GB993808A - Improvements in the propulsion of supramarine craft - Google Patents

Abstract

993,808. Air cushion vehicles. A. P. PEDRICK. March 26, 1964, No. 43753/62. Heading B7K. A craft adapted for movement over the surface of water with the major part of its base surface close to, but supported away from, the surface of the water, so that when such craft is proceeding at its normal operational speed, such speed being greater than some predetermined minimum, the aerodynamic drag operative against such forward movement is greater than any hydrodynamic drag also effective against such forward movement as a result of intermittent contact of the base surface with the water, or slight penetration of the water by projections below said base surface, and wherein also the force for propulsion of the craft, at said normal operational speed, is derived to a greater extent from hydrodynamically produced force than by aerodynamically produced force, is characterized in that the craft is of such a size, in relation to its weight, that, at such normal operational speed, the aerodynamic forces thereon resulting from the relative airstream derived from its forward speed only, are sufficient to support its weight. The craft comprises a hull 1 of aerofoil section capable of deriving sufficient lift at normal operational speed to support the craft, side plates 7 and 8 preventing outflow of air from the lifting surfaces. A pair of gas turbine engines 9, 10 drive a pair of paddle wheels through gear-boxes 11, 12 and to provide sufficient lift at low forward speed a chamber below the craft is pressurised through a duct 19 from the gas turbines, the forward part of the chamber being sealed by a pivotal flap located between the side plates 7. A further embodiment is described in which the means of propulsion comprises gas turbine engines, the jet pipes of which act as ejector pumps to draw water from beneath the craft and eject it rearwardly. Specification 332,437 and U.S.A. Specification 1,003,364 are referred to.