Accession Number : ADP004068

Title :   Full Scale Experiments into the Use of Large-Body-Breakup Devices for Drag Reduction on Aircraft,


Personal Author(s) : Bertelrud,A.

Report Date : AUG 1984

Pagination or Media Count : 16

Abstract : 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 M=0.92 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.

Descriptors :   *Swept wings, *Boundary layer control, Drag reduction, Flight testing, Skin friction, Eddies(Fluid mechanics), Subsonic flow, Transonic flow, Stalling, Sweden

Distribution Statement : APPROVED FOR PUBLIC RELEASE