Abstract: Two arms rotatably mounted in slideable abutment with an interior wall of a nozzle. The arms extend from a common axis of rotation, and each includes a bump having a crest running radially from the axis of rotation to the tip of the arm. Together with the opposing ceiling and adjacent sidewalls of the nozzle, the arms define the moveable throat of the nozzle. The ceiling of the nozzle opposite the arms is contoured so that rotation of the arms changes the area of the nozzle throat while changing the direction of fluid medium flowing through the nozzle. The arms are connected by a linkage which coordinates their movement. Coordinated rotation of the arms can simultaneously change the throat area of the nozzle and the direction of fluid flow, or change either the throat area or the direction of fluid flow while keeping the other constant.

Abstract: Tapered disc rotatably mounted in the exhaust duct of a propulsion system. The disc can be rotated about an axis normal to the yaw plane. A disc bump projects from both the upper and lower surfaces of the disc, and extends diametrically across it. When fluid is flowing through the exhaust duct, the bump, together with the opposing surfaces of the exhaust duct, chokes the flow and causes a sonic plane to be formed at the bump. The supersonic flow downstream of the disc bump remains approximately normal to the bump for angles of rotation of up to 20.degree. from normality between the bump and the upstream flow. Rotation of the disc thus causes deflection or turning of the fluid flow. The resultant thrust vectoring enables the yaw of the propulsion system and, therefore, a vehicle containing the propulsion system, to be controlled.