Douglas A-20G-20-DO Havoc, serial number 42-86657, in flight. The A-20G variant was produced in greater numbers than any other A-20 variant. The A-20G was first ordered on June 1, 1942 and first delivered in February of 1943. A total of 2850 were built at the Douglas Santa Monica plant from 1943 to 1944. The version resulted from field testing by 5th Air Force mechanics, who deleted the bombardier position and enclosed the greenhouse. Mounting four to six .50 caliber Browning machine guns in the nose, the speed and maneuverability of the Havoc allowed fast ground strikes with withering firepower. The A-20G was very effective against Japanese transports, often consisting of coastal barges and small ships that lacked armor and "melted" when hit with armor piercing rounds. With production block A-20G-20-DO, an electrically-driven manned Martin power turret equipped with two 0.50-inch machine guns was introduced in place of the single hand-held machine gun in the rear compartment. To accommodate this new turret, the fuselage had to be widened by six inches in the area of the gunner's compartment. The turret could rotate 360 degrees, and the guns could be elevated from horizontal to directly upwards. At the same time, the .30 caliber machine gun in the ventral tunnel position was replaced by a .50 caliber Browning. Also introduced on block -20 was a pair of bomb racks stressed to carry 500-lb bombs underneath the outer wing panels. Internal fuel capacity was increased from 540 US gallons to 725 gallons, and provision was made for the mounting of a 374-gallon drop tank underneath the fuselage. Some of this production run was converted to P-70B-2 night fighters, an interim solution to interlopers until the purpose-built P-61 Black Widow was available. The bulk of A-20 Havocs went to the Soviet Union through Alaska. It was not until late 1943 that the 5th Air Force could get enough A-20s to expand their operations against the Japanese.