TIME-DEPENDENT DOWNWASH AT THE TAIL AND THE PITCHING MOMENT DUE TO NORMAL ACCELERATION AT SUPERSONIC SPEEDS

摘要

The time-dependent downwash behind a wing in a supersonic stream is analyzed for the case when the angle of attack varies linearly with time. The result is applied to the calculation of the contribution of the horizontal tail to the pitching moment and lift due to normal accel-eration of the airplane. The method employs an extension of an unpub¬lished solution of the linearized potential equation for unsteady flow by Clifford S. Gardner. The pitching moment due to normal acceleration, together with the damping in pitch, determines the damping of the short-period mode of longitudinal oscillation for ar. airplane.