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The Consolidated B-24 WWII Liberator Heavy Bomber
 The origins of the Liberator stretch back to the earlylmid-1930s, an era in which projects such as the Boeing XB-15 and Douglas XB-19, and development of the B-17, brought a farwider knowledge and appreciation of the 'big bomber'. The Liberator represents the next generation, its evolution spurred by the tense political situation in Europe and the growing threat of Japanese militancy. In January 1939 the US Army Air Corps invited Consolidated to prepare a design study for a heavy bomber with performance superior to that of the B-l7. Consolidated wasted little time in sub- mitting a design proposal,
identifying it as the Consolidated Model 32 and, as long range
was paramount, it was designed round the Davis wing, first introduced
on the company's Model 31 flying-boat design, of which a prototype
was then nearing completion. In reaching a decision togo ahead
with prototype construction of the Model 32, the US Army almost
matched the speed set by Consolidated, and in awarding the contract
on 30 March 1939 they maintained the tempo, insisting that construction
of the prototype, designated XS-24, must be completed by the end
of the year. This was achieved by the company, with the first
flight being made on 29 December 1939. In size the XB-24 was marginally smallerthanthe Fortress exceptinspan; in terms of wlng.area that of the XB-24 was approximately 26 per cent less, err~phasising the high aspect ratio of the Davis wing, To ensure maximum capacity within the fuselage structure, the wing was high-mounted in shoulderwing configuration, and to provide good low-speed handling characteristics and an acceptable landing speed, wide-span Fowler-type trailing-edge flaps were f itted. Construction of the fuselage was conventional, but deep in section to allow for installation of a bomb bay which could accommodate up to 3629 kg (8,000 Ib) of bombs stowed vertically. The bay was divided into two sections by the fuselage keel beam, this being utilised to provide a catwalk for crew transition between the fore and aft sections of the fuselage. The most inusual feature of the bomb-bay was the provision of unique 'roller shutter' doors which retracted within the fuselage when opened for attack, causing less drag than conventional bomb-bay doors. The tail unit, with its easily recognisable oval-shaped endplate fins and rudders, was generally similar to that developed for the Model 31 flyingboat. Retractable tricycle landing gear and four wing-mounted 895-kW (1,200hp) Pratt & Whitney R-1830-33 Twin Wasp engines completed the configuration. Even before the prototype had flown, Consolidated had begun
to receive orders for its new bomber, These included seven of
the service test Y~24 and 36 of the initial production S-24A models
for the USAAC, and 120 aircraft 'off the drawing board' for a
French purchasing mission. Early flight tests proved successful,
but to meet the USAAC specification some development was necessary
to achieve higher speed; however, there was no doubt that the
XB-24 was able to demonstrate excellent long-range capability.
Furthermore, the large-volume fuselage lent itself to adaptation
to fulfil other roles and it was this versatility combined with
long range that was the key to success for the B-24. The XB-24 was followed during 1940 by the seven YB-24s for service trials, and these differed from the prototype by the provision of pneumatic dc-icing boots for the leading-edges of wings, taliplane and fins. By the time that the first production aircraft began to come off the line at San Diego, France had already capitulated, and the aircraft of the French order were completed to British requirements, as specified in an order for 164 which had been placed soon after that of 120 for France: the French order was later transferred to Britain. 
Although overshadowed by the B-17 Flying Fortress, the B-24
had a number of virtues which made it a much more sought-after
bomber: it was fast (300mph at 30,000ft), capable of carrying
80001b of bombs, and had a range of more than 2000 miles. The
prototype XB-24 flew in December 1939 and first deliveries were
made in 1941 to the RAF. The worth of this big aircraft was soon
realized and production took the design through nine major variants
to peak at 18,482, a run greater than any other US World War 11
combat aircraft.
The RAF 'ocated the name Liberator to its new oomber. this being adopted later by the USAAF, and the first of these (AM258) flew for the first time on 17 January 1941. They were, however, designated LB-30A by Consolidated, indicating Liberator to British specification, and the first six of these reached the UK during March1941, flown directly across the North Atlantic. These initial aircraft were used as unarmed transports by BOAC, and later by RAE Ferry Command. The next batch, received in mid-1941, joined the RAF with the designation Liberator Mk I for service with Coastal Command and were modified in the UK to equip them with an early form of 'ASV (Air-to-Surface Vessel) radar, and to increase the standard armament of five 7.72-mm (0.3-in) machineguns to include an underfuselage gun pack, toward of the bomb bay, housing four 20-mm cannon. Liberator Mk Is began to equip No. 120 Squadron of Coastal Command in June 1941, and were the first RAF aircraftwith the range and endurance to close the 'Atlantic Gap', that area of the ocean in which, until that time, sea convoys were beyond the range of air support from either North America or Great Britain.
Meanwhile, the XB-24 prototype had been modified to a new XR-24B standard, introducing self-sealing fuel tanks and armour, but the most significant improvementwas the installation of turbocharged R-1830-41 engines. This resulted in the second of the Liberator's easily identifiable features, oval-shaped nacelles, entailed by the relocation of the oil coolers in the sides of the front cowlings. With the introduction of these features, plus dorsal and tail turrets each withtwo 12.7-mm 10,5-in) machine-guns to supplement the original hand-held guns in beam and nose positions, nine aircraft were produced for the USAAF with the designation R-24C.  They were followed by the in-24D, the first major production variant and the first to be employed operationally by USMF bomber squadrons. This differed initially by the installation of R-1830-43 engines, but subsequent production batches introduced progressive changes in armament, provision of auxiliaryfuel intheouterwingsandbornbbay, increases in gross weight and bombload, and in some late production examples external bomb racks below the inner wing for the carriage of two 1814-kg (4,000-Ib) bombs. In RAF service the B-24D was designated Uberstor Mk Ill: Uberator Mk EllA identified similar aircraft supplied under LendLease with US armament and equipment. Most Liberator Mk Ill/IllAs served with Coastal Command, eventually equipping 12 squadrons. A total of 122 was modified extensively in the UK, receiving ASV radar equipment including chin and retractable ventral radomes, a Leigh Light forthe illumination of targets at night especially surfaced U-boats), increased fuel capacity, but reduced armament, armour and weapon load. These were designated Liberator GA. Mk V. Some were provided with small stub wings on the forward fuselage to carry eight rocket projectiles. The USMF also operated A-24Ds in an anti-submarine role, and in 1942 the US Navy began to receive small numbers of this version under the designation PB4Y-1. However, at the end of August 1943 the USAAF disbanded its Anti-Submarine Command, handing over its aircraft to the US Navy in exchange for an equivalent number of aircraft of bomber configuration to be produced against outstanding US Navy orders. These ex-USMF B-24s, which were equipped with ASV radar, were also designated PB4y-1 by the US Navy. This service later acquired the specially-developed PB4Y-2 privateer, which introduced a newtail unit with a single tall fin and rudder, a lengthened forward fuselage, changes in the armament to provde a maximum of 12 12.7-mm (0.5-in) machine-guns, and the installation ofPratt & Whrtney R-1830-94 Twin Wasp engines without turbochargers. The deployment of USAAF B-24Ds in the Middle East began in June1942, one of the first operations being launched by 13 aircraft against the Romanian olifields at Ploesti on 11/12 June 1942. All 13 aircraft completed what the USAAF described as 'an unsuccessful attack. its only success being to alert the defences of their vulnerability. Consequently, it was a very different story on 1 August 1943 when units of the 8th and 9thAirForces sent 177 B-24sagainstthe same target. Although rather more successful in terms of damage caused, of the force which set out from Benghazi 55 Liberators were lost, 53 damaged, and 440 crew killed or posted missing. By that time, of course. B-24s were being built at an enormous rate, by Consolidated at San Diego and Fort Worth, Douglas at Tulsa, and Ford with a specially built new plant at Willow Run. In mid-1942 the first transport variants began to appear, with nose and tail gun positions deleted, a large cargo door installed in the port side of the fuselage, and accommodation provided for passengers or cargo. The USAAF acquired 276 under the designation C-87 with accommodation fora crew of five and 20 passengers; 24 similar aircraft, but provided with side windows, served with RAF Transport Command as the Uberetor C. Mk VII and examples flown by the US Navy were designated RY-2, Similar aircraft, but with R-1830-45 engines and equipped asVlPtransports, were identified as NY-i and C-87A by the US Navy and USAAF respectively. The US Navy also acquired 46 of a transport variant designated RY-3, and 27 similar aircraft were delivered in early 1945 for use by RAF Transport Command. One special logistics version was the C-lOB fuel tanker, used to ferry 10977 litres (2,900 US gal) of aviation fuel per load over the Himalayan 'hump', to supply Boeing B-29 Superfortresses operating from forward bases in China, An XF-7 prototype of a reconnaissance version was also produced in 1943, with bomb racks removed and extra fuel tanks provided in the forward section of the bomb bay. This retained the normal defensive armament, and could also accommodate up to 11 cameras. F-7s were used extensively in the Pacific theatre, and later versions included the F-7A and F-79 with differing camera installations. The first production aircraft to come from the Ford plant at Willow Run was the B-24E, generally similar to the B-24D except for different propellers and minor detail changes, and this version was built also by Consolidated and Douglas, some having R-1830-65 engines. There followed the 9-24G. all but the first 25 of which introduced an upper nose turret and had the fuselage nose lengthened by 0.25 m (10 ml, These came from a new production line operated by North American Aviation at Dallas, Texas. Similar aircraft produced by Consolidated at Fort Worth, by Douglas and by Ford were designated 9-24H. The major production variant was the B-24.J 16,678 builtl, which came from all five production lines, and which differed from the B-24H in only minor details. B-24H and B-24Js supplied to the RAF under Lend-Lease were designated Liberator GR. Mk V~ when equipped for ASW/maritime reconnaissance by Coastal Command, or Uberator B. Mk VI when used as a heavy bomber in the Middle East and Far East. Those used by the US Navy were identified as the PB4Y-1. The final production versions were the 9-241, similar to the B-24D with the tail turret replaced by two manually controlled 12.7-mm (0.5-in) machine-guns, of which Consolidated San Diego built 417 and Ford 1,250; and the B-24M which differed from the B-24J in having a different tail turret. Convair built 916 of this latter version at San Diego and Ford another 1,677. Odd variants included a single B-24D provided with an experimental thermal de-icing system as the X9-24F; the XU-24K prototype of the single vertical tail version which it was intended should be produced in large numbers as the B-24N, although only the XB-24N prototype and seven YB-24N service test aircraft were built before production ended on 31 March 1945; the single experimental XB-41 bomber escort, armed with 14 12.7-mm (0.5-in) machine-guns and converted for flight engineer training under the designation AT-22 (later TB-241, Most of the USAAF's Liberators were declared war surplus at the war's end, only afew remaining in service and the very last of these was disposed of in 1953. From first to last more than 19,000 Liberators had been built. In addition to those supplied to the RAF, USMF and US Navy, others had been operated by units of the Royal Australian Air Force, Royal Canadian Air Force and South African Air Force. Nowhere had they been of greater value than in the Pacific theatre, where their long range and versatility made them true 'maids of all work'. Variant ConvaIr Model SO~ this was an attempt to break into the post-war transport market, and took the form of the wings, powerplant and landing gear of the 6-24, the tail unit of the PB4Y-2 and a new fuselage able to carry 45 passengers or 5443 kg (12,000 Ib) of freight; the sole prototype was evaluated by the US Navy as the R2Y. GLIDERS / HELICOPTERS / JETS / LIGHT AIRCRAFT / RACERS TRAINERS / WEIRD AIRCRAFT / WWI / WWII CD ordering information |
