Technical Note: Analytical Estimate of Rotor Controls Required for a Propeller Wake Disturbance Rejection

During helicopter air-to-air refueling, the aircraft propeller’s jet can engage with the helicopter rotor. The impact on the helicopter rotor thrust and aerodynamic hub moments is solved analytically for the first time, based on blade element momentum theory. The collective and cyclic blade pitch controls needed for disturbance rejection are computed for a typical air-to-air refueling scenario. A propeller jet affecting the retreating side of the rotor requires much more pilot controls to retrim than an impingement on the advancing side.