Curtiss B-2 Condor
A similar arrangement (using nacelle-mounted gun platforms) was adopted in the competing Keystone XB-1 aircraft.The XB-2 competed for a United States Army Air Corps production contract with the similar Keystone XB-1, Sikorsky S-37, and Fokker XLB-2.The other three were immediately ruled out, but the Army board appointed to make the contracts was strongly supportive of the smaller Keystone XLB-6, which cost a third as much as the B-2.However, the superior performance of the XB-2 soon wrought a policy change, and in 1928 a production run of 12 was ordered.The B-2 was quickly made obsolete by technological advances of the 1930s, and served only briefly with the Army Air Corps, being removed from service by 1934.