Consolidated B-24 Liberator

The B-24 Liberator came to life during 1939, when in January of that year the United States Army Air Corps asked Consolidated to produce a design study of a heavy bomber whose range, speed and service ceiling in particular as well as overall performance being an improvement on the Boeing B-17 Flying Fortress.

Consolidated named their design the Model 32 and it would use the Davis wing. With Consolidated speeding ahead with the heavy bomber project the United States Army Air Corps were keen to keep the pace going and on the 30th March 1939, just two months after the design study began, a contract to build a prototype, known as the XB-24, was awarded, but this had to be produced by the end of the year. So with two days to spare, on the 29th December 1939 the prototype Liberator made its maiden flight. Powered by four 1,200-hp Pratt & Whitney R-1830-33 Twin Wasps engines and featuring tricycle landing gear and roller shutter style bomb bay doors which could contain a bomb load of 8,000lb.

Flight testing showed the aircraft to have potential and although a few changes were needed to meet the specification set out by the United States Army Air Corps, it was good news for Consolidated especially as a French purchasing mission had ordered 120 and the USAAC had ordered seven YB-24s for service testing and thirty six B-24As before the prototype flew. The YB-24s were delivered in 1940, but unlike the prototype, featured pneumatic de-icing boots on the leading edges of the wings, tailplane and fins.

Despite France being the first export order, when the first B-24s were ready France had surrendered to Germany so the Royal Air Force would receive the 120 ordered on top of the 164 ordered by the RAF already. The first one, designated LB-30A, flying on the 17th January 1941 with the initial batch of six being received by the RAF two months later in March. These six aircraft were unarmed and used as transport, firstly by British Overseas Airways Corporation and secondly by Ferry Command, to fly back pilots and crews who had delivered aircraft. A role the United States Army Air Corps would also use their B-24As for. The next delivery of aircraft occurred in June 1941 and saw the name Liberator given to the type by the RAF and the Mk I, also known as the LB-30, saw service with Coastal Command. These aircraft included four 20mm cannons as additions to the five 0.30-in machine guns and the installation of Air-to-Surface Vessel radar.

It was to be the Liberator II which was to be the first bomber version and as such had increased armament in the form of eight 0.303-in machine-guns, four a piece in turrets, and had an increase in space to accommodate up to ten crew members. As with the Liberator I Coastal Command used the type and it was whilst with Nos. 159 and 160 Squadron, who were based in the Middle East, during June 1942 that the type was first used in its intended role as a bomber, and although the Royal Air Force made use of this variant the United States Army Air Force did not.

A sole XB-24B prototype appeared featuring a number of changes and powered by R-1830-41 engines. Other changes included dorsal and tail turrets with a pair of 0.50-in machine-guns in each.

It was to be the next variant, the B-24D, also known as the Liberator Mk III, which became the first B-24 to be mass produced. Power would be supplied by four Pratt & Whitney R-1830-43 engines and as production progressed each batch of B-24Ds featured various changes over the previous batch produced. It would be the B-24D that the United States Army Air Force would use for the first time in the aircraft's intended role as a bomber and deliveries of the type to squadrons based in the Middle East began in June 1942.

One of the earliest raids the B-24 undertook for the USAAC was on the 12th June 1942 when thirteen were dispatched to Ploiesti, Romania to attack the oilfields there. One hundred and seventy seven B-24s would take part the following year in the Ploiesti raid on the 1st August 1943 but suffered very heavy losses with fifty three B-24s lost. 1943 also saw Very Long Range Liberators start to enter service and along with escort carriers helped to close the Mid-Atlantic gap which had previously suffered from no air cover leading to increased shipping losses in this area due to U-boat activity.

The B-24E was next to be produced and featured minor changes and new propellers, whilst some had R-1830-55 engines installed. These were followed by the B-24G which had the fuselage nose lengthened by 10 inches and a gun turret installed in the upper nose, except for the first twenty five produced and these were exclusively built by North American with a B-24H designation given to similar B-24s built by other manufacturers and were also known as Liberator Mk VI.

The next version to follow was the B-24J, also known as the Liberator Mk VIII, and this differed very little from the B-24H, with the major change being the design of the B-24D being re-engineered so it could have the A.6 tail turret modified to fit in the nose. The redesign was required due to the Emerson nose turrets being in short supply, although not all B-24Js were modified in this way. A B-24D would provide the basis for the XB-24K which had its own twin tail replaced with the single tail from a Douglas N-23 Dragon. This improved both the handling and stability of the aircraft.

The B-24L and M were to become the final production variants featuring differences in the tail turrets over their predecessors. The planned B-24N was to feature the single tail as tested on the XB-24K and just over 5,000 were ordered but with the Second World War (1939 - 1945) coming to an end only the prototype, designation XB-24N, and seven YB-24N test aircraft were built by the time production ended on the 31st May 1945.

The United States Navy also used the type under the designation PB4Y-1 Liberator which lead to a fully navalised version coming to life known as the Consolidated PB4Y-2 Privateer. A special fuel tanker version of the type was also produced, known as the C-109, to deliver aviation fuel for B-29 Superfortresses operating in China. The B-24 was also used by the Royal Australian Air Force and Royal Canadian Air Force. Captured B-24s were used by KG 200, the special operations unit of the Luftwaffe. British Prime Minster Winston Churchill would also use a B-24 named 'Commando' as transport.

With 18,475 Liberators rolling of the production line the aircraft would be found in all theatres of war up until the end of the Second World War and post-war the B-24 was used in the Berlin Airlift (26th June 1948 - 30th September 1949).