Supercavitating airframe

摘要

A method is described for reducing drag in airframes or airfoils. The method includes inducing cavitation in the boundary layer separating the airframe or foil skin and the air currents passing thereover to produce a reduced pressure area instead of turbulent flow. In one embodiment of this invention, a nose cone is provided for the airframe which at the juncture of its base portion provides a step between the terminal portion of the nose cone and the adjacent portion of the fuselage skin. This provides a circumferential step surrounding the fuselage which in its leeward direction induces the cavitation necessary to reduce drag. In another embodiment of this invention, steps can be provided longitudinally at mutually spaced circumferential locations extending from the front along the fuselage toward to the rear to ensure that a continuous boundary layer is provided of reduced pressure. In a third embodiment of this invention, the stepped areas are provided on the upper surface of an airfoil to extend lengthwise rather than circumferentially and provide the reduced pressure area along the upper surface to enhance lift as well as reduce drag.