Oscillating foil propulsion system

The invention provides a propulsion system based on "thuniform" movement of a foil member to achieve desired directional movement of a vehicle such as an unmanned submarine type of vessel. A pair of foil members are mounted to the vehicle body for reciprocating oscillating movement towards and away from each other, creating forward movement due to the compression of a fluid medium between the foil members and the expulsion of the compressed fluid rearwardly of the foil members. Each foil member is mounted to a pivot shaft for limited rotational movement with respect to the vehicle body. Damping means are connected between each pivot shaft and its associated foil member so that during operation of the propulsion system damping torque will offset hydrodynamic loads imposed on the foil members by the fluid medium. The damping means will in turn control the pitch angle of the foil members during operation, meaning that a thrust is generated for rigid foil members when moving at zero forward speed. The propulsion system of the invention exhibits increased efficiency and thrust in comparison to other such propulsion systems. The foil members are mounted to the vehicle body in such a manner that the thrust vector thereof can be directed through a full 360 degrees relative to the vehicle, thereby achieving superb maneuverability when the vehicle is provided with sets of the thrusters suitable located thereon.