1、Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA RM No. 306 r2 0 $2 : LATERAL CHARACTERIsI?CS OF A 45 SWEPTBACK WIIJC: WITH S-CAL CIRCULAR-ARC SECTIONS By Eugene R. Guryanslq and Stanley Lipson SUMMARY .- $3 “ An investigation has been conducted
2、in the Langley full-scale tunnel to determine the longitudinal characteristics of several leading-edge and trailing-edge flap configurations md the lateral characteristics of oae flapped configuration of a 45 sweptback wing having circular- arc sections, an aspect ratio of 3.5, and a taper ratio of
3、0.5. Tests were also made of chordwise fences with and without a rounded leading- edge modification installed on the outer semispan of the wing in an attempt to alleviate the early tip stall. 1 the test results are presented for a Reynolds number of 4.5 X 10 The maximwn lift coefricient is 0.87 for
4、the wing with flaps neutral, 1.07 with the full- pan leading-edge flap deflected 40 (not completely stalled), 1.05 with the full-span trailing-edge flap deflected 40, and 1.26 with the cornbination of the two flap configurations. configurations investigated provided completely satisfactory longitudi
5、nal stability characteristics throughout the entire lift-coefficient range. Some imiprovement in the longitudinal characteristics of the wing in the moderate to high lift-coefficient range is provided by the leading- edge flaps. None of the No appreciable improvement in the stability of the wing at
6、stall is realized as a result of the installation of either the outer semispan rounded leading edge or of the chordwise fences or of a combination of these two configurations With the full-span leading-edge flap deflected 40 and with the semispan trailing-edge flap deflected 600 the wing has positiv
7、e effective dihedral throughout the angle-of -attack range of the tests and attains a maximum at a lift coefficient of 0.96. flap configuration and reaches a maximum Cn value of about -0.001 at a lift coefficient of 0.97. value of 0.0036 per degree The wing is directionally stable for this cz 11, Jr
8、 For a representative wing loading, 40 pounds per square foot at sea level, high gliding and sinking speeds are characteristic of this wing for a11 the flap configurations tested. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-2 NACA F therefore? fu
9、ll-spa leading- edge flap deflections greater than 40 were not tested. It is probable that the increased bsnd at the 0.20 station associated with the large flap deflections produces a cqaratively laxge pressure peak which induces flow separation over the forward part of the airfoil. It should be men
10、tioned that in several inatances maximum lift was not actually attained due to limitations of the apparatus which prevented increasing the angle of attack abae 26O. of the leading-edge flap deflected 20 and 30 are presented in figures ll(b) and ll(c). the flap makes no appreciable change in the maxi
11、mum lift coefficient of the plain wing for either of these two deflections. 50 percent of the flap deflected 200 and 30, however, the lift coefficient at the highest angle of attack attained is increased 6 percent and 17 per- cent, respectively. Futher increases are obtained when the outboard The re
12、sults presented in figure (a) A 23-percent The results for th?e 40 flap configuration showed an Results of tests with different sections The deflection of the outboard 25 percent of With the outboard Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-UA
13、CA RM No. bO6 7 75 percent of the flap is deflected, but for a spanwise length greater than 75 percent, very little gain in lift coefficient is realized. coefficient slightly up to a lift coefficient of about 0.3 but decreases it at all greater lift coefficients. deflected 40, the decreaae in drag c
14、oefficient at a lift coefficient of 0 . is 67 percent of the drag coefficient for the base condition. A similar effect is obtained when sections of the leading-edge flap are deflected and the magnitude of the drag decreases with increases in the span of the deflected flap and with angle of attack ar
15、e also shown in figure 11. With flaps retracted, the wing is neutrally stable to a lift coefficient of 0.3, then slightly stable to 0.53, and finally unstable to the maximum lift coefficient with .a stable break occurring at the stall. The shapes of the pitching-moment curves for the wing with the f
16、ull-span flap deflected are similar to those for the plain wing up to a lift coefficient of about 0.5. the onset of the instability of the wing to hi the lift coefficients at which this instability occurred increased with an increase in the angle of flap deflection. Deflecting the outboard 0.25 of t
17、he leading-edge flap increased the stability of the wing in the higher lift-coefficient range and provided a stable break past the stall similar to that obtained with the basic wing. Increasing the b b deflected leading-edge flap span to 0 302 and 0 -75- produced still 2 greater increases in stabili
18、ty in the higher lift-coefficient range but gave an unstable break past the stall. The defleotion of the full-span leading-edge flap increases the drag With the full-span leading-edge flap The vartations of pitching-momnt coefficient with lift coefficient The effect of deflecting the leading-edge fl
19、ap is to delay b Trailing-Edge Flaps The effects of semispan and fullcspan trailing-edge flap deflection on the characteristics of the wing are shown in figures l2( a) , l2( b) , The inboard semispan flap contributes approximately one -half the and l2(c). increment in Ch obtained with the full-span
20、trailing-edge flap deflected 20, as shown in figure =(a), but produces a much greater pementage of the total increment at angles of attack below that for Cbo Figure 12 shows that the Ch obtained with the inboard semispan flap deflected is the same value (Cbax range of flap deflection. slightly incre
21、ased from 20 to 40 (Cbx of 1.01 as compared with 1.03), but a further increase in the Tull-span flap deflection fails to produce any further increase in Chaxa At low angles of attack, deflecting the trailing-edge flap produces large increments of lift but the effectiveness decreases rapidly as maxhn
22、umlift is approached. 0.93) for the test The effectiveness of the full-span flap is Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-8 NACA RM No. 81x16 Deflection of the trailing-edge flap results in significant drag reductions above lift coefficient
23、s of 0.60 as compared with that for the basic wing. The effect of this drag reduction produced bp the trailing- edge flaps on the landingperformance characteristics of the wing will be discussed later in the report. The shape of the Cm - CL curve for the plain wing is not greatly altered by deflecti
24、on of either the semispan or full-span trailing-edge flaps. The neutrally stable portion of the curve is extended to higher lift co2fficients and is then followed by a severe decrease in longitudinal stability up to maximum lift. pitching-moment curve occurs for all of the trailing-edge flap configu
25、- rations tested. At the stall, a stable break in the Flap Combinations The results for the combinations of leading-edge and trailing-edge flap deflections are shown in figure 13. the results of various full-span trailing-edge flap deflections for a range of full-span leading-edge flap deflectioas f
26、rom loo through bo. Figures l3(e) and 13(f) show the results obtained with the inboard semispan flaps deflected 60 in combination with a number of leading- edge flap configurations. Figures 13(a) to 13(d) present As shown in figures 13(a) to 13(d), the effectiveness of either the full-span leading-e
27、dge or trailing-edge flap is unaffected by the presence of the other flap when tested in combination. is approximately equal to the sum of the lift-coefficient increments contributed by the individual flaps. As previously discussed, at a given lift coefficient (above CL = 0.60) and with the trailing
28、-edge flaps neutral, increasingly large drag reductions were obtained by deflecting the full-span leading-edge flap. When the leading-edge flap is operated in combination with the trailing-edge flap, however, this effect is materially reduced with the magnitude of the drag reductions becoming less w
29、ith increasing trailing-edge-flap angle The configu- ration with both the full-span leading-edge and trailing-edge flaps at high deflections produced increases in the longitudinal stability in the lower ll,ft-coefficient range. the pitchi.ng-moment breaks at the stall are unstable. The increment in
30、maximum -lift coefficient produced by the various flap combinations, therefore, For all the flap combinations tested, 0 The effects of deflecting sections of the leading-edge flap 30 with the inboard 50 percent of the trailing-edge flap deflected 60 are shown in figure l3(e). edge flap produces no e
31、ffect on the maximnun lift coefficient, but deflection of the outboard 50 percent, outboard 75 percent, and full span of the leading-cage flap increases the of 0.13, 0.23, and 0.18, respectively. Deflection of the outboad 25 percent of the leading- Cbx of the wing by increments Provided by IHSNot fo
32、r ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA RM no. 8.06 9 With the inboard semispan trailing-edge flap deflected 60, as the b 2 span of the leading-edge flap was increased from 0.25 to full span, the drag of the wing at the higher lift coefficients was proportio
33、nally decreased. outboard hal5 of the leading-edge flap with the inboard semispan flap deflected 60 is to increase the loagitudinal. stability of the wing at the higher angles of attack. deflection of the outboard 75 percent of the leading-edge flap changes the flaw characteristics of the wing. stal
34、ling appears before any central portion of the wing is completely stalled, thereby making the wing highly unstable at angles of attack frm 20 throa lift characteristics are not materially changed by these modifications. The Provided by IHSNot for ResaleNo reproduction or networking permitted without
35、 license from IHS-,-,-NACA RM No. 8Do6 13 4. For a representative wing loading, 40 pounds per square foot at sea level, high gliding and sinking speeds are a characteristic of this wing for all the test flap configurations. 5. With the full-span leading-edge flap deflected 40 and the semispan traili
36、ng-edge flap deflected 600 the wing has positive effective dihedral throughout the angle-of -attack range tested and attains a nuxcimum value of c of 0.0036 per degree at a lift coefficient of 0.96. 9 6. The wing is directionally stable for this flap configuration of about -0.001 at a lift coeffi- c
37、% and develops a maximum value of cient of 0.97. Langley Aeronautical Laboratory National Advisory Committee for Aeronautics Langley Field, Va. 1. Proterra, Anthony J.: Aerodynamic Characteristics of a 45O Swept- Back Wing with Mpect Ratio of 3.5 and NACA 2S-30( 0)-50( 05) Airfoil Sections. NACA RM
38、No. LTCll, 1947. 2. Neely , Robert H , and Koven, William: Low-Speed Characteristics in Pitch of a 42O Sweptback Wing with Aspect Batio 3.9 md Circular- Arc Airfoil Sections. NACA RM No. L7E23, 1947. 3. Gustafson, F- B., and OSullivan, William J., Jr.: The Effect of High Wing Loading on Landing Tech
39、nique a.nd Distance, with Experimental Data for the B-26 Airplane. NACA ARR No. L4KO7, 1945. 4 Pearson, Henry A. , and Jones, Robert To : Theoretical Stability and Control Characteristic8 of Wings with Various Amounts of Taper and Twist. NACA Rep. No. 637, 1938. Provided by IHSNot for ResaleNo repro
40、duction or networking permitted without license from IHS-,-,-14 NACA RM NO* 806 Figure 1. - System of axes. Positive values of forces, moments, and angles are indl cated by arrows. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-I?ACA RM NO. 806 Prov
41、ided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-16 L NACA RM No. 8Do6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA RM No. 806 (a) Fence at the .75b/2 station (not to scale) (b) Fence at the .50b/2
42、 stallion (not to scale). Figure 4.- Dimensions of the Rrll chord fences. The station8 refer to their spanwise location. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Provided by IHSNot for ResaleNo reproduction or networking permitted without lice
43、nse from IHS-,-,-NACA RM Nom 8Do6 Provided 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-,-,-NACA RM No. 806 21 -Direction of ilar -Direction of rough flow Intermi
44、ttent stall Figure 6. - Tuft studies of the wing with all flaps neutral. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-22 NACA RM No. 806 4 Direotion of t+. Directtion of Intermittent Figure 7.- Tuft studies of the wing with the outboard 25 percent
45、 of the leading-edge flaps deflected 30 ; trailing-edge flaps neutral. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA RM NO. bo6 23 CL = O .86; 26.6 Figure 8.- Tuft studies of the wing with the outboard 25 percent of the leading- edge flaps def
46、lect$ 30, and with the inboard 50 percent of the trailing-edge flaps deflected 60 . Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-24 NACA RM NO. 8006 Figure 9.- Tuft studies of the wing with the outboard 50 percent of the leading- edge flaps deflec
47、ted 30, and with the inboard 50 percent of the trailing-edge flaps deflected 60. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA RM NO. 806 25 Figure 10.- TTdt studies ofothe wing with the outboard 75 percent of the leading- edge flaps deflectgd 30 , and with the inboard 50 percent of the trailing-edge flaps deflected 60 . Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-26 XACA RM No. 806 (a) Full-span deflection. Figure 11.- The effect of deflecting a leading-edge flap on the a
