1、RESEARCHMEMORANDUWIND-TUNNEL INVESTIGATION OF HORIZONTALTAILS. V - 45SWEPT-BACK PLANFORM OF ASPECT RATIO 2ByJulesB.Dods,Jr.Ames AeronauticalLaboratoryMoffettField,Calif.NATIONAL ADVISORY COMMITTEEFOR AERONAUTICSWASHINGTONSeptember27, 1949Provided by IHSNot for ResaleNo reproduction or networking per
2、mitted without license from IHS-,-,-NACARMAm05,NATIONALADVISORYCO- FORRE3EARCHM!WRmmMTECHLIBRARYKAFB,NM1111111111111111111-”olJ4i+5u -AERONAUTICSWL 11W?ZSTIGM!IONOFHm3330mTAILS.v- 45SWEPT-RACKPLANFORMOFASPECTRM102ByJulesB.Dode,Jr.HIMMARXTheresultsofawind.unnelinvestigationofthelow-sedaerna?niccharac
3、teristicsofa k5mept+ackhorizontal+ailmodelofaspectratio2am presented,andme co-ed withpreviousresultsforamdel ofthesam aspectratiohavinganunswepthingeline.Thesedatasupplemntpreviouslyreportedresultsoftestsofmodelshavingunswepthingelines”andmodehavingthe0.2hordlinesweptbaak35withaspectratiosof3,4.5, a
4、nd6. #Testresultsarepresentedforthe4.50Sweek el withandwithoutstandardroughnessontheleadtngedge,witha sealedradius-noeeelevator,andwithanunsealedradius+mseelevator.ThetestRelds numbersvariedfrom3.0 to7.5 million.Thetestsincludedmasuremntofthemodelliftandpitchingmomat,oftheelevatorhingemomnt,andofthe
5、pre,ssuredifferenceacrosstheelevatornoseseal.Tuftstudiesoftheairflawoverthemodelwith-theelevatorundeflectedandwithitdeflectedarepresented.Themajoreffectsofsweepbackasmmsuredinthelowspeedtestsofthemodelsofaspectratio21weretoincreasethenegativerateofChS,Il ofhinge+mnentcoefficientwithengleofattack,tor
6、educethenegativerateofchangeofhinge+omntcoefficientwithelevatordeflec+tion,andtoreducetheelevator-effectivenessparamter.Sweepbackalsoreducedthestaticlongitudinalstability.A systematictivestigationoftbecontrol+mrfacecharacteristics,w piCU.1= the hinge+nomntparamters$ofhorizontal+ailsurfaceshasbeenund
7、ertakenbytheNACAtoprovidedesigndataenderimntel* a71Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-resultsforcolqp=isontiththepartersestimatedbythelif%ing-surfacetheory.Experimentalresultsi%ornwind-tunneltestsofmodelshavingunswepthingeIixmsandmodelsh
8、avingthe0.thetestswiththeelevatornosesealremovedweremadewitha smoothleadingedge.Theleadingdgerough-nesswasappliedasdescribedinreference2 forstandardroughness.Thestudiesoftheairflowoverthemodel,asindicatedbyshorttuftsofthread,weremadeataReynoldsnumberof3.0million.Theliftandpitchingmomentofthemodelwer
9、emeasuredbymeansofthewind-tunnelbalancesystem.Theelevatorhingemomentwasasuredbymeansofaresistemce-tyyetorsionalstraingage.Pressuresaboveandbelowtheelevatorhosesealinthebalancechanberweremeasuredbytheuseofamanometerconnectedtotheorificesinthebalancechamber.CORRECTIONSAllcoefficientsandtheangleoftheef
10、fectsofthetunnelwallsbythedatawerecorrectedasfollows:,attackhavebeencorrectedfor=thodsofreference3. The.a =%+0.934 cq +o.17k(8*=o)Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACARMA9D05c%+0.00499cchu+0.00678c%00993c%wherethesubscriptu referstothe
11、uncorrectedcoefficientorangleofattack.RIISUIXANDDISWSSIOI?Theresultsoftestsofthe45swept-backmodelofaspectratio2arepresentedinfigures3to10. Thevariationsoflift,hhge-moment,andpftching+ucnnentcoefficientswithangleofattackforvariousele-vatordeflectionsaregiveninfigure3. Hinge-momentcoefficientsarealsos
12、hownasa functionoftheelevatordeflectionforvariousanglesofattackinfigure4. Thevariationofthepressurecoefficientacrosstheelevatornosesealwithangleofattackispresentedinfigure5.EffectsofthevariationoftheReynoldsnumber,ofthestandardrough- a71ness,andoftheelevatornosesealontheliftandhingment coeffi-cients
13、areshowninfigures6 to8. Tuftstudiesoftheairflowoverthemodelareshowninfigures9 and10withtheelevatorunreflectedandwithitdeflectedup15, respectively.Inthefol.lawingdiscussiontheresultsofthepresenttestsarecomparedwiththoseofreference1,partIV,foramodelhavingthesameaspectratioandtaperratio,butwiththehinge
14、lineunswept.Themodelwiththeunswepthingelinewillhereinafterbereferredtoastheuusweptxmdel.Theunsweptmodelhada smallamountofsweepbackOf the0.2hordline(16.70),whichwastheresultoffollowingnormaldesignpracticefortailshavingthecontrol-urfacehingelineina plansWkpendiculartotheplaneofsymmetry.Thesweepreferen
15、ce.lineforthe45swept-backmodelwasthelinejoiningthe0.2hordpointsoftheNACAthechangein Ch8= wasfrom-o.oa tO-0.0057;andtheelevatorffectivenesspartheaerodynamiccenterwasshiftedforwardabout2 percentoftheman aerodynamicchord.Bothmodelswerestati-callyunstableatsmallanglesofattackasevidencedbya valueof(d%/du
16、)8e.0 of0.0023fortheunsweptmodelanda value of0.0031fortheswept4ackmcdel.Theexperimentalresultswhichindicatea destabilizingeffectofsweepbackforthemodelsofaspectratio2 anda stabilizingeffectofsweepbaokforthemodelsofaspectratiosof3, 4.5, and6 arenotinexactagreentwiththetheoreticalresults shovqinfigurek
17、 ofreference4. Thetheoreticalresultsindicatetwoeffects:(1)astabilizingeffectofincreasingthesweepbackfona constantaspect%he valuesoftheliftandhinge+nonmntparameterswerederivedfromlargcaleplotsofthedata.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-8
18、 liACARMA91X15ratio,and(2)a destabilizingeffectofreducingtheaspectratiofora constautangleofsweepback.Theconibinaticmofthesetwotheoreti-cal.effectsresultsinnochemgeInstabilitybetweenamodelofaspectratio3 sweptback350andamodelofaspectratio2 sweptbackko.Experimentally,huwever,therewasa destabilizingshif
19、tintheaerdynsmiccenterofshout.4percentbetweenthesemodels.Theresultsofa statisticalenalysisofa groqpofplanformsof,variousaspectratiosandenglesofsweeackpresentedinreference 5indicatethatthestaticlongitudinalstabilityatthestalldecreaseswithincreasingsweepback.Theexperimentalresultssreinagreementwiththi
20、sreference,sincetheyindicatea decidedincreaseinthestaticlongitudinalstabilityatthestallfortheunsweptmodelbutonlya slightticreaseinthestabilityfortheswep=ackmodel.(Seefig.3(c)partTV,fig.4(c).)EffectofReynoldsNumbertieeffectsofvariationoftheReoldsnumberfroms.oto7.5millionareshowninfigure6 fortheswepao
21、kmpdel.ThenwimumliftcharacteristicsofthemodelwererelativelyunaffectedlythiswxriationofReynoldsnumber,buta smallreductionin Ce wasnoted(asmeaswedthroughzeroaugleofattack).Thevalueof CremainedneexlyconstantwithincreasingReynoldsnumber,buttherewasa smallincreasein Ce.Themaximumliftcoefficientoftheunswe
22、ptmodel(reference1,partIV)increaseilslightlywithincreasingReynoldsnmber,buttherewasnochangeintheliftorhinge+omentpxrsmeterscorrespondingtosmallliftcoefficients.l!lffectofStandardRoughnessTheeffectsofstandardleaMng-edgeroughnessupontheliftendhinge-momentcoefficientswiththeelevatcmnosegapsealedareshow
23、nh figure7 fortheswepackmodelofaspectratio2. Asshowninthisfigure,endintable11,therewasnochangein C CLber Chaybuttherewasareductioninthenegativevalueof Ch8frcm-0.0057to-0.0055.Atthelargerelevatordeflections,theefectofroughnesswastoreducethehingemomentsslightlyatthesmalleranglesofattack.Fortheunsweptm
24、odela similarreducticmin C%e uasmeasured,and,inaddition,thevalueof C% wascheageafrom-0.0002to0.0006.r.“Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a9NACARMA9D05 /EffectofRemovingElevatorNoseSealThemajoreffectofremovingtheelevatornoseseal(modelssm
25、ooth)wastoreducetheelevatorlift-effectivenessparametercLe ofthesweptiackmodelwitha consequentreductionof e. Asshownhfigure8andtableII,C% wasreducedfrcm0.021to0.018.Thelift-curveslomeG rethisfacthasalsobeenindicatedbyliquid-filmstudies.Furtherincreasesintheangleofattackcausedtheareaofroughflowtoprogr
26、essinward.Figures9(k)and9(1)illustratetheconditionsexistingJustbelowtheangleofattackforthemaximumliftcoefficient,whichwasapproximately27,andfigures9(m)to9(p)illustratetheconditionsatthestall.ThestudiesofthetuftsonthemodelwiththeelevatordeflectedUT15,presentedinfigure10,showthattheroughflowagainstart
27、edatthetipandprogressedinward.Themaximumliftcoefficientoccurredataloutthe.sameangleofattackasitdidwiththeelevatorunreflected(fig.3(a).Aninterestingfeatureofthetuftstudiesofthemodelwiththeelevatordeflectedwasthereductionintheoutpd flowalongthelowersurfaceoftheelevatorastheelevatorbecamemorecloselyali
28、nedwiththeundisturbedairstreamatthelargeranglesofattack.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-10 NACARMACONCLUSIONSTheresultsoftestsconductedtoevaluatethelow-speedaerody-namiccharacteristicsofaT.E.Radius0.023a1aSam forboththeNACA64AO1Osecti
29、onandthemodel.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-14 NACARMA9D05TABLEII.-A SUMMARYOFTEEHFIANDHINGE-MOMENTPfWWEYERSOFTHEUN$WFFTANDTHE45SWEPT-BACKMODELSOFASPECTRATIO2 (R,3.0X 106)ModelConditionParameterModelothj ModelwithstandardModelsmooth
30、;elevator roughness;elevatorelevatorsealsealed sealed removedUhsweptac% -0.0002 0.0006 -0.0002Chbe -.Oop .0070 -.0074c24 m b z.-32 -28 -24 -20 -/6 -12 -8 -4 0 4 8 /2Elevator deflection, &e,degFigure 4.- Variutionof hinge-momentcoefficient withe/evutordeflectionfor voriousonglesof ottock for the 45 s
31、wept-backmode/of uspectratio 2. R, 3.OXIO6L.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a71 M(?ARM.Angle of attock, Q, oeg(u)a=q 0:-4:Figure 5- Variation ofpressure coefficient across elevator noseseal with angle of attackfor the 450swept-hack mo
32、del ofaspect ratio 2. R, 3.OxIO!Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-24 NACARMA9m5 ,Figd.4.20.2,-.-.4-.60.fl I I I I I I II I I-. z-.4-.6 Ii iiI 1w 1 1 1 ! 1-. 80-.2-.4-.6-.8-Lo-4 0 4 8 /2 /6. 20 24Ang/e of attack, U, deg(b) & =-9:-/-ZO:ff
33、e 5-Concluded,.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.,.NACARMA91X)5 25/.4IL2Lo.8.6 FI.4 A / 7& I.*.2 $ I2 v724 rRx/06-.4 , o 3.0a75 40“o5.076A 7.578 W-/.0_4 o4 8 12 16 20 24 28 32Angleof uttock,a, deg(IOJLift coefficient.Figure 6. Comparis
34、on of the lift and hinge-moment coefficientsfor vurious vuluesof the Reyno/dsnumber for the 450 swept-bockmode/ of ospect ratio 2.-.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.26 MiCAI?MA95(b) Hinge-momentcoefficientFigure 6.- Concluded.,Provide
35、d by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACARMA9D05 27/.4/.0.8.64s-.6-.8-!0I M I 1-HI I I I I I/ , / I I 1 I11111 111 1 ! 1 I II A=2Im-4. 0 4 8 /2 /6 20 24 28 32 360) Lift coefficient.Ang/eof airock,u, degof thelift undhinge-momentcoefficientsa71Fig
36、ure Z- Comparisonfor fhe 450 swept-buck model of uspecf rufio 2, withandwithout/euoing-edgeroughness,R, 3.Ox/O5Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.NACARMA91D5. 47 :,/A =2I A-4 0 4 8 /2 /6 20 24 28 32 36Angleof ottuck, Q, tieg(b) Hinge-mo
37、mentcoefficient.Figure Z :Conc/udeo!.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACARMA91X)5 29./.6. I I/.4 o Seu!edo doL2 v doa75 UnsealedA do/.0 D do.8 ,8e4Ui .6 - A P* =-/5.s.s .4 kg.2 g%Jo“-.2 74 “ . f-.6. D ,/:8- A=2*-ko-8 -4 0 4 8 /2 16 20 24 28 32 36Ang/eof ottock, a, deg.(0.)Lift coefficientFigure 8.- Gomparkonof the lift and hinge-moment coefficientsfor the 45” swept-bockmode/of aspectratio 2, withandwithoutelevatorseal. R, 3.OXIO6-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
