Abstract: The ejector ramjet engine is a propulsion duct having normal augmented ramjet elements of an inlet, mixer, diffuser, combustor and exit nozzle. At the upstream end of the mixer an injector assembly is mounted in the fluid flow path to form an ejector. The injector assembly has one or more injector rings which have alternatively offset injector exhaust nozzles or slots to direct fluid toward the engine internal wall or the engine longitudinal axis respectively to improve fluid mixing for use of a shorter mixer section. The supply of fluid to the injector exhaust nozzles may be by fuel flow pumps and other elements connected to injector chambers in the injector ring or by an injector combustor external to the mixer. A movable plug is mounted on the center body fairing to provide adjustment for varying velocity and pressure conditions within the engine over the operating environment. This velocity/pressure regulation results in increased engine thrust and specific impulse performance.