In 1943 the Douglas XB-42 project was designed to create a twin-engined bomber having a maximum speed in excess of 400 mph
and capable of carrying a bombload of 2000 pounds to targets within a 2000-mile radius.
The XB-42 bomber was unique in that both of its engines were located inside of the fuselage (turning a pair of contra-rotating propellers in the tail).
The aircraft had a crew of three, and was armed with a turret contained two .50 caliber machine guns in the trailing edge of each wing.
The first prototype flew in May 1944, and proved to have outstanding performance. Its top speed was over 400 mph,
which was comparable to the fast British Mosquito, but the XB-42 carried twice the maximum bombload, and was better armed.
Development continued until December 1945.

Plans for production version included replacing 2 bug-eye canopies with single canopy (as on second XB-43). XB-43s performed quite well.
Second XB-43 delivered to Muroc Lake May 47 and used as engine test bed.
One J35 engine replaced with a GE J47 and was kept flying by cannibalizing first XB-43 which was damaged 1 Feb 51.
Late 1953, second XB-43 retired. By then, newer jet bombers were on drawing board (including B-45 and B-47) and USAF dropped further consideration.