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 effect of various high lift devices on a highly sweptforward wing with a leading edge sweep angle of 55 degrees and on a straight wing, both wings having an aspect ratio of 1.72 and the same span. Experimental tests were made in the Cal Tech - Merrill low speed wind tunnel at Pasadena City College on both types of wing with and without fuselage. High lift devices investigated were extended leading edge flaps, plain leading edge flaps, extended trailing edge flaps, and split flaps. Both 70 per cent and full span configurations were used in each case except for the plain leading edge flaps. All force data was reduced to standard non-dimensional lift, drag, and pitching moment coefficients, and the results presented in standard graphical form. In addition, photographs of tuft surveys were made for typical configurations. The maximum lift coefficient obtained from the basic wings was approximately the same for both, but the angle of attack for maximum lift was appreciably lower for the straight wing than for the sweptforward wing. The addition of the fuselage increased the maximum lift coefficient of both the basic wings and of the sweptforward wing with flap configurations, but the fuselage was detrimental to the lift for the straight wing with flap configurations. Straight wing configurations gave respectively higher maximum lift coefficients and larger lift curve slopes than on the comparable sweptforward wing models. All high lift devices investigated were more effective on the straight wing than on the sweptforward wing. Extended trailing edge flaps were the most effective of the flaps investigated in increasing the maximum lift, but gave the largest negative increase in the pitching moments. On the straight wing the 70 per cent span split and 70 per cent span extended trailing edge flaps at optimum flap deflection angles gave a higher maximum lift coefficient than the full span flaps at the optimum flap deflection. When the straight wing was mounted on the fuselage, this effect was true only for the split flaps.