Douglas DC-4E

The Douglas DC-4E was an American experimental airliner developed before World War II. Its single prototype first flew on June 7, 1938 from Clover Field in Santa Monica, California, piloted by Carl Cover, but testing issues delayed certification and the design never entered production because it was superseded by an entirely new and much more successful design, the Douglas DC-4 and C-54. Many of its innovative features nonetheless found their way into the Nakajima G5N bomber, after the prototype was sold to a Japanese airline and clandestinely dismantled for study by Nakajima at the behest of the Imperial Japanese Navy.