Some exploratory jet-flap tests on a 60-deg delta wing

Abstract

Summary.--As a preliminary investigation of the effects of high sweep and low aspect ratio on jet-flap wings, some wind-tunnel experiments were carried out on a half-model of a 60-deg delta wing, already tested with blowing to prevent flow separation over a trailing-edge flap. Much larger values of the blowing-momentum coefficient C than before were achieved by using a low tunnel speed. Balance measurements were made of lift, pitching moment and thrust for C values up to 1.5, wing incidences between - 4 deg and + 20 deg, and flap angles of 30, 60 and 90 deg. Although substantial magnification of the direct jet lift occurred, the movement of the centre of lift was appreciable and positive values of the thrust occurred only at the lowest flap angle.