The lateral stability of a ground effect machine 1

Abstract

The equations of motion of a ground effect machine in lateral motion are stated and estimates of the lateral stability derivatives are obtained. The equations of motion are reduced, for free motion, to a quartic equation in p (the Laplace transform varable) known as the System Characteristic Equation. The roots of this equation, which determine the craft’s lateral stability, are obtained numerically and in terms of the vehicle stability derivatives. The lateral modes are also calculated and the motion is shown to consist of two essentially uncoupled, lightly damped modes. The first mode has low frequency and represents a yaw-sideslip motion with little roll. The second mode has a somewhat higher frequence and represents a rolling motion with little yaw or sideslip. Finally, the most important derivatives and craft parameters are discovered and the stabilization problem briefly discussed.