The Design and Development of the Thiokol XLR99 Rocket Engine for the X-15 Aircraft

Abstract

This paper describes the design and development of the Thiokol XLR99-RM-1 rocket engine for the North American X-15 research aircraft. The engine is a turbopump-driven unit of 58,000 lb. thrust at vacuum conditions utilising liquid oxygen as the oxidiser and anhydrous liquid ammonia as the fuel. The design is notable for a number of features incorporated into a rocket engine of this size, in that it is primarily an aircraft engine with all of the control and safety attributes pertaining to conventional manned flight.The general development of the engine is reviewed on a component basis with brief digressions into the historical and political background.