Abstract: A method for producing a permanent combustion under detonating or substanlly detonating conditions within a stream flowing at supersonic speed, consisting in subdividing a stream of combustion-sustaining fluid into two parallel streams, modifying the speed of at least one of said streams, causing said streams flowing at different speeds to meet again inside an area wherein a diabolo-shaped system of shock waves is formed and injecting fuel into the stream flowing at the higher speed, the combustion starting on the downstream side of a flat surface extending perpendicularly to the direction of flow and forming the surface of minimum cross-sectional area of the diabolo-shaped system.