Book Description

A low-speed investigation was conducted to determine the dynamic stability derivatives in pitch, roll, and yaw over an angle-of-attack range of -10 [degree] to 110 [degree] for a twin-jet swept-wing fighter model. Several frequencies and amplitudes were investigated to determine the effects of these variables on the stability derivatives. The effect of the vertical and horizontal tail, and horizontal-tail incidence on the derivatives was also evaluated. The results indicate that the model exhibited stable values of damping in pitch over the entire angle-of-attack range, but marked reductions of damping in roll were measured at the stall, and unstable values of damping in yaw were present for the very high angles of attack associated with flat spins. Either removal of the horizontal or vertical tail or full up deflection of the horizontal tail eliminated the unstable characteristics of the damping-in-yaw derivatives.