AERODYNAMIC CHARACTERISTICS AT A MACH NUMBER OF 1.38 OF FOUR WINGS OF ASPECT RATIO 4 HAVING QUARTER-CHORD SWEEP ANGLES OF 0°, 35°, 45°, AND 60°

摘要

A description of the Langley 6-inch supersonic tunnel is presented together with results of tests conducted at a Mach number pf 1.38 and a Reynolds number of 390,000, to determine the supersonic aerodynamic characteristics of four sweptback wings and wing-body configurations. The wings were all of aspect ratio 4, taper ratio 0.6, and NACA 65A006 airfoil section. The sweepback angles used were 0°, 35°, 45°, and 60°.nAt the low Reynolds number of the present tests, laminar separation occurred near the trailing edge of all wings producing reduced stability in the low-lift range. The effects of increasing angle of sweepback were to reduce the lift-curve slope and zero-lift drag coefficient, to increase the maximum lift-drag ratio, and to produce an outward shift in the lateral center of pressure. The measured lift-curve slopes were less for all wings than those predicted from linearized theory. Good agreement was obtained between theoretical and experimental aerodynamic-center location in the lift-coefficient range not-affected by separation effects for sweep angles up to 45°. For the 60° sweptback wing at lift coefficients above 0.2$, a leading-edge separation vortex produced severe instability with reduced lift and increased drag. At lift coef¬ficients below 0.25, this wing exhibited a considerable proportion of the theoretically available leading-edge suction. Addition of either leading-edge roughness, blunt trailing edge, or a fence to the 60° wing improved the stability characteristics at low lift coefficients. The fence also decreased the instability of the 60° wing at high lift coefficients.