z!-

a NATIONALADVISORYCOMMITTEEFORAERONAUTICS

“TECHNICAL NOTE4058

CALCULATEDEFFECTOFSOMEAIRPLANEHANDLINGTECHNIQUES

ONTHEGROUND-RUNDIS’T4iNCEIN LANDING

ONSLIPPERYRUNWAYS

ByJohnA. zdOVCik

LmgleyAeronauticalLaboratoryLangleyField, Va.

WashingtonJuly1957

https://ntrs.nasa.gov/search.jsp?R=19930084913 2018-05-30T12:31:18+00:00Z

TECfILIBRARYKAFB,NM

K lilllllllllfllllllllilllNATIONALAJXCSORYCWITTEE FORAERONAUTICS Uffbb7:7

TECHNICALNOTEk@

cAL~ Em?EcTal?S(MEAIRPLmEHANDLINGTECENIQW

ON THEGROUND-RUNDISTANCEINLANDING

ON SLIPPERYRUNWAYS

~ ~dm A. =lOVCik

SUMMARY

Somecalculationsweremadeon thebasisof simplifyingassumptions_&mdeterminetheeffeeton theground-rundistanceofmaintaininga nose-highattitudeinsteadofa three-pointattitudein landingsof severaltypesof jetairplaneson slipperyrunways.Theairplanesconsideredwerea swept-wingtransportandunswept-,swept-,snddelta-wingfighters.Theeffectof suchfactorsas speed,brakingeffectiveness,andresidualthruston thedifferenceinground-rundistancewiththetwohandlingtechniquesisbrieflyconsidered.Somecomputationswerealsomadetoindicatetheeffectof instantaneousflapretractionon

INTRODUCTION

Intheproblemofsz’restingairplanes

theground-rundistance.

landingon slipperyrunways,someqwstionhasbeenraisedastowhethera shortergroundrunmaybeeffectedby nosinganairpl&medowntothethree-pointattitudeimmedi-atelyaftertouchdownandapplyingthebrakesthanbymaintaininga nose-highattitudeangleforscmedistancedowntherunway,stisequentlyloweringthenosewheeltotherunway,andthenap@yingthebrakes.Pilotsof scmefighterairplanesls.ndingonrunwaysduring,or imw=di-atelysd%er,a heavyrainhaveben reportedtomakeuseofthenose-high-attitudetechnique.Thistechniqpeisalsoreportedtohavebeenusedby sanepilotsoftransportsondryrunways.

Thechiefpurposeofthisanalysisisto indicateby simplifiedcal-culationthepossibledifferencesinground-rundistancesforseveraltypesof jetairplanesobtainedby usingthetwopretious~describedtechniquesinlandingon slipperyrumways.Theeffectof suchfactors

. as speed,brakingeffectiveness,andidlingthrustonthedifferenceinground-rundistancewiththetwohandlingtechniquesisalsobrieflyconsidered.

*

2 NACATN 4058

Becausethequstionisoftenraisedastotheeffectivenessofretractingflapsduringa groundrun,smneresultsarepresentedfortheeffectof instantaneousflapretmctionatwound contactontheground-rundistance.

Gromd-rundistsncesarepresentedforrunwaysurfaceconditionshavingmsximumavailabletire-to-groundfrictioncoefficientsbelow0.3.Frictioncoefficientsinthiscientstypicaloflandingsonrunways,andon icysurfaces.

rangewouldinclude,forexsmple,coeffi-wetrunwaysathighspeeds,on snuw-covered

SYMBOLS

airplanedragcoefficient

airplaneliftcoefficient

incrementindragcoefficientduetoflap

incrementinliftcoefficientduetoflap

Iaccelerationdueto gravity,32.2ft sec2

wingincidencewithrespecttofuselsgereferenceline,deg

airplanelift,lb

dynamicpressure,g, lb/sqft

airplanewingarea,sqft

ground-rundistance,ft

residualor itiingthrust,lb

the, sec

airplanespeed,ft/sec

airplaneweight,lb

angleofattackoffuselagereferenceline,deg

.

.

NACATNh58 3

Cfm angleofattackmaintainedaftertouchdowninlanding,deg

P sea-leveldensity,slugs/cuft

v frictioncoefficient

pa maxianmavailabletire-to-groundfrictioncoefficient

~b airplanebrakingcoefficient

h rolling-frictioncoefficient,0.02

Subscripts:

13 atthree-pointattitude

max maximum

n at timewhenairplaneisnoseddownfrm a high-attitudeangleduringgroundrunto a three-pointattitude

s at stall;alsoattimewhen W = SqC~,w

t atmomentoftouchdown

METHODOFANALYSIS

Airplanes

Forthepurposeof evaluatingtheeffectof a nose-highattitudeangleon theground-rundistancenecessaryinairplanelandings,severaljetairplanesconsideredtypicalofmodernaircrafthavebeenselectedforstudy..Theairplsneschosenincludea sweptback-wingjettrans-port,threesweptback-wingfighters(identifiedasfightersA, B, andC),sm unswept-wingfighter,sada delta-wingfighte+.Someof thephysicalcharacteristicsof theseairplanesaregivenin tableI. me aerodynamiccharacteristicsnecessaryforthecalculationswereobtainedfromavail-ablewind-tunnelandflightdata,orwereestimatedwhensuchdatawerenotavailable,andareshowninfigure1. Correctionsforgroundeffectwereestimatedbymethodof reference1.

Theeffectof flapretractionon landingground-rundistancewascalculatedforallairplanesexceptthetaillessdelta-wingfighter.Theincrementsinliftad dragcoefficientscontributedby theflapsaregivenin tableII.

,

4 NACATN 4058

EffectofAirplaneAttitude

Landingdistancefor Vt = 1.05V~.- ThetypeofvariationofattackwithspeedassumedinthecmnputationoftheJandingrundistanceisillustratedinfigure2 fora toucMownspeed~ pe?.’centabovethestallingspeedVs,whichcorrespondsto acoefficientof 0.91~,=. Thecurve~abeled“a”corresponds

*

of angle●

ground-Vt of —lift —toa“

landinginwhichthepilotmaintainstheangleofattackcorrespondingto ~ percentabovestallingspeeduntila speedVn isreached.Theangleofattackisthenasswedtobe decreasedinstantlyat speedVnto thethree-pointattitudeandkeptatthisattitudefortherestofthegroundrun. Thecurvelabeled“b”correspondsto a landinginwhichthepilotnosestheairplanedowntothethree-pointattitudeattheinstantof contact.Inthehandlingtechniqpeindicatedby curvea,thebrakesareappliedonlytitertheairplaneisnoseddowntothethree-pointattitude.Forthetechniqueindicatedby curveb thebrakesareassumedtobe appliedimmediatelyontouchdown.Duringbraking,theentireverticalload(W- L) isass&edtobe takenonthemainwheels.Forthehandlingtechniqyeindicatedby curveb, thisassump-tionwi31smounttotheuseof justenoughelevatortokeeptheloadoffthenosewheel.At speedsbelow Vn theairplanewillbeatthethree-pointattitudeforbothhandlingtechniqmsand,consequently,thatpartoftheground-rundistancebetweenspeedsVn and O isthesameforbothtechniques.Fortheunswept-andswept-wingairplanesconsideredherein,theflapssmeassumedto remaindownthroughoutthegroundrun.

?

Thelandingground-rundistanceintheabsenceofwindiscanputedonthebasisoftheeqmtion

—

or,inanalternateform,i

1 dq CDq.— =-— .gpds CL,tqt (

~1-

-L)+T

cLq ) T

cL,tqt‘F

where,attouchdown,itisassumedthat

w = cL,-@&a

(1)

.

*

.

#

.

.

Intheintegrationofequation(l),thefrictioncoefficientv istakenasa constantrolling-frictioncoefficient~ duringthenose-high-attitudepartofthegroundrunsmdas a constantbrakingcoeffi-cient ~b duringthethree-point-attitudepartof the run. Sincethevalueof & issmall(takenhereas0.02)(refs.2 and3), itsvaria-tionwithspeedwouldhavea negligibleeffectonthelandingground-rundist=ce. Thebrakingcoefficientpb dependsonthepilot’stechniqueinapplyingthebrakes,ontherangeoftire-skiddingvelocitiesoverwhichantiskiddevicesoperate(iftheairplaneissoeqpipped),onthebrsk.etorqpelimitation(whichisa functionof speedandbraketemper-ature),andontherunwaysurfacecondition(whichdeterminesthemaxi-mumavailabletire-to-groundfrictioncoefficient~). Informationonthevsriationof pa withspeedisverymeager.On slipperysurfaces,suchasthoserepresentedby valuesof ~ between0.05and0.32 ~aprobablydoesnotvarymuchwithspeed.Inviewofthevarying”natureoftheseveral.factorsthateffectPb,thevalueof ~ cannotbeexpressedexplicitlyasa functionof speedand,hence,isassumedtobe constantfora givenrunwayconditionintheintegrationofequa-tion(l). Onthebasisoftion(1)@elds theground

(

theseassumptions,theintegrationof-equ-distances,asfollows:

1s=~ 1m cD,t

lo%‘D.t T

Vr-—CL,t

1CL,g CD,g

~b~- CL,tY

(. )%,t%Tkc-kc- -—~

cL,t % +n—-—cL,t w

(2)

Thefirsttermontheright-handsideofequation(2)representsthedistanceduringthatpartofthegroundrunwiththenose-highattitudeandthesecondterm,thedistanceduringthatpartwiththeairplaneatthethree-pointattitude.Solutionofeqution(2)forvariousvalues

of %— < 1.0 yieldstheground-rundistanceforcurvea offigure2;%

6. NACATNko58

qnwhereasthesolutionwith — = 1.0 givesthedistanceforcurvebqt

sincethefirsttermontheright-handsideofequation(2)becomeszero.

Eqyation(2)isvaliduptothelowestvalueof ~ thatpermitsdevelopmentofmaximumbrakingtorqueforcontinuousoperation.Forthepresent-daytransportsthemsximumbrakiqgtorqueforcontinuousoperationappearstobe intherangethatwouldprovidea deceleratingforceduetobrakingof 0.234to 0.3W. Ifthehigherofthesetwovaluesisassumed,as itisherein,thelowestvalueof ~ atwhichmaximwubrskingtorqueforcontinuousoperationisdevelopedwillbe,foreqle, 0.3for Vb =%, O.lfor Pb = 0.’75~,and0.6for~b = 0.50va. T@ calculationsarethereforemadeforvaluesof ~ Upto thatatwhichtbemaximumbrakingtorquewillbe developed.If stop-pingdistmcesathighervaluesof Va aredesired,ttifriction~~V(W- L) ineqwa.tion(1)willhavetobe replacedby O.~ atthetimeduringtherunwhenmaximumbrskingtorqueisdeveloped.

Theground-rundistemceforattitudeangles~ otherthanthat

.

m

correspondingto a speed5 percentabovestallingspeediscalculated.—

fortheswept-wingfightersB andC andthedelta-wingfightertouchingdownat 5 percentabovestaUingspeed.Theassumedvariationofangleofattackwithspeedfortheseairplanesisillustratedinfigures3 ?to 3.

—

Landingdistancefor Vt = l.30vs.-Forcomparisonwiththedistanceata touchdownspeedof5 percentabovestallingspeed,thegroun”d-rundistanceforthedelta-wingfighteriscalculatedfora touchdownspeedof30percentabovestallingspeedwithseveralattitudeangles~.Theassumedvariationofangleofattackwithspeedduringthegroundrunforvariousattitudeanglesis HJ.u,stratedinfigure6. Forattitudeangles”greaterthantheangleofattackcorrespondingtoa speedN per-centabovestallingspeed,thepilotiSass~d to increa=theangleofattackasthespeeddecreases)in sucha waYt~t t~ ~ft oft~airplaneiseq~ totheweightuntilthedesiredground-attitudeangleisattained.ThegroundrunisthencontinuedatthisangledowntospeedVn atwhichtheangleofattackisassumedto decreaseinstantlytothethree-pointattitudeandthebrakesareapplied.Theground-mdistanceisgivenby theeqmtion

NACATN k058 7

.

.

[

()l% - MCD,S % T-—— -.

q~ 1 CL,S % ‘+G CD,s 10% CD,S T

&-- —- —CL,S CL,S w

1-

1

CL,g CD,g‘bCL,~

—-—CL,s

!-+loge

( CL,g cD,g %

)b-;- ~b~-—— CL,S %> 1

.

(3)

Thefirsttermontheright-handsideofequation(3)isthedistanceduringthepartoftherunwhen L =W. Thesecondtez?nisthedistsmceforthatpartoftherunwiththeconstantnose-highsingleofattack.Thelasttermisthedistanceforthebrakingpartoftherunwiththeairplaneatthethree-pointattitude.Forattitudesingleslessthanthatcorrespondingtoa speedof~ percentabovestallingspeed,theangleofattackisass-d to decreaseinstantlyat contacttothedesiredattitudeangle.Thegroundrunisthencontinuedatthisatti-tudedownto speedVn atwhichthemgle ofattackisassumedtodecreaseinstantlytothethree-pointattitudeandthebrakesareapplied.Theground-rundistsmceisgivenby equation(2)forthiscase.

EffectofFlapRetraction

Theground-rundistancewithflapsretractedis calculatedforall “airplanesexceptthetaillessdelta-wingairplaneby usingequation(2)~ndassum$ngthattheairplaneisnoseddownto a three-pointattitude

k=‘)1 0 withtheflapsretractedattheinstantofgroundcontact.

me entirevertical.loadisassumedtobe carriedonthemainwbeel.s.

.

u

8 NACA~ h.058

RESULTS .

EffectofAirplaneAttitude.

Landingdistanceat Vt = l.05Vs.- Thelandingground-rundistanceforseveraltypesof Jetairplanestouchingdownat 5 percentabovestallingspeedisshowninfigure7 forvariousconditionsoftherun.way,as indicatedbythemsximumavailabletire-to-groundfrictioncoef-

ficient

ficient

friction

Vn2 ~l% andfor=ious =Iues of

()~ ‘~” Thebrakingcoef-

~b isassmnedeqyaltothemsxinnmavailabletire-to-ground

V2coefficient~a. H~ CUI’VeSlaleled ~~ = 1.0 represent

the ground-run distancescurve b infig.2) where

thethree-pointattitude

\’t/

forthehandlhgtechnique(indicatedbytheangleofattackisdecreasedimmediatelyto

Vn 2attouchdown.Curveslabeled

()86=0 .,0.,

~and0.4 representground-rundistancesforthehandlingte-chnique(indicatedby curvea infig.2)wheretheattitudeanglecorresponding “to thatfor5 percentabovestallingspeedwasmaintaineduntilthe-C pressure had decreasedtovaluesof80,60,and4-0percentofthedynemicpressureattouchdown,respectively. w

—

Accordingtofigures7(a),7(b),and7(e)thereisnoadvantageinmaintaininga nose-high-attitudeangleaftertouchdownfortheunswept-wingfighter,theswept-wingfighterA, ortheswept-wingtransport.Infact,forthesethreeairplanestheground-rundistanceincreasesconsiderablyfortire-to-groundfrictioncoefficientsgreaterthan0.05,whichrepresentsa veryslippe~surface.Fortheswept-wingfightersBandC (figs.7(c)and7(d)),somesmallreductioninground-rundistsmcecanbe obtainedforvaluesof & lessthanabout0.10.Atvaluesof ~greaterthan0.10,theincreaseinground-rundistanceisappreciable. ——

Theeffectontheground-rundistanceoflimitingtheattitudeangleinlandingisillustratedinfigures8 to 10. Ifthemadmumattitudeanglewerelimited,forexsmple,by tail-pipeclearance,to 10°insteadof 16°forswept-wingfighterB,andto 5°insteadof9°forswept-wingfighterC,thenose-high-attitudetechniquewouldresultinan increaseinground-rundistanceevenatvaluesof’~ downto approximately0.05.Forthedelta-wingfighteroperatingatanattitudeagglecorresponding -to 5 percentabovestallingspeed(about_20°),thereductioninground-rundistance(fig.10(a))isobtainedatvalues of Pa belowapproxi-mately0.2withratherlargereductionsobtainableonveryslippery m

K

.

.

NACATN4058 9

(-f== Pa ‘ 0.05).Foranattitudeangleof15°,onlysmallreduc-tionsindistanceareobtainedandonlyatvaluesof ~ lessthanapproxhately0.08(fig.10). Foran attitudesinglelimitedto a maxi-mumof100,noreductionisobtainedwiththenose-high-attitudetech-niquedowntoaval.ueof ~ of0.05.

t

Landingdistanceat Vt = 1.30Vs.-Theground-rundistanceforthedelta-wingfighterlandingata speedof ~ percentabovestallingspeedis showninfigureU forseveralattitudeangles.Thecurveslabeled

()

Vn 2

~ = 0.26,0.39,and0.52 correspondto curvesoffigure8 labeled

Vn2() 0.k, 0.6, and0.8,respectively,inasmuchasthecorresponding~=curveshavethessmevalue of Vn. A comparisonoffigures10and11indicatesthatthevalueof ~ belowwhicha reductioninground-rundistanceisobtainedwiththenose-high-attitudetechniqmisaboutthesue forthetwotouchdownspeeds.Thereductionor increaseindis-tancebothinpercentandinabsolutemagnitude,however,isappreciably

. greaterforthehighertouchdownspeed.

Landingdistancewithreducedbrakeeffactiveness.- Theground-rundistanceforthedelta-wingfighterwithreducedbrakeeffactivenessisshowninfigure12fora touchdownspeedof5 percentabovestallingspeed.Theangleofattackduringthenose-highattitudeofthegroundrunwastakenas 20°. CurvesareshownforbrakingcoefficientsUbof100,~, and50percentofthemaximm.navailabletire-to-groundfric-tioncoefficient~. A brakingcoefficientconsiderablylessthanthemaximumavailabletire-to-groundfrictioncoefficientmaybe obtainedasa resultof cyclingofthemtiskiddeviceovertoogreata rangeofskiddingvelocities,of inefficientbrakingby thepilot,orof insuf-fi.cientbraketorque.As aaexampleoftheefficiencyof oneinstaUa-tionofantiskiddevices,somerecentNACAtestsofan airplsneequippedwithonetypeofantiskiddeviceindicatedan averagebrakingcoeffi-cient ~b ofabout O.7pa whilethedevicecycledovera rangeoftire-skiddingvelocitiesfranO to about 70percentoftheunbraked-wheelrollingvelocity.Theresultsinfigure12 showthat,asthebrakingcoefficientVb isreduced,thenose-high-attitudetechniquegivesgreaterreductionsinground-rundistanceontheveryslipperysurfaces.Thevalueof pa belowwhichthereductionsareobtained.is increased

./

by thefactor~ Vb. Forexsmple,forthedelta-wingfighterwith

% = 20°,reductionsareobtainedat ~ *1OW about0.2for Ub = &. andat ~ belowabout0.4for Pb = O.51Ja.

10

Landingdistancewithresidualthrust.-(idling)thrustT onthegroundrunofthecatedinfigure13,whichshowsa comparison

NACATN4078

Theeffectoftheresidualdelta-wingfighterisindi-oftheground-rundistance

for T/W= 6 and0~025.Fora ratioofmaximumthrusttoweightof0.5,thevalueof T/W= 0.025 correspondstoa residu@.thrustof5 percentofmaximumthrust.Withthisresidualthrusttheground-rundistance

(onveryslipperysurfaces~a = 0.05)is,of course,excessivefortheconditionwhentheairplaneisnoseddowntothethree-pointattitudehmnediatelyandbrakesareappliedVn( = Vt). Althoughthereductions

!.. indistanceobtainedbymaintaininga nose-highattitudeareratherlsrgeforthissurfacecondition,theground-rundistanceis stillsogreatasperhapstorequireotherarrestingmeans. (Itshouldbe notedthatanantiskiddeticewhichwouldgivea brakingcoefficientequaltothemaximumavailabletire-to-groundcoefficientisassumedtoW operatingduringbraking,a conditionthatdoesnotappeartobe realizedinpractice.)Thereductioninground-rundistanceobtainedbymaintaininga nose-highattitudeisobtainedatvaluesof ~ lessthanabout0.2fora residualthrustofbothO and 0.025W,butthereductionsaregreaterwitha residualthrustof 0.025W..Theeffectoftheresidualthrustatthelowvaluesof Wa isapproximatelyequivalentto a reduc-tioninthevalueof Va by thevalueof,T/W.

.

—

Energyinputtobrakes.-Theuseofthenose-high-attitudetechniqueresultsina reductionintheenergyinputtothebrakesandhenceinareductionofbrakeandtirewear. Thereductionintheenergyabsorbed aby thebrakes,expressedasa fractionoftheener~ absor~edby thebrakes

Vn

(())

22when — = 1.0,isgivenapproximatelyby theexpression1 -Vt Vt “Fortheconditionsinwhichthenose-highattituderesultsina decreaseintheground-rundistance,theadvantagesofthistechniqpearetwofold.Forconditionsinwhichthenose-highattituderesultsinan increaseinground-rundistance,thereductioninenergyinputtothebrakeswindependontheincreaseinground-rundistancethatcanbe tolerated.Whentheairplanehasinsufficientbrakecapacityto absorbthekineticenergyoftheiirplaneincourse,be usedifmeansofarresting

Theeffectof

landing,thenose-~gh-attitudetechniqpemust,of ‘-sufficientrunwaylengthisavailable;otherwise,othertheairplanemustbe provided: ..

EffectofFlapRetraction

instantaneousflapretractionontheground-rundis-tanceduringbrakingis showninfigure14fora touchd&nspeedof5percentabovesta~ingspeedwithzeroresidualthrustand ~b = ~.Fortheswept-wingtransport,reductionsinground-rundistanceare

NACATN !L058 .32

. obtainedthroughinstantaneousflapretractionatvaluesof & downto 0.05(fig.lk.(e)).Thereductionsatthehighervaluesof pa are

. appreciable.Withgraduslflapretractionthereductionwouldbe smallerandwoulddependontheflapretractiontime. FortheotherairplanesinstantaneousflapretractionproducesMttl.eor noreductioninground.rundistanceabovevaluesof ~ ofabout0.2(or0.4for Pb = o.5~a)anda relativelylargeincreasebelowthesevalues.At thehighertouch-downspeeds,20percentabovestalJingspeedfortheswept-wingtransportand~ percentfortheunswept-wingsadswept-wingfighters(fig.1~),thevalueof ~ abovewhichthereduction(orbelowwhichan increase)inground-rundistanceis obtainedisaboutthessmeas atthelowertouchdawnspeed,butthemagnitudeofthereduction(orincrease)isconsiderablygreater.Withresidualthrustof 0.02~ (fig.16),instantaneousflapretractionincreasestheground-rundi.stsmceappre-ciablyabovethatwithzeroresidualthrustatthelowvaluesof ~.At thehighervaluesof ~a theresidualthrustof O.O& hasa neg-ligibleeffectonthedecreaseinground-rundistanceobtainedwithflapretraction.

CONCLUDINGREMARKS

Calculationsofground-rundistanceforseversldifferenttypesofjetairplaneshavingbrakingcoefficientsequalto themaximumavailabletire-to-groundfrictioncoefficientindicatedthatnoreductioninground-rundistsmcecouldbe effectedhy maintaininga nose-highattitudeduringthegroundrunfora swept-wingtransport,anunswept-wingfighter,andonetypeof swept-wingfighter.Somesmallreductionsinground-rundistancewereindicatedfortwootherswept-wingfightersona veryslip-peryrumway(atvaluesofmaximumavatlabletire-to-groundfrictioncoef-ficientlessthanabout0.10).A nose-high-attitudeangleintheneigh-borhoodofthestallangleofattackduringa groundrunofa delta-wingfighterresultedinan appreciablereductioninlandingdistanceatval-uesofmaximumavailabletire-to-groundfrictioncoefficientlessthanabout0.2(orabout0.4forbrakingcoefficientseq~l to x percentofthemaximumavailabletire-to-groundfrictioncoefficient).If,however,thenose-high-attitudesinglewerelimitedby tail-pipeclearanceorbyotherfactorsto abouthalfthestaU angle,noreductioningroundrunwouldbe indicatedforthedelta-wingfighter.Retractingtheflapsattheinstantof groundcontactledto reductionsinground-rundistancefortheswept-wingtransportfortire-to-groundfrictioncoefficientsdowntoabout0.05.Fortheunswept-andswept-wingfighters,flapretractionresultedinanappreciableincreaseinground-rundistanceatmsxbnumavailabletire-to-groundfrictioncoefficientslessthanabout0.2

12 NACATN 4058

(orlessthanabout0.4forbrakingcoefficientseqpalto 50percentof -themaximumavailabletire-to-groundfrictioncoefficient).

.

LangleyAeronauticalLaboratory,PWi.tiOIIal Advisory COMMit%efOrAeronautics,

LsngleyField,Vs.,April22,19570

REFERENCES

1. ‘Tani,Itiro,Taima,MSUO, andSimidu,SOdi: ThelMfectof GroundontheAerodymunicCharacteristicsofa MonoplaneWing. Rep.No.156(vol.XEH, 2),Aero.Res.Inst.TokyoImperialUniv.,Sept.1937.

2.Wetmore,J.W.: TheRollinglRrictionofSeveralAirplaneWheelsandTiresandtheEffectofRollingFrictiononTake-Off.NACARep.NO. 583,1937.

3. Pike,E. C.: CoefficientsofFriction.Jour.R.A.S.,vol.53,MC. 1949,pp.1085-1094.

.

r

NACATN 4058

TAELEI.-AIRPLANEPHYSICALCHARACTERISTICS

w/s, A~pct Sweepbackofwing ~g, ~,Airplane lb/sqft ratio qpsrterchord,

deg deg deg

Unswept-wingfighter 54 0 0Swept-wingtransport 70 ;:: 3; 3 0Swept-wingfighterA 4.8 0 0Swept-wingfighterB G Z o 0Swept-wingfighterC 52 ::; 35 0 0Delta-wingfighter 28 2.0 52 0 0

I

‘TABLEII.- FLAPCHARACTERISTICSATANGLE

OFATTACKFORTHREE-POINTATTITUDE

7

Airplane ‘L,f ‘D,f

Unswept-wingfighter 0.78 0.132Swept-wingtrsnsport .87 .044Swept-wingfighterA .4Q .060Swept-wingfighterB .31 .084Swept-wingfighterC ●39 .098

211

1.6

CL 1.2

.8,

.4

-—- —--. —— —---.— —

—— -——— —-—

0 10

Figure

20a, deg

1.- AerOdymmic

u-t-au fidt=>fl- ~~.%@.-awfighterA, fI.wsd~n9WPHI’W fii@ter% f@s dmm-IL@ fWtir C, EI.6PdamDdta-ming $i@tter.Suept-wingtramporb,flaps&ma

CD

c~act.erlstlcstith groundeffect~l*d”

. . * .

●

a 1’1“

b——~- ]7V+

0 vFigure 2.- Assmnedvariationof angle

groundrun.

~m, deg

I !6

of,attackwithV* = l.o~s.

speedduringlanding

f

Tazchdom

c!

A

!f -1 ●91CL,=

10I

I .\lVn I/Vt0’-~-—

0 vFigure3.- Assumedvariationof angleof attackwith

qmund runforswept-wingfighterB. Vt =speedduringlanding1.o~vs●

16 NACATN 4058

a

am,deg9

V 5

‘“N’ ‘ .UzkLbo v

Figure4.-Assumedvariationof angleof attackgroundrunforswept-wingfighterC.

withspeedduringlandingVt = 1●05VS,

.

Y

am,deg20

a& .—— — —.

10 I\t 7 I v~

‘n\ o I,/—— —v

q=oo

Figuxe5.- Assumedvariationofangleof attackwithspeedduringLandinggroundrunfordelta-wingfighter.Vt = 1.05VS.

am, deg

23 .————

a 15 4_ 10 ~__

ffVn

x fVt

o_.____i!L_ ~=oo v

Figure6.- Assumedvariationof angleof attackwithspeedduringlanding .groundrumfordelta-wingfighter.Vt = l.yv~.

.

.-

, #

8

6

s, ft 4

2

(VJQ21.0

.-. —- --—— ::—-— .I1

103

~,\.

o .1 .2 .3 .4

PO

(a)Unswept-wingfighter. ~ = $P.

F5.gure‘j’.- Ground-rundistancefor severalVt = 1.05V6;T

x, I

o .1 ,2pa

(b)Swept-@mgfl@rt&A.

Edl’’pknesend variou2valuesof= O; ~b = l,la.

.3 .4

~ = 140.

(/)Vnv~ ‘2.

(VJVJ2

03—

Ii\\

o

(c)

\__

\ .

.1

swept-wing

1::-. —— —--—.—.— ::

I

.2 .3 .4Pa

fighterB. ~.16°.

Figure7.-

o .1 .2 .3 ,4

I-b

(d) Swept-wingfighterC. ~ = 9°.

Contitiued.

..

s ,

12xlCF—

10 I

8

S,ft6

4

2

-— —— -..——

—.—

\8

\ -1.

\ \\\

\

‘-.‘\\ .

(K@— 1::

.6

.4

\

\

o .1 .2 .3 .4t%

(e)Swept-ting iransport. ~ = 70.

Figure 7.-

0 .1 .2 .3 .4

%

(f)Delta-wingfighter. ~ -20°.

Clxlduaed.

(q#’fJ2

103—

3\\

o

m f3.-

1::--....———— .6—–— .lt

.1 .2

Pa

(a) ~ = 160.

Ground-rundistancefor

.3 .4

swap-bing

.1

(b) s

fighter B for two valuesofT= O; Vb=Ua.

.2 .3

Pa

= 100.

theattitude

.4

4s

8 XKF

\

6 -

\s,ft4 ‘

2

,

(VJVJ1.0

——-———-—. f!—. — .IL

~

-%\

. ,

0 .1 .2 .3 .4 0 .1 ,2 .3 .4

PO Pa

(a) ~ = 9°. (b) ~ = 5°.

Figure9.-Ground-rundistancefor swept-wingfighterC for twu valuesof ths attitude angle ~.Vt E 1.05vB;T = 0; ~b = I.La.

22 NACATN 4058

.

.

s,ft

8X103

4

2

8

6

s,ft4

2

0 .1 .2 .3 .41%

(a) ct = 20°.XI03

\ \

. \ _ . —\ \

-+... --\

0 .1 .2 .3 .4Pa

(c) ~ = 10°.

0 .1 .2 .3 .*Pa

(b) a = 15°. , .—.. ,

(W%)*1.0________ .8.-—— .6—-— J!

Figure10.- Ground-rundistancefordelta-wingfighterforseveralvalues.

ofattitude“angle~. Vt =-l*05Vs;T = 0; Vb = ~..

NACATN k058 23

0

.

.

10XI03

81\

6;1

s,ft

2

0 .1 .2 .3 .4Pa

(a) ~ = 23°.

IOXI03

8 . (VJ%)*1.00--—_____.s2—— .39

6—-— .%

Ys,ff

4

2

0 .1 .2 .3 .4l%

\~

\ ‘

0 .1 .2 .3 .41%

(b) ~ = 20°.

o

. (c) ~ = 150.

Figure11.- Ground-rundistancefordelta-wing.ofattitudeangle ~. Vt = 1.30VS;

-—.1 .2 .3 .4

1%

(d) ~ = 10°.

fighter forseveralvaluesT = o; Pb = Pa.

.

s,ft

s,ft

10 XI03

8

6 ‘“ ‘i\

~\\\

4 \\

2

0 .1 .2 .3 .4Pa

(a) k+)= p~*12XI03

10 ~I\\\

8 \l\

\\!\\\\

6- ‘I“\

y :\\\‘&. ,\\

4 \..

2

0 .1 .2 .3 .4Pa

(c) ~ = o.50pa.

F\\\\\\,\\\\o- .2 .3

Pa

(b) ~b= o.75~.—

1.0--- —-----—— ::—.— .l!

.

.—.

—

.—

.

Y.

—

Figure12.- Ground-rundistsnce for delta-wingfighter for several.of brakeeffectiveness.Vt = 1.OXS;M = 20°.

●

values

, .

12

10

8

S,fi6

4

2

xlo3--l----

t

(Vn/%t)21.0

----------———. —

—-

0 .1 .2 .3 .4

t%

(a) 9?=

Figure13.- Effectof

o.

0 .1 .2 ,3 .41%

(b) T = 0.025W.

residualtit on ground-rundistancefor delta-wingfighter.Vt = 1.Q3’’JS;Pb = ~; ~ = ~.

mapsdcun

---–-– KIApsup

0 .1 .2 .3

\

\\

3\\\\\

.4 0 .1

‘\

\

.2I.&-1 i%

(a)Unswept-wingfighter. (b)Swept-wing

I?Y.gurelk.- Effectof flapson ground-mudistancefor severalVt = 1.05V~;T = O; ~b = Pa.

.3

fighter A.

alrplatles.

.4

. ● .

-.

,

12

10

8

S, ft 6

4

2,

03—

I

\

\\\

1\\\\

0

(c)

\

L‘\ \\ \

.1

swept-wing

Flsp dan

–-–--– m.apsnp

.

.2 .3 .4

Pa

fighterB.

m 14.-

1I

I\i\\\

0

(a)

Continued.

.1

\\“\

k\\\\.

Swept-wing

.2

* t

.3

Pa

fighter C.

.4

k?

28

.

●

s, ft

I2 xlo3—

10 \

\\\

8 \\1\\I

6 ,

4

2

0

T‘\\‘, \

\\ \

.4.1 .2 .3

— Flap*

–-–—––maps up.

.

%

(e) Swept-wingtransport.

Figure14.- Concluded.

.

.

?NACATN L058 29‘K

“

.

s,ft

(a)

.,

s, ff

12xlo3,iII

10 \\\\

8 [I\\\

6 \\\\\\

4 \‘\‘.,

2

0 .1 .2 .3 .4

Swept-wingtransport.Vt = 1.2VS.

12XI03,II1I10 iI\\

8 \

6\ \\

4- \\

2

0 .1 .2 .3 .4Pa

.(c) Swept-wing fighterB. Vt = l.~~.

1

1I1\\

\

\\

‘\\ \.

‘\(\\

\

o .1 .2 .3 .4w

(b)Unswept-wingfighter.Vt = l.~~.

b Figure15.- Effect of flaps onground-rundistance. T = o; ~~ = Ma.

s, ft

‘o .1 .2 .3,%

(a) T = O.

Figure16.- Effectof flapsend residuaJ-fight.er.

,

.4 0 .1 .2 .3 .4t%

(b) T=

thrust on ground-rundistanceVt = 3..05VB;Lb= pa.

‘. ,1

.

O.wjw.

for the straight-wing

. r

!2