naii12i - nasa effect of propeller operation on ... aclp =,----- !––- sin ~ (v/nd)2 %17 (6)...

/● ✎ ✎ ✎

☛✍

. ~ NOV*:947“ . .’ m May1941.

. “- ..

+:G-..

-++-MAllo~AL ADVISORY COMMITTEE FOR AERONAWKS

l\’’j-’’IEI]]IEI]] ltluwr’1’ORIGINALLY ISSUED

May 1941 asA&vatnoeConfidential Report

EE’FWT (l?I!ROI?ELZEROI?ERM?IONON !l!3EPI~

MCMENR3 OF SINGLE-EIIGINEMONOPIAN=

~ HfKL’z7J. Goett and H. R. Pass

-.Ian@.ey Memorial Aeronautical Iabomtoq

MwO-ey Yield, Va.

.... . . .

NAii12i.“

WASHINGTON

NACA WARTIME REPORTS arereprintsofpapersoriginallyissuedtoproviderapiddistributionofadvanceresearchresultstoanauthorizedgrouprequiringthemforthewareffort.Theywerepre-viouslyheldundera securitystatusbutarenowunclassified.Someofthesereportswerenottech-nicallyedited.Allhavebeenreproducedwithoutchangeinordertoexpeditegeneraldistribution.

L -761

https://ntrs.nasa.gov/search.jsp?R=19930092507 2018-06-02T11:42:01+00:00Z

ITATIOIWLJUWLSORY COMM3WEEWOR AERONAUTICS

By IMrry J. Goet’c aid H. R. Pass’ .,

S’UWLMY.,.,

~k investigation of the effects of prop611@r operationon pitchinq nor.ents has ‘~ee:l,rm.dewith particular referenceto t’Qe effect of propeller forces9 tk.e field of flow in theslipstream, and. the increments of lift on the winq and thetail. ~VJO ~tn~~e...~nfi;~ner.o:lomlanes with.oqt flaps were tested+in tb-e z“ull-scale wir-d tunnel and efforts were n.ade to cor-relate the remits wit’h the aw.ila-lle theo2*y of t’ne phe-nomena involved..

A procedure, directly applicable only to sin%le=enginemonoplar.es without flaps~ has “oeen set up for predicting ,the effect of propeller operation on pitc12iny moments.TM.s procetiure is, at Least for t~c pressnt3 a satisfacto-ry Cnytaceric% approxi~atiom, as indice,t’ed by the chocks .o%tainod for the two airplanes ttisted. Anexample illus-trati~z”; the procodure bas.been included. ~~ “ ““:

INTI3ODUC!?1ON

SYMBOLS

lift coefficient .

dr:: coefficient . “

section profi.le-draq ,coefficient

propollor dimcter unions subscripted

revolutions por second ~

: TC (thrust dis’k-loadin.~ coefficient --~-—zg—--—. .,. pV (disk area) )

,..’

.’ !“. .,

,.,. ,, ..,.’ ,#, .

.,, 3A

%p ,propeller ho,rnal-force, coefficient(;:; )

%,, 24-

. ., ,,

(;:F)P’porer co”effici, ent

,.P power input to propeller

Q local dynamic prmisure (..$p ~“),, ,.

qo f3?f)f2-StTea~i dynar.licpressure,,.,..

Cl/qo, , ratio of iocal dyna125c pre~sure of air stream” to

free-strem tiynanic pressure... ...’.1,.,

a velocitybincrenent factor at propeller lisk~ ...,

V(l~a) ~air velocity t:hrouqh -propelller disk

s velocity-increnent factor back of propeller disk

8 K. . function of l?/nll acd. 131ade an%le for an inclinedpropeller for deternininq nor~a~ fmrce a~tin~ on

propeller (C@h CLT)

paraneter for deterninin~ do~$nwas~ behind an iti-

(cli2ed propeller !--—~—)

~Tc(V/nD)2 ,

c function of thrust distribution in normal-forceequation

a. lift-curve sIope for infinite aspect ratio

s area

chord .’,.

.distance from. propeller disk to center of qravity

of airvlane (measured parallel to thrust line)

‘.’

d.i$tance fron trailinq etqe of root chord to elevator

him%e llne (measured parallel to thrust line)

distance from quarter-chord point of 17inq to thrtist

line (measured -perpendicular to thrust line)

diste,nqe from elevator hin$e line to thrust line (neas~

ured perpendicular to thrust line) ‘,

dis%aace from q,wirter-chord point of :rinq to centerline of slipstream (measured perpendicular to thrust

. ~i~~e)

distance fron elevator hin~e line to centerliile of

sli,pstrean (measured perpendicular to thrUst line)

distance fro~ center of qravity of mi”rplcme to thrust “

line: negative when tho center of qravity is %elov

thrust line (nemsured perpendicular to thrust line)

distance above wake ceatcr litio (neasurci por:pendicular

to wake center line)

radial distancp from. co’nter line of tuselr.fie to a

point ifi the “ooundmy laydr.,

propeller radius unless su%scriptcd

ar.%lc of r.ttack of t:hrust axis

propeller %ladc anqle

,2,n?lC of tail setting rel,ntive to thrust axis

w’JG;lG h~ty:ecn tIhi?USt liIICj M!Id liai? Joid.n-% trailin%

edqe of root chord arid elevator hinqe

(lTheT. the thrust line is used as P. reference, the m-qle is positive if the tnil is above the trni,lin~~dqc. )

control-surface deflection (rith subscripts): %oundary-

laycr thickness

dot~ny{agh ~~.~le

+% theoretical ‘.<,.+’”ctiorused in dbteminiqg iq,creaie in

tail lift due to slipstream . .‘ “’.,...,,

4 ail~le of inclinatioiz. of ,wtn%, ,wnkei radians,, .,,,,,, .,,.

Subscripts:,.,. ..:,

17‘!

s.. ...

.,h,ori.zonta,l tail > ,, ,..

fuselr.qe ,. .,. .

~air~l<o.ne. .

olevatorr .

,..: ,.,,.. ,: . ...!”.... ...... ....,,. ,...”,..:,”-

,,.”.. ,, )“.,,.,?, !“

..,.....”

/,, ..,, .“,>... . .. .,

.., . . . . .

,“.,

station at intersection of win% r.mi fuselage.,

~ortion innersed in slipstream

is012.ted. ,.“

sliystreml ,..,.... ,, ?...L.’... . .

i., . ,..... . “>..>, ,:,. ...! .,,,.. -

.,, q“&!j’s .... ...’ ‘, ’..‘,:

,, ,,, . . . . . ., .. .. .

., .,. ., .-J :The ,~irplanes usbd” ‘for.the ~e~ts ~:ere th,e 3reys5er,,.

XSBA-1 and the Nort$ Anjeric,an 3T~93; their principal .di.nen-sions ,a”re.Tiven in fin;urks 1 rind’2, respectively. A ,de~scrip tion of the NACA full-scale vi.nd tunnel LL21.dL the nethod:of correctj,~~ the &,PutPw,Ire .yi-~en j,n ~~fel.~nc~s 1, 2, ~+~d 30The tests consisted of ext~xis~”v~’velocity and stream-angle..Surveys in t’ae rcqi. on. of the airplme tail md force roecas-

..,,. ,

I.* THI’10RYMD DISCUSSION 03 RESULTS

In the analysis, the effects of’propeller operationon longitudinal-stabilit~~ charac%eri.stzcs have been con-sidered in three parts: [1) the direct effect of th~2yro-peller forces on the lift and. the pitching moment,the chanyes inposed. by the slipstream on the field of flow

at the vinq and at the taii, and (3) the increments oflift on both t~e ~~in~ anfl th~ ~ai~ resU~tin$ fro~ tb~sechanqes. !llmse factors are discussed in the followinqsections,

Effect of Propoller Forces on Lift and Fitchi.n? Eomcnt

~~e “result~n~ force exerted by a prope~~er y:i,thiisaxis inclined, may be divided into two components in the7crt~cal plane: the thrust e,cting alon~ the propelleraxis aad the force Aornal tO this axis at the propellerdisk, !I!heresultant lift iimd pitchin~-nonent incretientsare:

AL = T si,n a~ ~ Np COS a~ (1)

All”= TZ + Nptl (2)

The value of T in this equation, as sho~.7nin reference 4,nay ‘ie ohtai.ned fron propeller data for an uninclined pro- .Teller, Glauert has Shol?n (references 5 ~nd 6) the normalforce on an inclined propeller Np to %e a function ofthe angle of inclination, of V/nD,’ of ~p , and of the

thrust distrilmtion alon~ the blade. The nornal force naybe e$pressed as

. ..,,

l?ron Glauer”tts equations,

where C is a function of the-$ hrust distribution. .Ac-Cordiilq to reference ~, G = 003fj5 an~, according to re.fmerence 5, C varies with lT/nDe The correspondence ofGlauert..ts theory with the experimental results of Lesley(rsference 4} is”shornlin fiqure 3. With C = 0.365, ex-cellent aqreenent is obtained, as noted %y Millikan in

““referenck.7. ,..,,,,

.,The fiveraye vti,riatioa of,. K, when C = 0.365,” ~~ith

the parar~otcrs V/nD and ~? is sllowg in fi$urc 4 for“the th,ree-bl~.de propnll.ers”o~ roferenc~s 8 and 9. up to“P,lade ,ano;los of 45° m,l. values of V/nD of 2.0, the vtir-

i’ous propc.ller$ slhow~cd l.i~t:le”difference so tliat the ,plot-tod”valuo V’acv“ho used $or. prelin~naq estinates of the..vorticc.l force On my conventional inclined propeller ,wi.th-in these liuits. The”da”ta ~f,rofe”rench 4 wore taken forIQaae .vm%le~ up to 28.6°; ,the~e* exists rio knoy{n exper’ip.~ntital vorificatio~l of the theory for the hiyhor %Iad.e .an-qlos. In add.i$ion, plots of ‘K against V/nD for thevnri.ous propellers are mry crrtitic,z-t v<?.luesof V/nD%reater thin 2.0. These limitations of the data are notconsidered inyorto.nt because ihe’se high values of bln.donn%le t~.nd V/nD r.re encountered at a hi~h speed,rhe~e t’he.anyle of’ Ctittaclrof the +Qrust axis is nornally small.Fiwro 4 my” be npplied with suffi.cicnt a.ccurac,y to .otti.ertb.n threo-’blc.de propellers hy mzltiplyin? K by N/3,where N is the nun%nr of blr.des.

,“,.

Equations (1) and (2) transfo”rned to coefficient formwith tlho coefficient based, on the wing dimensions ‘Decone

“ CT [2D2

)ACLP =,------- !––- sin ~

(V/nD)2 %17(6)

(where tho effect of the vertical force has been neglected%qcause it is snail) ana ~~ ,,.,.

A’cn = ~~~:[sl, )

.—----“? ‘( ){&)2 ~ CT ~: + K sin aT +: ‘

(7),..,

The vari.a%las that detornir+e the offcct of the Qropsl-

ler, and vkich are under” tfie control of the desi%ner, axe

the vertical location of the center of gravit:? wit% respect

to the thrust axis anti”the angle Of inci5ence of the thrust

axis with .res~~ect to the vin$. It vill %e noted t~atth~se variables primarily control the value of ~/c17*

dtstance of the propeller forward hi the, center of Srav-ity has only a .&q~i+qt “ef”fect p.ad.,y~ill prO-Da,-~l~?be estab-

lished lY:?other considerations. Fiyures 7, 8, and 9, inwhich only the propeller forces- are ~:ariedz demonstratethe effect of the relati7e position of the center of %ra7-

ity apd, tlze propeller on the ;3it,clii.n~nonent. In any prac-

tical application ot~.er i’actor,fi’,.,notabl;~ the flow at thetail , require cansiieration and woulii j?ro’%ably ~odiiy tk.eresults of’ those fi?ures.

The velocity in t-no reqion of the horizontal tail nay

lo considered as the resultant of thre~ supcrinposod fields,

.,,. ““ {8).

line and 6 is the tb.iclkr.ess01” the %ou~-dar7? layer. 1$m,o.~r‘oe’assumed that the. momentum loss in the boundar~~ lay~rn ear the rear of tho fuselage corresponds to the ,entirefuselage drag Df (reference 11); thus

A/_--.--———.—--————-

f5=- 2.,67 Rf + 2.78’Rf2 + 2-72 ~Df Sw (~~) :,,- 6I-J

The variation in d.~?namicpressure in the wi,n.qwake 5.s?;iven as a ~’unction- of the nrofile d.ra~;of the Ivin%j the~iistan.ce“ot>hindthe !~ing, and the distance a%ove or ‘lelowthe w,ake center lir.e. The profile drag of the inboard scc-tiou. of the wing, the wake 05 ~hich passes over the t24il,

me?r %e estimated from airfoj.~ datae The distance beM.ndthe ‘sing;can he determined directl:~ from t~~e dimensions ofthe airplane. The distqnce of the tail a-oove t~ae ~7ake cen-ter line may %e expresse& as f~llo~s (see fi~;. 27):

.m=l.z [tan (aT - <w) - tan Yj (11)

;~hich , for moderate anqlesa %ecomes

. lists vaizles of ~ torwinqsofvariou. taper rati.s and

aspect ratios.

The foregoing method was used to determine the valuesof ~/ !10 due to the wing wake at the tail location. of th,e

Sl+astrezih velocity.- The simple momentum theory indi-_—=&...-_.._.._,—_____—___cates that tko, relation %etwecn the propeller thrust and

the, increnent of d?~namic pressure in. the slipstream may “oeexpres.set as folloy;s:

!JJ,liesimple theor?~ .assunes a uniform incr’enent in velocityover’ the slipstream area, Owin.q to the nonuniform ‘dis-’

,, tribuiion of thrust. alonq ,the propeller, the rat~o A !t/q.

varies coi:sidera%~y over the,propel l.er-disk area; tlhetheoretical e.xpies~io:n,’h07.”:evcr”,”may “oe used as a qood ap-pro::inati. on of the average.

No allowance is made for the distortion of’ the ‘slip-Strep. m caused lIV the fuselao;e or the wake. Yor the XS3AM1r,and the 3!i!-9Bairplane s,,the slipstream diami?ter in the re-‘;ioa CIf the tait mRY’ ‘De taken to hereqtial to the propellerdiameter D inste~,d of equal to O*8D to 0.9D, as would ‘oecc.lcul~~ted from the momentum t’hcory= A comparison %c,tweon$he ~,~lcu~ated eund the .e~pOrinenta~ @no~mic pr~s~ur~ incre-ment Aq/qo, ~.vera~ed over t~ge propeller d.i.aneter “at tlhe

slipstream center line, is ~iven in fi,~;u~~e29 for the,XSBA-1 .L~,ndthe 3T-93 airplanes. It wi 12. ~~e noted that theeXyetiinental points ‘and the t~,eore~ic.~1 curve. ayr~e ~Vithin‘1O ,percent: it ma?’ therefore %e conclude d.tlmt the ,averan;e .characteristics of tune slips tre~.m correspond fairl~t wellwith those ihctitated by theory despite, ii~teri’grence effects-

As the taii moves” a~ray f’+o~ the center line of the

idealized ci.rculqr sJ!.ip:,’:ream, the avera?e value. of Ad q.taken over a span equa,. : ,,;::e propeller diameter would

vary ai2cord.5n% to the followin~ relation :

I-lcrenent of do\Tn~7asl~ due to the slipstream.- The..-G_-__.a___ ____________ - ________

theoretical ~.n.~le of d.ownfloY,r Of the slipstream behind an

inclj.,necl propeller is qj.ven by (llauert (reference 5) as

;:h.ere k is defined in terns of the normal~force constantof’ equation (5):

,, .,, 3.3,,-......,:, ...

It appeared from the surve~:s,,.@, the tail that, to afirst approximation, ~~e &olrnfIOTv du& to the propeller and

that due to the wing are addi~ive; that is, the averas;e

d.owuwash angle at the tail is the sum of’ the wing d.owz?-washail%le $CL and t’he slipstream dommash angle avera~;ed. .

(# ~ )I?t.

~ across the tail span ACL17+”~p ~&’ where the factor

bt is the tail span immersed in the slipstream, as d.e-i

.rived ir~ tie next section. In the theory, the downvash in-crement is assumed to “~e uniform and confined to the slip-stream; actually, because of turbulence ~~a interi’erence,it appears to affect a considerable reqion ou.$side the Zim-its of the slipstream. For this reason the incren&nt imsavsra?;et!.across the tail span when the surveys were evalu-,:~ted. Comparisons of the averaqe experimental downwash-an%le increment due to the propel?.cr across the tail withthe calculated increment for the XSBA-1 and th~ T3T-9B a~r- ,planes are shown iii.f.io;uros32 and 33, resnoctively..,.

An illustration of t>a actue,l dovnwas%-n.nqle disiriW-tion across the span of tho tail for a power-on conditionis sho’,:n in fiqure 34. The extent to which such hiqh ro-tations 2s shovn here complicate the calculation of taillift is unknown. Tho availa-lle data indicato that, unlessthe rotation is sufficient to cfiuse stall~n% Qf the tailon tho s“idc ‘,:hcrethere is s,n V.pm,sht it does not requireseparate consideration. In ftqurc 35 are shown sorie re-sults of Unputliskea tests of the XF4-U-1 airpli.nc in vhichsimilar thrust conditions :?ere obtaiqod with various val-ues of B and V/nD, correspoadin~ to various officicQ-

cies and vartous nmounts of rotation. From this, fi$uro

the p~tchin~;-~.omant increment appears to ‘be a function onlY

of the thrust’ coefficient rad is essontiall~~ independentof $.

The assumed slipstre.zn chr.r.acteristics o.t the tq.illocation, to~other with the “correspo~din% theol*ctical ni~dexperi.ncntc.l ~h,n.rr.ct~.yistics, nre as follows: .

., . . .

,“. . . :.,.,.’ ‘...

,,.,,, . ,. .:

sO-LI.3?CG

Surveys

Assmnp-.tfcln,

V@locit’r n.nit down-—---—.-*---- --..--—wash increr.onts——--——.- .—-.——.

Uniform ar=d COn- yfin~~ to c~?lin~~r

zNonuniform rwndspre~,d ovor ,?.I.-most entire tail,span (for thelt~D rn~ios

tested)

Uni20rm and con-fined to cylin -

Location of the sli.~str”o,~mwith rosnect to the tail. -.-—— —-- .———- ——-— —.- —— -------.-—— —.-_——It is assumed (fiq. 36) thnt the” slipstream is inclined atan angle cp “oet~een the propeller and the win% and at o.n

an.%le ~p ‘+ ~w between the winq and the tail..

The diS-

tance from the elevator hin~e line to the center of the .

slipstream is then .

. .whi,ch, for small an%les, reduces to .

where CR is assumed to he equal to @Lw 8 The SPall Of

Pthe tail immersed in the slipstream is

“f—----—

‘~i = 2 R2 - ht2

Increments of”.Lift on the Wing and on the Tail

The problem of an airfoil imnersed in an acceleratedjet of air has beQn studied theoreticall~~ hy Koning (rcf~?r-encc? 15) and experimentall~~ @ Smelt and hvies (reference16).

Sm31t and’ I)aTies’p“resent their results in tbe form(cknqed to ~~ACA notation)

where CL is t’he lift coefficient of the isolated air-, isfoil in t-he uniform field, h is yi~~n ‘~y the e~perimcn-

tal curve of fi%urc 37 aS a function of %i/Zi , ~nd A!

is 0.6. As n matter of interest, the correspoadinq theo-retical curve$ %e.sed on Koninq!s ~osuits, is also shownin the fiqure,. The first tern of equation” (20) corre-sponds to the increased velocity in the slipstream (Or d~-

crer.sefl’veloc~t~r in a rake) and the second term corre-

sponds to the change in the local nn~;le of ‘~.ttack.m“&.~e

present dtscus~ion is concera”ed mainl~~ with t’he applicat-ion of %M.s.equation.

Increment of lift on the Wingq- Inc.s~uch as no fuse-----—-—-...-———.--—-.--...—------.-la%e was used iil the tests of.reference 16, direc~. appli-cation of the results to the l;;in$of a sinqle-enq~ae mono-plnne ma~?,p.p~ear questiono.blec Comparison of the co+lcu-lated results from reference 15 with the results of i~.epresent tests (figs. 38 o.nd 39) ~.nd also vit”h the resul’ks

of a P-35A model tested ii~ the NAGA 7- b~~ 1“0-foot !~indtunnel (fiq. 40), hot+ever, shored satisfactor:r r.qreerient;none of the more obvious modific,ntions of the method totake care of the presence of the fuselage seemea to in-prove the ,aqreement. Accordingly, it ~ppears that ther:ethods of reference 16 mn3~ be directly appliefl rit%outreg:.rd to the presence of the tusela%ea ~he methods of

estinatinq the constants of equation (20) r.re here su~~n~’-rized:

The nn~;le of inclination of the slipstream CP isfouna fron ~iqure 31 for the given v~.lues Of Tc an d“

K/( V/nD)2 . T!he velocit~?-increment factor back of the pro-

peller disk s is taken as tvice the ve].ocit~~-increment

factor at the propeller:

The tiistance of ‘:he vinq liftinq line from the nx.isof the slipctrefn~~ is

is i~mersefi an the sl.ipstre”an 5.S” ‘

I/..-.—--—

l)wj = Df - 4h172 ‘ .’

~Foi the por;er-on condition, the increnent of 15.ft and

the elevator effectiveness due to the slipstream is super-

i~.posed’ on tti.e (ne%ative) .increnent just discussed. . Cal-culation of the chanqe “in elevator effecti.ve-noss.by t’aeprecedinq method, ho~~ever, qave results’ niich lo~:er thanthe experimental results. (See table 111. ) ~he tiiscrcp-

ancy apparently cones fro~ the use Of the experimentalA-curve of fiqure 37, which is pro ba%ly not applicable tothis ,case,because ratios of 3/D co~erin% tail planesverc not tested and Koni,nq~s theoiy tildicates that this

para~.eter requires consideration. Koninqts theoreticalresults (reference 15) were therefore worked. up for a ranqeof “o/D coveriti% tail planes, and a At-curve was ob-

tained (fi%. 41)0 The a~;reenent between the experimentalelevator effectiveness and. the calculated values %ased 0i2this curve is nuch better than before (see last ti~o col-

,, . . . .“. . . –L—. . %.. _. J--- .“..J-L.. a A.-

Dct,nilcd Frocoiiuro .

1...-.-..—--..——.

s = 2a, =-1 ~ 1 ~ :Tc .

where C- is the power-off lift cocfficient~ a. is ~~~

inf’inite~~spect ratio lift-curve slope (0.11), and AC =Cp is the chanqe in. anqlc of attack %etvcen propeQer-

operatinq and propeller-rer~oved conditio~s-.“

!I!hopropoller-oporatinq cha,raeteristics as doterniilod.ir. step A are calculated for a pctbclty %ased ou the po’,~cr-

off lift coefficient. Althouqh the approximation is fairlyclose, a second a~~proxi. mat ioil with tyhe usc of the power-on

lift coefficient may he made at this point if further re-finement is desired. The results of the illustrate-re ex-ample presented in a later section, ip.di.cate that this sec-ond approximation iS usUal~?7 ~nneceSsary. The chante intail lift may be assumed to be negli%i,%le.

D. Location of the tail rel.aiive to the slipstream centerline ai~d the immersed span of the tail

., 1. Tlhe looation i.s

2. The yortion of the span of the tail immersed inthe slipstream 5,s

- --—---

lti=2R2-ht2

.-portion is ‘~ti/ctiB

E. Velocity increments at the tail

It is assumed that the tail area outside the slip-stream is acted on “Dy t’h.e free-stream dynamic prcs-

1. The velocity-increment factor due to, the slip-

stream is

---—-.. .

Ss =I +; TG -1 .

.,s,. =’ ‘- ().(27,-

., s.=/=”G:~’-1,.where (from reference. 12) “,

2.42 Cd.1/2

——— —-- ---

z.: -1- 0,3Cr

:; .--. -— —----- .—.--..e-- -

0.68 c~o1/2.(

-~ + 0.15Cr )

and %. is the section profile-draq coefficieilt in the

~ici~i.t:r of. the root chord.

F. Effect of slipstream On the tail pi.tchiny moment.

~~~~er of t~~o ~rcjce~ur~.may ‘be followed tO OlltaiP.

the effect of ~he slipstream on the tfl.ilpitchinqmoment , dependin~; on t-he mnnner in which tae isolat-ed tail lift is determined. Fio;ure 44 illustratesthe situation.. Note that all coefficients are “easedon win% area.

1; The value of ‘Lt+s ,Inay .oe dctermiiled from

propeller-ronoved tail-on and t.ail-renoved tests and ii

%t= --=------- .-——-——- _&L--------------

is ~ + 2(Izf-1”8)-.---—...—--- Zti (q “+ SJAs%

2 (.Rf +8-— .-.--,—

where ..

g. ‘

G. Calculate d,’ef.fects of pro~eller,,,, .. .. ... .-

1..’,

The. FO\&LOh ,lifti~.~”’,,:,~’.,,. . ,,

operation...

+ ACLt

rmv usually be neq,lected.

powor-on pit chin% m.onent is

c G13D = El. + %.p + AC rl~.

the “O:ffect of propeller operation on pitchinq nonents maybe .d.otcrnine,d. ,, ,..,.i , .“:,

., .,,*’

., ef?e~ti.veness for e~ch anqle of attack. The ,proced.ure,,.. is very similar to t~nat,u.sedto det”eriine the tail+;

lift increment wit~a propeller operati.o~’:.. *

.. .. .. . . .- ..

1.‘acu(d)It it is assumed that --- is ~;iven, ‘ ,.,.,

.’; .. . . ,. .~e 0,.. ,..:.:...

. .. .,, “.”

‘()‘.,’, ..,...,. .

‘ dc~ “ , .,, ,..:.,., ::. . . . .,: -—

()d6 ,.

:% e. ,.,= . . . .. . ..- -—.- —-- .— -- —--- +.-.

~ +“2(Rf +.6) _ ,,.is (Sf ”,+S17)A ““” :. ----~~–— Cti

~..’,. ,,,,. . .,,“.:, ...

‘“..2.‘The mower-on olevr.tor effectiveness ~s, ~~;,i~en;gy.

.}. . . .. .

.,,,.. .

‘ht.z~. -“2(Rf-@ZtQ

j.+ -----~ A ‘s -1-‘<de “’ -

()_--_--..--k h@j:(37 +~lr) ,l%E

t,s.s’~ ,$St,’ ;’ .’ ., ’;. ,.e. .1s., ,,

also be expressed Pws.,. . ,.. . . . .. . ,.,,, ,.,... . .,

25... ... .. .... . .. .

.. . .,.,

Airplang (cont.):,.,. ,,,.,, ,,

Aspect ratio of “tail :-‘- ‘m”. .. .

!?npbr ra~i.o’.of tai J. - -’ -

%b2, tio of

engine

,,, .’:

.’ ., .

:..,, .,. ..--.. ----. . . -“ 2.83:1

~I?= bt/bV,,- - - - -, .306

lCOC horsepower at 2100 rpn

“.ifi~tqure 45, are of .“t’he same. qeneral nature a~ tl.lose03-.tai-ned from the tests of the -tw-a airplanes. in the full-

scale win~ tunnel. In general.y... t%e effectso~ the’increasedvelocity and the &ownWas-h On the horizontal tail ten& to

CaaCel, althou,qh the difference may still affect’ the pitch-

ing monsnts. The results also iadicate that the direct.ef~ict of the proneller i’S proba-oly. the moist important sin-gle parameter influep.cj,ng t’he, ~onqitudintil ,stability.

Fi~;fire 453 in addition, presents the. pitchinq-nomentcurves for.various elevator deflections ai~d it shou%d bo

. noted that the lon~itudina~ Stability c~lanqes with elevator

deflection=,. ,.

. . .,,

,. .,,, ,. ,,.,, ,,. .,

,---. .

c!oITCLUSICnTs ,,

13m The velocit?~ distributiaa “in the fuselaqe ‘oound-ary layer at the tail approxinatel~p obeys the l/7-yo*::er19.7.7,and the thickness o,f the ‘ooundary layer correspondsto th:e.e.n%i,.refuselage diaq,””

7. !lhe locatiofi of t~ae l~inq<wake and .the.velocit;~distrilwti’on in the wake correspoild satisfactorily to oqua-

tion,s, deriv’od in NACA Reports Nos. 351 and 648*

27 “●

Rmiilms,,..,

1. DeFrance, Einith J,: The N.A,C..A, Full-Scale ’Tind Tw.t-nel. Rep. NO. 459, NACA, 1933. .

) .““.2* Theodorsen; Theodore: and Silve’rstein, A%e: lZxyeri-

i nental Verification of the Theory ‘of T7iy.C~YT~nllel

Boundary Interference. Rep. ~~o, 478, IJ-i@i,3934.

3. Silverstein,vAbe, anti Xatzof~, S.: Experimental Znvesp -ti%ation of Wind-Tunnel Interference on the Down-was% ‘o,e’kindan Airfoil. Rep. No. 60S, ~M.CA,,1937.

Gle,uert, ~.: A~rplane Propellers. To 1,. IV, tiiv, L ofAerodyn&mic !lh~ory, T?. F. Durnnd, cd.., JV.Si-.zsSprin%er (3erlin),”’1935, pp. 351R359..

6. Gi@.uert., H.,: The Sta-oili.ty ~erivr.tfves of an Airscrew.. R: & M. ito. 642, British A.C,A., 1919.

‘7* l:lillik?n, Clark B.: The Influence of Running Propel-lers on Airplane Characteristics. Jour. }.ero. SC5.,-701. ?’, no. 3, Jan, 1.940, Pp. 85-10%.

8. ~iermann, David, and lh.rtman, Edwin P.: Tests of !??’iO

Full-Sc,ale Propellers with Different Pitch 3istri-‘Dutions, at Blade Anqles up to 60°. Re~. NOX 658,NAM, 1939.

9’ Theodorsen, Theodore: Stickle, Georqe 17., r,nd Ere”mort,U. JO: Characteristics of Six Propellers In,cluFLinc;the Hi7h-Speed R~.nqe. Rep. No. 594, NACA, 193’7,

10, ~ilve~stein, A“~e: ~oJ7ard ~ R~tion~bl ~,fe~~~odof Tp.Il-

Plane Desiqn. Jour. Aero. Sci., vol. 6, no. 9,JUIY 1939, pP. 361-369.”

11, Freemen, l?iu~h g.: Keasurenents of Flow in ~he BounfiaryL~.yer of a l/40-Scc.le Koiel of the U.S. Airship

!4 ‘lAkron-.II Rep. No, 430, NACA, 1932.

12. Silversteig$ Abe, Kntzoff, S., and Bullivant, W. Kenneth:“Down~Yash and wo,ke.-o,?~lindrl~di~lai~d Flapped Airfoils.Rep. No. 651, NACA, 1939. 9

1’4.

,.....

.’. ,,. ..

. TABLEI

valw~ of &@.e of Inclination of Wing ~?ake

A,eJectratioI

Taper ratio

-t-—--;t

92“35

“--”-—--–-—+---” , ‘-235

#(radian)

0.10.13913.14

0.08.10,17.●12

0.05.08.09.10

TABLE11

Ex~@rimen’taland-Calcvlatod Elevatar Effectivenessfor XSIM-1 and N!-PB .Air@ms ~ Pro@ler Removed

(The h--curveof reference 16 used for “ccqnrtations)—..—.—-

Airplmm

Xmfi”l

.-— .—.—BT-9B

aT = “o●07 + sjT(deg) ‘0

1.3 -0.113~T -,137-7 -.09

12.7 “*O7

002 -0.0’(3.7 -.0’/7.7 “.07

11*9 -s07

Jlevatoreffectiveness ~ dCn/&8e. .—Experib-ntal I Calculated.

“o.014 -o.ol~“.013 -#015-.015 -.015-,016 “.015

———-0 .OM I -0,014“.013- .ol~“.013

U!___aTM celculatwivalues were obtained from the followin~. equation:

5!ABLE 111

--- ..-_.._.,

hirplms

-----------1XS3A-1

I1-——-__....--...

TIT-93

-.—-----

:de’:;)

-,.-._-%3.’77’,7??’?L2,71.2.7

3;’7I 3.’7I 7,?

1---------- -—........

-----2.39~54.:731.301,60-!--------0.]-4

91● -----*42●42

-..-_,z.-

,--— —-.- —------ ------------------ ______

Elevator effecti.~-c+~es~,d0::./d8e---------------

Ex. pe ri-.‘“.c?n.tal

—---------- ...,

4.020~,fjao

-;023*qfllg

+.030.--. —-....- _____

-439015

-.016+0Q~5

-3--------------

----.-.----—— -~e,le~~a~ed Calculatedfron A- fron ht -Cur’re of curve ofreference refer ~n,ce

151s (a)(b).

...—.--—- -~ ---=..-.----_—_

-C: O1’7

-0:01’7w+.018 -+ 319-*019 -P020-,~~~ -*~24-eo~~ ~,026

----------—------ ........-------.0.014 -Oq 014~, ~1~ -,gl~-0~35 -.016-.015 -.016

--,-——.--...—-.,..-.--—-,——-------

eq-~atior.:

TABLIZ IV

The Uffect of Propeller Operation on theLoaqitudtnal Sta~ili~y of the XS~4-]. Airplane

---------—--—.-. --—..--———---——-..-—--———4—--—-—---—1Longitudinal st,abtlity, -acn/dq ~

-----._— _________

: Tc CLT = 70-—---—--f ------- ____

~1E2cperi- Calculateiig.ental

--- ---— . -----—----

$;’ 000090 ~-...?----------

? .013 9.011%9 ------- -------___

lqo ----- - ------ ---1.2’ ------ ------ ---1,3 ------ --- =-. ---1.5 --.--- ------ ---1*5 ------ --.--y----

------ _—___ —-------,,apromeller rC.~OVC~O

- -—,

.0.2.3,5q?

. 1.01,3

--—-.

%= loo

i aT= 130

-----------—-------- -----—.Experi -LIQr.t2:1--.—-—-.

0F015.D1’7.0180018.018●o~8

4----.---.--

.- —-—--

Calculate dlE!xpcri-Delltal

----—-—-- ——--—.--.--- -.,-- 0.026

0.016 .026.016 .025.016 .024.016 .025.016 .,025

------ -.- .025-.--.--.-y--

.---—--- --------“

!!!.4BLEV

.- -----——cp.~c~l~.ij~d

-----— ----------- ---

.027r)Py...-.c)z~•fJ~7

.02’7

---—— -—_--

Lonqitudinal ~t,a,~j,~~ty,--de,.______________ ___

- _.___._=.

fixperi-r.eiltal.-._— —.

();o~~

.008,00’7

-.-----------

_______

—..— .. __ ____ja~eulated

.- —- _____

------ ------

0.011.011.008.007

------ ----------- ---

___________

lxpt2ri -nt2r-tal—- -—- ..-.

0.011.011,.011.009.!008

-------------- ...

,— —----

.--- ———— -

!alculat ed

------- .-

0=011.fj~~

“ .011,009

---------------- ---

,——.—_ -----

/d~ ~.-—_ —___________

.—-%-_=_ ----——- ---

Uxpsri - ‘Calculatedn ental I

-i.----— — —--— -_,__—

0,012 ‘ .----------.012 0.013.012 .013.012 ,013•o~2 ,,014.012

I.,,● o~~

.012 ,rJl~

-——..——d ____ _______

L-761’ “

TIDLE VI zc1

ILLITS1’llATIVEEXAI<IPLE*

A. Determination of pro~eller-o~eratingchnracterl.stica B. Direct effect of C. Wing lift increment due tO SllDStreamthe ~ro~eller

HCLO &

—. —.-— ———0.251 0.501

$ ;$7~ ;:!;

12 11.0 2 ~.03214 1.195 1.093

/ ‘v ml(m~h) (a:g) CT Tc K

---—- .—— ..—.——— ------——---—. ——.-283.5 O.qoo 2b.’j0.084 0.104 0;;rl~~20:.

?.655 22.5 .107

:F:z13<8 :2;; :::2

,015it

.1592 ::;$ .07.091 .07:;$; :fg: ;::3;130.0 .@3 20.8 .133 ::;!; .1.22 ::g “.079

A?. Det,erminatlonof propeller-o~erat,lng D. Tail l.mmergionincharacteristics (2d a~prox.) slipstream

E.iE.IEo.2y2 0.511

i : 888 :1%12 1.2 ‘7 1.13014 11.4 3 1.210

sd:) (2) %)

---------—..—--- --0.2 0.13 8.8 o:;~ 3.0091.0 .

k7 8.5 .037

2.8 .1 8.2 .7 .07

2:; :;:; ;:; :7; ::4

h. Velocit~ increments at thetail &ver immersed area

=s >‘f Sw Estimated

cDfI—-—- . —- ——-— —-— .—

-0.07 -0.06 0.021-.07 -.07 .023

:$7 -.07 -.04 .027“5 -.07 0 .033’73 -.07 0“ .036

~. Efiect of glipstre~monpitchl~’ G. Summation H. Ulevatoranglerequiredfortrimmoment (At = 1.55)

fdcm%i s ACL. AC cLmt

! Oc% q

o6eo &)is (?)p ,:~ ,,(c’ieg)

-—- ---

1 -0.012 -0.Dllk 0.3 -0.002

0.0;6I 0.259 0.037 -0.013 2.0 -0.016 -0.016 2.3.00

.00 1.2 0 0 .522 .01’9 -●012 -.015 -.018.02 .02

3.2 .005 -.014 :-.033 ~ $g :::~~ :;::$ j:! ::y12 .0 .053

.01214 .07 .07 ;:; .027

::%-.07 ~ . -.1

-;:8. -.028 -5.9 j

b 14.83*~

L-761 ‘

.. ........-..,x.._

HTm=---

(---- l-i-la!==)w

--–/w.\! A

0.” >

figure 1.-

-4 l-- I.w’

. ● ✎✌

L -“J’~

L-761,

* , > ! , .

.036 Experf’n7em7W(reference 4)--—— — Culculufed ( II 5)

V/nD vlno ol-*

, . , L-761 c I

.06 - 0>_- ---- --- -

- ---- ---. -. --- ---(— — — 12.4

.04 -.02,~ Experimental

.02 -.04 -.-.

h ~’ d =,deg6.5-

d o +.06j“ .06 ;0-.u

~ .04 ~ -.02(o 7.7

--o- ~-.

~ (~ -- ~s.

-0 < ---G

s .02-.-

0 –. 04~

--E -.

fjo8,6

g -.O;> .06~

.04~ Exper;menfd------– Calculated –.02 <

. Y - -..-0 .C&$g.

--.02 ~- — — - — ‘-

- ----.04

<.u - ---

--- .-.. .

-.06010.9

0 .2 .4 .6 .i? 1.0 1.2 f.4 .2 .4 .6 .8 Lo L2 LThrusf disk-looding coefficient:~ Thrusf disk-loading coefficient+,;%

Figmre 5.- Gompariaon of calculatedand experimentaleffwt of Figure 6.-propelleroperationon pitchingmement of MBA-1 airplane .

C0mP9ris0nof calculatedad experimomtal●ffeot of

with horizontaltail renwed.propelleroperation on pitching moment of BT-9B airplame

with horizontaltail removed.

liACA Figs. 7,8,9

J .1 ..

Prope//er -axis;L1 -----------.. -1-----__ setting,deg

—--- ----- - ---- ---- ‘5 I&-------

0 -c-1 -. --~.

-.0 -..

G_/. 0..

c1.. .~ -..

‘“..5downmc

..~.%-.2d .2 .4 6 8 1.0 /.2

‘L’if+ coeffiiien t, CL

Figure 7.- Calculatedeffect of

normal foroeonpitohing moment fora range of l,/ewfor a1000-horsepowerjsingle-enginemonoplane.

Figure 8.- Calculatedeffeotof

thruston pitchingmoment for a rangeDf z/15wfor aLOOO-horsepower,6ingle-engineaonoplane.

Figure 9.- Calculated8ffeot of

tiltingpropelleraxieaboutpropellerlmbonthe pitching momentfor a 1000-horsepower,single-enginemonoplane.Centerof gravity,1.5 ~baok of propeller.

MAOA Figs.10,27

. / ~ -y-””-”--”-/

Resub7t flow... ;

‘.fl~ ..

~-t-t-—-—\-—- \\ -

1/\ \ ,,() J\ \ —-..\\ kuselaue I ;Averc

Y)Yge flow-----~; ‘=.j

P’%.. / -.. ,..1S,/ -Y---

9,= -- ‘age \;1

/-Uurtdary ..=””.’” ~ ‘Iuyer ------”.O/

Tiguro 10.-Idealizedcrossseotionof fieldof flowat the tailof a single-enginenonoplano.Dyna8ic-preesure di8tributlonin a vertical plane through

oenterofftaeehge.

/----Propellerdisk

.--Winddirecfion,,,.,,,,

Figure 2?.- Locationof tail relative to center of vingwk~

i’I,11,I

L-761 ‘ ‘

(ti)Dynamio-pressure (q/q.) con~urs.

1 L%=-J

t6 4 z + 6’

Dk+o$ce fmm cenf~r /%e.ftFigure 11.- Air flow in the planeof the elev=torhln~;eline of th. MEA-1 -airplane* ‘iew 10&in~ f‘mard;‘Tc* ‘=30;~*”pelL‘r ‘e=ovca”

t ,L-761 ‘ ‘

(b]Down~ash-m@e COm.muw.

Figure 11.-

DkX7Ce 7%oz7 center Ah=, ftCont4ude4.

.2 .4? 6

‘?Jl-.m

l--ra),,-c-w-s-e (q/qo) oontoum.”

Fi$mrc 12..- ~r flowin the planeof the elemtor hlngo line of theXSBA-1airplane.

View lookingff.?rmti.a7 y 1.3°;~To $0.4.1

I I1,1

L-761 I

III‘1I IIi,‘1

,(5 Downwash-sn$le ~onro~as,

-4 Dynamic-pressure621Fifurt\?J.-Airflow In the plani of the elevator hlnga line !

of-the XSBA-1airplane.View lookiw forward. ar y 3.6°. ~opeller re-moved. J J T

z Ill //Ill /--

, , .L-761 ‘

Tz 4 6

. t L-761

lr”tbJ.

~~oc-=- -

_—— — __ —— —.—+-_— L.— .—— ———

< (U) Dynemle-presswe (q/qo) mntours.~f”~c Is.-Air flow in the planeof the elevatorhingeline

of the XSBA-1 airplane.view 100WW forwerd~,ar} ~.’/O;~ropellerremoved. 1

_— —— ————

D/Wwcc

ff6w/ Cerltcl” An. , ft

4? 6 =Jw.

L-761 ‘

~l;fonc-c ‘fro>) cc/2fcr mQ’

,L-761 ‘

,L-761

4(b) I)ownwash-an Ie cotitou~s.fi,wrc*IL.- G.ck. ~

A&, 7?’6

‘xll-.Oa.I.-1

@ Dymdo-pre.sme (Ao) Umtou’s.Fifuve17,-Alrflow in the plane of thet&3VatOr hinge line Of tie

XS2A-1 airplane.View lookingfo~fi. ttT, 12.4°j yropeller-removed.

.L-761 ‘

.2 4 6

%1l-.ql

L-761 ‘

(2?). Dgnmic-preeaure(#qo)_Fi~n~elA.-Alrflow in the plane

XSBA-1 airplane.View 100ki~fOr~tij

DZv%..ce- 7%049 cem%r Iinc, f t - : -

eonteurs.or the elevatorhinge Mm, of the

=T ; 12.4°; :Toj 1.29.

(b) Bown wasl-angle contoufis,

Ffwz lb.- &J.dcJ .

//nc, ft-4

(id Dyncunic-pressure (q/qo)

$@re ~%-Air flow in the planeXSBA-1 airplane.

View looking forward;

I / L..———————————/-# ).,

4D/sfo;ce

,L-761 ‘

contours.

Of the elevator hinge line of We

/“1.00

7%497 cef7/iir/ine,+*2

I4 \\\ =\\\ \

“\”<\ I \

-- ‘/7 /+

L-761 * ,

Fij.tvt l%- bwl.ded. “

I,-1?1I II I

/ I;, I, 1

I ‘I I

‘1 IIII .;

‘q\ --0

-—.-—- .-.-——

~6) Dw-ic-wm-s (dqo)fi’f.rt20.-Alr flow in the plane

the BT-9B airplane.VI*W looking forward;

contours.

of the elevatorhingeline 01’

a~ ~ O. .?O; propeller removed.

‘ FQSQi6

DA font: fri Ol>phfle”cenfcr I/kc, &4 6

; ; /b’ // v———’//,

6 oCenjer /in c,

(20 Dynamic-pressure (q/qo)

~i@r, u. – Air flow in the planethe B’T-9.Bairplane.

VieW looki~ forwarti3

contours. :

of the elevator hinge line of~

a8O.z”j ;Tc , 0.15.‘r)

P/\ (it’

4 2 .0

DI>+U:CC ffOZ’ ccn+c:/ine, f~ ‘ . “ “

I “1I II \\

6 -4 4 G

, “, .

L-761 I .

=+4---------- -

--.-—_ %-—.-’---—- ____

4-- i-/-

@l Dyne.mic-presmu.e”(q/qn) contuuxw.

~~qr( 23.-Air flow In the plane of the elevator hingeline of the B!C-9Bairplane. $

View looking forwardj a7 > 3.70; :To , oo~. g105,

1.15=ss /

6 4 z .0&7%nce fmm cc..fcf. &, f+

> . t ,L-761 ‘ “

6 4? .4 6

+“/%%4----

(?) D9wit.-pr...~.(q/qo)Fifk x.- A~r flow h the plane

tie B1’-9Bti,plane.vi.W 100klng forw~d.

Icontours. Iof tie .~evator hinge llne of

a~ ,. 11.9°;pweller removed.~

s bL-761

zDH7’%CC f~-m ce~ff’r /;&., f#- -2

, $ . \L-761

-4 (b) ~OwllWaSh-ill@e CrJntOUM.

Fi+m z +- C..d.ded

(</j/ j ‘((1}\.d -(~..—-$,.iI ,

II1I\\ ,. .

4 6%P.pN~

(a),-,..,,.s,.,. (q/qo,~ifmn 25,.-Airflow in the plane

the BT-9B airplane.V1OW looki~ forwtij

contours.

or the elevator hinge Mne of

8~ , 11.9°; ;Tc j 0074.a{

/“,~/.t$,z“/“

4 2’

, . . L-761 , ,

(h)Xk7wnwaSh-anyle conif.u=s.

%jL4r<2$.- Cfi,lded.

i’”Ii \1,l’,!11

/‘“/

6 4 ,2 O_ z 4 6.LMmce Az-7 ccnfer k, f f

(a) Dymml-pre-we (d,o) contours.~ifurr .2f=:Air flow in the plane of the elevator hinge line

of the BT-9B alrplme.View looking fo~=d;

8a~, 11.9°; ;To ) o.71+.

———— –—-+-l-i_____F .—.———_—__—___LLJl

\ /——————J1/k

\ /’:.3.>.

\. — /./o—

-’”00”-1

—“------

I —0

/af7—

III\\\

liACA Figs . 28,29

— — — — — — — —

!7 — Theordicd

50 Experimental

0 .2 .4 .6 .8 1.0 /.2

Li.ficoefficientCL

Figure 28. - Comparison oftheoretical and

experimental values of q/q.at tail looation ofX8BA-1 airplane due towing wake.

A ~~-9L?XSBA-I

—0— Theoretical // A

yI/ I I I I I I I I I I I I I

Figure 22. -Comrxirieon ofexp&imental andtheoretical valuesof Aqlqo at theslipstream oenterline of the XSBA-1and BT-9B 8.1rplanss.Points givenrepresentaverageincrementaver aepan of4.5 feet(pro-peller radius) .

0 .2 .4 .6 .8 /.0 L2 /.4

Vw-us+ disk-loading coefficient< ~ ~

lfACA Figs. 30,31 ‘

d“-;d

—sllpstreum h*, f}

Figure 30.-Compari80nof variationof actual‘averageElipstrewbvelocitywith thatexpect+~from anidealized(cylindrical)slipstreamfor differentdletancesfrom theslipstreamcenter.(Resultsbased on aoonstantpropellerdiameterof 9 ft.)

.2 : / /

I .08- ../

:.04- ..

: .o/-- ..——.. ——- ---- . .. -------- . . . . ...—..“j

, ,, , , , I 1 , 1, , I 11 11 , , ILLIJo ./ .2 .3 ‘ .5 .6 .7 .8 .9

Thrus4+ coefficient T=T

Figure 31.- Effect of propeller operating characteristics on downwash. Tc = – ‘–x= -k -#p’ fv/fl)?

lrAcA Figs.32,33

‘UzJ I & ,Ag T= kxpe>imeh?b/ Co/culufed

7.7 0. /92 A .— —

7.”7 .267 x --. —----,2.4OJ —.507 o —-—

‘b F

s .0 I I /1 I I I I 1 1 [ 1-- 1q

(i&bo xp. x

---- ---- ___QQJ

-- x-- ---

~$, .d --- -- ---7 A

A — A ..LL -1

I I I I I 1 1 1 1

~3I I I I I 1 r I 1 ! I I

-2 -1 0 / 2 3Ver+icu/o’is+uncefrom fhru.+ uxis,f?

Figure 32.- Oomparisonof oaloulatedand experimentalaveragedownwashangle due to propelleraorosstail span of XSBA-1airplane.

4h=, O’eg 2+= ExpeAimeA/ ko/cblufe&’

7.7 0.334 A —-- —

n —- —

QI/?;—:% o .—

~$! If.7 .291 .x ---——-—-

~ b3 o — —~

$ d’ /“/“

‘$jg; x o *

Q Q2 -0

>?- ---- ---------- ---- --x---- -- -- -- ---—. - -..

L?)Q ..- ‘..-1’ -- A --, ---

b~ - Ab%

~Q) a A.—- .— --—+$ f -—- —

n~3 -2 -1 0 / 2 3

Ver+icalo’i.s+uncefrom fhrus+ oxis,#F@ure 33.- Comparl son of caloulated and experimentalaveragedownwash

angledue to propelleraorosetail span of BT-9B airplane.

b-$8 /

<’86

%4kow \ J ‘by$

076 5 4 3 2 / o / 2 3 4 5 6 7

lkmimce from cenfer hne of ukpbne, ft

Figure 34.- Oomparisonof theoreticalalxiexperimentaldownwash-an@e dletrlbutionin propellerslip~tream.Acroee the himge line of theXSBA-1 airplane; d ~ , 7.70 ; 8/n Tc , 0.27 .

%AOA Figs. 35,36

US .08.

.040L1

~ 3 a!r>go -E- x- + . 0

& xs?rk+?_+&x.=L‘$ v$-.04 — — — — — — — — — — — –

0 .04 .08 ./2 ./6 .20 .24 .28 .32 .36ThruSfimeff/k;en~ TC

Figure 35.- Effect of propeller operation on pitohing moment of XF4U-1 airplane (fromunpublished data of 20-ft wind tunnel).

-.Propel/erdisk

Figure 36.-{

“--------Location of tail relative to slipstream oenter line.

Exper/tienfo/------- - Theoretical

2.4 : (2 veroge curve forwing aspecf ru+iosfrom 2.6 +0 12.8).

/--.e--~-

.0/’/

— — — — —

,0 .“ 2 4 6 8

I I I I

I , 1 , , , 40 ./ .2 .3 .4 .5 .6

Thrusf coefficienfi T=

Figure 37. - Comparison of A - ctu?ves Figure 38.- Comparisonof calculatedand experimentaleffectoffrom references15 and 16. propelleroperationon lift of XSBA-1 airplane

with tail removed. C?a4

d=, deg

~- ~--- /0.9~. -_-

~ + “--

- 8.6 . .~ : --- --

~ ------

/ - --- 75--- ---

=====“--- -- 6.5

Experimental-------- Cu/culafed

.3 .4 .5Thrusf coefficienfiTC

Figure39.- Comp8ri00n of calculated and experimental effeot ofpropeller operation on lift of BT-9B airplanewith

tailremoved.

/.2ctT, deg

10-- ---- -- ____~--------- ------------/.0 .-

- ------------ 8---- --

Q ----------- ------------$’.8 -

~ .6.x4 -- 4-. ----- -----

txperinenfol

.4--------Co/cuL.ufed

0 .1 .2 .3 .4 .5 .6Thrusfcoefficien~ TC

Figure 40.- OomparieOn of calculated and experimental effectof propeller operation on lift of P-36A airplane

model with tail.(From unpublished aata of ‘?-by10- ft wind 3tunnel.) fi

.oJm.~

Pitchhg-momenf coefficient+ t’.

, , t , t t , I , # , 10 2 4 6

hj/t5~Figuse 41.- Values of At based on reference 15%

for use with tail planes. The-+curve 1s an average one for tail aspect ratios~

from2.6 to6.4 .

NACA Figs. 44,45

c.Uo CL,,= cLtp

cLt—0

“Lkf+w)

AOL2(Rf+6)5t

iq f+w) = St A (Sf+ SW)CL

Figure44.- Graphicalrepresentationaf tail lift increments.

I I Ic

—. — C; ~A C.p I

-- — CmO+ ACmP+ACm (o’uefoincreased ve/ocifyover fuil~---- - CmO+ACmP+ACm (due ioincreused velocifyover fuil)

.2 +ACm(due toincreused downwushon foil)= Cmp

---- ---- ----./

----, -------- ----

---- ----- ----- --- ----us ---- ---- ---- -..-- -.----. ----- ‘.?

.---.$ 0 — — — ~ =+ w > --+

‘N, de,deg-..-‘.. \

.. -.~.

\-- ‘.

k“ -5‘. ‘ .

0 ~..~

. .0 <, Y .Q ..~ .,, ‘+b ‘3% ..p Ig

b N.~ ..2” ‘o–<~.. NQ.

-.3 ..

0 2 4 6 8 10 /2 /4Angle ofatfack of fhrusfaxis, d.,deq

Figure45.- hnm;ry of resultsof illustrativeixamjle.

naii12i - nasa effect of propeller operation on ... aclp =,----- !––- sin ~ (v/nd)2 %17 (6)...

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