Combined Experimental and Analytical Investigation of the Influence of Low Level Wind Shear on the Handling Characteristics of Aircraft. Executive Summary

摘要

Wind shear is a vertical gradient in wind speed occurring close to the ground. The magnitude of this gradient is determined by atmospheric conditions and local terrain. This report discusses the effects of wind shear on the longitudinal and lateral aircraft motions. The longitudinal and lateral perturbation equations of motion were altered to account for wind shear and were solved for several representative aircraft. For the longitudinal motion, the wind shear had only a slight effect on the airplanes' short period mode. However, the long period mode could become unstable for large wind gradients. The lateral modes were also affected by the shear, with the spiral mode being the most sensitive to the shear. Wind tunnel measurements of the roll moment produced on small wings in a shear flow are also included in this report.