Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781723052477
Category :
Languages : en
Pages : 184
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A wind tunnel test was conducted on a six percent model of the F/A-18 at the NASA Ames 7 X 10-Foot Low Speed Wind Tunnel. The primary objective of the test was to evaluate several forebody vortex control configurations at high angles of attack in order to determine the most effective method of obtaining well behaved yawing moments, in preparation for the rotary balance test. Both mechanical and pneumatic systems were tested. Single and dual rotating nose tip strakes and a vertical nose strake were tested at different sizes and deflections. A series of jet blowing configurations were located at various fuselage stations, azimuth angles, and pointing angles ranging from straight aft to 60 deg canted inboard. Slot blowing was investigated for several slot lengths and fuselage stations. The effect of blowing rate was tested for both of these pneumatic systems. The most effective configurations were then further tested with a variation of both sideslip angle and Reynolds number over a range of angles of attack from 0 to 60 deg. It was found that a very robust system can be developed that provides yawing moments at angles of attack up to 60 deg that significantly exceeds that available from 30 deg of rudder deflection (F/A-18 maximum) at 0 deg angle of attack. Kramer, Brian R. and Suarez, Carlos J. and Malcolm, Gerald N. and Ayers, Bert F. Unspecified Center AIRCRAFT CONTROL; ANGLE OF ATTACK; BLOWING; F-18 AIRCRAFT; FOREBODIES; STRAKES; VORTICES; WIND TUNNEL TESTS; BOUNDARY LAYER CONTROL; LATERAL CONTROL; REYNOLDS NUMBER; YAWING MOMENTS...
Author:
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 188
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 188
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Author:
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 228
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 228
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Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781723577345
Category :
Languages : en
Pages : 222
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Book Description
A rotary-balance wind tunnel test was conducted on a six percent model of the F/A-18 at the NASA Ames 7 X 10-Foot Low Speed Wind Tunnel. The data reduction was specially written for the test in National Instruments' LabVIEW. The data acquisition, reduction and analysis was performed with a Macintosh computer. The primary objective of the test was to evaluate the effectiveness of several forebody vortex control configurations in a rotary flow field. The devices that were found to be the most effective during the static tests (Volume 1) were investigated and included both mechanical and pneumatic configurations. The mechanical systems evaluated were small, single and dual, rotating nose tip strakes and a vertical nose strake. The jet blowing configuration used nozzles canted inboard 60 degrees. A two segment tangential slot was also evaluated. The different techniques were evaluated at angles of attack of 30 degrees, 45 degrees, 51 degrees, and 60 degrees. Sideslip and Reynolds number were varied for some of the configurations. All of the techniques proved to be effective in the rotating flow field. The vertical nose strake had the largest 'envelope' of effectiveness. Forebody vortex control provides large, robust yawing moments at medium to high angles of attack, even during combat maneuvers such as loaded roll. Kramer, Brian R. and Suarez, Carlos J. and Malcolm, Gerald N. and Ayers, Bert F. Unspecified Center NASA-CR-4582-VOL-2, A-94055-VOL-2, NAS 1.26:4582-VOL-2 NAS2-13383...
Author: Brian R. Kramer
Publisher:
ISBN:
Category :
Languages : en
Pages : 183
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Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781723488238
Category :
Languages : en
Pages : 108
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Book Description
Wind tunnel investigations have been conducted of forebody strakes for yaw control on 0.06-scale models of the F/A-18 aircraft at free-stream Mach numbers of 0.20 to 0.90. The testing was conducted in the 7- by 10-Foot Transonic Tunnel at the David Taylor Research Center and the Langley 7- by 10-Foot High-Speed Tunnel. The principal objectives of the testing were to determine the effects of the Mach number and the strake plan form on the strake yaw control effectiveness and the corresponding strake vortex induced flow field. The wind tunnel model configurations simulated an actuated conformal strake deployed for maximum yaw control at high angles of attack. The test data included six-component forces and moments on the complete model, surface static pressure distributions on the forebody and wing leading-edge extensions, and on-surface and off-surface flow visualizations. The results from these studies show that the strake produces large yaw control increments at high angles of attack that exceed the effect of conventional rudders at low angles of attack. The strake yaw control increments diminish with increasing Mach number but continue to exceed the effect of rudder deflection at angles of attack greater than 30 degrees. The character of the strake vortex induced flow field is similar at subsonic and transonic speeds. Cropping the strake planform to account for geometric and structural constraints on the F-18 aircraft has a small effect on the yaw control increments at subsonic speeds and no effect at transonic speeds. Erickson, Gary E. and Murri, Daniel G. Langley Research Center DIRECTIONAL CONTROL; F-18 AIRCRAFT; FLOW VISUALIZATION; FOREBODIES; STRAKES; SUBSONIC SPEED; TRANSONIC SPEED; VORTICES; WIND TUNNEL TESTS; YAW; AERODYNAMICS; ANGLE OF ATTACK; FLOW DISTRIBUTION; MACH NUMBER; PLANFORMS; PRESSURE DISTRIBUTION; STATIC PRESSURE; VORTEX BREAKDOWN; VORTEX GENERATORS; YAWING MOMENTS...
Author:
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ISBN:
Category : Aeronautics
Languages : en
Pages : 440
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Author: Gary E. Erickson
Publisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 172
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