Douglas B-18 Bolo (1936-1940): The twin-engine B-18 Bolo (1936 - 1940) was the first Douglas medium bomber to enter production. It was basically a combat version of the DC-2 commercial transport. The Army named it Bolo because the B-18 was considered, in 1936, to be the Air Corps’ sharp edged offensive weapon. The B-18’s mission was to find and bomb an approaching enemy fleet while still a thousand miles from U.S. shores. The B-18A Bolo was designed with watertight outer wing panels and had hydraulically retractable landing gear and flaps. The Bolo was sent to Air Corps units in the Panama Canal Zone, Hawaii, and the Philippines. It was the first modern offensive weapon in the Pacific theatre, and the first indication of the build-up of air power over sea power as the first line of defense. By 1941, B-18 Bolos, although obsolete, made up most of the bomber force deployed outside the continental United States when the war began. But the B-18’s saw very little actual combat. They were used primarily and successfully for anti-submarine operations in American and Caribbean waters. Twenty served as general reconnaissance bombers with the Royal Canadian Air Force as Digby Mk1s. After the war, a few were stripped of military gear and converted for cargo use or crop spraying.