Download Due to Aerodynamic Interaction between Rotor and Wing at Hover

Abstract

Download due to aerodynamic interaction between a rotor and a wing/body of a winged compound helicopter is analyzed at hover condition. At first, the experimental data available in the literature are examined to find effective wing design parameters which describe the correlation of the download with the rotor thrust. The examination indicates that the projected areas of the wing and body on the rotor disk are the most effective parameters. The ratios of download to the rotor thrust in the experiments are correlated well with the ratio of the sum of these projected areas to the rotor disk area. Secondly, the influence of the arrangement of the fixed di-/anhedral wings on the download is investigated numerically using a rotorcraft CFD tool, rFlow3D. The numerical results show that the download of the anhedral wing with the high-wing arrangement is reduced 4% smaller than other configurations. The small reduction ratio implies that the di-/anhedral angle is a minor parameter in the aerodynamic design of the winged compound helicopter.