Development of the A-6/Circulation Control Wing Flight Demonstrator Configuration

Abstract : Wind tunnel investigations were conducted on a 1/8.5-scale model of the A-6/Circulation Control Wing (CCW) flight demonstrator aircraft in order to confirm the high lift capability of the concept, to improve lifting and control surfaces and to provide supporting data to assure safety of flight and adequate handling of the full-scale aircraft. The best configuration developed during these investigations produced a 2.2-fold increase in C sub L max over the conventional A-6A high lift configuration. This CCW configuration was compromised to simplify testbed aircraft modifications, reduce construction costs, and provide a larger range of parameters obtainable during flight testing, yet in the final configuration, still provided trimmed aerodynamic C sub L max double that of the standard A-6A. Additional studies included: Reynolds number and slot height variations, operation in ground effect, stall and stall hysteresis, effect of lifting surface imperfection, additional drag generators, flow field at the tail surface, and longitudinal stability levels with aft c.g. shift. Data from the present studies should provide an adequate base upon which to construct the full-scale flight demonstrator and predict its STOL performance and longitudinal flying qualities.