TRW pintle engine heritage and performance characteristics

The pintle injector rocket engine is fundamentally different from other rocket engines, which nearly universally employ a series of separate propellant injection orifices distributed across the diameter of the headend of the combustion chamber. The pintle’s central, singular injection geometry results in a combustion chamber flowfield that varies greatly from that of conventional rocket engines. These differences result in certain operational characteristics of great benefit to rocket engine design, performance, stability, and test flexibility. The mid-1950’s origin of the pintle injector concept and the subsequent early development work and applications in rocket engines are reviewed. The pintle engine’s key design and operational features are compared to conventional rocket engines. Pintle injector design refinements and associated recent applications are discussed. The presentation includes photographs and summaries of many different rocket engines that TRW has developed and successfully flown, each of which used the pintle injector.