Abstract: An apparatus is provided for effecting rapid changes in the geometry of a flexible wall structure forming at least a part of the cushion seal on an air cushion vehicle. The apparatus comprises one or more inflatable members co-operating with the flexible wall structure and an air ejector for rapidly introducing pressurized air into each inflatable member. Each inflatable member may be constituted by a wall structure portion of hollow construction. The invention finds particular application in assisting directional control of an air cushion vehicle.

Abstract: The inflated geometry of an inflatable skirt wall constituting at least a part of the cushion sealing means on an air cushion vehicle (A.C.V.) is changed to effect a shift in the center of pressure of the vehicle supporting air cushion for assisting in directional control or to reduce the overall width dimension of the A.C.V. when the skirt wall projects outwardly of vehicle rigid body structure while maintaining a skirt structure sufficient to contain an air cushion for slow speed maneuvering of the A.C.V. Means for changing the inflated skirt wall geometry comprise duct means and co-operating valve means for controlling supply of pressurized air to one or more compartments of the skirt structure, and further duct means and co-operating valve means for venting air from said one or more compartments.

Abstract: Cushion sealing at the rear of an air cushion vehicle comprises a flexible skirt that is attached to rigid body structure of the vehicle so as to extend downwardly therefrom and define a plurality of inter-communicating inflatable compartments positioned one above the other. These inflatable skirt compartments communicate by way of a first duct with a source of pressurized air on the vehicle, and by way of a second duct with cushion space at the underside of the vehicle. The second duct offers low impedance to the transfer of air between the skirt compartments and the cushion space, whereby in operation, when the skirt is deflected, air transfers from the skirt compartments to the cushion without any substantial rise in the skirt inflation pressure, which would tend to increase the stiffness of the skirt.