A Locking System To Guarantee Aeroelastic Stability Of A Wing Movable Surface

Abstract

When dealing with Civil Tiltorotors, safety assumes a crucial role in the design of the entire machine. The Leonardo Helicopter Next Generation Civil Tiltrotor is featured with a wing movable surface (called Morphing Wing) whose actuation and aeroelastic stability is ensured by means of two hydraulically independent actuators controlled by the same computer. Nevertheless, to comply with Civil Aviation rules, a passive mechanical system has been developed to backup the hydraulic actuators in case of their failure: the Locking Mechanism. Made of a spring-based component and a levers system, the Locking Mechanism is a passive reversible system that is engaged and disengaged by the moving surface actuators. It is able to provide a tunable preload in order to ensure the desired connection stiffness of the moving surface, moreover its levers system provides advantageous forces throughout its movement. A numerical analysis performed through Matlab and Amesim verified the Locking Mechanism capability to satisfy design requirements and has allowed to identify the mechanism performances, highlighting its tunability hence the wide usage spectrum.