LONGITUDINAL STABILITY AND CONTROL IN WIND SHEAR WITH ENERGY HEIGHT RATE FEEDBACK.

The longitudinal linearized equations of motion in wind shear have been derived for the NASA Terminal Configured Vehicle, a modified Boeing 737 airplane. In addition to the apparent acceleration terms resulting from wind shear, the equations include altitude-dependent stability derivatives. A linear analysis of these equations indicates a first-order divergence type of instability due to wind shear in which head wind decreases with altitude. Furthermore, this instability cannot be stabilized by altitude control alone. However, altitude control used in combination with an additional feedback loop which consisted of the energy height rate feedback to the throttle proved to be effective in suppressing instability due to wind shear.