Rocket injector subscale stability assessment with telescoping piston

A subscale rocket injector stability test system comprising:

• a chamber;
• a modular injector plate coupled to the chamber and comprising one or more injectors;
• and
• a piston positioned at least partially within the chamber and configured to move to vary a combustion volume of the chamber, the piston comprising a head on an upstream end thereof and an extension rod extending downstream from the head through a downstream exit of the chamber, wherein the piston and a sidewall of the chamber define an annular flow path around the piston configured to act as a chokepoint allowing exhaust to exit the chamber.

A method of subscale testing rocket injector stability, the method comprising:

• injecting into a combustion chamber one or more propellants from one or more injectors supported by a modular injector plate to cause combustion;
• continuously moving a piston within the combustion chamber to continuously vary a combustion volume within the combustion chamber with an extension rod of the piston moving through a downstream exit of the combustion chamber;
• and
• detecting data from within the combustion volume as the piston moves.