EFFECT OF SIDESLIP ANGLE ON THE BALANCE OF AIRCRAFT MOMENTS THROUGH STEADY - STATE SPIN

The present paper studded the low-speed lateral-directional aerodynamic derivatives due to the rate of change of sideslip ̇ and includes a comprehensive bibliography on this and related subject matter. The results presented show that the magnitudes of the aerodynamic stability derivatives due to rate of change of sideslip become quite large at high angles of attack for swept and delta- wing configurations, and that such derivatives have large effects on the calculated dynamic stability of these configurations at high angles of attack. The paper also studded the wind-tunnel test techniques used to measure the ̇ derivatives and discusses various approaches used to predict them. Both the conventional oscillating-airfoil theory and the lag-of - the-sidewash theory are shown to be inadequate for predicting the vertical-tail contribution to the acceleration-in-sideslip derivative ̇ however, a flow-field-lag theory, which is discussed, appears to give qualitative agreement with experimental data for a current twin-jet fighter configuration.