ACTIVE CONTROL OF WING ROCK USING TANGENTIAL LEADING-EDGE BLOWING

Experiments were performed to demonstrate positive poststall roll cont rol of a free-to-roll wind-tunnel delta wing model using tangential le ading-edge blowing. Previous static experiments had shown that signifi cant rolling moments could be produced up to an angle of attack of 55 deg using asymmetric tangential leading-edge blowing. The implication was that poststall dynamic roll control ought to be possible using onl y blowing. To demonstrate experimentally that this was indeed the case , a free-to-roll wind-tunnel model sting mounting system and a pair of fast acting blowing control servo-valves were developed and manufactu red. An automatic feedback roll control algorithm using tangential lea ding-edge blowing was then synthesized and implemented on a digital co ntroller. Results from the present dynamic experiments indicated that with just symmetric blowing alone, wing rock at an angle of attack of 55 deg was damped. Furthermore, with the use of an automatic roll feed back control algorithm employing asymmetric blowing, the same wing roc k was stopped in less than one cycle of the limit-cycle oscillation.