MODELING OF THE DYNAMIC INFLOW ON THE MAIN ROTOR AND THE TAIL COMPONENTS IN HELICOPTER FLIGHT MECHANICS

This article deals with the importance in helicopter flight mechanics of the modeling of the velocities induced by the main rotor wake. The dynamic inflow on the main rotor affects its on- and off-axis responses (pitch-roll cross-couplings). The interactions on the tail surfaces and the tail rotor affect mainly the pitch behaviour (pitch bump, phugoid mode, etc.) and secondarily the lateral-directional behaviour (bank angle, dutch-roll mode, etc.). These phenomena have been studied with an extended version of the Pitt and Peters dynamic inflow model and a dynamic multi-vortex-rings model.