Experiments on a 60° delta wing with vortex flaps and vortex plates

Abstract Low speed wind tunnel tests have been made to investigate the flow around a leading edge vortex flap at the maximum LID condition. Tests were also made to measure the performance of a vortex plate. The force measurements and flow visualisation tests were conducted on a 0·53 m span 60° delta wing model. Results indicate that the lift to drag ratio is a maximum for any given flap deflection angle that the flow comes smoothly onto the deflected vortex flap without forming a large leading edge separation vortex on the flap surface. The benefit of the vortex plate is seen in the drag results which are smaller than those for the datum wing. This benefit is due to leading edge suction acting on the forward facing region between the delta wing and the vortex plate.