Historical RamJet Designs

Ram Jets had their first Golden era right after World War II as designers try to decide between a variety of jet engine designs ranging from pulsejets, to turbojets, to ram jets..
At right an example of a subsonic ram jet designed in the early fifties for use at the tip of a helicopter rotor. Notice that the inlet nozzle is not a Laval type (converging/diverging) but a simple subsonic expansion diffuser. Also note the exhaust nozzle is subsonic as well, a converging nozzle.
subsonicram.gif
subsonicram.gif
The next design is for a ram jet combuster can on a 16" ram jet run in a wind tunnel (also early fifties). Unlike the above subsonic engine, this one is designed for supersonic flight.
combustor.gif
combustor.gif