Low-speed tunnel model tests on tailplane rolling moments in sideslip

Abstract

To provide data for stressing purposes, measurements have been made of the effect of sideslip on the rolling moment on a 41.5-deg swept-back tailplane mounted at three heights on the fin of a one fifth scale model of a single jet aircraft with a 4O-deg swept-back wing. Incidence and tailplane setting were varied, and the effects of rudder deflection were obtained with the tailplane at the top of the fin. Brief results on a delta aircraft model with a delta tailplane at the top of the fin are also included. (a) At zero tailplane lift, for tail heights, 0.31, 0.62 and 0.99 times the fin height external to the body, the values of (-lv tail) are 0.111, 0.172 and 0.199 respectively. These values are increased slightly by increase of incidence. (b) The variation with tailplane lift is as estimated for the tailplane alone. (c) Deflecting the rudder changes the rolling moment on the high tailplane in proportion to the change of side force on the fin and rudder. A smaller effect would be expected on lower tailplanes where the flow round the body contributes more to the rolling moment.