The Kronach Lorin was a small ramjet engine, for aircraft propulsion, that was statically tested in Vienna during the later stages of World War II.
It was initially proposed that a wire-mesh basket holding coal be mounted behind a nose air intake, protruding slightly into the airflow and ignited by a gas burner.
[1] The coal was to take the form of 135–180 kg (300–400 lb) of small granules instead of irregular lumps, to produce a controlled and even burn, and the basket was altered to a mesh drum revolving on a vertical axis at 60 rpm.
A jet of flame from tanks of bottled gas would fire into the basket once the P.13a had reached operating speed (above 320 km/h), whether by using a RATO unit or being towed.
A burner and drum were built and tested successfully in Vienna by the design team before the end of the war.