Martin XB-51

XB-51
First prototype, 46-685 during testing
Role	Bomber Type of aircraft
Manufacturer	Glenn L. Martin Company
First flight	28 October 1949
Retired	25 March 1956
Status	Canceled in 1952
Primary user	United States Air Force
Number built	2

The Martin XB-51 was an American trijet ground-attack aircraft. It was designed in 1945 and made its maiden flight in 1949. It was originally designed as a bomber for the United States Army Air Forces under specification V-8237-1 and was designated XA-45. The "A" ground-attack classification was eliminated the next year, and the XB-51 designation was assigned instead. The requirement was for low-level bombing and close support. The XB-51 lost out in evaluation to the English Electric Canberra which - built by Martin - entered service as the Martin B-57 Canberra.