FLIGHT DYNAMIC STABILITY ANALYSIS OF A FLEXIBLE FLYING WING

摘要

A method for flight dynamic stability analysis of flexible aircraft has been presented in this paper, which considers the rigid-body degrees of freedom as well as the elastic degrees of freedom of aircraft. The equations of motions of a flexible aircraft have been derived by using the energy function and Hamilton theory. The unsteady aerodynamics in time domain is computed by doublet lattice method and rational function approximation. The linear state-space model of the aircraft is then established based on the small disturbance theory, then the stability characteristics is computed by eigenvalue analysis of the characteristic matrix. For instance, the longitudinal stability analysis of a flying wing with large-aspect-ratio wings has been carried out by both the classic rigid flight dynamics and the method promoted. Results obtained by these two methods are compared, which indicate that the structural vibration of the flexible aircraft will interact with rigid-body flight dynamics, and it will have a great influence on the flight stability of the flying wing.