1、I,11,/a71 a15 a15 a15a11a14. NOV*:947“ . . m May1941. “- .+:G-+-MAlloAL ADVISORY COMMITTEE FOR AERONAWKSlj-IEIIEI ltluwr1ORIGINALLY ISSUEDMay 1941 asAner.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 with the aw.ila-lle theo2*y
2、 of tne phe-nomena involvedA 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 tc pressnt3 a satisfacto-ry Cnytaceric% approxiatiom, as indice,ted by t
3、he chocks .o%tainod for the two airplanes ttisted. Anexample illus-tratiz”;the procodure bas.been included. “ “:INTI3ODUC!?1ONProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-2SYMBOLSc!r:cdoTNpTClift coefficient .dr: coefficient . “section profi.le-dr
4、aq ,coefficient.propollor dimcter unions subscriptedrevolutions por second : TC (thrust disk-loadin. coefficient -zg-. .,.pV (disk area) )a71a15.:,.,. !“. .,Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-,.,. , ,. ,#, ., 3A%p ,propeller ho,rnal-forc
5、e, coefficient (;:; )%, 24-. ., ,Cp.,(;:F)Pporer co”effici, ent3s,.Ppower input to propellerQ local dynamic prmisure ($p “), ,.qo f3?f)f2-StTeai dynar.licpressure ,.,Cl/qo, , ratio of iocal dyna125c presure of air stream” tofree-strem tiynanic pressure . .1,.,a velocitybincrenent factor at propeller
6、 lisk ,V(la) air velocity t:hrouqh -propelller disk, .“s velocity-increnent factor back of propeller disk8 K. . function of l?/nll acd. 131ade an%le for an inclinedpropeller for deternininq nora fmrce atin onpropeller (Ch CLT)paraneter for deterninin do$nwas behind an iti-(cli2ed propeller !-),.Tc(V
7、/nD)2 ,c function of thrust distribution in normal-forceequation -.a. lift-curve sIope for infinite aspect ratios areac “.chord .,.distance from. propeller disk to center of qravityof airvlane (measured parallel to thrust line)Provided by IHSNot for ResaleNo reproduction or networking permitted with
8、out license from IHS-,-,-., .d.i$tance fron trailinq etqe of root chord to elevatorhim%e llne (measured parallel to thrust line)distance from quarter-chord point of 17inq to thrtistline (measured -perpendicular to thrust line)diste,nqe from elevator hin$e line to thrust line (neasured perpendicular
9、to thrust line) ,dis%aace from q,wirter-chord point of :rinq to centerline of slipstream (measured perpendicular to thrust. ie)distance fron elevator hine line to centerliile ofsli,pstrean (measured perpendicular to thrUst line)distance fro center of qravity of mi”rplcme to thrust “line: negative wh
10、en tho center of qravity is %elovthrust line (nemsured perpendicular to thrust line)distance above wake ceatcr litio (neasurci por:pendicularto wake center line)radial distancp from. conter line of tuselr.fie to apoint ifithe “ooundmy laydr .,propeller radius unless su%scriptcdar.%lc of r.ttack of t
11、:hrust axispropeller %ladc anqle,2,n?lC of tail setting rel,ntive to thrust axiswJG;lG hty: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,lindqc. )control-surfac
12、e deflection (rith subscripts): %oundary-laycr thicknessdotnyagh .lea71Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. .:5“,-,.+% theoretical . , ,fuselr.qe , . .,. .airl . ., . . .,“.,.,station at intersection of win% r.mi fuselage .,ortion inners
13、ed in slipstreamis012.ted. ,.“sliystreml , , ?.L. . .i., . ,. . “, ,:,.! ., -., q“ their principal .di.nen-sions ,a”re.Tiven in fin;urks 1 rind2, respectively. A ,descrip tion of the NACA full-scale vi.nd tunnel LL21.dL the nethod:of correctj, the losof 45 m,l. values of V/nD of 2.0, the vtir-ious p
14、ropc.ller$ slhowcd l.it:le”difference so tliat the ,plot-tod”valuo Vacv“ho used $or. prelinnaq estinates of the.vorticc.l force On my conventional inclined propeller ,wi.th-in these liuits. The”da”ta f,rofe”rench 4 wore taken forIQaae .vm%le up to 28.6; ,thee* exists rioknoyn experip.ntital vorifica
15、tiol of the theory for the hiyhor %Iad.e .an-qlos. In add.i$ion, plots of K against V/nD for thevnri.ous propellers are mry crrtitic,z-tvhindthe !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,
16、me?r %e estimated from airfoj. datae The distance beM.ndthesing;can he determined directl: from te dimensions ofthe airplane. The distqnce of the tail a-oove tae7ake cen-ter line may %e expresse. 27):.m=l.z tan (aT - a actue,l dovnwas%-n.nqle disiriW-tion across the span of tho tail for a power-on c
17、onditionis 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 stalln% Qf the tailon tho s“idc ,:hcrethere is s,nV.pm,sht it does not requiresepara
18、te 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$urothe ptchin;-.omant increm
19、ent appears to be a function onlYof the thrust coefficient rad is essontiall independentof $.The assumed slipstre.zn chr.r.acteristics o.tthe tq.illocation, toother with the “correspodin% theol*ctical nidexperi.ncntc.l h,n.rr.ct.yistics, nre as follows: ,. . .,“. :.,.,. .,., . ,. .:,.,Provided by IH
20、SNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-14sO-LI.3?CGSurveysAssmnp-.tfcln,I IVlocitr n.nit down-.-*- -wash increr.onts-.- .-.Uniform ar=d COn- yfin to c?linrzNonuniform rwndspre,d ovor ,?.I.-most entire tail,span (for theltD rniostested)Uni20rm and con-fine
21、d to cylin -Location of the sli.str”o,mwith rosnect to the tail. -.- - .- - .- -.- .-_It is assumed (fiq. 36) thnt the” slipstream is inclined atan angle cp “oeteen the propeller and the win% and at o.nan.%le p + w between the winq and the tail. .The diS-tance from the elevator hine line to the cent
22、er of the .slipstream is then . .whi,ch,for small an%les, reduces to .where CR is assumed to he equal to Lw 8 The SPall OfPthe tail immersed in the slipstream is“f-i = 2 R2 - ht2Increments of”.Lift on the Wing and on the TailThe problem of an airfoil imnersed in an acceleratedjet of air has beQn stu
23、died theoreticall hy Koning (rcf?r-encc? 15) and experimentall Smelt and hvies (reference16).Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-i5Sm31t and I)aTiesp“resent their results in tbe form(cknqed to ACA notation),where CL is the lift coefficien
24、t of the isolated air-, isfoil in t-heuniform field, h is yin y the eperimcn-tal curve of fi%urc 37 aS a function of %i/Zi , nd A!is 0.6. As n matter of interest, the correspoadinq theo-retical curve$ %e.sed on Koninq!s osuits, is also shownin the fiqure,. The first tern of equation” (20) corre-spon
25、ds to the increased velocity in the slipstream (Or d-crer.seflveloctr in a rake) and the second term corre-sponds to the change in the local nn;le of .ttack. m“;in$of a sinqle-enqae mono-plnne ma?,p.pear questiono.blec Comparison of the co+lcu-lated results from reference 15 with the results of i.ep
26、resent tests (figs. 38 o.nd 39) .nd also vit”h the resulksof a P-35A model tested iithe NAGA 7- b1“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 ,aqreeme
27、nt. 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 ofestinatinq the constants of equation (20) r.re here sun-rized:The nn;le of inclination of the slipstream CP isfouna fron iqure 31 for the given v.lues Of
28、Tc and“K/( V/nD)2 . T!he velocit?-increment factor back of the pro-peller disk s is taken as tvice the ve.ocit-incrementfactor at the propeller:(21)The tiistance of :he vinq liftinq line from the nx.isof the slipctrefn is(22)Provided by IHSNot for ResaleNo reproduction or networking permitted withou
29、t license from IHS-,-,-,is imersefi an the sl.ipstre”an 5.S” I/.-.-l)wj = Df - 4h172 .Foi the por;er-on condition, the increnent of 15.ft andthe 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 effe
30、cti.ve-noss.by taeprecedinq method, hoever, qave results niich lo:er thanthe experimental results. (See table 111. ) he tiiscrcp-.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.ancy apparently cones fro the use Of the experimentalA-curve of fiqure
31、37, which is proba%ly not applicable tothis ,case,because ratios of 3/D coerin% tail planesverc not tested and Koni,nqs theoiy tildicates that thispara.eter requires consideration. Koninqts theoreticalresults (reference 15) were therefore worked. up for a ranqeof “o/D coveriti% tail planes, and a At
32、-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 tio col-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-18, . . . .“. . .
33、 L. . % _. J- .“J-L a A.-Dct,nilcd Frocoiiuro .Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-191.-.-. s = 2a,=-1 1 :Tc .where C- is the power-off lift cocfficient a. is infinitespect ratio lift-curve slope (0.11), and AC =Cp is the chanqe in.anqlc
34、of attack %etvcen propeQer-operatinq and propeller-reroved conditios-.“!I!hopropoller-oporatinq cha,raeteristics as doterniilod.ir. step A are calculated for a pctbclty %ased ou the po,cr-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-20off lift coe
35、fficient. Althouqh the approximation is fairlyclose, a second aproxi.mat ioil with tyhe usc of the power-onlift 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.catethat this sec-ond approximation i
36、S 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 aid the immersed span of the tail.,1. Tlhe looation i.s2. The yortion of the span of the tail immersed inthe slipstream 5,s/- -lti=2R2-ht2.-portion is ti/ctiBE
37、. Velocity increments at the tailIt is assumed that the tail area outside the slip-stream is acted on “Dy th.efree-stream dynamic prcs-sureg1. The velocity-increment factor due to, the slip-stream is“f- .Ss = I +; TG -1 ., s,. = - ().(27,-Provided by IHSNot for ResaleNo reproduction or networking pe
38、rmitted without license from IHS-,-,-.2i., s.=/=”G:-1,.where (from reference. 12) “,-1for2.42 Cd. 1/2 - -z.: -1- 0,3CrCOS2D.,:; .-.- - .-e- -1 1720.68 co1/2.(- + 0.15Cr )and %. is the section profile-draq coefficieilt in theicii.t:r of. the root chord.F. Effect of slipstream On the tail pi.tchiny mo
39、ment.er of to rcjceur.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 dct
40、ermiiled frompropeller-ronoved tail-on and t.ail-renoved tests and ii%t = -=- .- _lift increment wita propeller operati.o: *. . .- 1. acu(d)It it is assumed that - is ;iven, ,.,.,.; . . ,.e 0, . ,:.:. .,“.”() ., ,.,. . dc “ , .,:.,., :. . . . .,: -() d6 ,.:% e. ,.,= . . . . - -.- - . - - +.-.de +“2(
41、Rf +.6) _ ,.is(Sf ”,+S17)A “” :. - Cti,. ,. . .,“.:, “2.The mower-on olevr.tor effectiveness s, ;,ien;gy., .=. . .,. . . ., , .ht.z. -“2(Rf-ZtQ1,.j.+ - A s -1- de “ -()_-_-k hj:(37 +lr) ,l%Et,s.s ,$St, ; . ., ;. ,.e.1s.,also be expressed Pws.,. . , . . . . ,., ,.,. . .,Provided by IHSNot for ResaleN
42、o reproduction or networking permitted without license from IHS-,-,-24.2504060001.44.98186.42:18=34a1212,27Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-25. . . . .,.,. .Airplang (cont.): ,.,. ,., ,Aspect ratio of “tail :- m”. .!?npbr rai.o.of taiJ
43、. - -%b2,tio ofengine, .:,. ., .:, .,. - -. . . -“ 2.83:1,I?= bt/bV,- - - - -, .306lCOC horsepower at 2100 rpn“.ifitqure 45, are of .“the 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 theincreasedvelocity and
44、 the fire 453 in addition, presents the. pitchinq-nomentcurves for.various elevator deflections aid it shou%d bo. noted that the lonitudina Stability clanqes with elevatordeflection=,. ,.,- .,. . .,. ., ,. ,., ,. .,- . .Provided by IHSNot for ResaleNo reproduction or networking permitted without lic
45、ense from IHS-,-,-c!oITCLUSICnTs ,13m The velocit? distributiaa “in the fuselaqe oound-ary layer at the tail approxinatelp 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 tae linqwake and .the.velocit;distrilwtion i
46、n the wake correspoild satisfactorily to oqua-tion,s, derivod in NACA Reports Nos. 351 and 648*Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-27 “a71Rmiilms ,1. DeFrance, Einith J,: The N.A,CA, Full-Scale Tind Tw.t-nel. Rep. NO. 459, NACA, 1933. .) .“.2* Theodorsen; Theodore: and Silverstein, A%e: lZxyeri-i nental Verification of the Theory of T7iy.CYTnllelBoundary Interference. Rep. o, 478, IJ-ii
