The Liberator was powered by four supercharged Pratt & Whitney R-1830 14-cylinder engines, each capable of producing 1,200 horsepower. Fully loaded with crew, fuel and ordinance (bombs), a Liberator had a top speed of slightly over 300 mph. The wingspan of the plane was 110 feet. The Liberator carried an 8,000-pound bomb load and had a maximum range of 3,000 miles. In terms of both bomb load and range, the Liberator easily bested the Army Air Force's other heavy bomber, the B-17. In total, over 18,000 Liberator bombers were built during WWII.
The Liberator was equipped with four machine gun turrets, located in the nose, tail, upper fuselage and in a retractable ball turret located in the belly of the aircraft. Each turret was equipped with a pair of Browning M-2, .50 caliber (12.7 mm), air-cooled machine guns. Located on opposite sides of the aircraft, forward of the tail section, were single .50 caliber "waist guns," each manned by an individual gunner. Belted .50 caliber ammunition was fed to those guns from wooden ammunition boxes, each of which held 500 rounds. As of 2010, the M-2 ("Ma Deuce") heavy machine gun has been in continuous use by all branches of the United States military since World War I.
The original prototype of the B-24 was developed by Consolidated Aircraft, but once the United States was fully engulfed in WWII, the demand for Liberator bombers outstripped Consolidated's ability to produce them. Thus, three other manufacturers were also given contracts to build the aircraft. Douglas Aircraft, North American Aircraft and the Ford Motor Company combined built thousands of additional planes. Of the three, North American had the most experience building Army bombers, as the company also produced the B-25 "Mitchell," a twin-engine medium-range bomber.
Depending upon which branch of the service it was assigned to, the Liberator was designated differently. In the Army Air Force, the plane was listed simply as the B-24. The U.S. Navy designated the plane as the PB4Y. Many domestically based PB4Ys were assigned to the Navy as coastal patrol bombers and as convoy escort bombers. Flying high above the ships, the planes kept lookout for German U-boats. The Liberator's 3,000-mile range made it ideally suited for missions of this type.