Influence of ship motion on the aeroelastic response of a Froude-scaled maritime rotor system

The influence of representative ship motion in various sea states on the aeroelastic response of a Froude-scaled, flap articulated, maritime rotor system is experimentally and numerically investigated. The design and construction of the rotor system are briefly presented. The rotor system was attached to a 6 degrees-of-freedom (6DOF) Stewart motion platform, which was programmed to produce Froude-scaled ship motion representative of a generic frigate. The experimental setup and runs are described and discussed. From the experimental and numerical results, it is demonstrated that in the absence of a ship airwake, certain combinations of ship roll/pitch frequencies and rotor hub frequencies are capable of producing elastic rotor tip displacements outside the acceptable safe operating range resulting in the possibility of tunnel or tail strikes. The experimental aeroelastic response of the rotor system throughout its operation envelope on a Froude-scaled moving ship is used to validate two geometrically exact multibody dynamics models of maritime rotors, which proves their validity for studying the problem of Helicopter Ship Dynamic Interface (HSDI). The relevance of this investigation and planned future investigations to the projected increase in maritime operation of rotorcraft is also discussed.Peer reviewed: YesNRC publication: N