The Liberator, commonly referred to simply by its model number ‘B24’ was an American four engine heavy bomber, carrying a crew of at least 7, developed by the Consolidated Aircraft Company, California. It was designed against a specification from the US Army Air Corp, to improve upon the speed and maximum bomb load carried by the Boeing B17 Flying Fortress. Design work starting in 1938, produced a first prototype in March 1939, with the first flight on 29 December of that year. The aircraft was notable for its high aspect ratio wings, twin rounded oblong fins, tricycle undercarriage, lower bulged fuselage and a dual bomb bay with roller style doors. Its drag factors were not low and the Pratt & Whitney Twin Wasp 14 cylinder twin row radial engines went through a number of Marks in order to meet the required power. The first engine model that addressed the initial power shortfall was the P&W R-1830-41 turbo-supercharged radial, rated at 1,200 hp (895 kW), allowing the aircraft to achieve a top speed of about 300 mph.

Bomb carrying capacity was 8000 lb (3,628 kg) for short range missions, falling to 5000 lb (2268 kg) for long ranges of the order of 800 mile (1280 km). Defensive armament comprised 0.50 calibre (12.7 mm) Browning M2 machine guns. These grew in number until model B24J when 11 guns were installed. Guns were located in powered turrets at the nose and tail and the top and bottom of the fuselage, together with two waist position guns. The underside gun ball turret could be retracted into the fuselage when not in action.

The B24 saw service with RAF Bomber and Coastal Commands. In the latter case the aircraft was based upon the B24D but armament was changed to a mix of 0.303 in. (7.7 mm) and 0.5 in. (12.7mm) Browning machine guns, together with weight reductions from fuel tank and armour reductions, in order to increase the fuel capacity and hence range.  In this guise it was classified as the Mk V. Several of the Mk V’s were modified specifically for anti-submarine patrols by the addition of a Leigh Light search light carried under wing, search radar and air to surface rockets. Coastal Command also used B24H’s, classified by the RAF as Mk VI’s, which had Bolton Paul tail turrets fitted as replacement to the the standard B24H fitted turret.

The aircraft was used for a number of alternative duties over the period of the war, including for passenger and cargo transportation. In its service as a bomber the B24 had its detractors who criticised it for its lack of robustness to ground fire and fighter aircraft. This was not helped by the fact that fuel tanks were distributed along the fuselage. It also posed problems for an emergency exit as its entry and exit points were located at the rear. It had a central catwalk for the crew, which was ominously narrow when carrying a parachute.

Despite its shortfalls as an operational bomber, a total in excess of 18,000 aircraft were produced; the highest figure for any American service aircraft, making it a valued contributor to the Allied war effort.

For their Coastal Command role, 311 Sqd trained on Mk III Liberators but for operationally they used:

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© 2010 Victor K L Marshall M Sc, C Eng, M I Mech E

Article last updated: 1 January 2012

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