Trims, Controllability, and Flying Qualities of a Tilt-Rotor Aircraft Slung-Load System

Abstract

This paper is aimed at investigating the risks associated with flying qualities of a tilt-rotor aircraft slung-load system. Taking the XV-15 tilt-rotor aircraft (Bell Helicopter Textron, Fort Worth, Texas) as an example, a coupled nonlinear mathematical model is first introduced red and trimmed, where a mass point model is used for slung load to study its effect on a tilt-rotor aircraft slung-load system. Second, the linearization of the previous nonlinear equations by small perturbation hypothesis is performed for open-loop frequency-domain response analysis. Finally, based on the flying qualities requirements for military aircraft, the results of tilt-rotor aircraft with and without slung load are thoroughly compared. The results presented are of significance for engineering reference because there are few open publications available to date on tilt-rotor aircraft slung-load system trims, controllability, and flying qualities. Results indicated that due to the slung load, the trim results of collective pitch increase significantly, the lateral response in hover is significantly affected in the lower frequency range, and in helicopter mode some flying qualities get worse while the others are slightly changed.