1、INAL ADVISORY COMMITTEE; : FOR AERONAI_ICS:, +-+. :; NATIONAL TECHNICAL + “:-= INFORMATION SERVICE ,- “- | U.S. DEPARTMENT OF COMMERCE + . “ “ l t SPRINGFIELD, VA. 22161 +-.;-:.+,+_,. ._ ,: ,_:.-=;+- _ _. ;-.- . +. . . .+ ,.i,+_.: .+:.:+.+;+at+_,_,_._:;,:+.: “ _-“ “ “ . ,- +. - “!o “.-_ _+ -+ .:+ +
2、_+0Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-REPORT No. 640THE AERODYNAMIC CHARACTERISTICS OF FULL-SCALEPROPELLERS HAVING 2, 3, AND 4 BLADES OFCLA
3、RK Y AND R. A. F. 6 AIRFOIL SECTIONSBy EDWIN P. HARTMAN and DAVID BIERMANNLangley Memorial Aeronautical Laboratory.(AJ8o779 :_- IProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NATIONAL ADVISORY COMMITTEE FOR AERONAUTICSHEADQUARTERS, NAVY BUILDING, W
4、ASHINGTON, D. C.LABORATORIES, LANGLEY FIELD, VA.Created by act of Congress approved March 3, 1915, for the supervision and direction of the scientificatudy of the problems of flight (U. S. Code, Title 50, See. 151). Its membership was increased to 15 byact approved March 2, 1929. The members are app
5、ointed by the President, and serve as such withoutcompensation.JOSEPH S. AMES, Ph.D., Chairmar_,Baltimore, Md.DAVID W. TAYLOR, D. Eng., Vice Chairman,Washington, D. C.WILLIS RAY GREGG, So. D., Chairman, Executive (ommiUee,Chief, United States Weather Bureau.WILLIAM P. MACCRACI(EN, .l. D., Vice Chair
6、man, ExecutiveCommittee,Washington, D. C.CHARLES G. ABBOT, Sc. D.,Secretary, Smithsonian Institution.LYMAN J. BRIGGS, Ph.D.,Director, National Bureau of Standards.ARTHUR B. Coo, Rear Admiral, United States Navy,Chief, Bureau of Aeronautics, Navy Department.HARRY F. GUGGENHEIM, M. A.,Port Washington,
7、 Long Island, N. Y.SYDNEY M. KRAUS, Captain, United States Navy,Bureau of Aeronautics, Navy Department.CHARLES A. LINDBERGH, LL.D.,New York City.DENIS MULLIGAN, J.S. D.,Director of Air Commerce, Department of Commerce.AUGUSTINE W. ROBINS, Brigadier General, United StatesArmy,Chief Matdriel Division,
8、 Air Corps, Wright Field,Dayton, Ohio.EDWARD P. WARNER, Sc. D.,Greenwich, Conn.OSCAR WESTOVER, Maior General, United States Army,Chief of Air Corps, War Department.ORVILLE WRIGHT, Sc. D._Dayton, Ohio.GEORGE W. LEWIS, Director of Aeronautical ReseatohJOHN F. VICTORy, SecretaryHENRY J. E. REID, Engine
9、er-in-Charge, Langley Memorial Aeronautical Laboratory, Langley Field, Vet.JOHN J. IDE, Technical Assistant in Europe, Paris, FranceTECHNICAL COMMITTEESAERODYNAMICS AIRCRAFT STRUCTURESPOWER PLANTS FOR AIRCRAFT AIRCRAFT ACCIDENTSAIRCRAFT MATERIALS INVENTIONS AND DESIGNSCoordination of Research Needs
10、of Military and Civil A clarionPreparation of Researcl_ lrvgramsAllocation of Problem8Prevention of DuplicationConsideration of InventionsLANGLEY MEMORIAL AERONAUTICAL LABORATORYLANGLEY FIELD. VA.Unified conduct, for all agencies, ofscientific research on the fundamentalproblems of flight.OFFICE OF
11、AERONAUTICAL INTEI,I,IGENCEWASHINGTON, D. C.Collection, classification, compilation,and dissemination of scientific and tech-nical information on aeronautics.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-REPORT No. 640THE AERODYNAMIC CHARACTERISTIC
12、S OF FULL-SCALE PROPELLERS HAVING2, 3, AND 4 BLADES OF CLARK Y AND R. A. F. 6 AIRFOIL SECTIONSBy Evwis P. HARTMAN and DAVID BIERM.I_NSUMMARYA_rodynamic t_sts were made _ se_en full-scale lO-foot-diameter propellers qf recent design comprising threegroups. The first group was composed of three propel
13、lershating _Yark Y airfoil sections and the second group wascomposed of three propellers having R. A. F. 6 airf,_ilsections, the propellers of each group having 2, 3, and _1blades. The third group was composed of two propellers,the 2-blade propeller taken from the second group andanother propeller h
14、aving the same airfoil section andnumber of blades but with the width and thickness 50percent greater. The tests of these propellers receal theeffect of changes in solidity resulting either from increasingthe number of blades or from increasing the blade width.It was found that (1) increasing the so
15、lidity by addingblades had a lesser adverse effect than increasing it byincreasing the blade width; (2) the loss in e.ficiency com-monly conceited to be the result of increasing the numberoJ blades was not fully realized, only about 2 percentdifference in peak efficiency between a 2-blade and a J-bl
16、ade propeller being measured; and (3) an increase insolidity tended to delay the stall and to increase theeficlency in the take-off range.Propeller design charts and meth,d._ ,_f cmnputingpropeller thr_tst are included.INTRODUCTIONPropeller theory indicates that, other factors remain-ing constant, a
17、n increase in the total blade area, orsolidity, of a propeller will generally result in a loss ofefficiency. Despite this fact the trend for a number ofyears has been toward a greater solidity as a result ofincreases in the power of engines and tip-speed or otherlimitations on the diameter. The 3-bl
18、ade propelleris replacing the 2-bh.lc propeller and in some cases, asin Ifigh-altitude flying, the 4-blade propeller appears tohLve a fiehl of use.Iropelhw resc_Lrch has lagged somewhat behind then_,eds of industry, particularly with regard to the needfor dat_ on lldl-scale propellers having mo(lern
19、 wide1)l_des and on propellers having more than two blades.Throughout the tirst part of 1937 the N. A. C. A.20-foot wind tunnel was engaged in a rather compre-hensive I)ropeller-research program covering severalphases of the subject. This report presents the resultsof the part of the program concern
20、ing the effect ofnumber of blades aml of bh_de width on the aerodynamiccharacteristics of full-scale propellers.The l)ropellers tested, especially those with (?lark Ysections, are typical of many in use today; ant thedata, which cover a blade-angle range up to 45 , shouhltherefore be useful for desi
21、gn purposes. The data arepresented in a form readily usable for the ealculatimlof take-off thrust, aud methods of making such calcu-lations for ikxed-pitch and controllable propellers aregiven in an appendix. The data provide a good com-parison of the performances of propellers having ClarkY and R.
22、A. F. 6 airfoil sections, but no point is madeof this comparison here because another report dealingspecifically with the effect of airfoil sections is inpreparation.APPARATUS AND METHODSTunnel.-The tests were made in the N. A. C. A.20-foot wind tunnel described in reference 1. Thetunnel has an open
23、 throat and is capable of producingair speeds Ul) to 1 t0 nliles per horn.Propellers.-The seven propellers tested may beclassitied as follows:1. A group composed of three propellers havingClark Y airfoil sections with 2, 3, and 4 blades.2. A group composed of three propellers havingR. A. F. 6 airfoi
24、l sections with 2, 3, and 4 blades.3. A single specially constructed propeller similar tothe 2-blade propelh, r of class 2 excet)t that its bladewidth and thickness are 50 percent greater.All the propellers have 10-foot diameters and, excep_for the special wide ()tie, have the same plan form. thick-
25、ness, width, and pitch distribution. The normal-width propellers arc all of Navy design and havedrawing nunlbem 586,_ !) and 5868 R6 for t.he bladesof (!lark Y and R. A. F. 6 sections, respectively. Thewide propeller is of N. A. C. A. design aml has an Armydrawing number of 37-3647. Its I)lade width
26、 is 50percent greater than that of the normal-width propellerexcept the shank, which is the same for both.1Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-REPORTNO.640-NATIONALADVISORYCOMMITTEEFORAERONAUTICSPhotographs of the normal-width blade and o
27、f tilespecial wide blade are shown in figure 1. Figure 2presents blade-form curves for all propellers and illus-F_(;t,-rtE l.-PropeUer bh_*_t.li,_l_ ,hl_rd; h, _!t.li_lt thh,kl+eSs;It, _4+!tJll_.at, lr_s(mted in li_mes 5 t_) 32. These figures l)n,sentthe hasi( (,ntves _mlix tstream, lb.P, power abso
28、rbed by propeller, ft.-lll./sec.n, propeller speed, r. p. s.D, propeller diameter, ft.p, mass density of the air, shrgs per eu. ft.V, air speed, f. p. s._, propulsive efficiency of propeller engine unit.Q, engine torque, lb.-ft.DISCUSSIONThe ideal efficiency of a propeller nccording to theaxial mome
29、ntunt theory may be writteu“2/2 it.06 .6.04 .4+_+_i;!02 _ ,0 .2 .4 .6 .8 1.0 I.,2VnOI:B;t IH_; I.- “%pi%“ . / _ P_ :/65. : + t _-.- + .30 L- -.x-+ - .I“1,_ Ill IL_ I;llhivm_ MlI_“, hl prnF, Iqhr ,b_i:“, I!, Il.ltk “_ :!_lim_, ; bl_,h“Provided by IHSNot for ResaleNo reproduction or networking permitt
30、ed without license from IHS-,-,-8 REPORT NO. 640-NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS._ _./8.0 .z .4 ,6 .8 1.0 z2 1.4 1.6 /.8 2.0 ,2.2I_IIRE 13.-ThrllSl-ef_lfh!ient rur,es fnr propeller ,q8418 _, (kirk Y section, 4 blade_:.4 25 2820Provided by IHSNot for ResaleNo reproduction or networking pe
31、rmitted without license from IHS-,-,-CHARACTFRISTICS O1. FULL-SCALE PROPELLERS HAVING 2, 3, AND 4 BLADES 9Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-10 IIt,_li_tlt, _ _I;l(l(?_.Provided by IHSNot for ResaleNo reproduction or networking permitted
32、 without license from IHS-,-,-12 REPORT NO. 6-10- NATIONAL A1 “_, lYCRY COMMITTEE FOR AEII()NAI“rI(;o(.thm, I ld l+h,s./.0.,5.6“r/.4.EProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-(_II_,tL_.CTI_:III,_TICS ()1,“ l,ll.l,-,_c._.lJ“_,_ “ : ) lind 35 f.
33、r all three I)rop(dh,rs of(laH_ Y secli()n.()wing I. ll. in,r_,ns_, in i.lh,w wh,ib / ,l / _; /4IJill1.1,i tkl, 1;, I_ll_l,;lll _,ll_*lli_i_,l_ ,lll_,rlnl,r,l*_il*l- h_,lll,t J,.i iI/,l I id,l,bIlu,llr.v uild CXllllilnelil:ll i,vhh,ncl, shiny. Illis ht,li_.f i,lie iiiit 111(,.The illli(erli voitex l
34、li(,lllV of llrOlll,lh,rs )ictures i,;Hliimilielh,r I)hide, (IS it deslrihos its helhli llilill thl_niThlhe lih, l(,livhl7 II eonliiiiious shiq, l of Vollices hehhid ilwhich, if ito IllllltiOlltll Jlllelf(,lell(l, veh.liv is ilSSllliilqt,illOVl,S straight t)illl_Willd with slilistreliin v_,hwiiv hi
35、:iill;llllll,l s()niewhlit siniilar t() the w_lv :1 sel(,w (.llllVi,Vl)lllllllelilS ht lilOVe. The slr(qiglii slid tmckwilr(t v_,h.itvof the vortex sheets delit,ll(l (ill the strellgth (if eil(lllli-ti(in ilrOlllltl the hhlde itself which, of (OlllSe, viuieswith the thrust (lid therefore with It(i,
36、1)lnde width.The air tral)l)ed between the sheets lllOVe._ hn(kwlirdwith theln excelit for tile part that slips flirwarl lir()lllidlhe edges of the sheets and l)l()dnces ii tip ill edg.,vortex. Th( edge vortex destl(ivs _.lilll(, ill the (irculs-lion nf the bhide lind produces whlil is hiiown (is li
37、“ill) Inss.“ilinn(ll hns shtwn (rl,rereii(e 4) lhlit lhe i,dg0 Ilow,:linl llu,ll,lllO Ih( lip hiss, i_ rl,dlilell i1 lhl, nclllii:ll_lislilliCe t)elwoen Iv.l_ CiiliSi,(liliv(, voili,x slliq,ls is Il,-dilC_,(I. ht, ilisliine, heiwt,(,n Vlilti,x ,_lleets ie,k ellieieluy tovary “lbout I perrt_pelk, r_
38、I _ i,_, 2, :L ;m,l I lJ_vle .I “ “% _“ 1 Ii sec.t i,)nsuits. The curves do show, in spite of these mim,rincot_sistcneies, that the direrenee in Ie_lk eflieietwy be-tween 2-blade 3-blade. aml 4-blade Ilrollellers ix small.The env.et,l)es tted against/t+l), as ill igtlle ;19, seellt ill l)etll tuft t
39、he theory thatthe dilleretwe in peak efli(ienlah, c(mstant-spced propelh:r and the other for thelixcd-pit(h propclh.r.M.my varieties ()l Sl)e(ializef th(, ai/pli/w, the (,n,:it)(, +u,I th( pr(,p(,lh,rtire kllOWl/:I “,), design air sl)eed, m. I). h.ix,(), desiLn engine Sl)ee,(h,sivn (,ticieney (high
40、Sl)ee(I ,)r eruisiu_).I), prol)elh, r (lianwter, ft._,_, design hht(h ingle nt 0.751+ ).The metho(t iuay (onvetdently he put into step f(,rmas follows:1. Using J,) and _., ol)tain (7.,) an(l (,., frmn (h.utsof (r an(I (v agaillst “I,./ItD.2. At even vahtes ()f J pick ()It vtthtes ()f (r uttd r+ah)ng
41、 line ()f constant 0. (iut(rl)olttte wht,u ueet,ssurv,.,l (r (.,)3. (Oml)ute , (-t, (z,.V ( ,-l. ()rUl)Ute ., = _, (,Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-CIIARACTERISTICS ()F FULL-SCAI,E PROPELIA_RS ItAVING 2, 3, AND 4 BI.AD.2S 23-,. (!Oml
42、)ute 7, v,_O. hi.)0 “:75l/I;,! A“,. (,)ml)ute 1“ I,XjX 2., , Ce,) Cr - Cr7. Coml)ute thrust I=ToXc_voX:_-e=tix_t.K 7LC“where “-_Cr oThis method assumes that the full-throttle enginetorque is ,onstlmt.As an ,x,mple, assume tlmt it is desired to ot)t,tin thepP()pelh,r thrust through the take-off and c
43、limbingrmges for ;m airplane hwing the following charac-teristics:U,)= 190; 3/o- 1,500; (b.hp.)0=600; J0 = 1.00;),_(2-blade)-_ 11 feet 1 _._;inches; _u=0.862; _o=25 .Blade section = Clark Y.The coraluteri data may be conveniently tabulatedns follows:Cr0 = 0.044S ; Cp o= 0.0520 ; T0 = 1,020 lb. ; J0
44、= 1.00.0, I2.3.45.I ,L, (v (“t“0 1 I. IHI . 1056,2 .107:5 . 017 2 i . 10,e_ . J72.I .105,5 .0911.5 .1037 .0858 .6 I)971) . ()_23 7 . I871) .0“D54).s s 0r;s . ,raa( 7_ ( “p1, I12_ 0591.1581. 207l. 1781. 100I. (r22I“ 7 ;(P_(P ;_J (m. .h.), (lb.)0, 493 , 0, 702 13 3 1. 232 I 512 i ,720 27 I 1.252 i.535
45、 i .731 417 1.:_7 571 .755 57.4 1. 370.6O7 .778 74.0 1. 427 632 i ,795 _) 6 1.392.(158 I ._Itl ll)K0 i 1.3X), 710 ! .812 12_ I I I. 210K. O.052O= il.644_ X 1,o2o= l, 1s2Effect of blade width and body.-The two methodsgiven )f eahul,tin,_, thrust, arid :llso the method if-;hwfiug I)POl)ellers, .ssume,
46、 I that the i)rol)ellers underonsiderati,m ha_l the same blade width as the ones forwhich the data are given in this report. Frequently itmay be required to ibm the diameter, the design bla(le-angle setting, and the thrust of It propeller having abl:Me width slightly different from those tested. As
47、wasmentioned earlier, it may be assumed that the l)owerand the thrust vqry directly with the blade areas (or,. widths) for propellers with simihtr shape char-aeteristies where the ditferences in areas are snndl.I n tile (nlculation of (, the power should therefore bemultiplied by the rail, of the thtde widths b_/b., whereb_ is tlw blade width ,t three-luarters radius of theIm)pelhw for which the design charts were made _md h:is the bh.le wi, lth .I lhe s_lrne r;.lius f,w the iWOlwJhr“(lllder e(msid(,lu ticql.The s.me P.tio sl.,uhl be used in
