1、r NASA TECHNICAL NOTE cy cy cy Y n z I-= EFFECT OF ENGINE POSITION AND HIGH-LIFT DEVICES ON LOA KI AERODYNAMIC CHARACTERISTICS OF AN EXTERNAL-FLOW JET-FLAP STOL MODEL Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-1. Report No. 2. Government Accessi
2、on No. NASA TN D-6222 .I 4. Title and Subtitle EFFECT OF ENGINE POSITION AND HIGH-LIFT DEVICES ON AERODYNAMIC CHARACTERISTICS OF AN EXTERNAL-FLO JET-FLAP STOL MODEL 7. Author(s) Charles C. Smith, Jr. 9. Performing Organization Name and Address NASA Langley Research Center Hampton, Va. 23365 2. Spons
3、oring Agency Name and Address National Aeronautics and Space Administration Washington, D.C. 20546 5. Supplementary Notes 6. Abstract TECH LIBRARY KAFB, NM Illllllllllllllllllllllll%11111 Ill1 0332939 3. Recipients Catalog NO. 5. Report Date March 1971 6. Performing Organization Code 8. Performing O
4、rganization Report No. L-7581 10. Work Unit No. 72 1-01- 11-06 11. Contract or Grant No. 13. Type of Report and Period Covered Technical Note 14. Sponsoring Agency Code An investigation has been conducted to provide some basic information on the aerody namic design parameters of an external-flow jet
5、-flap configuration. Included in the inves tigation were static Porce tests to determine the effects of engine vertical and longitudinal position, jet-exhaust deflectors, flap size and type, leading-edge slat chord and deflection, and gap and overlap of the slats and flaps. The force tests were made
6、 in the Langley full-scale tunnel with a model having an unswept untapered wing and powered by four simulated high-bypass-ratio turbofan engines. 17. Key-Words (Suggested by Authoris) 18. Distribution Statement External-flow jet flap Unelassified - Unlimited High lift Stability and control STOL 19.
7、Security Classif. (of this report) II 20. Security Classif. (of this page) II 21.NO. of Pages 1 22. Price. Unclassified Unclassified 140 $3.00 For sale by the National Technical Information Service, Springfield, Virginia 22151 Provided by IHSNot for ResaleNo reproduction or networking permitted with
8、out license from IHS-,-,-EFFECT OF ENGINE POSITION AND HIGH-LIFT DEVICES ON AERODYNAMIC CHARACTEFUSTICS OF AN EXTERNAL-FLOW JET-FLAP STOL MODEL By Charles C. Smith, Jr. Langley Research Center SUMMARY An investigation has been conducted to provide some basic information on the aero dynamic design pa
9、rameters of an external-flow jet-flap configuration. Included in the investigation were static force tests to determine the effects of engine vertical and longi tudinal position, jet-exhaust deflectors, flap size and type, leading-edge slat chord and deflection, and gap and overlap of the slats and
10、flaps. The force tests were made in the Langley full-scale tunnel with a model having an unswept untapered wing and powered by four simulated high-bypass-ratio turbofan engines. The results of the investigation showed that higher lift and better turning of the jet were obtained with the engines up c
11、lose to the wing rather than well below the wing. Exhaust deflectors improved the lift and turning of the jet for a given installed engine thrust especially for the engine positions well below the wing. Large-chord flaps were found to produce more lift for a given installed engine thrust than small-
12、chord flaps. Leading-edge slat deflections and chords slightly larger than those used for more normal lift operation were found to be necessary for high-lift jet-flap operation. Double-slotted flap and leading-edge slat gaps and overlaps generally used for normal lift operation were also found to be
13、 effective for high-lift jet-flap operation. INTRODUCTION At the present time considerable interest is being shown in jet-powered STOL (short take-off and landing) aircraft. One promising means of achieving the high lift required for operation of such aircraft is the external-flow jet-augmented flap
14、. Early experimental work demonstrated the lift capability of this concept. (For example, see refs. 1 to 5.) Recent extension of this research into the area of high-thrust-weight-ratio turbofan aircraft has shown that the external-flow jet flap effectively produces the high lift required for STOL op
15、eration (refs. 6 to 9). Although considerable wind-tunnel research has been conducted on the external-flow jet-augmented flap, the main objective of most of the work in the past has been to explore Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-the
16、general area of performance and stability and control with particular reference to problem areas and to finding practical solutions to the problems, so that the overall fea sibility of the concept in terms of practical reliable application could be accurately assessed. This research has provided the
17、 necessary information to show that the external-flow jet-augmented flap effectively produces high lift on turbofan STOL aircraft but has provided very little information relative to the optimization of the jet-flap param eters involved. Because of the increased interest at the present time in the j
18、et-flap con cept, there is now a need for more detailed information for the rational design of such systems. A program has been started at the Langley Research Center to provide basic design information on the effects of geometric variables such as wing planform, engine location, jet-exhaust deflect
19、ors, flap span, flap size and type, leading-edge high-lift devices, and horizontal- and vertical-tail locations. The program will consist mainly of static force tests but will also include pressure distribution measurements for deter mining lift distribution along the wing chord and span. This paper
20、 presents the results of part of the general investigation and consists of static force tests made to determine the effects of engine position, thrust deflectors, and leading-edge and trailing-edge flap geometry on the aerodynamic characteristics of an external-flow jet-flap configuration without ve
21、rtical- and horizontal-tail surfaces. The model used in the investigation was powered by four simulated high-bypass-ratio turbofan engines and was equipped with an unswept untapered wing with double-slotted flaps. The tests were made over an angle-of-attack range for several thrust coefficients and
22、for several flap deflections. SYMBOLS The data are referred to the stability-axis system with the origin at the center-of gravity location (0.40 mean aerodynamic chord) shown in figure 1. Measurements were made in the U.S. Customary Units; they are presented herein in the International System of Uni
23、ts (SI) with the equivalent values in the U.S. Customary Units given parenthetically. CD drag coefficient, FD/qS CL lift coefficient, FL/qS CL,trim trim lift coefficient, Cm cL+l/c Cm pitching-moment coefficient, My/qSc c, gross -thrust coefficient, T/qS 2 Provided by IHSNot for ResaleNo reproductio
24、n or networking permitted without license from IHS-,-,-Y 6f 6f1 6f2 local wing chord, 0.254 m (0.833 ft) net axial force, N (lb) drag force, N (lb) lift force, N (lb) normal force, N (lb) tail length (assumed), m (ft) pitching moment, m-N (ft-lb) free-stream dynamic pres sure, N/m2 (lb/ft2) wing are
25、a, 0.45 m2 (4.86 ft2) total installed engine thrust, N (lb) longitudinal coordinate of airfoil chord, percent vane or flap chord airfoil upper surface ordinate, percent vane or flap chord airfoil lower surface ordinate, percent vane or flap chord angle of attack, deg flight-path angle, deg total def
26、lection of double-slotted flap, 6fl + 6f2, deg deflection of vane from wing chord, deg deflection of flap from vane chord, deg Fjet or flap turning angle, tan-1 3,deg FA 3 X Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-deflection of leading-edge s
27、lat from wing chord, deg VFJ+ FA flap turning efficiency, T MODELANDAPPARATUS The investigation was conducted on the four-engine high-wing model illustrated in figure 1. The wing was unswept and untapered and incorporated a leading-edge slat and double-slotted trailing-edge flaps. An NACA 4415 airfo
28、il section was used on the wing. The airfoil sections for the vane and flap were identical, and their coordinates are pre sented in table I. Detailed sketches of the wing-leading-edge slat and trailing-edge flap assembly are shown in figure 2. Also shown is the position of the moment reference cente
29、r relative to the wing. Changes in the leading-edge slat and trailing-edge flap deflections, overlaps, and gaps were obtained by using special brackets for each setting. In all tests with flaps deflected, 6fl = 6f2. No vertical- or horizontal-tail surfaces were used in the present investigation. The
30、 model engines represented high-bypass-ratio fan-jet engines, and compressed air-driven turbines drove the fans. The basic engine is illustrated in figure 3(a) and details of the jet-exhaust deflectors used in some tests are shown in figure 3(b). The deflector design was based on that of the small d
31、eflectors discussed in reference 6. Four sets of engine pylons were provided to give four different engine positions relative to the wing leading edge. (See fig. 4.) The model was sting mounted on a six-component strain-gage balance in the 9.1- by 18.3-m (30- by 60-ft) test section of the Langley fu
32、ll-scale tunnel. TESTS AND PROCEDURES In preparation for the tests, engine calibrations were made to determine gross thrust as a function of engine rotational speed in the static condition (zero angle of attack with the thrust deflectors off). These calibrations were made with bellmouth inlets insta
33、lled on the engines. The tests were then run by setting the engine rotational speed to give the desired thrust and holding these speeds constant over the angle-of-attack range. Tests were made at zero airspeed to determine flap turning angles 6j and turning efficiencies under static conditions. Thes
34、e tests and the wind-on tests were made with the small-vane-large-flap configuration deflected 35O, 55O, and 70. The trailing-edge flap and leading-edge slat parameters used in these tests were as follows: 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IH
35、S-,-,-Vane, 0.02gap Flap, 0.02gap Slat, Overlap, 0.02gap Slat chord, 0.19 Slat deflection, 55O For flap deflections of 35O and 700, four different engine positions with and without exhaust deflectors were tested. For a flap deflection of 55O, only engine positions 1 and 4 were tested. Tests to deter
36、mine the effect of wing-flap geometry were made with the flap deflected at 55O only. In these tests, various changes were made to the double-slotted flap element gaps and overlaps, flap chord and element arrangement, and leading-edge geometry. All the wind-on tests were made over an angle-of-attack
37、range from -4O to 31 at gross-thrust coefficients Cp of 0, 1.38, 2.75, 4.13, and 5.50. The free-stream dynamic pressure was 154.17 N/m2 (3.22 psf) which corresponds to an airspeed of 15.85 m/sec (52 ft/sec). The Reynolds number was 2.78 X lo5 based on the wing chord. No wind-tunnel jet-boundary corr
38、ections were considered necessary since the model was very small relative to the test-section size. RESULTS AND DISCUSSION The longitudinal aerodynamic characteristics of the model with flaps retracted (6f = OO), with engine position 4, and without exhaust deflectors are presented in figure 5 as an
39、aid in analysis of the test results. Effect of Engine Position on Static Turning Since the effectiveness of a jet-flap system is dependent to a large degree upon the capability of the system for turning and spreading the jet exhaust efficiently, static turning tests were first made of all the config
40、urations included in the present investiga tion to identify the relative performance of each. Results of these tests (figs. 6 and 7) show that jet turning angles were higher for the engines positioned vertically close to the wing (positions 1 and 2). For engines positioned low and forward of the win
41、g (positions 3 and 4), tilting the engine nose down (position 4) produced some improvement in jet turning angle. For almost all the engine positions, jet-exhaust deflectors used to direct the exhaust toward the leading edge of the flap system improved the turning angle. The ratio of normal force to
42、thrust FN/T is plotted as a function of the ratio of net axial forces to thrust FA/T in figure 7. The data indicate that the average losses caused by turning and spreading the jet were about 20 percent for 35O flap deflection, about 35 percent for 5 Provided by IHSNot for ResaleNo reproduction or ne
43、tworking permitted without license from IHS-,-,-55O flap deflection, and about 40 percent for 70 flap deflection. The deflectors were generally detrimental to the turning efficiency, but this effect was not consistent since for some engine positions at the high flap deflections the deflectors actual
44、ly increased the flap turning efficiency. Effect of Engine Position on Aerodynamic Characteristics The basic aerodynamic data for the model with engine positions 1to 4 with and with out exhaust deflectors are presented in figures 8 and 9 for 35O flap deflection, in fig ures 10 and 11 for 55O flap de
45、flection, and in figures 12 and 13 for 70 flap deflection. These data show that increasing the thrust coefficient caused an increase in stall angle of attack, maximum lift coefficient, and nose-down pitching moments. For the highest flap deflection (6f = 700), maximum lift coefficients up to about 1
46、2 (untrimmed) could be pro duced for a gross-thrust coefficient of 5.50. In order to show the effects of engine position on the longitudinal aerodynamic char acteristics more clearly, the data of figures 8 to 13 have been replotted in summary form for two values of Cp (2.75 and 5.50) in figures 14 t
47、o 19. These data indicate that gen erally the highest lift was obtained with the engines vertically up close to the wing (posi tions 1 and 2) for all test conditions. For the 35O flap deflection (figs. 14 and 15), moving the engines forward from position 1 to position 2 actually increased the lift p
48、erformance slightly; whereas, for the 70 flap deflection (figs. 18 and 19), moving the engines from position 1to position 2 caused an appreciable drop in lift. The deterioration in lift per formance for engine position 2 with increasing flap deflection is probably the result of an excessive amount o
49、f the jet exhaust being induced over the top of the wing by the high cir culation lift. Previous investigations (for example, ref. 7) have revealed that when this condition exists, there is a tendency for the flow to break away from the wing at the flap instead of turning and following the flap as it does for lower surface blowing. For the low engine positions, having the engin
