1、312 Copy55JQ6 NACA E FIL RESEARCH MEMORANDUM 0 LOW-SPEED STATIC STABILITY CHARACTERISTICS OF A COMPLETE CA MODEL WITH AN M-WING INMID AND HIGH POTION AND WITH THREE HORIZONTAL-TAIL HEIGHT By Paul G. Fournier Langley Aeronautical Laboratory Langley Field, Va.1 OCUiNT al Defense of the United States w
2、ithin the mean of the espionage laws, Title 18, U.S.C., Secs. 793 and 794, the transmission or revelation of which inmanner to an unauthorized person Is prohibited by law. oNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS WASH INGIOK: January 4, 1956 Restriction/Classification CancelledRestriction/Classi
3、fication CancelledRestriction/Classification CancelledProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA RN L55J06 NATIONAL ADVISORY COMMITTEE FOR AERONAUTICSRESEARCH MEMORANDUM LOW-SPEED STATIC STABILITY CHARACTERISTICS OF A COMPLETEMODEL WITH AN
4、M-WING IN MID AND HIGH POSITIONSAND WITH THREE HORIZONTAL-TAIL HEIGHTS By Paul G. Fournier SUMMARY An investigation was made of the low-speed static longitudinal and lateral stability characteristics of a model having an M-wing in mid and high positions and with three horizontal-tail heights. The wi
5、ng, having its sweep discontinuity located at 40-percent wing semispan, had an aspect ratio of 6, a taper ratio of 0.60, NACA 65AO09 airfoil sections parallel to the plane of syimnetry, and 450 sweep of the quarter-chord lines. The high wing improved the longitudinal stability characteristics of the
6、 mid-tail configuration and, in effect, made the stability character-istics of the mid-tail configuration approach the more favorable pitching-moment characteristics of the low-tail configuration. For either the mid-or high-wing arrangements, it appears that some longitudinal instability near maximu
7、m lift may exist when the T-tall configuration is used. The results indicate that raising the wing from the mid to the high position provided a slight decrease in drag at the higher lift coeffi-cients, but essentially caused no change in maximum lift-drag ratios. The results also indicate that, alth
8、ough raising the wing from the mid to the high position reduced the directional stability of the tail-on configurations by a substantial amount at low lift coefficients, the effects of wing height were negligible at high lift coefficients. All tail-on configurations were directionally stable through
9、out the lift-coefficient range, including the stall. Also, a positive increment of effective dihedral, over that for the inid.wing configuration, was noted for the wing-fuselage configuration with the high wing and. was in the same order as would be expected for swept or unswept wings. Restriction/C
10、lassification CancelledRestriction/Classification CancelledProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-2 CONFIDENTIAL NACA RN L55J06 INTRODUCTION Results of tests to determine the effect of spanwise location of the sweep discontinuity of M- and W
11、-wings on the static longitudinal and lat-eral stability characteristics of a complete model are presented in ref-erences 1 and 2, respectively. The results show that these wings (espe-cially the N type) provide favorable longitudinal stability characteristics and good directional stability at high
12、lift. Little advantage in sta-bility appeared to result from locating the sweep discontinuity of N-wings outboard of the 40-percent-semispan location; and since, from divergence-speed considerations for a given ratio of torsional stiffness to bending stiffness, it is desirable to keep the sweptforwa
13、rd panels of an M-wing relatively small (ref. 3), the M-wing with its sweep discontinuity at 40- percent semispan was selected for further study. During the tests of reference 1, it was noted that the flow above the sweptforward panel was directed toward the fuselage at positive angles of attack and
14、 that separation at the wing root occurred at low angles of attack. It was reasoned that flow separation at the wing root might be delayed somewhat by mounting the wing with .its upper surface tangent to the top of the fuselage, rather than having the chord plane of the wing located on the fuselage
15、center line. The present investigation there-fore was intended to determine any possible advantages of raising the wing height and, in, addition, to extend the range of tail height covered in references 1 and 2 to include a horizontal tail mounted at the top of the vertical tail (T-tail). The M-wing
16、 tested had an aspect ratio of 6, a taper ratio of 0.60, NACA 67A009 airfoil sections parallel to the plane of symmetry, and 470 sweep of the quarter-chord line. The data presented herein were obtained from tests in the Langley 300 MPH 7- by 10-foot wind tunnel. COEFFICIENTS AND SYMBOLS The stabilit
17、y system of axes used for the presentation of the data and the positive direction of forces, moments, and angles are shown in figure 1. All moments of the basic data are referred to the quarter-chord point of the wing mean aerodynamic chord. b wing span, ft CD drag coefficient, CD = -x CL lift coeff
18、icient, Lift qS CONFIDENTIALProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA RM L55J06 CONFIDENTIAL C1 rolling-moment coefficient, Rolling moment qSb Cm pitching-moment coefficient, Pitching moment qS C yawing-moment coefficient, Yawing moment qS
19、b Cx longitudinal-force coefficient, Longitudinal force qS C lateral-force coefficient, Lateral force qS C1 rolling moment due to sideslip, per degree Cnp yawing moment due to sideslip, per degree CY CY lateral force due to sideslip, - per degree wing mean aerodynamic chord, ft horizontal tail mean
20、aerodynamic chord, ft it angle of incidence of the horizontal tail with respect to fuselage center line, degreeCtIt tail length, distance from to ft q free-stream dynamic pressure, lb/sq ft S wing area, sq ft V free-stream velocity, ft/sec a. angle of attack, degree f3 angle of sideslip, degree AW i
21、ncrement due to wing height AV increment due to the contribution of the vertical tail (wFv-WF) P mass density of air, sings/cu ft CONFIDENTIAL5Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-COIWIDEWrIAL NACA RM L57J06 Notation of configuration: F fu
22、selage 11L horizontal tail, low tail HM horizontal tail, mid tail HT horizontal tail, T-tail T.O. horizontal tail off V original vertical tail V1 alternate vertical tail W wingMODEL AND APPARATUS The present investigation is a detailed study of a configuration having an M-wing with sweep discontinui
23、ty at 40-percent sernispan, for which some results have been presented in references 1 and 2. The wing had an aspect ratio of 6, a taper ratio of 0.6o, NACA 65AO09 airfoil sections parallel to the plane of symmetry, and 50 sweep of the quarter-chord lines. The horizontal tail had an aspect ratio of
24、ii-, a taper ratio of 0.60, 470 sweepback of the quarter-chord line, and NACA 65A006 airfoil sections parallel to the plane of symmetry. The fuselage had a fineness ratio of 10.86 which was achieved by cutting off a portion of the rear of a fineness-ratio-12 closed body of revolution, the ordinates
25、of which are presented in reference 1. The fuselage was constructed of wood and the wing was constructed of wood-bonded-to-steel reinforcing spars. A three-view drawing of the model with the wing at mid height is shown in fig-ure 2. The longitudinal reference location of the quarter-chord point of t
26、he wing mean aerodynamic chord, about which all moments and forces were taken, remained the same for both wing heights. The original model was constructed so that tests could be made with the horizontal tail at two tail heights, a low tail located on the mid-wing chord plane extended and a high tail
27、 located 20.8-percent wing semispan above the mid-wing chord plane extended. (See refs. 1 and 2.) CONFIDENTIALProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA BM L75J06 CONFIDENTIAL 5 In addition, to the low tail and high tail, the present invest
28、igation includes tests of the model with a T-tail located 47-percent wing semi-span above the mid-wing chord plane extended. This was achieved by using an alternate vertical tail which allowed the horizontal tail to be mounted as a T-tail. In order to clarify the notation of the location of the hori
29、-zontal tail in the present paper, the original high tail (refs. land 2) will be called the mid tail. The horizontal tail heights will now be des-ignated as a low-tail EL, a mid-tail EM, and a T-tail Details of the vertical location of the wing and the vertical loca-tions of the horizontal tail, inc
30、luding the alternate vertical tail, are presented in figure 5. The model was mounted on a single-strut support, which was in turn fastened to the mechanical balance system of the Langley 300 MPH 7- by 10-foot tunnel.TESTS AND CORRECTIONS All tests were made at a dynamic pressure of 45.22 pounds per
31、square foot, which for average tests conditions corresponds to a Mach number of about 0.17 and a Reynolds number of 1.27 X 106 based on the wing mean aerodynamic chord of 1.02 feet. The present investigation consists of tests made to determine both the lateral and longitudinal static stability chara
32、cteristics of the model with three tail heights. The parameters C 1 , C, and were determined from tests at sideslip angles of 5 through the angle-of-attack range from approximately -40 to 320. The angle of attack, lon-gitudinal force (-drag), and horizontal-tail-on pitching moment have been correcte
33、d for jet-boundary effects on the basis of unswept-wing theory by the method of reference 4. Reference 5 shows that the effect of sweep on these corrections is small. The dynamic pressure and drag coefficient have been corrected for blocking caused by the model and its wake by the method of referenc
34、e 6. Vertical buoyancy on the support strut, tunnel airflow inisalinement, and longitudinal pressure gradient have been accounted for in the computa-tion of the data. These data have not been corrected for the tares caused by the model-support strut; however, tare tests of a similar complete-model c
35、onfiguration have indicated that the tares corresponding to the lateral coefficients are small, that the correction to longitudinal force coeffi-cient is about 0.009 at zero lift, and that the correction to pitching- moment coefficient is small and independent of angle of attack through most of the
36、range.CONFIDENTIALProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-6 CONFIDENTIAL NACA RM L55J06 RESULTS AND DISCUSSION The basic longitudinal stability results are presented in figures 4 and 5 and are summarized as a function of lift coefficient toge
37、ther with data from reference 1 in figure 6. The basic lateral stability charac-teristics are presented in figure 7 and are summarized as a function of lift coefficient together with data from reference 2 in figures 8 and 9. Longitudinal Stability Characteristics The pitching-moment characteristics
38、included in the basic data (figs. 4 and 5) represent a center-of-gravity location at 0.25E. The static margin, therefore, varied somewhat with wing height and with tail configuration. In order to provide comparisons of pitching-moment curves under fairly realistic conditions, the summary data have b
39、een transferred to a center-of-gravity location such that a static margin of 0.10E is obtained for all configurations having it = 00 at zero lift (fig. 6). Complete-model configuration.- Comparison of the longitudinal sta-bility data of the complete model with the M-wing (static margin 0.10), presen
40、ted in parts (a) and (b) of figure 6, shows that the variation of wing height within the range considered, had little effect on the overall pitching-moment characteristics for either the low-tail or T-tail config-ration, except that the high wing with the T-tail showed some improve-ment above 280 an
41、gle of attack. However, the high wing improved the lon-gitudinal stability characteristics of the mid-tail configuration and in effect made the stability characteristics of the mid-tail configuration approach the more favorable pitching-moment characteristics of the low-tail configuration. This effe
42、ct is similar to that noted in previous investigations for several different configurations. (For instance, see ref. 7.) The effect of wing height on the lift-curve slope of the model with the various horizontal-tail heights (fig. 6(c) is small. The drag polars (fig. 6(d) indicate that the maximum l
43、ift-drag ratio is about the same for both wing heights but the high wing showed a slight decrease in lon-gitudinal force at the higher lift coefficients for all the horizontal-tail heights. Results of some tests (not presented) with tufts attached to the upper surface of the wing indicated that flow
44、 separation at the wing root was delayed somewhat by moving the wing to the high position. This prob-ably results from the reduced restriction to the flow above the wing sur- face at the plane of symmetry due to the absence of any part of the fuselage.CONFIDENTIALProvided by IHSNot for ResaleNo repr
45、oduction or networking permitted without license from IHS-,-,-NACA RM L55J06 CONFIDENTIAL 7 Although the vertical tail for the T-tail configuration was not the same as for the low- and mid-tail configurations (fig. ), it is felt that this difference would have a negligible effect on the longitudinal
46、 data presented herein.Lateral Stability Characteristics The basic data of the aerodynamic characteristics in sideslip of the model with the high wing as well as data with three horizontal-tail heights (low tail, mid tail, and T-tail) are presented in figure 7. It should be pointed out that there ca
47、n be no direct comparison of the lat-eral stability characteristics between the T-tail and the low-tail and mid-tail configurations because of the difference in the vertical tail used with the T-tail configuration. Therefore, the discussion of the lateral stability characteristics will not include a
48、 discussion of the contribution of the alternate vertical tail (Avl) to the lateral stabil- ity parameters. Comparison of results for the mid- and high-wing configurations are presented in figure 8. The largest effect of wing height on the aero-dynamic characteristics in sideslip of the WF configura
49、tion (fig. 8(a) is in the change of the effective dihedral C 1 . At zero angle of attack, the high wing contributes a positive increment of effective dihedral, _CZ 0 This effect is as would be expected for swept or unswept wings (see ref. 8) and results from the cross flow about the yawed fuselage which induces a positive angle of attack for the leading wing (increased lift) a
