The lateral dynamic stability and control of a large receiver aircraft during air-to-air refuelling

Abstract

SummaryThe lateral dynamic stability and control of a large receiver aircraft was considered during air-to-air refuelling. A simple aerodynamic model was developed in order to determine the aerodynamic forces and moments acting on the receiver aircraft due to the tanker aircraft's vortex field. These forces and moments were then expressed in derivative form and included in the linearised equations of motion. Solution of these equations revealed a divergent oscillation, characteristic of air-to-air refuelling and consisting mainly of bank and sideways displacements. An approximation to this mode, which highlights two important aerodynamic derivatives was made. The values of these derivatives depend mainly on the vertical separation between the tanker and receiver aircraft and the ratio of the tanker-to-receiver aircraft wing spans. In flight, it appears that the pilot controls the divergent mode by frequent alternate movements of the ailerons.