REG NACA-TN-3857-1956 Experimental investigation at low speed of the effects of wing position on the static stability of models having fuselages of various cross section and unswep.pdf

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1、6xlta“%JNATIONALADVISORYCOMMITTEEFORAERONAUTICSEXPERIMENTALTECHNICAL NOTE 3857INVESTIGATIONAT LOWSPEEDOFTHEEFFECTSOFWINGPOSITIONONTHESTATICSTABILITYOFMODELSHAVINGFUSELAGESOFVARIOUSCROSSSECTIONANDUNSWEPTAND45SWEPTBACKSURFACESByWilliamLetkoLangleyAeronauticalLaboratoryLangleyField,Va.-WashingtonNovemb

2、er1956AFMDcProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-wingTECHLIBRARYKAFB,NMNATIONALADVISORYCOMMITTEElKIRAERONAUTICSIlllllll!lllullll!llllllll-TECHNICALNOTE3857 acihL?37EXPERIMENTALINVESTIGATIONATIQWSPEEDOFTHEEFFECTSOFWINGPOSITIONONTHESTATICSTAB

3、ILITYOFMODEISHAVINGFUSEIAGESOFVARIOUSCROSSSECTIONANDUNSWEPFAND45SWEPJBACKSURFACESByWilli.smLetkoSUMMARYAnexperimentalinvestigationwastie todeterminetheeffectsofpositiononthelow-speedstaticlongitudinalsadstaticlateralstabilityderivativesofairplmemodelsham fuselsgesofsquareandrectangularcrosssections

4、unsweptandk”sweptbacksurfaces.ThehorizontaltailofeachmodelwaslocatedonthefuselsgecenterHne.Theresultsoftheinvestigateionindicatedthatatlowanglesofattackthecompleteunsweptmodelswiththewinginthehighpositionweremorestableorleastlongitudinallyunstable;whereas,forthesweptmodelstherewaallittlechangeinlong

5、itudinalstabiliwithchangesinwingposition. Forboththesweptandunsweptccnrpleteconfigurationsthelow-wingpositionwasgenerallytheleaststableinthemediumsngle-of-attackrange;whereas,athighanglesofattacktherewaalittlesi.gnificsntdifferenceinthestabilityofthemodelsduetowingposi-tion.Theresultsalsoshowedthati

6、nthelow mediumangle-of-attackrqe movingthewingfrcmthelowtothehighpositiongenerallycausesadecreaseinthedirectionalstabillforboththesweptandunsweptconfigurations.Thelow-wingconfigurationwasindicatedtohavethesmallestdetrimentaleffectscausedbysidewashonthetailcontributiontothestaticlateralstabilityderiv

7、ativesforalmosttheentiretestangle-of-attackrange.-Theresultsalsoshowedthatwing-fuselsgeinterferencecausesanincreaseineffectivedihedralsnglewhenthewingismovedfrcnnthelowtothehighpositionasoccurredforthecirculsr-cross-sectionfuselagereportedoninpreviousinvestigations.Provided by IHSNot for ResaleNo re

8、production or networking permitted without license from IHS-,-,-2INTRODUCTION.GPitch-upandlossindirectionalstabilityathighanglesofattackhavebeenencounteredinsomehigh-speedairplanesandhaveledtotheconsiderationofchamgesinvariousairplanecomponentsinanattempttoalleviateortoeliminatethesedifficulties.San

9、eofthechangesunderconsiderationareinwingposition,fuselagecross-sectionalshape,andhorizontal-tailposition.Severalsystematicinvestigationshavebeenmade”todeterminetheeffectsofthesechangesonthestabilitychsmcter-isticsofmodehwithfuselagesofcircularcrosssection(refs.1 and2,forexample)andtheeffectsoffusela

10、gecross-sectionalshapeonthestaticstabilitycharacteristicsofmidwingmodebhavingunsweptud45sweptbacksurfaces(ref.3).Thesamemodelsusedintheinvestigationofreference3wereusedinthepresentinvestigationwhichwasconcernedwiththeeffectsofvsxyingthewingpositiononthestaticstabilitycharacteristicsofmodelshavingfus

11、elagesofsquareandrectangularcrosssectionsandhavinginterchangeableunsweptend45 sweptbackwingandtailsurfaces.Forthepresentinvestigationthehorizontaltailwaslocatedon thefuselagecenterline,aswasthecaseintheinvestigationofreference3. *Thedataarereferredtothestabilitysystemofsxeswiththeoriginonthefuselage

12、centerline;thelongitudinallocationisattheprojectionofthewingaerdymmiccenteronthefuselagecenterline.Positivedirectionsofforces,moments,andangulardisplacementsweshowninfigure1. ThecoefficientsCL liftcoefficient,FqG Idr% coefficientF;q%andsymbolsaredefinedasfollows:% lateral-forcecoefficient,FY/Wcl rol

13、ling-momentcoefficient,Mx/w% pitching-momentcoefficient,My/q*% yawing-momentcoefficient,%/W%JFL liftProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NAC!ATN3857 3drag(approximatelateralforcerollingmomentpitchingmomentyatingmcunent-c pressure,1V2Pfree-

14、streamvelocitymassdensiofairaspectratio,span,measuredplan-formarea#/$perpeticu tofuselagecenterlinechord,measuredparalleltoplaneofsymmetryrootchordtipchordmeanaerodynamiccoordinatealongJ%+chord;forexanple,w=% Cl 2WY-sxis,measuredfrcmplaneofsymmetor taillength,distancepsralleltofuselagecenterline/fro

15、mmountingpointtO Ev 4averagefuselageheighta%wingrootaveragefuselagewidthatwingrootperpendiculardistancefromfuselagerootchordcoincideswithfuselage/or 75H4center line to EJ4 (tailcenterline)Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4AhRrwdxiAAP4a

16、NACATN3857#wingheight,perpendicul.sxdistancefromfusehuzecenterlimetowingchordcenterline)localradius oflane(positivewhenwingisabforsqusrefuselege,d =wlongitudinaldistancealongfuselagecenterlinemeasuredframfusee noseeffectivedihedralangle,degtaperratio,ct/crangleofsweepofangleofsideslipazimuthangleang

17、leofattackquarter-chordlineyp%J contributionofthetailgrouptoderivatives;thatis,forforforthewingon, + =P (%)PwFvH-thewingoff, = (%)FVH -awing-tailconfiguration,Myp*Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-5Subscriptsandabbreviations:w wing;used

18、withsubscripts1,2,and3 todenotewingpositionrelativetofusele(seefig.2)F fuselage;usedwithsubscripts1to4 todenotevariousfuselsges(Seefig.3)E horizontaltail;usedwithsubscripts1 and2 todenoteunsweptandsweptconfigurations,respective(seefig.k)v verticaltail;usedwithsubscripts1and2 todenoteunsweptandsweptc

19、onfigurations,respectively(seefig.4)APPARATUSANDMODEISThetestswereconductedinthe6-by6-foottestsectionoftheLangleystabilitytunnel.Themodelsusedweredesignedtopermittestsofthewingalone,thefing-tailcombination,thefuselagealone,thewing-fuselsgecombination(withthewingatseveraldifferentpositions),orthefuse

20、lagewithanytailconfigurationwithorwithoutthewings.Therelativelocationsofthewing,fuselage,andtailsurfacessreshowninfigure2.FuselagesofsqusreandrectangularcrosssectionshavingroundedcornersweretestedA sideviewandcrosssectionofeachfuselagearegiveninfigure3togetherwiththedesignationbywhichthefuselagesare

21、Identified.Thecoordinatesofthesquareandrectsmgulsxfuselagesweresodeterminedthatthevsriationofthecross-sectionalareaofeachfuselagealongthelongitudinalaxiswasthessmeasthatofthecirculsr-cross-sectionfuselage(Fl)discussedinreference3.Thecoordinatesofthefuselagewithcircularcrosssectionaregivenintable1.!T

22、heconfigurationstestedhadbothsweptandunsweptwingandtailsurfaces.Thequsrter-chordLLnesweresweptback and45fortheunsweptsadsweptsurfaces,respectively.Thewingshadataperratioof0.6- anaspectratioof4. Tnetailsurfacesalsohada taperratioof0.6. Theaspectratioandothergecmetrfccharacteristicsofthevarioustailsur

23、facesaswellasthoseofthewingsaregivenintableII. Thegeaetriccharacteristicsofthevarioustailsurfacesareshowninfigure4 togetherwiththedesignationchosentoidentifyeachsurface.T wingsweretestedatthemtdwinglocationsndalsoatposi-tionsone-thirdofthemaxtmumlmdydepthaboveandbelowthefuselagecenterline.Alllifting

24、surfacesweresetatO0 incidencetithrespecttothefuselagecenterline.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-6 NACATN3857xThemodelsweremountedona singlestrutsupportatapointonthefuselagecenterline,locatedforthesweptandunsweptconfigurations Passhown

25、infigure2. A photographofthesweptconfigurationwithfuse-lsge2 andwiththewinginthemiddlelocationisgivenasfigure5.Forthewing-tailconfigurationsthetailwasmountedonasteeltubeofsmalldiameterwhichwasfastenedtothewingorwingmountingbracket.Thelocationsofthewingandtailcorrespondedtothelocationsofthewingandtai

26、lwhentestedincombinationwithafuselage.Theisolatedtallwasmountedonthesanetubewhichwasthenattachedtothemodelsupportstrut.Forthewing-tailsndisolated-tailtests,thetailareaincludedtheportionnormallyenclosedinForcesandmaentsweremeasuredbymeanscomponentbalancesystem.TESTSANDCORRECTIONSthefuselage.ofa conve

27、ntionalsix-Testswerered-eatamnic pressureof24.9 poundspersquarefootwhichcorrespondstoaMachnumberofabout0.13andaReynoldsnumberofabout0.71X 106basedonthemeanaerodymsmicchordofthewings.The Pmodelsweretestedthroughanangle-of-attackrangefrom-kuptomdbeyondmsdmumlift(ofwingsalone)atsagles.ofsideslipof0and5

28、.Testsofthecompleteconfigurationswerealsomsdeatanglesofattack however,somedataarepresentedtoshowthesupport-strutinterferenceforseveralcomplete-ndel configurations.RESULTSANDDISCUSSIONPresentationofResultsThestaticlongitudinalstabilitycharacteristicsofthemodelsaregiveninfigures6 to13andthestaticlater

29、alstabilitycharacteristicsme presentedinfigures14to26. A summaryoftheconfigurationsinves- .tigatedandofthefiguresthatpresentthebasicdatafortheseconfig-urationsisgivenintable111. 7Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACATN3837StaticLongitu

30、dinalStabilityCharacteristicsCompletemodels.-Theeffectsofwingpositiononthestaticlongi-tudinalstabilitycharacteristicsofthecqlete modearegivenfigure6. In thelowangle-of-attackrangefortheunsweptconfigura-tions,themodelswiththewinginthehighpositionwerethemoststableorleastlongitudinallyunstable.Forallwi

31、ngpositionstheconfigura-tionswiththeshallowfuselagewereunstableinthelowangle-of-attackrangeduetothelargeinstabilityoffuselage4. Wingpositionhtilittleeffectonthelongitudinalstabilityoftheswept-wingmodelsinthelowangle-of-attackrange.Althoughdifferencesintheterevalues,showninfigure8,causedsomechangeint

32、rimfortheswept-wingmodels,thestabilityinthisrsmgewaaunchangedbyneglectingthetaredata.Forboththesweptsadunsweptmodebthelow-wingmodelwasgenerallytheleaststableinthemediumangle-of-attackrange.Atthehighanglesofattacktherewaslittlesignificantdiffrenceinthestabilityofthemodehduetowingposition.Forsnglesofa

33、ttackjustbelowthestall,theunsweptconfigurationwiththelowwingsmdthesweptconfigurationwiththehighwingappeartohaveslightlybetterlongitudinalcharacter-isticsthantheotherconfigurations.Boththeunsweptandsweptmodelsshowedapitch-uptendency;how-ever,fortheunsweptmodeltheangleforpitch-upwasabovethestallsingle

34、ofattackandtheeffectforanactualairplanewouldnotbeasimportantasthatforthesweptmodelswhichshowedthistendencyatanangleofattackbelowstall.Wingpositionhadlittleeffectonpitch-uptendencyofthemodels.Asamatterofhrterestandinordertogiveanindicationofthechangesintrimthatmsyoccurwithangleofside- slip,changesinp

35、itching-momentcoefficientwithangleofsideslipforthecompletemode atseveraldifferentanglesofattacksrepresentedinfigure7.Thedataoffigure6 showthatforboththesweptandunsweptcon-figurationschangesinwingpositioncauselittlechangeindragcoeffi-cientatlowanglesofattack.Atthehighanglesofattackchangesinwingpositi

36、ongenerallycausea lsrgerchangeindragcoefficientforthesweptmodelsthanfortheunsweptmodelstiththelow-wingmodelsprovfdingthelowestdragandthehigh-wingmodelsthehighestdragcoefficient.Thereasonforthelowvaluesofdragcoefficientuptoansngleofattackof8fortheunsweptcompleteconfigurationwithfuselage3 isnotclesrsi

37、ncethedataforthewing-fuselageconfigurationdonotshowthiseffect(seefig.g(b).Fortheunsweptmodelsthelow-wingconfigurationsgen-erallyhavea slightlyhigherliftcoefficientatlowuglesofattackthsmthemidwingorhigh-wingconfigurations;whereas,forthesweptmcdelsthelow-wingconfigurationsgenerallyhavea slightlylowerl

38、iftcoeffi-cientthanthemodelswithotherwingpositions.Athighanglesofattacktheeffectofwingpositionisgenerallygreaterforthesweptmodelsthanfortheunsweptmodelswiththehighwingpositionprovidingthehighestliftandthelowwingpositionthelowest.Provided by IHSNot for ResaleNo reproduction or networking permitted wi

39、thout license from IHS-,-,-8In ordertogive, CL,and CD foranindicationofthethecompletemodels,lUICAl!N3857.struttsrecorrectionstofigure8hasbeenprepared.9Althoughthecorrectionshavenotbeenappliedtothedata,itappearsfromthefigurethatthegeneralconclusionssrenotalter. Inthe applicationofthecorrectionstheval

40、uesoCL and showninfig-ure8 shouldbeaddedtothedata,whereastheincrementsof C; shouldbesubtractedfromthedata.Ingeneral,theeffectsofwingpositiononthelongitudinalchar-acteristicsofthemodelswiththesqusreandrectangularfuselagesmeshnilartothoseobtainedwiththecircularfuselagereportedinrefer-ence1.Wing-fusel.

41、age configurations.-Forthewing-fuselageconfigurations,changesinwingpositionhadonlya smelleffectonthelongitudinalstabilitythroughouttheangle-of-attackrangetested.(Seefig.9.)Themidwingconfigurationgenerallywaslessunstablethanthehigh-orlow-wingconfigurations.Therewereonlysmallchangesindragcoeffi-cienta

42、tlowanglesofattackduetowingposition.Aswasthecaseforthecompletemodels,chmgesinwingpositioncsuseda lsrgerincreaseindragcoefficientforthesweptmodelsthanfortheunsweptmodelsathighanglesofattackwiththelow-wingmodelshavingthelowestdragandthehigh-wingmodelshavingthehighest.drag.me effectsofwingpositiononthe

43、liftcoefficientforthewiyg-fuselageconfigurationsweresimilartothosenotedforthecompletemodels.Fuselageandfuselsge-tailconfigurations.-Thedataforthefuse-lageandfuselage-tailconfigurationshavekeenpresentedinreference3butarealsopresentedhereforcompleteness.Infigures10and11arepresentedthesta-t_iclongitudi

44、nalcharacteristicsofthefuse-e adfuselage-tailconfigurations,respectively.Thepitch-uptendencyshown “forthefuselage-unswept-tailconfigurationatmoderateanglesofattmk .is,ofcourse,duetostallingofthehorizontaltail.Theresretwosetsofpitching-momentdataforthefuselagealonesincethecenterofmomentswasslightlydi

45、fferentdependingonwhetherthefuselagewasusedinconjunctionwithsweptorunsweptwg-tailsurfaces.is differenceincenter-of-momentlocationcausedonlyasmalldifferenceinthelongi-tudinalstabilityofthefuselages.wing,wing-tail,smdisolated-tailconfimrations.-Thelongitudinalcharacteristicsofthewing,wing-tail,andisol

46、ated-tai_lconfiationsaregiveninfigures12mi-13.Ismuch”asthecharacteristicsofthesesweptandunsweptwingshavebeenrepor%ed=+useve?%lothernvestigat+onsJsuchsareferences1,5, ti 6, theyarenotdiscussedherein.Aswasmentionedinthesectionentitled“Apparatw.andModeM”thewing-tailandtail-aloneconfigurationsweretesteQ

47、withthetail.-4*-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACATN3857 9mountedattheappropriatetaillengthona steeltubeofmnalldismeter4 whichwasfastenedtothewingorwingmoktingbracket.Thelocationsofthewingandtailcorrespondedtothelocationsofthewingan

48、dtailwhentestedinconibinationwithafuselage.Sincetheeffectsofchangesinwingpositionwerethelargestforthemodelwithfuselageofdeeprectangularcrosssection(F3),onlytheresultsforthewinglocationsthatcorrespondtothoseoffuselage3 arepresentedinfigures12and13.Alsoinfigure13arepresentedthelongitudinalcharacteristicsoftheisolatedtail.Figure12showsthatthereislittleeffectofwinglocation-thatis,winglocationwithrespecttothebalancecenter-onthestaticlongitudinalcharacteristicsofthewings.A ctudyoffigure13showsthataddingthewingtotheisolatedtailcausesadecreaseinlongitudinalstabilityatlo