Abstract
Aircraft adopting USB(Upper Surface Blowing) concept as a powered lift system achieves powered lift augumentation by deflecting the engine exhaust flow over the wing and the extended USB flap by Coanda principles. To obtain higher powered lift, optimal engine exhaust nozzles design and engine allocation which enhance effectively exhaust flow turning performance are important factors.
This report describes the exhaust flow characteristicsin the case of varying space between two engines installated on the semi-span USB powered lift model. Measurements of Exhaust flows behind two engines were made by a traversing wake rake with 5-holes pitot tube in NAL 2m×2m Gust Wind Tunnel.
