Notes on the dynamic response of an aircraft to gusts and on the variation of gust velocity along the flight path with special reference to measurements made in Lancaster P.D. 119

Abstract

A collection of records showing the time histories of strains and accelerations at various parts of a Lancaster flying in turbulent air is presented and discussed. The records include specimens taken in cloud at moderate altitudes and in clear air at low altitudes. Two points of interest regarding the response of the aircraft to gusts are brought to light :- (i) The amount of fundamental oscillation excited by a gust appears to be affected to a marked extent by the variation of gust velocity across the span. (ii) The amount of oscillation excited does not appear to show any marked decrease as the airspeed of the aircraft is increased. Some decrease in the oscillation excited might be expected due to increase in aerodynamic damping. An attempt is made to deduce the variation of gust velocity along the flight path from the measured response of the aircraft. The results indicate that a large up-gust is often closely followed by a large down-gust and vice versa.