The Douglas Aircraft Co. developed the B-18 to replace the Martin B-10 as the Army Air Corps' standard bomber. The Bolo's design was based on the Douglas DC-2 commercial transport. During Air Corps bomber trials at Wright Field in 1935, the B-18 prototype competed with the Martin 146 (an improved B-10) and the four engine Boeing 299, forerunner of the B-17. Although many Air Corps officers believed the Boeing design was superior, only 13 YB-17s were initially ordered. Instead, the Army General Staff selected the less costly Bolo and, in January 1936, ordered 133 as B-18s. Later, 217 more were built as B-18As with a "shark" nose in which the bombardier's position was extended forward over the nose gunner's station.

By 1939, underpowered and with inadequate defensive armament, the Bolo was the Air Corps' primary bomber. Some B-18s were destroyed by the Japanese on December 7, 1941. By early 1942, improved aircraft replaced the Bolo as a first-line bombardment aircraft. Many B-18's were then used as transports, or modified as B-18Bs for anti-submarine duty.

SPECIFICATIONS
Span: 89 ft. 6 in.
Length: 57 ft. 10 in.
Height: 15 ft. 2 in.
Weight: 27,000 lbs. loaded
Armament: Three .30-cal. guns (in nose, ventral and dorsal positions), plus 4,500 lbs. of bombs carried internally
Engines: Two Wright R-1820-53s of 1,000 hp. ea.
Crew: Six
Cost: $80,000
Serial Number: 37-469
C/N: 2469
Other Registrations: N58674