Patent ID: 7406821

Claim:
An adapter device for controlling a rocket engine nozzle, having a jet, under conditions of external pressure that can lead to the jet separating inside the nozzle, the nozzle being fitted with a diverging portion that is movably mounted relative to a nozzle throat, said nozzle throat being stationary, thrust deflection then being achieved by swivelling the diverging portion so as to deflect the jet of combustion gas in contact with the inside wall of the diverging portion, wherein a structure is disposed inside the diverging portion and formed separately therefrom to increase a surface area over which pressure forces are exerted by the jet on the diverging portion when the diverging portion is swiveled to decrease jet separation and so as to reduce the diverging nature of the flow section thereof, the structure including a plurality of protuberances that are distributed on the inside wall of and along the axis of the structure and that project some radial distance into the flow section to provide additional surface area for deflecting the jet in said flow section, the plurality of protuberances having a streamlined shape whose radial distance of projection into the flow stream substantially increases in an axial direction towards the downstream end of said structure before decreasing proximate said gas outlet portion of said diverging portion; and wherein said structure is fixed with respect to the diverging portion.