Nonlinear Analysis of Flapping Motion of Helicopter Rotor Blades in Hover with Gust Effects

This work presents a study of the nonlinear flapping motion of rotor blades in hover considering gust effects. The nonlinear differential equation for the flapping motion is obtained and the computational simulations show that above a critical collective pitch angle, large flapping oscillations can occur, particularly under high winds and with reduced rotational speeds. These large, possibly destructive, oscillations are not predicted by the linear model and may be related to the phenomenon of blade sailing.