THEORETICAL STUDY OF THE LATERAL FREQUENCY RESPONSE TO GUSTS OF A FIGHTER AIRPLANE, BOTH WITH CONTROLS FIXED AND WITH SEVERAlL TYPES OF AUTOPILOTS

摘要

A theoretical approach has been used to determine the lateral fre¬quency response of a fighter airplane to side gusts and to rolling gusts at a Mach number of 0.7 and an altitude of 50,000 feet. The frequency response and the power spectral density of the motion of the airplane in response to gusts were determined for the airplane with controls fixed and for the airplane in combination with three different basic types of attitude autopilots.nThe response to gust Inputs for the airplane with controls fixed exhibited a large resonance associated with the Dutch roll mode of the airplane. When the airplane was combined with the various autopilots, the addition of yaw damping greatly reduced the resonance. The addition of autopilot components to supply heading stability and roll stability provided good regulation in that the yaw and, roll responses to gusts of the airplane were greatly reduced. Autopilots that controlled side force to low values and that provided good course response to command signals resulted in large roll response to side gusts.