Aerodynamic characteristics of crescent and elliptic wings at high angles of attack

Abstract

Static longitudinal- and lateral-directional forces and moments were measured for an elliptic- and crescent-wing model in the NASA Langley Research Center 14 x 22 ft subsonic tunnel for an angle-of-attack range that included stall and poststall conditions and at a Reynolds number of about 1.8 X 106, based on the average wing chord. The force and moment data and the flow-visualization results indicated that the crescent-wing model, with its highly swept tips, produced better high angle-of-attack aerodynamic characteristics than the unswept elliptic model. Leading-edge separation-induced vortex flow over the highly swept tips is thought to produce this improved behavior. The design concept of combining vortex flow over the outboard wing portion at high angles of attack and attached flow over the entire wing at cruise/climb conditions should result in safer and more efficient airplanes.