Abstract: A combined ramjet and rocket engine, operates as a ramjet in atmosphere, and a rocket engine in space is provided with a rectilinear duct. The engine has interior of the rectilinear duct paired and hinged rectilinear baffles which move from one of the duct walls. These hinged rectilinear baffles move into and out of the planar duct wall and define both the constriction of the Venturi for the ramjet engine configuration or the closure of the duct for the rocket engine configuration. The hinged rectilinear baffles are given leading and trailing wall surfaces so that during movement within the duct for the ramjet configuration, alteration of the slope of the collector and diffuser of the Venturi can occur. The hinged rectilinear baffle bordering the diffuser is manifolded to supply fuel when the engine is ramjet configured and fuel and oxidant when the engine is rocket engine configured.