A wind tunnel investigation of the aerodynamic characteristics of high-lift devices on supersonic wings at low subsonic speed

Abstract

An investigation was made to determine the effects of various full- and partial-span high-lift devices on the lift, drag, and pitching moment characteristics of a straight wing and a highly sweptforward wing, both having an aspect ratio of 1.72 and a thin double wedge symmetrical airfoil section. Split, extended leading edge, and extended trailing edge flaps were tested at various deflection angles on each wing alone and also on wing-fuselage combinations. In addition, plain leading edge flaps extending over a portion of the outboard span were tested on the sweptforward wing. Tuft surveys were made on typical model configurations to determine the change in stall pattern due to variation in the angle of attack. From the results of the tests it was found that a given flap configuration produced approximately equal increments of maximum lift on the sweptforward wing alone and on the same wing combined with a fuselage. Comparison of the results obtained with the straight wing showed that the maximum lift increments were lower for a given flap used on wing plus fuselage than those obtained with the same flap on the basic straight wing. When considered from the maximum lift standpoint, the extended trailing edge flap was superior to either split or extended leading edge flap. Reduced span flaps were not as effective on the sweptforward wing, as the comparable full span flap. In the case of the straight wing alone, reduced span split and extended trailing edge flaps produced higher maximum lifts than did the corresponding full span configuration. This effect was also observed with the split flap tests on the straight wing combined with the fuselage. The experimental work was performed in the Cal Tech-Merrill wind tunnel located on the Pasadena City College campus.