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TECHNICALNOTE
No.1474
WIND-TUNNELINVESTIGATIONOF”EFFECTSOFUNSYMMETRICAL
HORIZONTAL-TAILAR.WINGEMENTSONPOWER-ON
STATICLONGITUDINALSTABILITYOFA
SINGLE-ENGINEAIRPLANEMODEL
ByPaulE. Purser andMargaretF. Spear
LangleyMemorialAeronauticalLaboratoryLangleyl?leld,Va.
=Kl!l!kg!=Washington
October1947
L ---- .
. . . .. . ..- . . ... . . ..
II
I
{
I
, .,-. .
._. —— - --—
‘iiiliiiiiio144b31
IWIXCONALADvmoRTCobim?lmmI?ORAEWNAUTICS
TECHNICALI’?()!PENO.1474.
. . .... .
Wmwcmmwmsl?mMxoN al?ElzE’Ec!rsg??mmm5TRIcALHOKCZQNUW!MIL~EMENTS ONRMER-ON
STATICIOM(WJ!lJDIIUIJ9ZKBIL33?YOFA
.
SINGIE-EI?GINEAZRPIME-.. . . ByPaulE.??urserandMargaretF● Spear
..
SuMMmY., ,,
A wind-tunnelinvesti~atlonhasbeenmadetodeterminetheeffectsofunsymmetricalhorizontal-tailarran@mentsonthepowwr-onstaticlongitudinalstabilityofa sin@e-engine’singl.e-rotationairpbnemodel. ..
.
. . AMho@ thetestsandanalysesshowedtheitex%remeaqmmetry“.inthehorizontaltailindicated.areductioninpowereffectsonlongitudinalstabtZityforsingle-engineEc@le-rctationairplanes,theparticular‘>ractical”arrangmwn,t%e~eddidnotshowmarkedimprovement,Differencesinaveragedownwashbetweenthenormal.tailarra~amsrtandvariousothertailamangementsestimirtedti-tancmputedvaluesofprupeller-slipstream!ro%ationa~eedwtthvaluesestimatedfrqpitcbingmmttestdatafor theflap~-upGoMiti~.(lowthrustqndixnque)andM,sa&ee&fartheflaps-downcondition(hi@thrustandtorque).ThisW3agreenmntindicatedthenecess$tyforc~tinuedresearchtodeteminethecharacteristicsoftheslip-stream.behindvarious@opener-fuselqje-v+.pgccnnbhati.ons.Ou&of-W?n lateralfoqcesandmamantsoftheuuqmmtri<ailarrange-mentsthatWrebestfromccmsiderationof@@tudinalstabilitywerenogreaterthanthoseofthencwmaltailarran@ment,
.’
TheIku@leyLaboratoryofthe‘NACAhas&&takenq @neral ,studyoftheproblemsofstabi~ityandcontrolinpower-onfli@* .foramodelofa sinQe-enginefj,@@r+ypeairplane;
Uptothepresent.time‘&e~tu@hat3incl@iOtla comparism+,ofmeasureama coqputed..out -of-trimlateralforcesmamomentstiawxil.
. . .
----- . . . .. -.--—- -. ---— ——— - -— —----- - .. ------- -—--- --- -- —-------- ----- --... ..,
----- ... .. .. . . .. . . .. . . . ------
2
bythepropeller-slips&-eQmengineairplanes(referenceengineskewontherudderandailerti
., .~CA~?NO.1474
thevertical@il onsingle-analysisoftheeffectsofcmxtrolrequiredinthetake-
offandh low-apeeapower-onfltglit(unpublielied).‘lhestudyhasalsoincludedwind-tunneltestsand.briefanalysesoftheeffectsofunsymmetr@alhorizon~tails‘onthepower-onstaticlongitudinalstebilityofsingle-en~qsin@e-rota%iona@iLanes.. “
Theusualpowereffects.on~h~.staticlongl.tuilinalstabiutyofsingle-enginekjngle-rotationairplanesmaybedivWeQintodirectandindirecteffects.TheUr-ect.effectsare●theforcesanathemomentsact~ onthepropellerandtheaomwashres@tingfromtheliftforceanthepropeller;.tq ..const~t-pol~roperatiwtheseeffectsare@neraU@aestabil.lz~.TheWect effectsarethechangestiwingandb@y forces,mcment.ej.anddownwashandthechangesinta5&effectivenessinaweabythei.ncreaseadynamicpressureoftheslipstream.Thechangesh wingandbodyfarces,moments,anddownwashmaybeeitherstabiliz~ordestabilizinganathechangesintaileffectivenessareusually’stabilizing,Anaddlticmaleffectfor ccms@nt-pol.mroperationisthe%we thlnudtandtorquevaryinsucha wayastoIncreasetheslipetreemrotatianwithincreasesinliftcoefficient.Thesideoftheairy-eonwhichtihe~ropelJwbladeisgo~ up(leftsideforright-hqndrotation),thbrefmejUnaergoesanincrementofupwaphthatipcreaseswithangleofattack;theoppositesi~undergoesanincrementofdoynwashthatalsoincreaseswithangleofattack.lj’orthenorma$horizontaltailtheeffectsofslipetremrotationanlpngitudi.nalstabilityaresmall.Ifthetell3.sunsymmetrical,howaverjthe*sl.ipstieamrotaticmpossililycanbe.util.izeatochsngetheeffectsofpower-onlon@tudinalstehil~ty.Thepresentpaperconta~nswind-tunneltestdataandanalysepmadetoindicqteme ad$.wtientinover-all.powereffects.3hatmaybe.expectedfrbmtbeUEJeofunsymmelmicalliurizontaltailsonsingle-enginesingle-rotationairplanes. ,.
..
comrcnmmANDSYMBOLS -
.Theresultsofthetestsarepresente~assta.naaraWA coeffi-cientsofforcesandmcznents.Rolling-moment,yawing-momeqt,andpitching-momentcoefficients_aregivenaboutthecenter-of-@a’vitylocationshowninfigure1 (28.2percentM.A.C..).!l!lnedataarereferreatothe.stabilityaxes,whicharea systemofaxeshavingtheiroriginatthecenterofgravity’andin~jhi.chtheZ-axisisintheplaneofsynmletryand~erpendicularto,therelativewind.theX-axisisintheplaneofs.-tryandperp”bndiculartothe.&cd.s,andtheY.-axl.sisperpendic~
—— .—. ..—- -r _— . .. —.= . ----- .. ---- -— .. —-..
.. . . . ..-
to theplaneof@mmetiy. me .. .
----- —----- .,, ,—-. . . . . . .,
d
u
u
..-”
NACATIJNo.1474 3
posftivedirectionsofthestabilityaxes,ofangularW@=wmentsoftheairplaneandcontmolsurfqces,andof-e momentsare.showninfi~e 2. .,
Thecoefficientsantisymbolsaredefinedasfollmw:
liftcoefficient(Lift/@)
tailliftcoefficient(~~@) .,..
lcngltudiml-foroecoef$30ient.(X/@) .
~teral-t%xrcecoefficient.(Y/@)., .
r?U3.ngmwnx@coefficient(L/@b)
pitch3ng-moment
pitching-mment
coeffici~nt(M~Sc’)
coefficientprovidedbytail.
yawing-momfmtcoefficient(I?/@b)
effectivethrustcoefficientbasedonwingarea(Ttif~@)
()“’Qtorquecoefficient—@%3
propelleradvance-diameterratio-
(-)Teffvpropulsiveeffici,encg
xl@
“z
@@tuMnalforce,pounds
lat~alfcmce,pounds -..:?
verticalforce,pounds
rollingmunaut,pound-$eet
pitchingmment,pound-feet-
.
.,# ,
.
.
.:
. . .. . .—. —— ————— . —— —... . . . . .. .. ... . . . ---- .— - ~.—.—— .—-. — -.= —,.-~ — - ,-—- ----—- ——-- — -- - -,.. , ... . .. . . . . . . ...- ., , ,-” “..
4 NACATNNO.1474
I?”.
%
‘eff
Q
. .
Ct
b
%
Y/bt
c%
‘t
W-=nt, pound-feet-“ .;..-c,-.“lJftofisolatedhorizo&al-tail,pouqds
propell~iffoctivethruetj.pound.s‘ . .
propell~rtcque,pounii-feet’-sY .. . . .
. .
. .. .
. ..’
. .....-: .-
..
(),?‘free-slreamdynamicpressure,potispers~uarefoot ~ .-.-
effectivedynamicyressureattail;poundsper.s&re foot
W.ngarea(9.40
horizontal+ail
airfoilsection
averau%airfoil
. .
sqft mmoieZ) . ,
area,squarefeit
chordjfeet .
:.
. .
chord,feet . . .
wtngmeanaerodynamicchor~(l!.A.C.)(1.31ft.on model) .
(! )b/2 ..“25 C2ab
o
horizontal-tazlmeanaerodynamicchord.-
win~qan (7.509ft onmodel)
horizontal-tailspan . : .
spanwlsestationofhqizcxrbaltail
pitching-rmnentcoefficientateffectivetail-offaetiod.yna&c-centerlocatiqc(zero-liftinterceptoftangent.totail-offpitching-mmentcurve) .
taillengthmeasuredfromneutrai’petittoquarter-chord.“pointofhorizontal-tail-meana,erodyn@cchord .....
().E& . . . ~horizontal-tailvolumecoefficient
.. @--’
, .
-.. ..-- .-—----- .---— .—. — .— ..—-.—. -=. -— ---- —---- — —— .-— —.—— - - —----
NACATNNO.1474 5“
.
airvelocity,feetpersecond . ... ..
prapell+d&meter(2’.27~ onnodel).. .propellerspeed;revoluttauspersecad‘.
massdensityofair,slugspercubicfoot
“’an@eof
angle.of
angleof
attaclsofthrus”tline,de~ees...’ ,..“
.
a’
attackofhqrizautal-tailchqrd,degrees‘. . ,.#
yaw,degrees. . . .. .. -.
angleofstabi~ztiwithrespectto’thrustline,positive‘whentrailingedgeisdown,ti~ees.
.,slotted-flapdeflection,degrees. . . ..
:pl@n-flapaefloctfm,de~ees ,
. .
‘. . -pY:pbllerbladeamglea%0.75radius(15°onmodel)-..,.
effectivetail-offaero@namic-center~ocation,p~cent :.:9”‘ wingmeanaerodynamicchord .
neutral-pointlocation,percent* meanaerodyn&nicchord(center-of-gravityloca%lonforneutral.s%abjlityin,trhmedflight) .“‘
t- .
.,
“.
b tr@nedcoptiticms@th centerof“gravity@ neubralpoint:. . .,
.“ ‘. .. . .
. . .M-AWq--- ~.... .. ..“.. CgmpleteModei- .,
. ., ,..... ,.
Them@elriqa. ‘+ma.le~$elofa.37,q-foot+ansingiA@nesin@e-rotati~a@@Laqe.Themodelhasa 30-percent-chord‘p&t~al-spanslotted$lapwithaninternallysealed10-percent-ch~dplain
#
.- .. . . .— . -, -.. —-——. ——-—---~ .-,- —-, —. .—— -—--- ----— ---— ——. - ------,..’, . . . . .
. .
6 l??ACATN~0.1474
traitig-edgeflap,anad$zstablestabilizer,andaretractablelandinggear.A sketchofa t~tcal.sectionof:%heflaparrangementusedfortestsofthemodelinthelanding.configuration(52= 37°).isshowninfigure3. !!!hefjeneralphj~icaloharacterzsticsofthenodalare@vanintable1t A three-viewdrq~ andaphoto~aphshowingthemodelmountedintheLangley7-bylo-foottwnnelareshowninfigures1and4,respectively.
Themodelwasegti~edwitha three-bled?,rtght-hanarotation:propelleranda 56-horsepowerelectricmotor.Morecampletedescrip-tionsofthepowerequipmentaregivpninreference1,
Themodelccnxfigurationsreferredtoherein.areasfollowa:1-
Of
%’ Ptithrespectto Landing- cowl
(deg) 810tt0aflap . @w flap“(deg)
o 0 Retracted Closed
y 30 .Extended open15°
FL9pdeflectionsweresetwiththeaidoffem@etqfurnishedwiththemodel.
Tail&mfigwationa-
b oraertoobtainrelativelyextmemeindicationsoftheeffectsofunsymmetricalhorizontal-tailconfigurations,themodelwastesteswithno~atl,withthenormalhorizcmtaltail(fig,5(a)),withtherightsemispanufthencwnwltail(fig.5(b)),andWththeleftsemispanofthenormaltail(fig.5(c)).“Anunsynmetrfca~arrange-mentthatwasthought%0bearelatively@acticalonewasdevised.framtwootheravai3ablehorizontaltailshav3nGplanfo& iaenticaltothenormaltail.This~angement,shcnmin f ime 5(a)andrefarreatointhetextastheasynunetr~ctail,hasapproximatelyorie-thirdoftheareaontherightandtwo-thirdsontheleft,mathetotalareaisabout~percentgreaterthanthatofthenormaltail:
.
.
... .7 —— ~ —-- --—-———. . . -. :...
.- . ..-. ,=, . . . ..+.., .,. . ,?-. ,-
.
.
~cJITN’l?o.1474 . . .. ..‘,. .
..- .mms “. .“.,
.... ... .Test&&ions .“
ThefollowingtablesummarizesthetestconditicnWforthe .variousmodels:
Model
Complete;poweroffandflaps-qppoweron;c’= lc~lfeet
Coqplete;flaps-downpoweron;
c‘= 1,31feqt
Isola&ed.as-trictail;c= 0.66fOot-
lsOl.&edp-l tail;c‘= 0.68foot
,I~ola~edaemispan”ofnormaltail;Ct= 0.68foot
16.37’
9.21
16.37
13.00
15.00,
. .
ITe@ Air-?epoldsspeednumber(m)
---t-
L,4,)O0,0001&3
750,00060
kgo,ooo80”
4%,00071,. .
kgo,ooo76.,.
!mr-bulerxxfactor
3..60..
1.60
1.60
1.93
1*93,
. . . .
corrections.!.
:.
..
Langleytunnel
..
7-bylo-foot
7-byJ&foot
7-by lo-foot
4-by6-footvertical
4-by6-footvextzl.cal
‘,.complete mcdel.-Alldatahavebeencozrectedfortar&caused
bythemo?ielsuppcxrtstrut.Jet-botidaryccn?rekti&shavebeenappliedtothe&glep;ofat@ck,theldngi%udinal-forcecoefficients,@ thetail-tipitching-mmentcoefficients,,The.cqrrectiaus.werOcqutedasf’ollowsbyuseofrefevence2: -.. .
LYZ=l.065GL~ . . .. ..q . -O.0157~L2
ion=. -7.w&&l,)($!%)
All jet-boundarycomectionswereaddedtothetestdata.
.
.. ..-.—.——.—— .—— ... —.—.- .=. .- — +.. . .- -.= -. - --- ——- ~- ———-——-— -.,. , ..: . . .
,..
. . . ..--. — ...... .. . --
.
.%
...
.
8
tail
.
-’‘~CA~ No..1474
Tailsurfaces.-Thetitafortheisolatedncrmalhorizcmbalwerecorrecteafartares.cauzeilbythemodelsumxn?tstrut.
ThetitsfortheasmtricW-ii.ti&e semispfiof-tienormaltailwereobtaineabytestsofthetailsmountedontheisolatedverticaltailand.wereapproximatelycorrecteafortaresbysub-tractingthedatafcmtheveriicaltailalonefromthe’dataforthecomldnatlcmiste@e& Thejet-boundarycomections,”xxmputeaby...methodej3jmilartothose,ofreference3,wereaddeatotheanglesofattackasfollqs: “v ,~...-:.. .-k..... . . ,o-
:, .. .Ycwthenbrmaltail ‘,’-:~..“ ,~-.: ,,,.
. . . .. . .Al&<’. . .......Forthesemispanofthezimmalstail ‘ :
Fortheasymmetric~il” - .’- - ,.
+ : o.21& :’ .,-.., .J -.
. . .. . .,
. . . ..,
b.
t. .. .
.-’ .
. ...*..,. ., . . . .
Test.~-awe. farQmqple*~-tiael .- ‘“.,.“.:’.. :.. . .A propellmca~brationws madeby~as~ing.@e longitudinal
forcOofwe modelwith$laps@ landinggearret$actda.pn~tii-1ofl.atanangleofattackof0°fcm.a”rq~eof@&pell.er&peed..Thrustcaefficimtstie *termineafr~ therel+t$cm”....’
Tcf=%‘ openeroperating,-%Bopeuer~mve~
ThetorquecQ6ffici&%s~p coqyztedby.use~ a calibrationofmotortbrqueasafunction& min@mucurrent.Theresu3.t8ofthemodelprqpellercalibratimarepres?ntda‘in?t.@re6..,...... .. .-. .. ,“~A1.~‘testB@ thec&plet&m&@~w&e-~d~ a~a &mic p?es-
sureof16,37POW* persquare’.“footexceptpower-ontestswithfk~sdeflected,whichveremadeat~ dyneaqlc.pret3sm0of9.21poundspersquarefoot.Thisdifferencewasnecessitated.‘bypowerlimitationsofthemodelmotor. .. -....
Duringthe.teststhqthrust.an~torquecoefficientvariedwithliftcoefficientas“shown.infi~et7,andthe’ccmfficia@susedcorresp~atothe‘daluesofhqsepomrshowninfi~e 8for,
. -. .- . . ,.:.
..—. . .. . .*. ..—
..”’ .. ,.... .
NACATNNO,1474 *1- “9
variousmodelwalesandairplahewingloa*33cThethmstcoeffi-cientfm thew@3mi11.ingtestswasabout-0.02.,.
Zongitmdinal+ta%ilityTestData
Neutralpoints,determinedfromthestabilizertest~ta offigures9to1.2bymethodEIoutlinedinreference4,arepresented.tnfigwe13.Changesinneutral~ointUcationcausedbyuseof,.powerandflapsarepresente~infigures14and15,ref3Pect2velY”.Theshort-dashedparteofthetail-offandsemispmncmal-hil“curvesrepresentare@onofliftwherea disc,ont~uityinthepitchingaomentm.mvesex@ts.me disconttntityappearstobea ..rathercommoncharacteristicC&wingsemployiwlcwtm+uPeafi-foilsectionsatReynoldsnumbersaslowasthoseU8edinthe ..presenttests,andthisdiscontinuityapparentlydisappearsastieReynoldsnumbersmorenearlyapproachfull-scalevalues.
“ !l!lietaibshouldbecomparedonthe
tiveness()~~,‘ “TM ri@tandLeA
3%shouldbeccnnparedjtherefore,sincefor
basis.ofequalbasiceffec-
semispansofthencwmaltail ..
Q%.‘ach‘dsw, r w= ‘Cow”
‘hen+1tai1(:%=080+=’as=*ictiil(O*01)formanatherpairwhichmaybe’oompared.
..Thecurvesoffig&es13to15showtheCeneraltrendsoftlieresultsobtainedin”thetests,btiInorde$?.toprov3deexplanationsfro?.thesetrendsa discussicmbasedonthevariouslongit@inaL-stabU.i%yparametersshowintheXollo.@hgequatianishezpfuls
. .
.
. .
no
.
..
1.A
——- - 1‘(%Fe/%p -——%&)./%
.
..
(1)
..-. .. _._. - ------ .-- —+-- ....... -: ;.,—..— ...-— ->---- ~ .= - --— ---- -— ---------- .-tt. . . ,.. . ..
...— —-- .—. . .. .. . _..— - ——. —.= —. --
10 NACATNNo.1474.
Thisequatimisdeveloped-ande~lninedtireference5. Thevariousparamet=shavebeenderivetibyproceduresexplalnedtireference5fromthestabilizertest”data.offigures9to12andtheisolated-taildataoffigure16.l?orthesakeofbrevtty,however,cwvesoftheseparametersarenotpresented,.
Forallconditionsthe‘sltghtlygreaterstabilityofthemodelwiththeasymmetrictailappearstobecaus@.prh@ya~bythetail-effectiveness-tem ofequation(1)shoetheothq?twoterlllElarenea-lyequalfortheas-tricandnarmaltailarrangements.Thisgreatertaileffectivenessmustresultfrmthesmallervaluesofeffecttve-downwashE andvariati~‘ofdo%mwashwithangleofattack~ fcmtheasymmetmi6tafiarrqymentsincethebasic
dataileffectiveness
()
~ w%
~Kof;heasymmetrictillIsslightly
lessthan-t@tofthenormal‘taK1..Farboththe~qeller-w!.ndmiuingandpower-onoases,thesmallervalu&of e and~~ areprobably
%a~esultoftiespsnwisevariationofdomwashbehindthe2:1taperedwing(refamnce6)sinceana~ses~esentedlatershowthatonly,smalleffectsofslipstreamrutationaretobeexpectedfortheP@:c* -Q3-t used● .
.withaf=00 andpoweron,themarkedly@eaterstabilityof
themodqlwithonlytheleft&mispantailascmpared%0”themodelwi.%hcuilytheri~tsenispantailappearstobecausedbythetail-effectivenesstermofeqwation(1)sincewe othertwotemns& theequationarenearlyeq~lforbothsemispan tailarrangements.Thisgreat=taileffectivenessfortheleftsemispantailarrangementresultsfromthesmallervaluesofeffectivedbmwam.e andvaria-tion& downwaahwithan@.eofattack$& becauseoftheslipsta?eaanrvtation.Athi@ Ufi’co&?ficientsthedifferencebetweentherightandLeftsemispantaileffectivenessisslightlyreduces,.apparentlybeoaweofthemailervariationofdynamic-pressure
a{~tl~)ratiolnlthtrllllliftco&ficimt- obtatiedinthedeyiva-%
tionofthevariousfactorsof..equation(1)fortheleftsemiepan“a(~tj~).
tail.Thereducedvalueof —d~b- isprobablycausedbya latcmal
shiftoftheslipstreamat~gh liftcoefficients.Thislateral. displacementoftheKKpstreamisprobablya-resultofthewingshear~therotatingstreamsothatthe~perpartoftheslip-
.
Streenlisshiftedtothert@t-for~i~t-hand-r~atimpropellers●
., “
. . .— ——. -— .- —-—-.“ .:.. . .. . :’ ,.*W . .
)
NACAl%NO.“1474 Xl..
b thepower-onflaps-dcn&mqditlontheaMitionofahmi-zonta.1tailon.themode-lwasgenerallyde@a’bi2.izing~Forthis -conditiontheadverseehlftinneutral-pointoausedbythe~-termofeq.mtion(1},isanimp&tantfactortidet~ neutral-point
. qlt(-fl)locationsothatsmallvaluesof — aredesirable.A
Wb .. ..a(qtpl)
deoreaseInthevalueof —, howqvti,alsorestit:m a ‘d%
decreaseintailefYec%iveness.Thisresultwaspartj.oular~noticeablefortheZ&t Semispan-ofthencwmdtail,andthemarked..
d(qt~qjdeoreaseti — wasprobablyoausedbythelateralshiftin. % “ ‘theslipstream.Forthisparticularmode+thefind~esultwasslightlygreaterthanwouldbeexpeoted.- theeffectsofonly‘slipstreamrotation.F%.otherairplanessodesiguedastohave
dC~,.-differentvqlues”of”no,“ ‘d c%’%~ :Wt E}
%&us& bythelateralshiftof
produoemarlmdlydifferentresults.
however,thechange
theslipstz&mmi&t
.
.
,.
Thecurvesoffi~e lhshtia oonsidemhlyfavorableohangeinpowereffeotswhentheleftsemispanofthenormaltailisusedratherthantherightsemispan.The‘&actical‘tasymetrictail,howevm,didnotshowamarkedimprovementtienccmparedtiththenwmal tail. Computations~esented.inthesec’k!.onerrtit~ed.‘!LongituUnal-Sta.bil.ityComputationsliagreewiththetest,‘datainshowinglittleimprovement$’ortheasmmio talldespjtethefavorableccmparieonbetweentheri@rtandleftsanis@msofthe‘ -nbrmaltail.. .’ .”. ,..
,... ...., .. -gitudinal-StablJ-ityCohput&iqns..Forthefourtailarrangemauts,canrputaticmsweremadeofthe
effectsofsl.ipsti.eamrotatfononthevariouslon@tudinal-stabiMtyparametersshownInequatim(1].Thpsecoqnztatimiswbremadeinordertoprovidea oheckonthevalidityofquantitativeestiinates~oftheadj~tmentinpowereffeotsthatmaybeobtainedmou@utilizationofslipstreamrotationwithinsymetricalhorizanbl-tailarrangements.Theparamtersofequation(1)thatareprimarily..
.
. . __ .-.+-. ... —.- —.— . . .—.,- ...— —. — .—.- ——..—. — - .—--———— -- - -. ...“: . . .. :..’.. ”-. -
.—...- ..-.
.
..
.
affecte~by-stitailarr‘aest.~~$;.
AWQe ~. ~ % :,%:.”........& ‘WW) , “ .“ , - ,Fcwthe.uodelccm+d=ed.,th@.inmternwconti~ .~
~“ . . ....areofsmhllimportanceat.’low-liftcoefficientsbedauseoftherelativelyhi@ locaticmof’thehorizontaltail..-Secona:order‘‘oeffectssuchasthechangesintheW?$a%imtith~ Of zt~~)~, and ~ causedbytie@&&es.&tieneu~al-po~tic%!~~;...wereneglect&l.forsimplicity,althou~tie.effects’cod heacco~tqdf’orbyuseofa stiiesofsuccessiveappro~t~o~●:.T4el?rOce~~eusedin.camputjmgtiechangesin de. . ~a.~ ‘“.%’.“are#vefi~ the s..::.
fo~owi~paragraphs. .. ..
DO%ZWEA.-!CI&diffe&&einawerq$.~ownmsh~et~~eentieno-ltaila3mmm0ntma thevariouaothertailarrangemmtsti~po~ronwasesthnaieiiframreferences3and7oneachhorizontal
thepropellerslipstreamcharaCWriSticsWywe ofto99 Dcwnwashduetotheslipstreamrotationtailwasccqutedfromthefollowingequation:
...
‘s=~jo‘f+’(t) ~. ~ (2)...
.%
w
where6H isthebmwu!hcontriloutedbytheslipstre~rotation,. ‘ma Vs isthec~ute~~@.eoft~?i8ttitheprope~ers~iPstre~~.directlybehindthepropell=disk.Valu&ontheleft-(Iook+ng.fmwami)werene~tivesincethepropeUercontributedupwaohontheleft,~ thecenterlinesofthemcilelanatheslipstreamwereassmed.tobecoincident.Theincrementsindownwashworoobtainedbysubtractinges foxthevariousunsymmetricaltailsfrom~sfarthencmmaltail.A smalladditicmaldifferenceof0.02betweenthe‘e~waluesf& theasymetricandnormaltails,@uloh’requl%ed
. fromdifferencesinspanwiselocaticqbehind.thewi& wascalculat~.,, .fromthetisi~*S ofrefq~ce6. “
Thevaluesofthe_. indovnwsshauOtohorizontal-tailarra.ngakmtsanil.estimated.f’romthepropd.ler-slipsweamcharacter-isticsa?mifr~.the-valuesOb&inea@mmthe.pitching%mmenttest
.
dataarecompareaiafigure17,Thecurvesreaminfairlyparalle~d
- ___ ...—.- —---- —- ._— —.. . .“.-: .. . . :J. ” . ... . . .. .. . . ......?... . . .
..
.
.
.
F.
iJACA-TNNo.,.:474. ...
wherea iliqorepancy0CCWU33..thetailby accowtforthe
13
!!?&W3placement-oftheslipstxea?gatdiffwenceinthe3ni*ialvaluesat
lowangleO-@-a~q’&... ..~.., .... . . .Ccmptiedvalues.of Ae.kotitheflaps-downco&U$&mw@e~.mu@
~eaterthanthe,valuesobtatiedfra”pitchlng+nt%pstdata.Thisresultwa”sprobab~Oauseabythelateral@lfkintheSlip-i3treau~OsOciatea.tiththe.hi@ val~softi~uqtanatqnwecopffi-ciehtsoocwring~ the fUps-a&nccdititi-and~ichWE meoessari.lynegl.eoteainthecogqxztations.,Theshift:of’theslipstream(refer-~ence1)WcmMbeinsucha Urecti&-astoreducethepreviousti“‘discussedeffeotsofslipstreamrotatfm. ,.’...,Thea~eemeqtoftestandmmputedvalueso~ A6 inthef-bps-up
(lowTc1 andQc”)condd.tionandthedisa~eementintheflaps-d~ (him Toi and-Qc?) oo@ltiaindicatethatmoreresearohis~ededinorderto.determi~etheactualcharacteristics& tieslipstreambehindvariouspropeller-fuseJ.age-~combinati~>.
-C-meame ratio.-“Attempts.toe@d&te;thediffwences_ theeffect~ve-c”presqme ratigsi’mthevarlousta~mwereunsuccessful.Thedynamic-pressureratioscomputed.fYathe~it&in&%omntdata~esentedinfire 18indickted,however,thatsucheffegtsactuallyexh$ted.t ..
.,-”tieutral..poin~s.-?hedifferenceinneutral-point3.ooation.
betweenthenormaland.theumymetrhaltailer.ran-tswascom-putedasfollows:. . . , ,.,.(a)we variousterms.ofequation(i)wereobbeinodf’oi‘the
nomaltailfromtheteatdataoffigures9and16by..... ln~nsof~ocedm.esowlilinedh rei’emmce7 .. .
.. .
“..‘ (c) Valuesof$hevariousteimdofequation(1)“fortheu&mP~trioaltailswereobtainedbyaddin~theincrements
.of ‘~efroma-imp (b)to.&&etasicvaluesfr.&.step(a)“aa
andbyconsideringthe.‘changesb tailaiieaandtiil .lift-curveslopO .
(d)Theresultingvaluesfromstep(c)wre $nsertid.inequa-tion(1)andvaluesof.~.,-... .
~ werecaqmted
. .... .. . ..-:..~..... .
---- -.—. — -.-~- ,.-—--— -.. . ...-..-,...=-- ..--— — -—- -. -—- —- .7.- - - .- ..... . ... .
.,
14.
.(ejTheincrementsof ~ were-obtafieaby
IJACATNNO.1474
snbt~ting thec~utea’valuesf=mthqu&at@.caltailsfromthecomputedvaluesforthemrmaltail.
The‘i.~uiedchangesin”~ a ** c-es ob~~edfr~tiletest.resultsare.comparedh fi~~e19?&ve~~t betw’een*WobtainedbytheccmptitiomiandtestdataisfairlyGOodatlowanglesofattack*spitethefactthatthecomputationsnegl.ectea
..a(qt/g)’‘r -“&nge8in q,~q and. .... Athighan@.ekofattack%here
‘%-c-Pressure effectswouldhe expect@.to-@ve ‘kOre.influqncef&rthe+1.dataobtainea
..
beingconsi&ere&~d.isapementefistsbetweenthebyccm?@xybionsand.thetestdatat\
LaterqlandDtrectiqnalTrW . ‘..
Lateral-forceendmcmmkcoefficientsforthe~aeltesteswiththe.horizontal-tail..conflgurationsatzeroyawarepresentedinftgure!20.Values.,fcmthemcd.elwiththetailoffandpoweron,
..andvalueswiththenormalhoriztialtailbothwindmillin~ati“yoweronareaveragevaluesfrompitchtest~P at5° yaw.All Aother measweavaluesarefro.qpitchtestsofthemodelatzeroyaw.. Thevaluesofrol.lingmameut coefficientat ~ 2 0 (modeltrimmdlcngttuUnaU.y)wereco?gptiedfrom-thepitcu—mmnmt aataof .figureb9to12bythefoUo~~ means:Theout-of+rimpitching-mcmentcoefficiwxtswereConvertedtotailloa&3thatwereassumedtoactatthelateralcenterofareaofthehorizontaltailbeingconsidered;thesetailloads~we converted.%0rolliqymomentcoef-ficientsbymultiply~thembythedistancefrathecentei?llneofthemodelto.tlm.lateralcenterof~}ea~ thetail;andtheresultingincrementalrol.ltng-mdmentcoefficientsweread,deiltothe .measureavaluesshowninfigure20.
I
.
Themainfacttobenotedisthattheunsymmetricaltailarran&-mentsW& arebestfromccmsid,eraticmof3.ongitudinalstabilityprovideo@-of-trim.latmalfo3cesma mcmmntsthatarenogreaterthanthoseprovidesbythenormaltailerra~ament.
.. .COIK!LUSIONS
Theresultsa?.~*a-t=z testsofa single-enginestn&le-rotatimatrplanemodel-equippedwithY&ioushmizontal-tai%. arrangemsn%shdl.catedthefollowingconclusicms:
.
.
.
——- ——— —-— —— --. . . ..’. — —.-
1. Althoughextremeas-try ~.thehorizontaltailindicatedareductiminpowereffecim‘onlcnigitudinalstabilitytheparticukc‘~ractica~”confi~aticmtesteddid.ROWshuw~kea imprownent.
Q,Differenc6sinaveragedownvasli“bstw%nthe&mmallxiil“-arran~ement.and,theyariousother‘tailarraiigamqntsest$matedfrc@mmputedvaluesofpropeller-slipstreamro%tiona~eedidthvalues.,eatimateilfrcmpitching—mamenttestdeita$orthefl.aps-~conditicn,(lowthrustandtorque).and.disa~eed,foqthefla9f3-.a0~~condition(hi@thr~tand%OrqUO)o ThisdisagreementWC-a.$edwe necessityfoticontinuedresearch%odeterminethechsrac$bristicso?theSUp-streambe- yar$ouspropeller-fuselage-wingccrabinati+.. .-
3. Out-of-tr@ I.atwalfaces and.wnegtsof the unaqwq@iCaltail arrangementsthat werebe6*i’rqpconsiderationof lqjitlidinkilstabilitywerenogrOatp~than.khoHO.d.we normaltatla~~gement..
LangleyMemcq?ialAeronauticalLaborat~.... . ..... .Natiopal’il~vikmry,CommitteeforAermymticB”. ‘.. Lan@.eyField,.Pa.,August13,1947
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. ..“ ., l., . . .. ..----- ,.
16 NACA!ll?No.1474v
.. “~@fJ.” , -
1. Purser,PaulE.,-andSpear,MargaretF.:.TeststoDet-eEffects~ Slips%re~RotationontheLateralStabili&Char-acteristicsofaSingle+?nginpLow-WingAjrplaneMotil.XWAz!NO.u46,19+6. .. .
.
2.GilUs,CZar~ceL.,~O_, .Ed~&,C.j ~d @w, JosephLti~Jr0:Chartsfor.DeterminingJet-BoundaryCarreotionsforCompleteModelsi.g7-by10-l?o@“C~sedRectangyilmWindTmpMls. ,NACAARRNo● L5G31,1945●
3.Swanson,Rob&tS.,”anaSclnzld~’ei,Ma&n J.:Jet-Bom&myC~ectionstotheDown~mshbehindPovereaMode%..inRectan-.gul.arWindTunnelswithIWauericalValuesfoi7-bylo-%’ootc~oseaWindTuuneIs. NACAAm,AUZ.1942●
4.Schulbnfmi,Mervin:SomeNotes-on”theDete~na~ion~ theSticls-FixedNeutralPointfromWind.-TunnelData.NACARBNo.3120,1943.
~!wa~-b am R., Rossi,Pe%erF., andWell+,EvalynG.: win&-Tunnellirresti~ticnoftheEffectof?owerandFlapsontheStdicLon@tudinalStabilityCharacteristicsofaSin@e-_ bQrWinGAmlaneModel.NACATNNo.2239,1947.
6,Silverstein,Abe,and‘~tzoff,S.:Desi@ChartsforPredictingDownwashAn@esand.WakeCharacteristicsbehindPlainandVlappedwings.u ReP● No.648,1939.
7.SMckle,(leor~e W.,andCri@er,JohnL.:propellerAIIEI~SUI
from ~erimembal. Data.NACARep.No.73.2,1941.
8. Cri@er~JohnL.: Comparisonof c~lcotea andExperimentalPropellwCharacteristicsfcr I!’our-,Six-, andEi@&BladeSingle-RotatingPropellers. NACAACRNO.4BOI},19k4.
9.Cri.gle?,JohnL●ZamiTallcln,Herbert1?.:Charts$orDeterminingPropellerEfficiency.NACkACRNO.L4129,1~~}.
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NACATN No. 1474.
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Figure1.-7%?(K-viewdrawin of ~ -Jcde model$showingnormoltoil. AHdi ens~onsin incha
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.
.
NACATN No. 1474 19
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Nx
Relativewind
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NATIONALADVISORYCOMMITTEEFORAERONAUTICS
t zFigurez .-Systemofaxesand-control-surfacehingemoments
anddeflections.Positiyevaluesof forces,moments,andanglesare-indicatedbyarrows.. Positivevalues~ftabhingemomentsanddeflectionsarein thesamedirectionsas thepositivevaluesforthecontrolsurfacestowhichthetabsareattached.
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Figure4.-Photographofthesingle-engineairplanewithnormaltailmountedin the Langley.y-byl(hfmt tunneL
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NACA.TN’No. 1474 . 25
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. Figure 9.- Cont#)uQd.
28 NACATNNO. 1474 .
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Lit’t coefficient] CL
(d) concluded.
Figure 9.- cone/udQd.
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mllmm~
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F&ure 12.- Ef? t of the o~~mmetrlc horlzo t /Ftoll on the Ong/t&/no/ chomcterhtlw (#A
Jingle - en.ghe airplane model.I
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. . . . .
● NACATN No. 1474 . 35
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Lift coefficient>CL.
(d)’ConcludedF/gu/w/.2,-co/7C/UdQd
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——————
L%’t c$eff/cf!!nt, &f’
F/gUrQ i~– ThQ effeci o? horlzo~ jal-toll urru@QmQt?t> on the“, neutrul-1 f
oint loco tion of the J/n IQ-en lne ulrplan~ model.f %$N,nornwl ail; L, left semiqpon ot notma totl
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F/gure/5.- The etteci of unsymmetricalhor)zontol tait!ra the ~h tt in ne utrta/-
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A ?%%72d‘N ~0m70t tai~9 nJ +& q$p -09 ) .)
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. .
NACATN No. 1474 . 39. .
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NATIONIUADVISORYCOMMITTEEFORAERONAUTICS -
-20 -/6 -/2 -8 -4 0 ‘4 8 /2./6 20Tail ongle of ottack, at] deg .
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NACATN No. 1474
––––– Edimfftedfrom propellersllp~treomcharOcter/W~cJ
E~timo&dfrompitching-momenttest o’ata
0Ang%?of %ockl’~’ deg
F@ure 17. - Compur230r7of vo/uQJof .chongQindownwo~hoz@k?A G du~ to hor/zonto/-tol/orrongemenLs of the ~/ng/e-OnginQoirplonemodel.d =O>q=1637p0ffn@pws uorefbd;poweron.N,norm6/hIl ● L k?f~&2mlspooo?!wrrnolto,l-~ rlgh(semq~n ofnbnlol tail; R,ostymmdrictai?.
NATIONALADVISORYcW41TTEEFORAERONAUTI=
4 I I I I I I I
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NATIONALADVISORYcoMMrnEEFORAERONAUTICS
F/@re/8.- Compori~onof voiue of thong< in/dynornic-pressure rut~o A(9 @dueto hor/zonto/-
toll orro~em~nts of thQ si&/e -engine oirplom?model.d =
Pi q4537 oundspersquore”fo@‘poweron;
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.
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NACATN No. 1474 41.>
q 10
,– — - — Con9pUt@dfmm tat Olztoof normu/~u// ofrffngement OM fi ure (6
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Angle“ofQttock,a, deg.
NATIONALADVISORY
lb}Power off COMMITTEEFORAERONAUTICS
●
F/4yure/9 .- Compor/>o~ of volues of chonge incomputed newtro/-po/ht Iocotion dnp due tohorizontal-fal arrungemerjts of the s/rig/e-eng/.nQ oirplone model.d =OO;~/6.37pund~pw
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Figure 20. - Cone/udQd ‘
Recommended