Full Scale Experiments into the Use of Large-Body-Breakup Devices for Drag Reduction on Aircraft,
AERONAUTICAL RESEARCH INST OF SWEDEN STOCKHOLM
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A flight test was performed to explore the feasibility of using LEBU Large-Eddy-Breakup devices to reduce the drag of aircraft. Two geometrical shapes of ribbons were used, and the development of local skin friction was monitored downstream. The aircraft was a swept-wing attack aircraft, and the flights covered the entire subsonic regime from M0.92 down to stall conditions. Flight altitudes were 1, 4.5, 7 and 10 km to explore various combinations of angle of attack, Mach and Reynolds numbers. An essential part of the study was 1 to learn how to apply the devices, and 2 to explore the effects the devices might have on the flight characteristics of the aircraft -- for example, close to stall or when a shock was present on the wing. Some information was obtained concerning the turbulence characteristics downstream. A discussion of the downstream amplification effect due to the drag at the device is provided.