An investigation has been made of the low-speed static stability characteristics of a canard model with a 45 degree sweptback wing and a 60 degree triangular horizontal control surface. The model had practically no allowable center-of-gravity range because of longitudinal instability that occurred at moderate and high lift coefficients with horizontal-control-surface incidences of 10 degrees or less. The horizontal control surface produced a sidewash which, at an incidence of 15 degrees at angles of attack greater than 7 degrees, was strong enough to make the model directionally stable with the vertical tail off. This sidewash caused a vertical tail mounted on the fuselage to be destabilizing at angles of attack above 11 degrees. Twin vertical tails mounted at the wing tips did not produce a similar destabilizing effect because they were located outside the sidewash field.

An investigation has been made to determine the damping in yaw and static directional stability characteristics for a flat-fuselage model having its major cross-sectional axis either horizontal or vertical, for a flat-fuselage model having its major axis horizontal in combination with a 45 degree sweptback wing, and for a canard model having a triangular horizontal control surface and a 45 degree sweptback wing.