Reynolds Number Effects on Off-Design Stability and Control Characteristics of Supersonic Transports

Abstract

A high Reynolds number wind-tunnel test was conducted to assess Reynolds number effects on the stability and control characteristics of a realistic, second-generation supersonic transport concept. The testing included longitudinal and lateral/directional studies at transonic and low-speed, high-lift landing conditions across a range of Reynolds numbers from that available in conventional wind tunnels to near-flight conditions. Results presented focus on Reynolds number sensitivities of the stability and control characteristics at Mach 0.30 and 0.95 for a configuration including empennage. The angle of attack where the pitching-moment departure occurred increased with higher Reynolds numbers for both the landing and transonic configurations. Stabilizer effectiveness and directional stability increased with the Reynolds number for both configurations. The landing configuration without forebody chines exhibited a large yawing-moment departure at high angles of attack and zero sideslip that varied with increasing Reynolds numbers. This departure characteristic nearly disappeared when forebody chines were added. The landing configuration's rudder effectiveness also exhibited sensitivities to changes in Reynolds number. This study extends the existing Reynolds number database for supersonic transports operating at subsonic conditions.