Computational Study to Assess the Usage of Asymmetric Canard as Yaw Control Device for a Generic Fighter Aircraft

The maneuvering capability of a fighter aircraft employing delta wings, at low speeds, can be significantly improved by enhancing the high angle of attack aerodynamic stability and control characteristics. Provision of additional control power through certain unconventional means would help in overcoming the loss of control power happening at high angles of attack due to certain flow features like vortex break down and fore-body induced asymmetrical flow features. This paper explores the possibility of using an asymmetric deflection of canard surface for generating yawing moments on a close coupled canard-delta wing fighter aircraft, at subsonic Mach numbers. RANS computations using CFD++ solver were carried out for the configuration with asymmetric canard deflection. The results from the computations were compared with the experimental wind tunnel test results for the same configuration. The yawing moments produced by the asymmetric canard deflection have been compared against that produced by the rudder and presented. The results from the CFD simulations were used to explain the interactions of vortices shed by the up and down deflected canard and the delta wing vortical flow, when compared to the undeflected canards.