Self-actuating control for rocket motor nozzle

A rocket motor comprising:

• a motor casing forming a combustion chamber and having propellant therein;
• an exhaust nozzle extending from said motor casing and being fluidly coupled to said combustion chamber, said nozzle having a throat;
• a pintle assembly including a pintle and a support member, said pintle being coupled to said support member for movement from a first position to a second position where said pintle is positioned farther in said throat than when in said first position;
• a locking member that secures sand pintle to said support member in said first position when the pressure in said combustion chamber is in a first range and releases said pintle from said support member when the pressure in said combustion chamber changes to a value in another range;
• an actuating chamber and a valve, said actuating chamber fluidly coupled to said combustion chamber when said valve is in an open position, said actuating chamber further being coupled to said pintle for exerting pressure thereon that tends to urge said pintle toward said second position when the pressure difference between said combustion chamber and actuating chamber exceeds a threshold value;
• and
• wherein said pintle includes a first end portion in the vicinity of said throat and a second end portion spaced therefrom, said second end portion being fluidly coupled to said actuating chamber, said pintle further including a channel having an inlet formed in said first end portion and fluidly coupled to said combustion chamber and an outlet formed in said second end portion and fluidly coupled to said actuating chamber.