Northrop acquired manufacturing rights of McCulloch engines.

-The 4318F engine is an aircraft adaptation, carried out at the Northrop facilities in Ventura City. They made them until the late 1980s.

-Northrop Ventura was the successor to Radioplane Corp. which had been building target planes and pilotless drones since the 1940s.

“4318F”

-This 2-stroke engine had four horizontally-opposed, air-cooled cylinders. It delivered 85 to 95 HP. The military specification for this engine was O-100-3. It was used on RPV and target aircraft.

"Drone production line"

From Appendix 6: The Norair Division of Northrop presented the Profac engine at the 1961 Paris Air Show to investigate the limits of the atmosphere.

“Northrop Norair cutaway”