Effect of Vortex Deflection on Vortex-Rotor Interference and Rotor Trim

The flight of a helicopter within the wake of a preceding fixed-wing aircraft, for example during air-to-air refueling, is accompanied by vortex-rotor interactions. The full mutuality of vortex and rotor wake interactions requires a free-wake solution that is applied at different advance ratios in this paper and compared to existing simplified models. The results indicate that the simplified models are valid for higher advance ratios whereas very small advance ratios require the use of a free-wake approach