1、OFKNIGHT WENZINGER -“REPRODUCEDBYNATIONAL TECHNICALINFORMATION SERVICEU,$. DEPARTMElaTOFCOMMERCE$PRIN_FIF.I,.,D,VA, 2Z16|Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ETC. “:aswith referenceSYMBOLSProvided by IHSNot for ResaleNo reproduction or net
2、working permitted without license from IHS-,-,-REPORT No. 317WIND TUNNEL TESTS ON A SERIES OF WING MODELSTHROUGH A LARGE ANGLE OF ATTACK RANGEPART I-FORCE TESTSBy MONTGOMERY KNIGHT and CARL J. WENZINGERLangley Memorial Aeronautical LaboratoryU S G_VERNMENT PRINTSNG OFFICE:IgZ9 1Provided by IHSNot fo
3、r ResaleNo reproduction or networking permitted without license from IHS-,-,-NATIONAL ADVISORY COMMITTEE FOR AERONAUTICSNAVY BUILDING, WASHINGTON, D. C.(An independent Government establishment, created by act of Congress approved ._arch 3, 1915, forthe supervision and direction of the scientific stu
4、dy of the problems of flight. It consists of 15 memberswho are appointed by the President, all of whom serve as such without compensation.)JOSEPH S. AMEs, Ph.D., Chairman.President, Johns Hopkins University, Baltimore, Md.DAVID W. TAYLOR, D. Eng., Vice Chairman.Washington, D. C.CHARLES G. ABBOT, So.
5、 D.,Secretary, Smithsoaian Institution, Washington, D. C.GEORGE K. BURGESS, So. D.,Director, Bureau of Standards, Washington, D. C.WILLIAM F. DURAND_ Ph.D.,Professor Emerit us of Mechanical Engineering, Stanford University, California.JAMES E. FECHET, Major General, United States Army,Chief of Air C
6、orps, War Department, Washington, D. C.WILLIAM _._. GILL,_dORE, Brigadier General, United States Army,Chief, Matdrie Division, Air Corps, Wright Field, Dayton, Ohio.HARRY F. GUGGENHEIM, M. A.,President, The Daniel Guggenheim Fund for the Promotion of Aeronautics, Inc., NewYork City.EMERY S. LAND, Ca
7、ptain, United States Navy.WM. P. MAcCRAcEZS, Jr., Ph. B.,Assistant Secretary of Commerce for Aeronautics.CHARLES F. MARVIN, M. E.,Chief, United States Weather Bureau, Washington, D. C.WILLIAM A. _OFFETT, Rear Admiral, United States Navy,Chief, Bureau of Aeronautics, Navy Department, Washington, D. C
8、.S. W. STRAPTON, So. D.,President Massachusetts Institute of Technology, Cambridge, Mass.EDWARD P. WARNER, M. S.,Cambridge, Mass.ORVILLE WRIGHT, So. D.,Dayton, Ohio.GEOEOE W. LEWIS, Director of Aeronautical Research.JOHN F. VICTORY, Secretary.H_.NR_ J. E. REIn, Engineer in Charge, Langley Memorial A
9、eronautical Laboratory,Langlny Field, Va.JOHN J. IDE, Technical Assistant in Europe, Paris, France.EXECUTIVE COMMITTEEJOSEPH S. AMES, Chairman.DAVID W. TAYLOR, Vice Chairman.CHARLES G. ABBOT. CHARLES F. MARVIN.GEORGE K. BURGESS. WILLIAM A. MOFFETT.JAMES E. FECHET. S.W. STRATTON._tVILLIAM E. GILLMORE
10、. ORVILLE WRIGHT.EMERY S. LAND.JOHN F. VICTORY, Secretary.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-REPORT No. 317WIND TUNNEL TESTS ON A SERIES OF WING MODELS THROUGH ALARGE ANGLE OF ATTACK RANGEPART I. FORCE TESTSBy MONTGOMERrK._IGSTand CARLJ.
11、 WEN_ZINGERSUMMARYThis investigation covers force tests through a large range of angle of arrack oa a series o mo_w-plane and biplane wing models. The tests were conducted in the atmospheric _v_nd tunnel o theNational Advisory Committeeor Aeronautics. The models were arranged in such a manner as tom
12、ake possible a deiermination of the effects of variations in tip shape, aspect ratio, flap .setting,stagger, gap, decalage, sweep back, and airfoil profile. The arrangements represented most of thetypes of wing sysiems in use on modern airplanes.The effect o each variable is illustrated by means of
13、groups of curves. In addition, there areincluded appraximate autorotational characteristics in the form of calculated ranges of “rotaryinstability.“A correction for blocking in this tunnel which applies to monoplanes at large angles of attackhas been developed, and is given in an appendix.INTRODUCTI
14、ONThe need of greater safety in airplane flight leads to a consideration of the characteristicsof wing systems at low speeds or large angles of attack. In general, the re,on of danger liesabove the angle of maximum lift, and comparatively little information has been published relatingto the landing,
15、 spinning, stability, and controllability of airplanes in tiffs region.In order to augment the information on this subject, a comprehensive test program isbeing carried out in the atmospheric wind tunnel a_ the Langley Memorial Aeronautical Labor-atory. This program includes force, pressure distribu
16、tion, and autorotation tests on a series ofmodels representing most of the wing systems in use on modern ai.rplanes. The angle ofattack range of the tests is sufficiently large to cover practically all attitudes attainable by anairplane in flight.The force test part of the program has been completed
17、, and the res,llts have already beenpublished in part. (Reference 1.) The present report gives the complete information as tolift, drag, and resultant force, and also includes the calculated probable ranges of “rotary in-stability,“ an important phase of autorotation. With reference to rotation abou
18、t a fixed axisin the plane of symmetry, and parallel to the wind direction, certain terms relating to autoro-ration are of importance, and may be defined as follows:I. “Rotary instabihty“ signifies a state of equilibrium in rectilinear motion such tl_atrotations caused by small disturbances will inc
19、rease in rate until a uniform angular velocityhas been attained.2. “Rotary stability“ signifies a state of equilibrium in rectilinear motion such that rota-tions caused by small disturbances will decrease in rate until the angular velocity becomes zero.3. “Neutral rotary equilibrium“ signifies that
20、state of equilibrium existing between theconditions of rotary stability and instability.8Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4 REPORT NATIONAL ADVISORY COMMITTEE FOR AERONAUTICSMODELS AND TESTSThe wing models which were constructed of lam
21、inated mahogany had a 5-inch chord andan aspect ratio of 6, except as noted in Tables I and II. The Clark Y profile was employed inall but a few of the tests in which the N. A. C. A. M-1 profile was used. With the exceptionof those tested to show tip effects, circular tipped models were used through
22、out.The upper and lower wings of the biplane models were connected by means of two stream-lined struts spaced 0.6 chord length apart, located along the span, 0.45 chord length from theleading edge and equidistant from the midspan. These struts fitted into sockets built into thewings. The sockets wer
23、e designed so that the struts could be inclined in a fore and aft direction,and clamped rigidly in position. This arrangement, used in combination with struts of differentlengths, made it possible to vary gap, stagger, and decalage as desired.All of the force tests were conducted in the 5-foot atmos
24、pheric wind tunnel (Reference 2),which has a circular, closed-throat test section. The models were mounted in the wind tunnelon the usual wire balance as shown in Figure 1:The tests were arranged to enable the determination of the effects produced by the varia-tions in the wing models shown in Table
25、s I and II. Lift, drag, and pitching moment wereFW,URZ l.-Biplanesetup inwindtunnelmeasured for anglesof attack ranging from -45 to + 90% Due to the nature of the set-up,itwas necessary for the complete teston each model to be made in three parts,the angle ofattack range ofone part overlapping by a
26、few degreesthatof thenext.The testswere conducted at an averagedynamic pressure of 19.93 kg.per m 2correspond-ing to an average airspeed of 17.9meters per second (40.0M. P.H.),and an average ReynoldsNumber of153,000.All drag readings were correctedfor the drag of thesupporting system. The biplanestr
27、utdrag was found tobe negligible,and was thereforedisregarded.The testresultsare not correctedfortunnel wallinterferencefor the followingreasons:a. The Prandtl correctionfor tunnel wall interferenceeffectson the wing-tip vorticesisknown to be accurate only up to maximum lift. In general, it appears
28、that at about 25 angleof attack this correction becomes negligible. However, between the angle of maximum liftand 25 the amount of the correction is not known, and in consequence it has been omitted.b. At approximately 25 the blocking of the air flow by the model causes an increase ineffective dynam
29、ic pressure in the region of the model. This effect reaches a maximum at anProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-WIND TUNNEL FORCE TESTSTABLE IMONOPLANE WING TESTSVariable T ip iITip Rectangular Negative rake , Circular !Aspect ratio . do .
30、 J:_ _ _do . Ii. d o .Flap (20 per cent chord)_ . do . ii . do ._ do . :. do . !do Profile . . do i!. do. IAspectratio Flap ProfileIl0 1 Clark Y 0: . !_ _do_-0 . - . do .0 . do .0 . do .0 !. do. !15 tip . I. do . I0 _ do . 15 down do .25 down do .30 down do . . _doII“ i N. a. d. X.:iq-_Figure No.2,
31、3, 4, 5, 6, 7.7, 8, 9,10, 11, 12.7, 13, 14, 15,16, 17, 18, 19.7, 20, 21, 22, 23.TABLE IBIPLANE WING TESTSStagger Gap/ ! Deca-Variable chord i lagei t i t. lI IPer cent i Degreesi _o_l 1. Oi 0Stagger ! 11.o oi+251 1.0 0_ +50Gap 000Decalage . L 0: 00Sweep back t_ 00+50-50Profile . 000I i 10 Sweep back
32、 ! Profile I Figure No.IUpper wing i Lower wing Upper wing Lower wing i .i ii f i I0 I 0 I Clark Y , Clark Y 24, 25, 26,0 . 0 . do . do . i 27, 28,0 . 0 do_ ; _do . r 29, 30.1.0 0 0 J 0 do do . J1.5 0 0 i 0 do . :. do 28, 31, 32,1.0 0 0 ! 0 ;. do_ . do_“ . - 33, 34,0. 5 0 0 ! 0 . . do . r. do . 35.1
33、. 0 +3 0 . 0 i. do . . do 28, 36, 37,1.0 0 0 i 0 I. do . . do 38, 39,1. 0 -3 0 0 I. do do 40.1. 0 0 Straight i Sweep back_ . do do_. 41, 42, 43,I. 0 0 Sweep back_ Straight do do . 44, 45,1. 0 0 _d(, . : . do do do . 46, 47.1.0 0 Straight Sweep back do . . do 1.0 0 0 . 0 -“ do do 28, 48, 49,1.0 0 0 0
34、 do . N.A.C.A.-MI_ 50, 51,1.0 0 0 . 0 N.A.C.A.-MI_, Clark Y . I ,52.* Stagger measured at midspan.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-REPORT NATIONAL ADVISORY COMMITTEE FOR AERONAUTICSangle of attack of about 90 for a #yen wing. Tests hav
35、e been made from which a correctionfor blocking has been derived, and the results are _ven in the appendix. This correction, how-ever, applies to monoplanes only, and hence it has not been used in this report, which coversbiplanes as well as monoplanes. The determination of the blocking corrections
36、for biplanewings is a problem which req aires further research.The lift, drag, and pitching moment were measured in general to within an accuracy of + 1.5per cent. In the construction of the wing models the tolerance with reference to the airfoilordinates was 0.003 inch.RESULTSFor purposes of direct
37、 comparison, the test results are presented in groups of curves anddiagrams, each group showing the effects of one of the variables as listed in Tables I and II.These groups, given in Figures 2 to 52, are arranged for each variable in four consecutive sectionsas follows:(a) Absolute lift and drag co
38、efficients vs. angle of attack (CL and C_ vs. a).(b) Polars (C_ vs. CD).(e) Center of pressure coefficients vs. angle of attack (Cp vs. a).(d) Vector diagrams.In the center of pressure curves for the monoplanes, the plotted points represent the inter-section of the resultant force vectors with the w
39、ing chord line. Similarly, the “mean chord“(halfway between the chords of the upper and lower wings as indicated on the vector diagrams)of the biplane models was used in obtaining the C_ values. It should be borne in mind that theCp curves illustrated hold good only for the base lines assumed, and t
40、hat any other referencelines would give different results.Lift and drag coefficients and angle of attack for each complete force test are given inTables IV to XXVII, inclusive.The calculated probable ranges of “rotary instability“ for each model tested are indicatedin Table III. These ranges were ob
41、tained by noting the points on the polar curves at whichradial lines through the origin were perpendicular to the curves. Each point of intersectionsignifies a state of “neutral rotary equilibrium,“ as previously defined, and is shown as suchon the comparative polar curve groups. Then where the slop
42、e of the curve is negative betweenthese points with respect to the radial lines, the wing model will be capable of autorotation, i. e.,will be in a state of “rotary instability.“ The negative slope indicates a decreasing resultantforce with increasing angle of attack, and this is the criterion for “
43、rotary instability,“ whichmay be expressed as-d (CR)d_ +- - - o_ . 12_ “ / II_+“+ - - oSP+ + +.i,.,.,+ _ o+;- +,.,- + + +.+ - +p/- +_._._ It + :+“ _ _ -.,-+- _ _- _. _ _ _ o_ _,.s - - F-L- +“._:-._-_-_-oor- ._,+ .+,- : _.- t/: +=o91 -_e_._ 11 “sz ou _ +.oOa _=-_I.D_ ._ t I +_. ._-_-_-_ _._-_-c-_-_ _
44、- _ p+_ ,_ , _._ , ,_ _:_; _7-_ +_I- _+_- _“ +_ “:_: _ t t+-ii 2 . L,:_ o+,_?.J+“_Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-WIND TUNNEL FORCE TESTS 130L.E.2Oj,o_oueoI I i I i I A_pec_ roho 4o GxT.E - 40 - 20 0“ gO 40 60“ 80 OtFlqux_ Z0.-_oeop_a
45、ne wings. Aspect ralio effect. Clark Y. Circular tips.5-inch chordProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-14 REPORT NATIONAL ADVISORY COMMITTEE FOR AERONAUTICSProvided by IHSNot for ResaleNo reproduction or networking permitted without licens
46、e from IHS-,-,-L4Z2LO.G42FIGURE 13.-Monoplane wings.cent chord.IIiIII!zo- 4o coo 80“Flap.setting effect, Clark Y. Flaps .20 perCircular tips 5-inch chord. A. R, 6Oii!00 _40 o -20 oTEFIGURE 15,-_onoplane wings.chord.I. (3 Flop 15“ Up 4, O- - Flop 25“ down3, + 15 down 5 x - 30 I-_._Po_nt of neu/rol eq
47、u#/Sr/u_n_!I70i0 .2 .4 .6 ,8 LO L2 1.4CoFIOUR_“ t4.-Monoplanewings. Flap-setting effect. Points. Clark Y, Flaps20 per cent chord. Circular tips, 5-inch chord. A.R. 8b0 20“ 40“ GO 80“FIap-settingeffect. Clark Y. Flaps 20 per centCircular tips 5-inch chord. ,_ R. 6 15Provided by IHSNot for ResaleNo re
48、production or networking permitted without license from IHS-,-,-.6 REPORTNATIONALADVISORYCOMMITTEEFORAERONAUTICS1111t,Fmuaz 16.-Monopiane vector diagram. Clark Y. Circular tips.5-1nchchord. A, R,6. Flapup 15L_LFZCiUR_ 7.-LVooopia_O vector diagrsm. Clark Y. Cireuiar tips.5-inch chord. A.R. 6. Flap down 15 Provided by IHSNot for ResaleNo reproduction or networking permitted without license f
