NACA-RM-L9F10

Abstract

INTRODUCTION <br>It has been indicated from recent research on wing plan forms suitable for moderate supersonic flight that the 1aw-speed longitudinal stability problems of the triangular plan-form wing appear to be less severe than for the conventional sweptback wing; because of its high taper and low aspect ratio, the triangular wing also has definite structural advantages over the conventional swept wings. <br>Theoretical calculations and experimental studies have shown that such wing plan form will develop lift-drag ratios at supersonic Mach numbers which are sufficiently high for flight, being, however, generally lower than those of other plan forms, Low-speed research has also indicated poor landing characteristics of delta plan forms because of the relatively low lift-drag ratios, -particularly in the high-lift condition. <br>The results of a theoretical study of triangular wings (reference 1) and a pressure-distribution investigation (reference 2) show that high loadings occur along the leading edge of triangular wings. These high loadings and their associated adverse pressure gradients result in separation over the leading-edge portion of the wing and develop vortices that flow back over the wing (references 1 to 5) even at relatively low lifts. <br>The present investigation made in the Lagley 300 PHZ 7- by 10-foot tunnel is a preliminary study aimed at increasing the low-speed lift-drag ratio by incorporating camber into a 60&#176; delta wing. Camber was simulated for this investigation by deflecting full-span leading-edge flaps in an effort to reduce the high peak pressure along the leading edge and thus retard the separation effects. The configuration tested was chosen as the first attempt at solving this problem became it approaches a conical shape, which was believed t o be efficient in unloading the lea- edge, and because of its structural simplicity compared to other leading-edge flaps considered.