Calculation of the response of a flexible aircraft to harmonic and discrete gusts by a transform method

Abstract

Summary. The equation of motion for a flexible aircraft responding to a step gust is derived, and the relation developed between this and the response to an array of harmonic gusts. A Fourier transform method is used to solve the equation of motion. This allows the rigorous inclusion of indicial effects in both the gust and response aerodynamic forces. As an example the symmetric responses of a flexible slender-wing aircraft in subsonic flight to harmonic and step gusts are calculated. The aircraft is given two rigid and four flexible degrees-of-freedom. Aerodynamic forces are calculated by a lifting-surface theory and include unsteady effects.