1、-: ,.,-= i-,=. .- .- ;i.-.FOR AERONAUTICSTECHIWCA1.NOTENo.1278EXPERIMENTAL DETERMINATION OF THE DAMPING IN ROLLAND AILERON ROLLING EFFECTIVENESS OF THREE /WINGS HAVING 2,42, AND 62 SWEEPBAC?KBy Charles V. Bennett and Joseph L. Johnsoni Langley Memorial Aeronautical LaboratoryLangley Field, Va.Washin
2、gtonMay 1947 N A L. A I.lHK:; -.1Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.NATIONALADVISORYCOMMITTEEFOR AERONAUTICS.,NOTENO. 1278EX.iWKIMZNTALDZfiERMINATIONOF TEEDAM21NGINROLLAND AILEHONROLLINGEFFIXTIVEN2S3OF THREEJ_NHAv_G20, 4flwe ding of Lle
3、st:.ld.andwing combinationfOrany.Venrateof rotationg.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-*NACATIJNO, 1278 5.For determinngtheaileronrollingeffectiveness,theaileronshei-eadjustedto obtainvaluesof pb/2V of 0.05and0.10foreachwing. The totala
4、ileronsettingsforpositiveandnegativerotationwereaveragedto givethetotaleffectiveailerondeflectionrequiredforthedesiredrteof rotation.At eachrateofrotationthedampingmomentof the standwasneutralizedby settingthefin toproducean equaland opyositemoment.,WHJLTS AND DISCUSSION.(o(The resultsof all testsar
5、epresentedinTig.xres4 to 7. IrIfu.re8 thedataare mxmnarizedandcomparedwithvaluescalculatedby the simplifiedtheoryfor dwqpt+backwings,whichwas verified.experimentallyin reference4. Since”the sweepbackinthepresentinvestigationwas obtainedby pivotingthe semispanof a givenwingaboutam axisin the planeof
6、symnetry,thetheorymaybe usedinthebasicformwithoutthe agyect-ratiocorrectionsrequireilfortheexperimentaldataof reference 4.The resultsof theteststo determinethelift,drag,andpitchingomantof thewingsare showninfigure4. Thesedata1indicaethatthelift-curveslopedecreaseswithincreasingsweepbackangle. The si
7、mplifiedtheoreticaltreatmentofreference4 showedthat variedwithswee,pbackas cosA.aThe experimentaland celcule.edvaluesof CL for thewingsi atestedarepresentedinfiguie8(a)and showgoodagreement.The resultsof thedamping-in-rolltstsare showninfigure5.The dataindicatethatsweepingthewingbackreducedthedampin
8、ginrollandthatthedampingin rollfor a givenwingdecreasedgraduallyoverthelinearportionof theliftcurve(upto CL = 1.0forthewingwith2 sweepbackandUD to CL = 0.6 for thewingswith42 and 62 sweepback).B:yondthelinearortionof theliftcurves,as themaximumliftwas approached,thewingwith2 sweepbackshoweda rapidre
9、ductionin dampingin rollandabovetherimumliftcoefficient,amarkedinstabilityin dampinginroll posi-)tive CZ .Thewingswith42and 620 sweepbackshowedan irregularPdecreaseinCz beyondthelinearportionof theliftcurveand-, 3retaineda smallamountof dampingup to an emgleof attackof 360.4Provided by IHSNot for Re
10、saleNo reproduction or networking permitted without license from IHS-,-,-6A reductionin Cl withsweephackforvis havingthePssrmbasicwing pinelsworldbe expected fmm a simyl.fiedtreatmentofthethee-ryof swept-backwins, The dampingrollingmcmentroducedawing rollingresvltsfromthe asymmetricliftdisti%utioria
11、longthe span,quchthat,foraqywing(1)For the swept-backwte!s,reference4 endthe eerimental dataof figure8(e.)showthat CL wxies as cosA; bJ gemnetrybucanbe sham to varyas cw A ard y is acsumd to varyapproxi-matelyas cosA sothattheratio y/b remainsaproxiaatelyconstanta71 Tho slfectiveincrementalangleGiat
12、tackresuliirfromuolliv.gAx, in degrees.canbe expressetiby theequation(2)Sincetheratio y/b is assumedto le constantif yb/2V isholdconstantwith sweep%auk,thenLaA = bdA=o (3)If theserel.ahionshipsere stibsti.tuteiiin equation1),the obtainedforthewingwith2sweepbackis in goodagreementwiththetheoreticell.
13、valueof CtPThe,measureds-tatica;.leronrollinmomentsforthewingstes-tecarepresentedin fiure6. Thesedataindicatethatwithincreasiucswecpbackeater ailercndeflectionsarerequiredtoproducea givenrOllingqyxnent,The ailerondeflectionrequired,fcm anysweebask,remainsessentiallyconstantoveithelinear-pOrticnofthe
14、liftcuye.Referenceh indicatedthatntheaileroneffcctiveriessof a sweyt-backwingwasreducedas COSLA, Figure8(c)showsthatthisrelationshipholdsaeasondblywellfurwingswith2 erli42sweeybacktThe dataforthewingwith 62sweepbacksrealsopresentedin figvre8(c)%ut sinceWe locationof the aileronson thiswing is notthe
15、 sameas thelocationof theaileronson thewingswith2 and4Z0sweelbackthe dataarenot directlycomparable.(See figo .)Theresultsofteststo determinethe ailerondeflectionsrequired,to producevdlmesof pb/2V of 0.05and.0.20arepresentedin figure7 withcalculatedvaluesot the ailwcondeflectionsrequired. The calcula
16、tedaileronrollingefl:ectivenesswas obtainedfromthe damping-in-rolldataof figure5 andthe staticaileron-rolling-m,omentdataof figvu+e6, The dataof fiCure“7showthatas the sweepbackwas increased.gzeateorailerondeflectionswererequiredto proticea givenvelv.eof pb/2ViThe dataof fiure7 showthatforthewinGwit
17、h2 sweepbackthe experimmtelaileronrollingeffectivenessremainednearlyconstantthroughoutth,eliftrge nvestiated.TilecalculateddataWe in fairaeementwiththe experinentaldata. Fie5and6shawthatforthewinswith2 sweep%ackthe aileronrollingeffectivenessrerminsconctantbecausethe aileron-rollingmoment%a decrease
18、din a%outthe sameratioas the dsrupingroll ClP to maximvmliftcoefficient.the exerimentaldataof figureFor thewingwith42 sweepback,7 showthataj.leronrollingProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-8 LN.ACAm NO,1278effectivenessremainedconstantup
19、to a liftcoefficientof 0.7andthatfroma liftcoe:?ficientof O.to C*95+dieailerondeflectionrequiredfora $envalueof pl/- decieased.Thecal.czil.eteddataverifythisreuctionsincethe dsmpinginrollC2- decreasedmorerapidlythanthe aileronuoQirrstJ;icva-iationofbaileronrequiredfora givenvelueof pl/2V isnotedfort
20、hewingwith 62sweepback.The calculatedandexperimentalvslues,hcwever,ewein qualitativeag!?eemenk.l?igure7 showsthatthe ailelsonscouldnotoduce a velueof pbV of 0.05nearmaximumliftcoeffi.ciertfarthewingswith 42and62sweep%ackbecause the aileroni+oll.l rmmentsapproachzercasmeximvmliftcoefficientsarereachd
21、 whilethewingsretaina smta31aount of dampi%a (Seefigs.s and 6.In figure8(d)themeasuredandcalculated.ailerondeflectionsreq.uiedto produce pbV of 0.05areplottedqpinst sweepbackanglea71 The calculationswere%asedontl.efoX1.owinGrelationship:cr(5)The expei+irintal.dataof fie 8(d)arein goodegreementwithth
22、e calculatedmliesforthewineswith2 and!2sweepbacli.Dataforthewi with o sweey%ackem y.lesente follows:,.1,Increasi,sveey%ackreducedthe ?aultiplyithe strai.ght-wirgvalueGf d.ampininrollby thecosinoof the sweepbackanai2. The d?Lninrollfor allthreewinesdecreasedwithincreasingli:ttcoefficient.3. Increasin
23、gtho amcymtof swcebaclcforinstabilityin.rollingasmsxirnumLiit4 Increasingthe mount of swee-gt,ackthe ailerotideflectionrecmiedto wroduce“et.”!ced the tendencyW.B approached.causedan increaseina givenvalueofhelixangl.oy-b/2vh5SThe aileponrolll.ngeffectivenessfort:ewinwith2sweepbackremainedapproximate
24、lyconstantuy to them.eximumliftcoefficientbecausethe aileronrollingmcmentsdecueasedapproxi-matelyin the sameratioas the danyinginrolls YCX+theingwith 42 sweerbackthe eilercnrollinGefieutivenossremainedconstentup to a liitcoefficientof 0,7,but froma liftcoefficientof 0s7 to 0995 the atlerond.flecti,o
25、nrequiredto y+oduce a givenvalueof pb/2l,decreased;ecausethe dem.pingin rolldecreasedfasterthenthe aileronrcllingmoments. No apparentsystematicvazziationwithliftcoefficientof the aileronrequiredfor agiverivalueofpb/ was notedforthewinflwith 62sweejbackt6. Therolineffectivenessof t?ez.ileronof theswe
26、pt-tackwingswas predictedwithfe.iraccuracyfromstaticaileron-rolling-?rKmEnttestsandwing-dmnpingtests.4.“LangleyMeu.ori.alAeronauticalLabo:at.oryNationalAdvisoryCommitteeforAeronauticsLareyField, Vat,May 31,1946Provided by IHSNot for ResaleNo reproduction or networking permitted without license from
27、IHS-,-,-1(IREFERENCES.NACATN NO. 2781* Zier=, C. E,: I?relimineryTestsin theN.A.C!,A.Free-SpinningWindTunnel. NACA1?ep.NO. 557,1936.2. Skm%el, JGseph,A, anda-pel”,John W.: Free-Flirt-TunnelZnvetiati,onoftheEffect01thel?useleLengthOM theAspectI/atioandSizeoftheVerticelTailonLatersLStalilityandControl
28、. NACAARR NO. 3B17, 1943.National.Adwisoryc-tte forAeronautics:ASwe-Backwings. NACA mNO. 1046,1946.5. Swarisc)n,RobertS., endRriddy,E. LaVerne: Lif-ting-Surface-TheoryVsluesoftheDzimpinginRolL andofthe?sraceterUsmi inllstimatingAtleronStickForces. NACAARRNo.L23,1945.*.Provided by IHSNot for ResaleNo
29、 reproduction or networking permitted without license from IHS-,-,-. .r . ,. ,.zFigure l.- Roll stand with model of wing with 62 sweepback attached,mounted in Langley 15-foot free-spinning tunnel.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.a71a1
30、5NACA TN No. 1278 Fig. 2(.l;-,.1.4. :5.:IJ# .,.:-7, ;:8. .-.-! “.,it “i.,1 “WIND1 Vane (to produce rolling moment) 62 Counterweight3 Torque rod (can be mounted in this 7head to measure roiling moment) 84 Scale (for reading torque-rod de-.flection in static tests) 95 Supporting arm (mounted to tunnel
31、wall) 10,.p.L ,.POlnter (to indicate t.orque-road=-lect.10ninSt,atlct*tS)Roll axisModel support (can be free in rollor restrained by torque rod)Mounting head (adjustable to desiredangle of .sttack)Yaw axisFigure 2.- Roll bracket used to determine damping in rolland rolling moments.iProvided by IHSNo
32、t for ResaleNo reproduction or networking permitted without license from IHS-,-,-$.,NACA TN No. 1278 Fig. 3bzr-;T=cz/”Lt. .42 sweepbmk/%z?t?=255qfi#spec/ rum =59062 sveepbmkNATIONAL ADVISORYCOMMITTEEFORAERONAUTICSF/gure 3.- Sketch o? w79 Don hw.5 u.s a)rfoll section onall wIn9s, Rhode St Gms 33, ere
33、ndic ular 70F0.5 chord )Ine. (for iQhode t Gene.se33 UI%4 see?Fe erence 3.JProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Fig. 4 NACA TN No. 1278b00NATIONAL ADVISORYCOMMITTEE FOR AERONAUTICS. .,Provided by IHSNot for ResaleNo reproduction or network
34、ing permitted without license from IHS-,-,-.NACA TN No. 1278 Fig.53Z?i?b/eCOMMITTEEFM AERONAUTICSProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.m3,002.00/o030 .4 .8 12 1,6L/t coefficient, CLNATIONAL ADVISORYCOMMITTEEFORAERONAUTICSfigure 6. Ailerw m
35、lllng moment forh?ree swept-back wjngs os defemvnedfrOm force ?ii5ts on mll siimd. g= 2.8. . *-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-,. . . ,. , s.s)- -H005 CMoon- -. o 4 .8 AZ M3-.0 .4 .8 AZ.- NWIONAL ADVISORYCOMMITTEE AESDHAVTICSProvided
36、by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Fig. 8 NACA TN No. 1278)0 Expertn?enti ICuic(.daki.0-A-,6CC71CUQ)Wfro? #r reference 4 (A= /0)G / ccf*1 I I I lv I t I I Idam W-l lllllfP P-NJ 1-1.tiiiiiii iiT*(L/(J I I I 1 I , 1 I I 1 1 0 I 140 I I I I I IFor = 0.05J -l P “+Cos o20 + “(d)I INATIONAL ADVISORYCOMMITTEEF AEROSAUTICSO /0 20 30 40 .50 60Angfe of sweepbock, A, deotqd 62 weeuck. CL=0.3.,.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
