Aerodynamic effects of canard position on a wing body configuration in symmetrical flow

A close-coupled canard-wing-body combination has been investigated experimentally in symmetrical flow. The configuration consisted of a delta canard and a delta wing (Ac = Aw = 2.3) and a body of revolution as fuselage. The vertical position of the canard as well as its setting angle have been varied systematically. Three-component and surface pressure distribution measurements as well as flow visualizations by means of the laser-lightsheet technique have been carried out at Reynoldsnumbers Re = 1.1 10 and 1.4 • 10. The aerodynamic characteristics of this configuration are governed by the interference between the vortex systems of canard and wing and by vortex breakdown within these vortices. The effects of the canard vortex system on the flow over the wing are large for low positions and large setting angles of the canard: Both vortex systems merge with increasing angle of attack and the vortical wing flow is finally destroyed by vortex breakdown. On the other hand vortex breakdown within the canard vortices is kept away from the canard due to the favourable acceleration effect from the wing up to very high angles of attack, and this leads to high maximum lift for high canard positions. At very low canard positions however this favourable interference effect is lost. Vortex breakdown within the canard vortices destroys the vortical canard flow at all angles of attack and this leads to a considerable loss of maximum lift.