1943: (Fred) Landgraf Helicopter Co, 135 St at Central Ave, Los Angeles CA.
Incorporated 1943 at Los Angeles by Fred Landgraf, after several years development of H-2 twin-rotor light helicopter, which first flew in 1944. U.S. Army development contract 1945. Retractable tricycle landing gear, and overlapping synchronised rotors. U.K. license held by Firth Helicopters of London, but parent company inactive by 1949.