The theoretical effect of flight path angle on the lateral stability and response of an aircraft

Abstract

The response of a typical aircraft of the dive-bomber class to various disturbances has been calculated at four angles of dive covering tile range 0 to 90 deg and for four pairs of values of lv, nv. The most notable effect on stability is the marked increase in spiral damping with increasing dive angle at the same T.A.S. This has little effect on the response, since in most components, this mode is scarcely excited. For dive angles up to 30 deg the variations in response are so slight as to be negligible, while for larger angles of dive the variation is small for the first 2 airsecs. Calculations of response in level flight, which slightly underestimate the response in a dive, can thus be assumed to give a sufficiently accurate picture of the behaviour at small flight path angles for most requirements.