1、RESEARCH MEMORANDUM AN INVESTIGATION AT LOW SPEED OF A 51.3 SWEPT i3ACK SEMISPAN HAVING THREE SPANS AND THREE TRAILING-EDGE ANGLES BY Jack Fischel and Leslie E. Schneiter Langley Aeronautical Laooratory Langley Field, Va. NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS WASHINGSTON July 21, 1948 Provided
2、 by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-HAVING Tm SPNS ABD THREE TRAILfNG-EDGE KNGUS By Jack Fischel and Leslie E. Echnsiter A wind-tunnel investigation wae made at low aped to determine the aerodynamic characteristics of a 5l.3O sweptback samiepan w
3、ing with a raked tip and with 16-7-percent-chord sealed plain ailerons. The ailerons had spans of 34, 66, and 93 percent of the span of a full- span aileron; each aileron had trailing-edge angles of Go, 14O, and 25O. Lift, drag, pitchingmaaaent, and hinge-mment data were obtained for the wingwith tr
4、ansition free and fixed and xfth various spans of aileron deflected 88 lift flaps. In addltion, the rolling-moment, yawing-mament, hinge-mament , and alleron-seal-pressure characteris tfcs were determined for each of the nine possible aileron-span and trafling- edge-angle caulbinations tested. The r
5、esults indicate that the effects on the wing aerodynamic and lateral-control characteristics of fixing transition at the wing leadiq edge were generally smdl or inconsequential. Increases in the span, deflection, or trailing-edge angle of the aileron (when used to simulate a lift flap) generally pro
6、duced the same trends in the wing lift, drag, pitching-martent, and lift-flap hinge-moment characteristics as are produced on unswegt wings, except at angles of attack near the wing stall. Increases in the aileron span, the aileron trailing-edge angle, the aileron deflec- tion, or the wing angle of
7、atteck generally produced effects on the swegt- wing rolling-mcenent, yswing-mannent, hinge-mmnt, and seal-pressure characteristics that were similar 1 trend to, but different in magnitude fram,the corresponding effects produced on unswept wings. The plain-flap ty-pe of lateral-control device is bei
8、ng considered and incorporated in the design of high-speed aircraft having swept wings. The design engineer on such aircraft is greatly hampered, hawever, by a lack of data upon which to barn estimates of the various afleron- design parameters at high sweep -ea. In order to help alleviate this diffi
9、culty, the National Advieory Camittee for Aeronautics is currently Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-2 NACA RM Wo L8F29 of obtaining aileron-design data similar to that available on unswept wings (references 1 to 3) Because RO adequate
10、theory is yet available for determining aileron effectiveness on swept wings, such as is available for unswept wings, the experimental approach is being followed in these investigations. Previous analyses (such as reference 1) have indicated that the effects of airfoil section on control-surface cha
11、racteristics result principally from variations In the trailing-edge angle of the control surface. In order to simulate approximately the effects of airfoil section or of fabric deflection on control-surface characteristics, three trailing-edge angles were investigated in the present paper. The data
12、 presented and discuased herein are the results of low- speed lateral-control tests of nine different 16.7-percent-chord sealed- plain-aileron configurations (three spans, each with three trailing- edge angles) on a tapered low-drag semispan wing having 5l.3O sweepback at the leading edge. The rolli
13、ng-mcanent and yawing-mment characteristics, as well as the hinge-raomnt and internal-seal-pressure characteristics, of each of the configurations o the X-axis. The Y-axis is perpendicular to both the X-axis and Z-axis. Au. three axes intersoci; at the intersection of the chord plane and the plane o
14、f symnetry of the model at the choxdwise location (32.6 percent OP the M.A.C.) shown in figure 1. CL lift coefficient Crn pi tching-mmnt coef ficlent pitching mment of semispan model about qs5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA RM N
15、o. L8F29 3 rolling-mameat coefficient yawing-mament coefficient aileron hingelKlment coef ffcient all elopes were measured in the vlcinity of 6, = oo and a = Oo. Subscripts 1 to.? have been used with the seal-pressure coefficient P to indicate the spanwfse station at vktch the pressure coefficient I
16、S measured- (See fig. 2- 1 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-5 The rollinglncgnent-coefficient and yawing-mment-coefficient data presented herein represent the aer-c moments on a onmplete wing produced by the deflection of the aileron o
17、n only one semispan of the cmplete wing- The lift, drag, and pitching-mament coefficients represent the aerodynmic effects of deflection in the lsame direction of the ailerons on both semispans of the cnmplete wing. All the test data have been corrected for jet-bomdaq and reflection- plane effects.
18、Blockage corrections, to account for the constriction effects produced by the wing model and wing wake, have also been applied to the test data. Wo corrections have been applied to *e data to account for the small Bmouzlt of wing twist produced by aileron deflectfon ar the tare effects of the root-f
19、airing body. The semispan-aweptback-ving model dl21 a raked tip waa mounted vertically in the Langley 300 MPE 7“ by 10-foot tunnel, as shown in figure 3. The root chord of the madel waa adjacent to the ceiling of the tunnel, the ceiUng of the tunnel thereby serving as a reflection plane. The model w
20、aa mounted on the six-caapnent balance system in such a manner that all forces and moments actipg on the model could be measured. A emall clearance wa maintained between the model and the tunnel ceiling so that no part; of the model cam in contact with the tunnel structure. A root fairing, consistin
21、g of a body of revolution, was attached to the root of the model in order to deflect the sparrwise flow of air that enters the tunnel test section thro the clearance hole between the model and the tunnel ceiling 80 as to minimize the effects of such spaarise flow on the flox over the wing model. The
22、 model wae constructed of laminated mahogany over a welded steel framework to the plan-form dimensions sham in figure 1. The model had wing sections of WA 651-012 profile perpendicular to the unswept 50-percent-chord line, with neither twist nor dihedral, an aspect ratio of 3-58, and a taper ratio o
23、f 0.44. Except where noted, tramition was fixed at; the leading edge of the wing for all tests. The transition strip, consisting of Bo. 60 carborundm graine, extended over the forward 5 percent of the wing chord on both the upper and the lover surfaces along the entire spanof the wing model. The car
24、borundum grains were sparsely spread to cover fram 5 to 10 percent of this area- Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-6 NACA RM No. L8F29 . The aemfspan wing model was equipped with plain radius-nose ailerolle that were 20 percent chord no
25、rmal to the unswept 50-percent-chord line and 16.7 percent chord parallel to the plane of symmetry. The ailerons had steel spars and were constructed with joints at two spanwise atations SO that aileron spans of 0.34ba1, 0.66ba, and 0.93ba could be tested- (See fig. 1. ) The three mahogany aileron p
26、rofiles used had trailing-edge aes in a plane approximately normal to the hinge axis of 6O (true contour of trailing edge of NACA 651-012 afrfoil), 140 (straight sides fran aileron hinge line to trailing edge of wing) , and 25O (beveled trailing edge) and were built to the sections Shawn in figure 4
27、. The aileron was tested with a plaetic impregnated cloth seal acroaa the gap ahead of the aileron nose, except at the point of attachment of the aileron- actuating mechanism and at the aileron support bearings. The seal extended and was attached to the bearing housing at the end of each aileron cha
28、mber, and the seal in each chamber was believed to be fairly cmplete. Pressure orifices were located above and below the seal in the wiw block ahead of the aileron at the spanwise locations shown iln figure 2. Two pairs of pressure orifices were located in both the middle and outboard aileron sectio
29、ns, whereae only one pair of orifices was located in the inboard aileron section near the outboard end of this section. A remotely controlled motor-driven aileron-actuating mechanism was used to obtain the various aileron deflections employed in the investigation. The aileron angles were indicated o
30、n a meter by the use of a calibrated potenticmeter which was mounted on the aileron hinge axis near the outboard end of the aileron. A calibrated electrical resfstance-type strain Gage was employed to masure the aileron hinge moment 8. TESTS AJl the teste were perfomed at an average dynamic pressure
31、 of apprarlmately 20.5 pounds per square foot, which corresponds to a Mach number of 0.12 and a Reynold8 nmber of 2,200,000 based on the wing mean aerodynamic chord of 2-48 feet. Wing angle-of-attack tests wlth the maximum-epan aileron G$ = 0.99 at zero deflection were made throughout an angle-of-at
32、tack range fram -loo to the angle of attack at which the wing etalled, whereas correaponding tests with the other ailerons = 0.34 and 0.66 at zero deflection 1 were made throughout an angle-of-attack range fram -loo to IOo. Additional Provided by IHSNot for ResaleNo reproduction or networking permit
33、ted without license from IHS-,-,-NACA RM No. Lle to a positive elope for the large trailing-edge angle. This effect will be discussed in greater detall in th? section of this paper entitled “Aileron hinge- mament characteristics. Increasing the aileron trailing-edge angle with the aileron deflected
34、or at high wing angles of attack produced less negative values of hinge-mament coefffcient, which corresponds to smaller reetoring or up loads on the aileron. In general, increaaes in the span, deflection, or trailing-edge angle of the aileron (when used to simulate a lift flap) produced the same tr
35、ends in wing lift, drag, pitching-mment, and lift-flap hinge-mameat characterietics as me poduced on unswept engs, except at -ea of attack near the wing stall. Laterel-Cmtrol Characteristics The variation of the lateral-control characteristics (rolling-men%, yarwing-mcrment, hinge-mament, and seal-p
36、ressure coefficients) with aileron deflection at various angles of attack for each of the cambinations of aileron span and trailing-edge an and hinge-moment character- istics. The data of figure 10 Fndicate, however, that seal-pressure data obtained with transition fixed 011 the wing generally were
37、more nearly llnear throughout the aileron-deflection range and exhibited more consistent trends with change in Q. than the corresponding data obtained with transition free. Rolling-moment characteristics.- Canparison of the rolling-moment data for the various percent span ailerons at f30 deflection
38、(table I1 and figs. 10 to 18) shows that, at a given trailing-edge angle, the O-34ba aileron produced apprcurimate hmever, the rate of increase of C with Increasing aileron spn was greatest for the aileron with the 60 trailing-edge angle and smallest for the aileron with the 25O trailing-edge angle
39、( fig. 19) . The data of flgure 20 more clearly Indicate the decrease in effectivemas caused by increesing the aileron trailing-edge angle for 8 conetant aileron span and show that this decrease is largest for the 0-93ba aileron. sa zb An unpubljshed analysis has indicated that the effectiveness of
40、ailercana on swept wings is given approximately by the relation where the factor Cz/ these values approximately correspond to the geamstric characteristics for the wing of the present paper when it is unswept. A value of 0.44 was used for y differ slightly fran experimental resulte. Yawingprament ch
41、aracteristics.- The total yawing-mament coefficient resultlng from equal up and dawn deflectione of the ailerons vas generslly adverse (sign of ya the maximum values of P vere invariably obtained at the sparrwlse station located nearest the inboard end of the aileron. The variation of P with 6a for
42、thie atation also exhiblted the mom nearly linear characteristics of all the atations at which the seal pressures were recorded for each span of aileron. In addition, for a given aileron span, the values of Pga and the values of P for given aileron deflections generally decreased In proceedlnq from
43、the inboard pressure-orifice stations to the outboard stations. No consistent trends in the variation of P6a with aileron span at constant aileron trailing- edge angle could be noted. Increasing the angle of attack had an incon- sistent effect upon Pea but generally resulted in a shift of the curves
44、 toward more positive values of pressure coefficient. - Because the slope of the curve6 of pressure coefficient plotted against aileron deflection generally did not tend to reverse up to the largeat aileron deflections tested, and because the values of preesure coefficient presented herein capre fav
45、orably with corresponding values obtained on unswept wings, sealed-internal balances probably will be satisfactory for swept-wing control surfaces. CONCLUSIONS A wind-tunnel investigation was made at lar speed to detedne the aerodynamic characteristics oP a 31.3O sweptback semfspan wing with a raked
46、 tip and with 16.7-percent-chord aealed plain ailerons. The ailerons had span8 of 34, 66, and 93 percent of the span of a full-span aileron; each aileron had trailing-edge -eo of 60, 14O, and 25O. The resulte o,P the inveetigatian led to the follaring conclusions: 1. The effects on the wing aerodyna
47、mic characteristics and on ;be aileron yawing-ament, hiwe-mment, and seal-pressure characteristics of fixing transition at the wing leading edge were generally small and inconsequential. Fixing transition, however, resulted in a decrease in both the total rolling-mr.xnsnt coefficient resulting fram
48、f3O0 deflection of the aileron at law angles of attack and in the slope of the curve of rolling-mmnt coefficient against aileron deflection Czg,. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MACA RM Bo. L8F29 13 2. In general, increases in the spa
49、n, A = 3.68; tqer ratio = 0.44. (AU dimensions in ft except as nbted.) . . . . Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-E57 Figure 2.- Location of pressure orifices on semispan wing model. (All dimemions in ft,) Provided by IHSNot for ResaleNo reproduction or networking permitted without lice
