U.S. Patent Specifications

A propulsion device for assisting an aircraft in take‐off, comprising a substantially cylindrical casing open at one end, a back end plate acting to close said open end, a nozzle mounted on said back end plate axially of said casing, a plurality of propellant charge units mounted within said casing, each of said units being of elongated cylindrical shape, the lateral surfaces of said units being sheathed in incombustible material, said units being mounted with their axes parallel to the axis of the casing so that the cross‐sectional area between the units remains constant during burning.