The Olympic brand name was briefly used by the Loughead brothers when the Lockheed company had been sold to Detroit Aircraft. The Duo-4 twin had only a few inches of clearance between the two propellers. It was reportedly damaged during its first flight here at the Muroc Dry Lake on 18 March 1931. Other sources say it first flew in 1930. It was later rebuilt as the Duo-6 with bigger engines. Photo from: San Diego Air & Space Museum