Behaviour of an Aeroelastic T-Tail Model with Rudder's Freeplay: Experimental and Numerical Investigation

Freeplay is one of the most important nonlinearities that affect the control surfaces of the aircraft; it can induce utter phenomena and limit the performances of the same airplane. To investigate the effect of control surface freeplay, an aeroelastic wind tunnel model of a T-tail has been developed. A variable amplitude freeplay has been introduced in the control chain by a specifically designed linkage. The numerical model was designed according to the modern aeroelastic approach, describing the dynamics of the tail by a state space system. The nonlinearity has been introduced has a lumped element in the actuator feedback loop. The paper presents the experimental setup together with the correlation obtained with the numerical model.