIIPRESENTATIONOFRESULTS(a)ResultsforvariousflapconfigurationsNACATN2468DynamicFigure Configurationpress”JreDataplottedI A .450I I I8 I Splitflap 3
36、6.5I againsta9 Three-stepflap 36.5 CD,c%/4 againstCL10 Six-stepflap 36.5 “u Slottedflap ;.; 12 Rotatedslottedflap .13 Splitflap. 30.5 againsta14 Three-stepflap 25.6 CDSc%/llagainstCL15 Six-stepflap 36.516 Slottedflap 25.61? Rotatedslottedflap 25.6(b)SpecialplotiFigure Dataplotted18-ACLmxduetoflaps,4
37、5wing ACLmxagainstf19-AC%ax duetoflaps,600wing ACLH againstf20-ACDduetoflaps,h”ting, ACDagainst-fatconstantCL21-ACDduetoflaps,600wing ACDagainstbf atCOI_IStWhcL22-.Tuftistudicsj45and600wing23-Aerodynamic-centershift,450 Aerodynamic-centerand600wing positionagainst25-ACLagainstA forsplit ACLagainstA
38、(a=O)flap0, 4s0and60v% “LmaxagainstA.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TAELEIIIAERODYNAMICDATA6f a (JAC GlideangleConfiguration L/Ilat1 lu.x (for;= 600) : at “ at (L/D)mL Rotatedslottedflap 15 1.27 10.4.23 1.o38 1.22 . 6.9aFlap deflecti
39、ongivingmsximomlift.b vSh13S COR(X3pOn to 6f for CL .cTheseflaps causeda daorement Of chat all deflection abovelo.1Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-18 NACATNU68.- .- .- _.“”-Figurel.-Photographof60mcdelmountedintunnel(openjet).1.Provid
40、ed by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-I * ,t-18”0.25 chordIUACA 65AO06.70-chofd axis .=!s=Figure 2.-pkn-form dimensions of 40sweptting.E!=8 square feet;A = 4; A = 0.6;E= 24.7inches; all flaps are full-span and are 0.30c.Provided by IHSNot for Res
41、aleNo reproduction or networking permitted without license from IHS-,-,-.-.L-t-18”NMA 6SAO060.25 chordn 7n. k-A -1.48-W.l V-tdlul u UAla(Flap hinge)Flap true length =83.71”. .3Flap autline11/ 1Figure 3.- Plan-fOlm dimensloneA=4; L= 0.6;zx=a1-of 60 swept wing. S = 8 Bquare feet; 1+zE = 24.5 tieE. ws
42、9 .Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACATNb.2468 21(a)Splitflap. (b)Three-stepflap.(c)Six-stepfla.(d)Slottedflap, (e)-Rotatedslottedflap.Figure4.-Flaparrangement-45model.vProvided by IHSNot for ResaleNo reproduction or networking permi
43、tted without license from IHS-,-,-22 NACATN2468,(a)Split-flap. (b)Three-step“flap.(c)Six-stepflap. .(d)Slottedflap. (e)Ro+atedslottedflap.Figure5.-Flaparrangement-60model.V-a71a15.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-, 1 f(a) Six-step flap
44、. (b) Three-step flap. (c) Rotated slotted flap.Figure 6Schematic arrangement of special flaps - 47tiel.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- .-(a) Six-step flap. (b) Three-step flap. (c) Rotated slotted flap.Figure 7.-Schematic ement of s
45、pecial flapa - 60 mciiel. ,iProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-, , , . 4 IAlkfllllllll-oll II/ 111111 -n-tillll111111-+- wllll=AAngb of attack, + dogFigure 8.- Aerodynamic characteristicsof 45 sweptkck wing with plainsplit flap. q = 36.5
46、 pods per square foot.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Dmg coaffkbnt , CD Rtching-nmmmtcoefficient, c,4(b) CL against CD and Cmc/.Hgure 8.- (!onchuied. tI. * . tProvided by IHSNot for ResaleNo reproduction or networking permitted witho
47、ut license from IHS-,-,-. t ,L2-1.0,.805 “6w.-0G +0* .4c1 400 -0- 30= * 60i .2 /o-T /-.E / /c /P ( =F%=-.4-16 -12 -e -4 0 4 8 Ii? 16 20 i24 26 32Anglo of attaok, oc,dog(a) CL against a.Figure 9.- Aerodynamic characteristicsof 45 swptM& wingstep flap. q = 36.5 POWS per squaza foot. with tbree-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.n)coDrag coofficicnt, CD Pitching-momont coefficient, Cmc,4(b) CL against CD d c%/4”F
