NASA NACA-RM-L8I03-1948 The effects of high-lift devices on the low-speed stability characteristics of a tapered 37 5 degree sweptback wing of aspect ratio 3 in straight and rollin.pdf
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1、Copy No. 134 FCM No. L8103 RESEARCH MEMORANDUrvr- THE EFFECTS OF HIGH-LIFT DEVICES ON TIZZ LOW-SPEED STABILITY CHARACTERISTICS OF A TAPERZD 37.5 SWEPTBACK WING OF ASPECT FZATIO 3 ti STRAIGHT AND ROLLING FLOW BY M. J. Queijo and Jacob H. Lichtenstein Langley Aeronautical Laboratory Langley Field, Va.
2、 w “G- 4 bq, a i oVNILBA DoC!ntmmtA DAtAd Prior to January 1, 1960 z Mover , until me#lrts, Researeb Authorizationa, eorro8pondonce, ph.OtogtAphS And other dOet8nOitatiOn. Earlfor, in 020,000, respectively. The results of the investigation indicate that the variation of the parameters with lift coef
3、f.icient is essent the same at low and moderate lift coefficients for all the conflgu2ations tested. The high-lift devices extended the initial trend of the derivatives to higher lift coefficients, and Fn some case8 also caused smaJJ. displacements of the curves plotted against lift coefficient. Ros
4、e flaps w-ere not as effective as slats inextendlngthe initial trendof the curves tohighlift coefficients. Combinations of split flaps and slats produced effects which were approximately equal to the sum of the effects of spLLt flaps alone and slats alone. Estimation of the dynamic fli L8IO3 C and s
5、ljlit flaps (fig. 3). All slats had chords which were 10 percent oe.tie wing chord (measured IIEJJ to the wing quarter- chord line) and all split flaps had chords which were 20 percent of the wing chord (normal to wing quarter-chord line). The slats were made by l 1 Provided by IHSNot for ResaleNo r
6、eproduction or networking permitted without license from IHS-,-,-S based on-unstiept-*tie theory, for the effects of the ilet .boUnaar+$ baveez,en applied ,taq.,w and the roJUng derivatives Cz pf %lg - cyp are presented in figures 12, 13, and 14, respectively. The data for the 10 model configuration
7、s are divided into three groups.in each ?i,gure. The groups are (1) wing with split flaps, (2) winewith slats or nose flap, and (3) wing with combi- nations of split flaps and slalq. The charaoteristico of the plain wing are included in each 09 the groups in order to provide a basis for com- parison
8、 witLresults obtained with various high-lift devices installed. Characteristics of PlM.r.Wing The characteristics of the plain wing generallg were good in that there werd no abrupt.cerivativer3at modgrlir_i;e lift coefficienti. The more favorable characteristics oethe present wing probably are a res
9、ult- of the moderate sweep angle in combination with a low aspect ratio. The pitchLngplomen$ curve of figure 8 is esgentially linear up to the stal.landhU a atable breakatthe stall. The effective dihedral parameter Cz $ increased linearly with lift coefficient up to approximately tiimum iift (fig. 9
10、) and then decreased very rapidly beyond tiimum lift. The directional stability of the Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA RM No. L8IO3 7 c Y c model C, If increased approximately as the square of the lift coefficient (fig. 10) as mi
11、ght be expected from the theory of reference 5. At about the maximum lift coefficient, C, f broke in a positive direction. The ds3npinSinrol.l Cz P (fig. 12) showed some increase with lift coefficient snd, although this trend is not indicated by theory been observedin other tests of swept wings (ref
12、erences 4 and 6j. it has Nega - tive damping ( positive CL was obtained beyond msximm lift, indicating that the model would autorotate if it were free to rotate. The yawing moment due to roll c“p was negative at all lift coefficients below maximum liftbut became positive beyond maximum lift (fig. 13
13、). Some of the important measured derivatives of the model are seized in table I. The experimental results are csed with the approximate theory of reference 5 and, where possible, with the theory of Weissinger (references 7 and 8). The ccznparison betweentheory and experiment Sener- ally is consider
14、ed to be fair with the excsption of ca/cL- The differ- ence between the theoretical snd measured values of %P probab1y Is caused by the wing-tip suction forces associated with asymmetric load conditions. Such forces were not accounted for in reference 5. Refer- ence 9 indicates that good agreement b
15、etween theoretical and measured values of C %I CL might be obtained if the tip suction forces were accounted for. Effects of Split Flaps The O.Y-span and l.O-span split flaps produced lift-coefficient incre- ments of about 0.33 and 0.48, respectively, and these increments remained approx.imately con
16、stant, even to the maximum lift coefficient. Tests of other swept wings (references 1 and 10) have indicated that flap effective- ness in producing lift generally decreases with increase in lift coefficient. Split flaps increased the longitudinal force very appreciably and made the pitching moment m
17、ore negative. The alsince the addition of split-fh3pswoul.d be expected to have little effect on either the maatude or the location of the center of pressure oftha incremental load caused by roll3n.g. For the model investigated, the additionof split flapsinvariably cause-d an extension to higher lif
18、t coefficients of the trends in the derivatives that-were noted at low lift coefficients for the plainwing. Effects of Slats end Nose Flaps The addition of slats or nose flaps caused the lift curve to be extended to higher angles of attack, thus providing increments in maximum lift coefficient amoun
19、ting to 0.18 for the 0.5-apan slat, 0.39 for the l.O- span slat, and 0.27 for the X.0-span nose flap. Thenoseflapandslats tended to move the aerodynamic center slightly forward, as is indicated by the decreased negative slopes ofthe pitching-moment curves (fig. 8). A forward shift in aerodynamic cen
20、ter would be expected since the nose flap and slats effectively extend the l however, the nose flap was not as effective as the slats in maintame the linear trends to higher lift coefficients. A relatively large displacementj in a negative direction, of the +-curve reeulted. * from the additionof th
21、e l.O-span slat. The slats axd nose flaps caused small increases in the dsmping in roll r egative Cz 1 atmoderatelift P coefficients .Thie probably resulta from the effective increase in wing area that accoeed the addition of either the nose flaps or slats. . - Provided by IHSNot for ResaleNo reprod
22、uction or networking permitted without license from IHS-,-,-Effects of Combinations of Split Flaps and Slats In general, combinations of split flaps and slats had two major effects on the wing characteristics. One of these effects was the exten- sion of the linear portion of the curves of wing chara
23、cteristics to higher lift coefficients, and the other effect was the displacements of some of the curve8. The data of figures 6 to 14 indicate that these extensions and displacements are approximately what would be expected from the results obtained for the effects of split flaps-alone ti slats alon
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