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 was made in the Langley 300 MPH 7- by 10-foot tunnel to determine the static stability characteristics of a cambered-delta-wing model. The cambered delta wing was derived from a segment of a cone selected so that the projected plan form with a wing dihedral angle of zero degrees was the same as a 60 degree delta wing. The projected plan form had an aspect ratio of 2.31.