Abstract: A ram jet engine including a combustion chamber ending in a gas injection nozzle, a cruising propulsion unit fee ding liquid propellant into the combustion chamber, and at least one air duct for feeding air intended for combustion of the fuel in the combustion chamber. A rigid tubular element is incorporated into the ramjet engine, with an interior volume of the rigid tubular element being divided into two spaces by an intermediate transverse partition. One of the spaces houses the cruising propulsion unit while the other space houses the combustion chamber. Passages are cut into the intermediate transverse partition to allow feeding of liquid fuel into the combustion chamber, and the air duct is mounted on the tubular element to feed the combustion air through the tubular wall of the tubular element.