Six-component low-speed tunnel tests of jet-flap complete models with variation of aspect ratio, dihedral, and sweepback, including the influence of ground proximity

Abstract

To investigate the basic aerodynamic characteristics of jet-flap aircraft, six-component force and moment measurements have been made on jet-flap complete models in the R.A.E. No. 2 11½ ft x 8½ ft low speed wind tunnel. The tests covered the effects produced by variations of wing aspect ratio, dihedral, and sweepback, and by ground proximity, on longitudinal and lateral static stability. Some of the more significant results outside ground influence include the high stalling incidence and CLmax values possible with a thick, heavily cambered jet-flap wing and the unexpected effects of the jet flap on lateral static stability. Proximity to the ground produced appreciable changes in downwash at the tailplane as soon as the jet sheet neared the ground, and caused large reductions in lift and stalling incidence once jet impingement occurred.