1、-1. NATIONALADVISORYCOMMITTEEFORAERONAUTICSqw.c(uTECHNICALNOTENo. 1378PRELIMINARY DW?ESTIGATIONAT LOW SPEED OF DOWNWASHCHARACTERISTICSOF SMALL-SCALE SWEPTBACK WINGSByPaulE.Purser,M.LeroySpearman,andWilliamR.BatesLangleyMemorialAeronauticalLaboratoryLangleyField,Va.WashingtonJuly1947Provided by IHSNo
2、t for ResaleNo reproduction or networking permitted without license from IHS-,-,-. NATIOJ?ALJUYZHORY00M41TTEEFORAERONAICS.TECHNICALNOTENO.1378PRELIMINARYINVESTIGATIONATLOWSPEEDOFWNWASHCHARACTERISTICSOFf34thereforethelowReynoldsnumberofthepresenttestsshouldhavelittleeffectonthevalidityofthepresentdat
3、aatlowIfftcoefficients.Sinceanalysisofthedatainvolvesadiscussionof%othtorce-testmeasurementsandtuftsumeys,acomparisonoftheresultsobtainedbythesetwomethodsis,showinfigures25end26,“Anincrementaldifferenceexistsbetweenthevaluesofdownwashangleobtainedbythetwomethodsthatisprobablycausedbytares;howeverthe
4、slopesofthecurvesareverynearlythesame.Thetuft-surveydatapresentedarevaluesfora stationatthemidpointof the tail semispanantinoattemptwasmadetoacccnmtforspenwisevarlattcnsofdownwashen$l.eandtailiftdistribution.AsnotedinthesecttonentitledCorrectionsneitherthedownwashanglesnortheanglesofattackfromthetuf
5、ttestshavebeencmrrected.Thecorrections andvalueof A*c/4 .Method(3).i%equivalenttQbasingthecomputationsonem -unsweptwinghavingthesamepemelsasthesweptdngsa71 . This ms3though strictlyempiricalandhavingnotheorq$icalbasis,gavetileclosetagreementbetweeneerti6ntQ.andcomputedvalues“.of dl/da.Computationsof
6、 d61/dczmadebyqethod(3) forfour completemodelshavealsoshcwagoodseementwithexperimentalvaluesobtainedh theLangley30dMPH7-“by10-foot.tunnel,. ,;, Effec%ofTaperRatioTheonlydirectlyccwqmrabledataontheeffectsoftaperratiowereobtainedformodelsD andE. ThesedataarecomparedInfigure28, whichshowsthatforthelowl
7、iftrangethemodelwiththanfromconventionaltape:= 2.0 .has,greate:ddwntniehanglethewingwithinversetaper,(=c).,l) aewouldbeexpectedthedesignchartsofreferences7and8. Thedataoffie 28Indicatethat-ingeneralamoreuniformvariationof c with-angleofattackIsobtainedfor.the”modelwithconve.ntlonaltaper.“Atm0.$ abov
8、ethechordline,forexample,themodelofconventionaltapershowsafairlyuniformincreaseindownwashanglewithangleofattack,whereasthdwfngcifverse,pprshowsaparticularlyrapidincreaseindowashenglebetweenanglesofattackof12end1.60. Thisresulttightbeexpectedsticetheforce-testdata(figs.16emd17)alsochowsme+.qr”derture
9、sfromlineart.tyfortheliftandpitching-momentcur%esfortheconventional-tape,Thedifferenceineffectii%”dowaahangleforthetwotailspanq,isagainprobalycqusedbyqniqboardshiftoftheliftload.forsweptback,wingsath anglesofattkwhenthetfps,stall. “,Tailposition.-Boththetuft-surveyandforce-testdatiindicatethelargeef
10、fectofboththevez%icalandlongitudinalpositionsofthetail,onthevariationofdownwashanglewithangleofattackinthemoderatetohighlift-coeffcientrsm.ge.Forexample,figures12to14showformodelsA,B,andC withtheshorttaillength(positionenincreasein dGf/daandacorremondingunstablechangein,slopeofthepitchingmomentneari
11、mum lft.-WhenVUG”talllehh“isficreased(gositim”2.formoel.eA;ondBandposition3formodelC)”theunstablechangesin del/thatis,insuchpositionsthevaluesof de/daeitherremainconstantorshowastabilizingdecreasewithincreasedliftcoefficient,ThisresultProvided by IHSNot for ResaleNo reproduction or networking permit
12、ted without license from IHS-,-,-10. .explainthedataofreferencobwhereinthe.-presenoeofa .shown,tcvimprovethelongitudinalstabilitycharaoterlsticsof,aunstablewing-.: .Jt.,5. Theuseoftrailing-edgeflapscal?sedaslightincrgese.in:de/du.qndcausedanincrementintheareanglesof”attackaboutthesti abwould”bb-exec
13、ted“bnanuzwyxwing. Lpading+dgeJohnG., andSchneiter,LeslieE.: InvestigationalLowSpeedoftheMngltudinalStabilityCharacteristicsofa60Swep/C# Shorttail Longtaillenh lengthA 0.44 0.0076 0,0072 0.0146B ,28 .0049 , .0080 ,0130c ,28 ,0049 .0030 .OoaD *53 .0Q93 .0069 .0117E a7132 .osolatedtailsaIaNocorrection
14、sappliedbecauseofsmallsizeoftails”., #NATIONALWSORY-COM!TTEEFORAERONAUTICS. -, , “ .,.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-14TABLE11_ TODATAFIGUKESNACATNNo. 13”(8. . , ., Tailpcmikfcm 2+j k. FigureModelconfiguration nuniber “$ . numberForc
15、e-testdata.vA,withandwithout 1 1*O 0,18 12(a) 1+ail , “,. 2 ZS5 .18 Y2(ll) IB, with and wlthc 1 I6 13(a)tail 2 ,. 2,4:Z 13(b)5 “1 1.5 a7129 14(a)C,withendwithout .2” ,1.5 .03 14(b)tail 2.3 14c),: 2.3 :; 14d)1 L,36 .43 15(a)2 1.36 .2115(3)D,withemiwithout,; 1,36 .03 15(C)tail z “ 1.91 ,43 ;(:5 1.%-An
16、aly6isplotsComparisonofforceandtuftdata 25and26Effectofaspectratio27Effectoftaperratio 28Effectoftailspan 29Compmisonofmeammedendcm.uputedvalwsof dcf/da30,1I.1VATI0NALADVIEWR%COWTTEEFORAJKOJ!7MJTICSProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.Fig
17、ure1.-0012 uirfo/.rectionY air foilsec.-, .NATIoNAL ADVISORYCOWITIEE KM AEMMA41TKS%DetailsofmodelA showingwing-tailcombinationstested.WinA =4.0;CR %*c/4 = 40.Tam. = 1.0; = 4.0;A = 40.CT c/4PCA3-amProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-b=“-/l
18、nevt7f fqilSand survey pk?nicsMTIONAL ADVISORYCDMTTEE FORAERWAUTICSfdllzFigure2.- %Details of model B showingying-ta.il combinations teded. W- = 1,0;A =2.5; pCT z J+ = 4=0;AC,4 = 40.CT*c/4= 40. Taih.-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.
19、.w and survey Plqnes94NATIONAL ADVISORYCOMNITTEE AERONAUTICSFigure 3.- %Deta51sof model C showingw-hil combinations tested. Wing: = 1.0; A = 2.5;%.1AC,4 = 40. Tail: = 1.0; At = 2.5; AC,4 = 40.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.v v /Low-
20、drag- type uirfo)J Se GtiCWjmaxhum thichnes= C?07ScQtO. *Cb=4Z(90”and surveyplanesNATIONAL ADVISORYfPosition PositionCCMEITTEEFM kmNAUTICS =0.617;A =3.0;Figure4.-DetaUsofmodelD shovdngwing-t.dl combinations tested. W:%CTAt/4 = 37.5. Tsik = 1.0; + = 3.6; LC,4= 40.CT.Provided by IHSNot for ResaleNo re
21、production or networking permitted without license from IHS-,-,-NATIONAL ADVISORYCOMMITTEE AERONAUTICSStetlol$ection A-AlatORDINATES FOR NACA 22 AIRFOIL ;and ordina+cs In emu.+ J wkq rhor41 ?m-F/.2525501:52021%70En1%Figure 5.- Details of flap and slat on wing of mcdel D.IJPW-2.005.40%!9,/1/;i3J42!2.
22、6011,129,1.s.XLd-?wrk2681.09:fB.0801:%3.084.76563579q.5.632.CnProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.2302 c7irfojl SectionY-y,. *urvey planesgFigure6.-DetailsofmodelE showingtuft-surveyplanes.c=204. A=3. ACT. . = 37.5. ; c/4:m-Provided by I
23、HSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-23012 q;rfoi secfionplanesl-+!+ /.86$+-.” -4 - -NATIONAL ADVISORYcO#MITTEE m AERONAlmcsFigure7.- %Details of model F showingW-surveyplanes. = 2.08;AT = 3.3; A 32.5.c/4 =Provided by IHSNot for ResaleNo reproduction o
24、r networking permitted without license from IHS-,-,-(a) High tail positio (b) Low Ml poSitiom .Figure 8.-FHngs forhighandlowta51positionsonfuselageofmodelsA,B,C,andD. All wCAYdimensionsininchesexceptwherenotsd. sProvided by IHSNot for ResaleNo reproduction or networking permitted without license fro
25、m IHS-,-,-IVACATIYNo.1378 Fig.9.2.+p-fy+”+p?”y+“+”f,1 i(Limd f/oof- ,I 1spat ed /4u1 NATIONALADVISORYCCWUITTEEFORAERONAUTICSFigure9.-Surveyrig for measuring downwash angles.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA TN No.1378.lag. 10Figure
26、10.- Sideviewoftuft-surveyrigintunnelduringtestrun.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.#iocus of iuiySurveypkie -NATIONAL ADVISOFIYCOMMITTEEM AERONAUTICSFigure11.-Locationofsurveyplanewithrespectton-mdelatvariousangles ofatkck.1-02a03c?.
27、Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-,Figure 12.-4UL!-J!0 _. 3?. 02.4 fibldlfff Coefficlmt,qj(a)Effect of horizontal M setting%model A. Wing: = 1.0; A = 4.0; AcL-A d otiocK,a,degPosition 1. position .onaerodynamic characteristics of40. Tai
28、h c/4 = 40.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-2-0 .2 ,4 .6 .8 /0 12L/Y/ coefficiiwt,Q“-4048/2/6202428Ae ofoiiocU,a,kvPosition 2.Figure12.-Concluded.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from
29、 IHS-,-,-.-2 o 2 46.01WL2Oft coeffiLYM.Q$ I -%- k 6=6-4 I II I I I I I I I I I I I I MH J2840.8-4 04 81J?16202ii28Am%of off0cK,a,d9q(a)Positionl.Figure 13.- Effect of horizontal tail setting snd position on aerodynamic characteristics of -in% %zcomodelB. Wing: = 1.();A = 2.5; AC,4 = 40. Taik = 1.0;
30、1+ = 4.0; AC,4 = 40.CT CTProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.Lift coefficient, QI I I I IiI 1 I 1 I I I I 1 1 1-4 048 Ii? 16 20 24 .28Ang/e of uitocfl,a,deg(b) Position 2Figure 13.- ConcMed. “1Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
