Aerojet-general Corporation

Aerojet Rocketdyne, Inc.

Dustin C Barr

Michael D Lynch

A propulsion system with a divergent-convergent nozzle is provided with variable thrust by a pintle whose position relative to the nozzle throat is controlled by an actuator that includes a rotor that external to, and encircling, the nozzle, and that is coupled to either the pintle or to the nozzle shell by a linkage that translates the rotary movement of the rotor into linear movement of either the pintle or the shell.

Pintle-controlled propulsion system with external ring actuator

Nozzles that offer shape variability to maintain or purposely change the pressure drop across the throat are obtained by constructing the nozzles with components that change their shape, angle, or curvature in response to temperature changes that occur during the flow of combustion products through the nozzle. The temperature change may be the gradual heating of the nozzle wall from hot combustion gases, and the shape change may result in a decrease in the throat diameter or an expansion of the throat diameter. A decrease in throat diameter will be useful when the depletion of propellant as burning proceeds causes a drop in the pressure or flow rate of the combustion gas and there is a need to compensate for this drop to maintain the pressure drop across the throat. An increase in throat diameter will be useful when an initial high thrust is no longer needed and depletion of the fuel by itself is insufficient to lower the thrust to its desired reduced level. An example of a temperature-responsive material is a shape memory alloy; other examples are presented as well.

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Fair Oaks, CA, United States of America

Dustin C Barr