NASA NACA-RM-A51D02-1951 Investigation in the Ames 12-foot pressure wind tunnel of a model horizontal tail of aspect ratio 3 and taper ratio 0 5 having the quarter-chord line swept.pdf

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1、COPY b RM A51D02 RESEARCH MEMORANDUM INVESTIGATION IN TEE AbleES Z.pea, square feet lateral diStall28 perpendicular to the plane of symmetry, f88t corrected angle of attack, degrees angle of attack, uncorrected for tunnel-wall interference and angle-of-ttack counter correction, degrees reduced aspec

2、t ratio (=A) elevator deflection (positive to increase lift) measured in a plane normal to the elevator hinge line, degrees ; -843 1.010 1.008 :gg 1.018 1.014 -920 1.022 Pressures measured at orifices in the wind4unnelwalle were used to determine the test conditions at which wInd4unnel choking may h

3、ave influenced the data. !.The positions of the tuunel*ll pressure orifices relative to the Illlode are shown in figure 3. It was noted that a local Mach n-81 of unity was attained at the wind-rtunnel wall at a free-stream Mach number consfderably less than the maximum free-tream Mach number thatcou

4、ldbe obtained. This suggeststhatpartial choking ofthetunnel existed at Mach numbers below that for which a normal shock wave extended Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-8 mc m 5mo2 across the test section. Some of the data were obtained

5、at test condi- tions for which the local Mach number at the aind-tunnelwall exceeded unity. These data are included in the figures but are faired with dotted curves to indicate that they may have been influenced by wind- tunnel choking. Approximate corrections to the drag were made to compensate for

6、 the drag force on the exposed turntable. These corrections were determined from tests with the model removed from the turntable. The corrections are presented in the following table: R X10+ M % 2.0 0.25 0.0028 2.0 ,60 .0030 2.0 .80 l m33 2.0 E:E :g 036 .0038 025 .0028 44: :E .0030 .0033 ,“: .85 *go

7、 .0034 .0036 ko“ 8:o :;4 00037 l 25 :Z! 12.0 l 25 do23 18.0 025 .0022 IVo attempt was made to evaluate tares due to possible interference between the model and the turntable. REST ARD DISCTBSIOR The effects of Reynolds number on the low-speed aeroaynamic charac- teristics of the model are shown in f

8、igures 4 through 8 and me summarized in figures 9 and 10. The effects of increasing the Reynolds ruutiher from 2,000,OOO to 4,OOO,OOO at Ee-mome nt coefficient was approximately linear through O“ angle of attack and O“ elevator deflec- tion for all Mach mmbers. Increasing the Mach number to 0.94 res

9、ulted in an increase in the absolute values of the slopes of the hinge-mommt curves andareductioninthe sngularrange overwhichthe hinge-momnt characteristics were linear. The Mach mmiber at whfch rapid changes occurred in the elevator hinge-moment coefficfents was dependent upon-the elevator deflectf

10、on and angle of attack. This is illustrated in figure 17(a) which presents the Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-mclcu5102 ll variation of elevator hinge-moment coefficient with Mach nu the magnitude of this reduction increased tith inc

11、reasing MEtch number. The effect of compressibility on the pitchfwment-curve slope at zero lift was reduced by the addition of leadiwdge roughness to the model. As would be expected, application of leading-edge roughness resulted in en ticrease in drag. Figures 24(d) and 26(b) show that the increase

12、 of minimum drag coefficient due to leading-edge roughness at 6 = o“ and CL = 0 was about 0.0040 at low speed and about 0 .W30 ac a Mach nuniber of 0.9. It can be seen in figure 26(a) that unsealing the elevator nose caused slight reductions in C and CLS but had no important effects on the hinment-c

13、urve slopes (fig. 26). Ffgure 26(b) shows that unsealing the elevator nose had little effect on the pitching-moment characteristics of the horizontal tail or on the minimum drag. The results of Wnd-tunnel tests conducted to evaluate the inde- pendent effects of Reynolds number and %ch number on the

14、aeroasnamfc characteristics of a horfzontal. tail of aspect ratio 3.0 with the quarter-chord line swept back 45O have been presented. acreasIng the Reynolds number from 2,000,OOO to 18,000,000 at a Mach nuriber of 0.25 resulted in a sizable reduction In the drag coeffi- cient at moderate to high lff

15、t coefficients. The lift characteristics of the horizontal tail were little affected by this change inReynolds nuniber, but the hinge+roment and pitchipment characteristics of the tail were affected by changes in Reynolds number, especially at the higher angles of attack or elevator deflectims. Prov

16、ided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-14 NAcA RM 51x12 As the Mach number was increased from 0.25 to 0.94 the lift-curve slope increased 36 percent, the lift effectiveness of the elevator increased 20 percent, the pitchfng+uosnt effectiveness o

17、f the elevator increased 74 percent, and the absolute magnitude of the variation of elevator hin;e-lmomsnt coefficient with either angle of attack or elevator deflection increased about 35 percent. These increases were measured through 0 angle of attackand 0 elevator deflection. Ths Mach number at w

18、hich compressibility effects resulted in large changes fn the elevator hingmment coefficient was dependent upon the angle of attack and the elevator deflection. Increasing the Mach nuniber from 0.25 to 0.94 also caused a reduction in the maximum lift-to-drag ratio of from 18 to 12 and a sma re arwar

19、d movelnsnt of the aerodynamic center. Measuremnts of the pressure difference across the elevator-nose seal indicate that, if the elevator were equipped with a sealed internal nose balance, the resulting h- nt characteristics of the balanced elevator would be nonlinear at the highsr Mach numbers and

20、 that only a small amount of balancing effectiveness would exist at elevator deflec- tfons greater than about 6O or 8O at Mach n 65146 70.12 74.67 79.12 83.48 87.74 ;z: 100:00 0 .673 .811 1.023 1.406 1.925 2.306 2.612 3.757 2.910 2.574 2.213 1.836 1.456 1.083 0720 -363 ,014 . .L Provided by IHSNot f

21、or ResaleNo reproduction or networking permitted without license from IHS-,-,-. I Dime&m shown in inches unless otherwise nated I_ 20.74 0.25 chord of NACA 64AOlO section Elevolor hinge, 0.70 chord of NACA 64A010 sections . t Aspect ratio 3.0 7iiper ratio 0.5 Ameo eemim MO83 ftp Ehvtor arw 2553 HP F

22、 2668 ft MA 0.679 ff3 SeCtEon A - A Figure t.- The hotYxont&toil model. 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-,-,-NACARMAJDO2 29 . Figure 2.- The horizontal tail model munted in the ADBS S-foot preseme w-flla t-1. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-