NASA NACA-RM-A7K28-1948 High-speed stability and control characteristics of a fighter airplane model with a swept-back wing and tail《带有后掠翼和尾翼的战斗机模型的高速稳定性和控制特性》.pdf

1、RESEARCH MEMORANDUM HIGH-SPEED STABILITY AND CONTROL CHaRACTERISTICS OF A FIGHTER AIRPLANE MODEL WIT A- -I SWEPT-BACK WING AND TALL s 2 I-rY By Charles P. Morrill, Jr. and Lee E. B and the chord waa 3.29 inches measured par . 35.59 Airfoil section (pdel to center lfne) WA 001064 Elevator Area (whole

2、 model). sq ft 0.405 spm (whole model). ft 2.310 Mean square chord. sq ft 0.0248 Stabilizer Area (whole model). sq f t . 0-95 span ( aqd data on the dive brake are given in figures 22 throup 25. Lfft, Drag, and Pitching Mmnt The variation of lift coefficient with angle of attack and Msch number ia p

3、resented in figure 5. me average slope of the lift cwe increased with increasing Mach number, but the angle of attack for zero lift remained essentially constant up to 0.90 Mach number. At low-lift coefficients the drag coefficients remained reh- tivelg constant to a Mach number of about 0.86, at wh

4、ich divergence occurred. At higher lift coefficients the divergence Mach number was lowered to approximately 0.825. (See f ig. 6. ) The variation of pitchinmoment coefficfent uith lift coeffi- cient of the model with the horizontal tail removed indicated longi- tudinal instability at Mach numbers up

5、 to approximately 0.85, at which the model became neutrally stable. (See fig. 7.) At higher Mach numbers the model exhibitsd stable characteristics. The pitchineanent coefficient at zero 1st showed only slight varia- tion within the Ifmits of the teat (-0.008 to 0.003). Pitchine moment characteristi

6、cs of the model wfth the horizontal tail (fig. 8) indicated Btatfc longitudinal stability for moderate 1Sf t coefficients at all test kch numbers. However, a strong tendency exiated for the model to became longitudinally unstable at the higher lift coefficients, especially Kith a negative deflection

7、 of the elevator or stabilizer. Lmpitudind Characteristics Figure 9 presents the variation of lif-tc and pitchin-nt- curve slopes with Mach number. At low lift coefficient8 the lift- cwe slope increased grsduallg with Wch number. The curve for 0.4 lift coefficient show8 a decrease of slope from low

8、to medium Mach numbers followed by a gradual incrgase, reaching a peak at 0.85 Mach number and decreasing rapidly thereafter. The static instability e%hlbited below 0.85 Mach number by the model wlthout the horizmtal tail increased ccmstderably at lfft coeff iciente greater than 0.4. However, addfng

9、 the tail reatored stability for moderate lift coefficients at all Mach numbere within Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-8 MCA EM lio. Ap8 the test limits. At lift coeff iciente above about 0.4 the degree of stability was appreciably re

10、duced. At a Mach number of 0.85 the longitudinal stability at zero lift.began to increase; however, the actual magnitude of the stability derivative did not exceed controllable limits up to a Mach number of 0 .go. The approximate variation of elevator and stabilizer effective- ness With Mach number

11、18 ahom in figure 10. kCOIIEliE,bnCieB in the data prevented. more detailed and accurate evaluation of these parameters. However, %he curves presented are believed to be representatlve of the characteristics of these control surfaces. me slope of the elevatodinge+nament curves (fig. 11) increased wi

12、th Mach nmhr for large elevator deflections but decreased for emall deflections. At amall deflections there was a tendency toward overbalance which actually occurred.at a Mach number of 0.875 with zero stabilizer incidence and 831 angle of attack of 4. While data for k0 angle of attack at 0.90 Mach

13、ntmiber are no% available, indication8 are that overbalarnce would have occurred. Little change in elevator hingeinwnent coefficient with change in stabilizer Inctdence wae noticeable below about 0.85 Mach number. - Figure 12 presents the variation of stabilizer hingelnament coefficient with elevato

14、r deflection. The variations of hinge-moment coefficient with both angle of attack and Mach number were relatively oonstat within the range of the test. The variation of etabillzer hinge-mament coefficient with stabilizer incidence le shown in figure 13. .i - The elevator anglea reqnfred for level f

15、light were calculated with an assumed gross weight of 13,100 pounds. Wse deflections together with the stick forcea required to mahtaln balance at several altitudes and zero stabflizer incidence are shown in figure 14. Since the stabilizer effectiveneee was approximately 2 to 3 times that of the ele

16、vator, it is apparent that the stabilizer X&B sufficiently effective to trim the model at all speeb included in the range of the teat. As indicated by figure 15, the aileron effectiveness remained easentially constant betwee3 Mach numbere of 0.3 and 0.9, although there W&E 8crme indicatlcm of reduce

17、d effectiveneee at the higher angles of attack at a Mach number of 0.90. At all other Mach numbers Kithin the range of the tests the effect of increasing the angle of Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-9 attack was noticeable but not ser

18、ious. Figure 16 presents the aileron hinge+uament coeff icients. A- Wing Leadin Slats The lift characteristics of the model for several positions of the leadinvdge slat are shown in figure 17. me effect of delayfng the stall at high let coefficients le clearly apparent at low Mach numbers. At a Mach

19、 number of 0.30 the extended slats increased the lift coefficient at which stall occurred about 0.25. At 6mall angles of attack the extended slat6 reduced.“Lhe lift coefficient slightly. However, this effect is diminished &a the angle of attack is increaeed and ia revereed at high angles - At low li

20、ft coefficients the extended slats also caused an increase in the drag coefficient of about 0.015 to 0 .020. However, because the extended slats delayed the stall, the drag coefficients at high lift coefficients were emaller with the slats extended. Be increment of drag caused by the extended slats

21、at low lift coeffi- cients remafned essentially conetant with Mach ntmiber (See fig. 18.) c Figures 19 and 20 &ow the effect of the ehts on the pitching- moment characteristics of the model. At low Mach numbers, the fully extended slat alleviatsd the tip stall encountered with the slat longitudinall

22、y stable. However, for a mKU range of Lift coefficiente immedfately below the stall the model exhibited a tendency for lnetability even with the slat extended. Externion of the slats at Wh numbers above 0.80 and lift coefficients below 0.20 resulted in serious loss of etatic longitudinal stability.

23、- retracted., so that at the maxlmrmL lift coefficient the model was Ffgure 21 presents the effect of the slats m the alhron effectiveness. In general, the slata decreased the effectiveness of the aileron for upward deflectiona and increased it for downward deflections. The effect WBB in both cases.

24、 There is sane indication that the intermediate positions of khe slats caused greater loss than the extegded positions. Fuselagg-Eiide Dive Brakes Extending the fuselage dive brakes produced negligible effect 011 the LCft of the model. (See fig. 22 .) Provided by IHSNot for ResaleNo reproduction or

25、networking permitted without license from IHS-,-,-10 - NACA RM No. A7IC28 The increase in drag coefficient due to the dfve brake8 amartlted to about 0.007 for each loo deflection d the brake and increased only slightly with Mach number. (See fig. 23.) Figure 24 shows that Me dive brakes supplied a p

26、ositive pitching-mament increment to the model approximately equal in effect to 0 .To of elevator deflection for each 10 of brake deflec- tion, giving a maximum effect comgazable to about 6 of upward elevator deflection with the brake completely extended. Bo important effect on the etatic longitudin

27、al stability wa noted. The effectiveness of the elevator WE reduced approximately 35 percent with the dive brakes deflected 850, ae indicated in figure 25. The percentage loa8 in effectiveness remained relatively constant with Mach number. (Discretion should be employed In the use of fig. 25 as the

28、limited amount of data obtained was somewhat . erratioJ The following conclusions may be drawn from the preceding discussion: 1. At low lift coefficiente divergence of the drag occurred at a Mach number of approximately 0.86. 2. The model exhibited no uncontrollable tendency to nose down at Mach nmb

29、ere within the limits of the tests (0.30 to 0.90) . 3. Btatic longitudinal stability began to increaee at a Nch number of about 0.85 but did not exceed controllable limits within the range of the tests. 4. The extended wing-leading-edepe alats cause longitudinal instability at low lift coefficients

30、and high Mach numbers but were otherwise effective in delaying the stall at high angles of attack and preventing instability at high lift coefficients. 5. Each IO“ deflection of the fwelage-side dive brakes supplied a drag-coefficient increment of about 0.007 and an incre- ment of positive pitchfng

31、moment about equal. that produced by 0.7 upward elevator deflection. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA RM Ro. Ap8 I1 6. The effectiveness of the elevator =E reduced about 35 e percent with the dive brakes deflected 850. he s Aerona

32、utical Lab oratory, National Advisory Committee for Aeronautics, Moffett FielB, Calif. 1. Bow, Lee E., and Morrill, Charles P., Jr. : The Aerodynamic Effects of Modifications to the Wing and Wing+?uaeiage htersection of an Airplane Model with the Wtng Swept Back 35. RACA CRM No. A7J02, 1947. 2. Bodd

33、y, Lee E., and Morrill, Charles P., Jr. : The Aerodynamic Effects of Rockets and Fuel Tanks Mounted Under .the Swept- Back Wing of an Airplane Model. TUCA CRM No. ATJ03, 1947. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. r Provided by IHSNot for

34、 ResaleNo reproduction or networking permitted without license from IHS-,-,-WARM Ro. Am8 13 (a) Wee-qwter front view. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Provided by IHSNot for ResaleNo reproduction or networking permitted without license

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