Abstract: The thrust of a rocket motor can be varied to optimize Nozzle Pressure Ratio (NPR) using a design that allows for adjusting the relative position of a plug and a combustion chamber exit. The plug or the exit may be attached to an adaptive control system for position modification. The relative position of the plug and exit may be adjusted to optimize NPR to account for changing propellant flow and/or changing ambient pressure.

Abstract: The thrust of a rocket motor can be varied while maintaining efficiency over a range of pressure ratios using a design that allows for changing the relative position of a plug and a combustion chamber exit. The plug or the chamber exit may be attached to an adaptive control system for position modification. The plug may be positioned in a plug nozzle configuration or in an expansion-deflection (ED) configuration. In either configuration, the elongated downstream portion of the plug allows for efficiency over a wide range of pressure ratios, while ability to change plug position with respect to the chamber exit allows adjustment of rocket thrust.

Abstract: The thrust of a rocket motor can be varied while maintaining efficiency over a range of pressure ratios using a design that allows for changing the relative position of a plug and a combustion chamber exit. The plug or the chamber exit may be attached to an adaptive control system for position modification. The plug may be positioned in a plug nozzle configuration or in an expansion-deflection (ED) configuration. In either configuration, the elongated downstream portion of the plug allows for efficiency over a wide range of pressure ratios, while ability to change plug position with respect to the chamber exit allows adjustment of rocket thrust.