Low friction, movable, rocket nozzle

Abstract

A ball-and-socket, thrust nozzle for rockets has a movable member retained by a stationary member attachable to a rocket. The movable member includes a venturi throat and an expansion cone for the propulsive gases. At least one of the nozzle members has a spherical surface concentric about the center of rotation of the movable member. The other member bears against this spherical surface via a bearing seal in the form of a thin, narrow ring of lubricous material. The bearing seal is located in a position to support the axial blow-out load imposed by the propulsive gases. It is made of fibers of lubricous material, filled with a solid, lubricous resin; and it is bonded to a nozzle member either with the filler resin or with some other bonding agent. The side of the bearing seal that is bonded to the nozzle member may be reinforced with fibers having high tensile strength, woven into the lubricous fibers, or with a thin sheet of metal. The unbonded surface of the bearing seal is convex to minimize its area of contact with the other nozzle member, while having a relatively large bonding surface. The bearing seal functions as a low-friction bearing and also as a seal for containing the hot, erosive, propulsive gases of the rocket. In a preferred embodiment, the fibers of the bearing seal are radially oriented by filament winding. This increases its strength by maximizing the density of the fibers therein and by orienting them so that they are always substantially paralell to the major travel of the surface against which it bears. For the latter reason, the coefficient of friction is also lowered; because the moving surface always moves esentially along the fibers.