By the early spring of 1942, theatre commanders had already recognized that the Liberator was insufficiently protected against frontal attacks, and depots in Hawaii and Australia had already begun to dismount tail turrets from Liberators and remount them in the nose, leaving the tail protected by manually-operated guns. The Eighth Air Force also experimented with the B-26 tail turret and the B-25 Bendix remotely-sighted turret. By the summer of 1943, the Army Air Depots were installing A6-A tail turrets in the noses of B-24Ds as an interim measure. Such modifications were known as B-24D1.
Since the B-24D1s were a success in the field, immediate plans were made to introduce the nose turrets as factory-installed equipment. Factory-installed nose turrets were first introduced on the Liberator production line with the Ford-built B-24H. However, some later-block North American-built B-24Gs were also delivered with factory-installed nose turrets. Plans were also made for factory-installed nose turrets to be introduced on the Consolidated production line, and the designation B-24J was assigned to these versions. The B-24Js were to be built in both the Fort Worth and the San Diego Consolidated factories. In the meantime, Consolidated had merged with Vultee and was now known as Consolidated-Vultee, or Convair for short.
It was initially planned that the nose turret used on all five Liberator production lines would be the electrically-powered Emerson Electric A-15 unit. However, it immediately became obvious that the supply of Emerson nose turrets would be inadequate to meet the demands of all five factories in the Liberator Production Pool. In order to make up the difference, Convair/San Diego was directed to adapt the A-6A hydraulically-driven tail turret for installation on the production line in the nose of the B-24J Liberator. The A-6A turret had sloped, flat transparent front panels as opposed to the smooth cylindrically-shaped transparent surfaces of the Emerson turret. The sloping front of the nose turret made the A-6A-equipped B-24J the longest of all the Liberator variants at 67 feet 7 5/8 inches. Later in the Convair production run, a switch was made from the A-6A to the A-6B turret. However, it was planned that all five factories in the Liberator Production Pool would eventually standardize on the Emerson turret as the rate of its production finally met demand.
At first, only the two Convair plants manufactured the B-24J, with Ford/Willow Run and Douglas/Tulsa continuing to produce the B-24H and North American/Dallas continuing to build the B-24G. The Convair plant at San Diego was the first to build the B-24J, delivering the first B-24J example to the USAAF in August of 1943. In September of 1943, a separate parts plant was built at Convair/Fort Worth, which began to supply sub-assemblies to the main plant, and Convair/Fort Worth began to deliver B-24Js as well. North American/Dallas continued to built the B-24G, and Ford/Willow Run and Douglas/Tulsa continued to produce the B-24H. During this period, knockdown kits from Ford/Willow Run still continued to be delivered to Fort Worth and were assembled there as B-24H-CFs in parallel with the building of the B-24J-CF. Consequently, B-24Hs and B-24Js were intermixed on the Fort Worth line from September 1943 to May 2, 1944.
Initially, only the two Convair plants built the B-24J. That was soon to change. In mid-1944, the Army directed that the C-1 automatic pilot and the M-series bombsight be installed on all production Liberators under the designation B-24J. This meant that for the first time, all five members of the Liberator Production Pool would be building aircraft under the same designation. Since the B-24J was built by all five members of the production pool, it was the Liberator version that was built in the largest numbers. Ford/Willow Run produced its first B-24J in April of 1944, with Douglas/Tulsa and North American/Dallas following in May.
By the spring of 1944, the Emerson turret shortage had been sufficiently alleviated that enough of these nose turrets were now available that both Convair/San Diego and Convair/Fort Worth could install them on their B-24Js in place of the Consolidated A-6B. This change was made at J-185-CO and at J-45-CF. By the time that production of the B-24J got underway at the other three members of the pool, enough Emerson turrets were available to equip these planes as well. By May of 1944, all manufacturers of the B-24J had standardized on the Emerson turret.
Generally, B-24Js built by the different members of the Liberator Production Pool were quite similar and could only be distinguished from each other by an examination of their serial numbers. However, careful observers could often tell the difference between the B-24Js from the different manufacturers by looking at the arrangement of the nose landing gear doors--some of them opened outwards, and some opened inwards. The initial Convair-built B-24J differed from the G and the H in having inward- rather than outward-opening nosewheel doors. The B-24J-CF initially had inward-opening doors, then later switched to outward opening doors at Block 70. The B-24J-CO with the NAA-style nose and the A-15 turret had outward-opening doors. All of the North American built B-24Js had outward-opening doors, as did all of the Ford-built B-24Js. Convair adopted the North American-style nose fairings, but Ford continued with the S-curve fairing that had been used in the H-series.
The B-24J also featured an electronic control system for the turbosuperchargers, which replaced the manual controls that had been fitted to the engine control pedestals on earlier Liberators.
Early in the B-24D production run, three fuel cells had been added in each wing aft of the outer engines to provide 450 US gallons of additional fuel. It was necessary to transfer the fuel from these tanks to the main tanks before it could be used. This transfer system was sufficiently awkward and cumbersome that a momentary lapse on the part of the flight engineer could result in the interruption of fuel flow to the engines and the loss of the aircraft. On the B-24J, the fuel transfer system was revised to make it a simpler and less awkward process.
The B-24J-CF added post type fuel vents atop the wing during block 20, switched from mast type to G-2 pitots at the beginning of Block 25, replaced the upper and lower wingtip lights in favor of a single unit in Block 30.
An RC-103 localizer receiver was installed beginning with B-24J-180-CO 44-40749,; B-24J-1-FO 42-50760; and B-24H-5-DT 42-78075. These planes could be recognized by a horseshoe-shaped antenna mounted on top of the forward fuselage.
Some B-24Js were modified with bulged spherical cheek windows at the navigator's position. A large squarish window was added to each side of the navigator/bombardier compartment starting with B-24J-185-CO 44-40849, B-24J-10-FO 42-51611, and B-24J-5-DT 42-51293. This window was fitted to all B-24J-1-NTs.
A thermal anti-ice system replaced the pneumatic boots with B-24J-180-CO 44-40749. It used hot air piped from the engines into ducting fitted inside the leading edges of the wing and tail assembly. This arrangement proved superior to the electric/rubber deicer boots of earlier versions, which had sometimes failed to prevent ice buildups. All North American/Dallas-built B-24J-NTs also had this system.
57 Consolidated/Fort Worth-built B-24J-40-CFs (42-50452 through 42-50508) were produced from sub-assemblies supplied by Ford/Willow Run. Sometimes these 57 machines are referred to by a separate block designation of B-24J-401-CF. This rather unusual-looking block number was chosen since the numbers 41-44 could not be used because they would have indicated field modifications to normal block 40 aircraft. This has produced no end of confusion, since their serials were a continuation of the last B-24H-CF serials. Since they were of Ford design, they retained the outward-opeing nosegear doors. They were also produced with the A-3D top turret and enclosed waist gunner positions, becoming the only B-24J-CF to be so equipped. The "normal" B-24J-CFs adopted the Emerson nose turret at Block 45, deleted the camouflage paint at Block 55, and never did enclose the waist gunner positions.
The fit of the front turrets was generally rather poor on the B-24G, H, and J Liberators, and there were lots of holes, crevices, and slots through which subzero drafts could enter, making the nose turret-equipped Liberators rather uncomfortable for their crews.
Another problem which made the B-24J unpopular with its crews was its excessive weight. By the time that the B-24J had been introduced on the production line, the empty weight of the Liberator had increased by 8000 pounds and the aircraft typically grossed somewhere between 50,000 and 70,000 pounds when on combat missions. Unfortunately, the Liberator's engines had not undergone a corresponding increase in power, and performance suffered. There was now very little reserve power for takeoff when the aircraft was fully loaded, and takeoff accidents were frequent. As compared to the B-24D, the rate of climb and the airspeed were slower, range was more limited, and the fuel consumption rates were higher. The weight increases had also made the aircraft less stable and more difficult to fly, particularly at high altitudes. As compared to the D, the J was much heavier on the controls and the response was much more sluggish, which made the Liberator more dangerous to fly in tight defensive formations, and midair collisions due to momentary loss of control by the pilot were a very real danger. The weight increases also made it more difficult for damaged Liberators to return safely to their bases, particularly if parts of the wing got holed or severely damaged. Aircraft damaged in such a fashion would often rapidly fall out of control, a recovery usually proving impossible.
Control was particularly poor when the retractable ventral ball turret was extended. In the effort to shed weight and to improve the handling, USAAF commanders in the South West Pacific ordered that the ball turret be removed and replaced by a pair of manually-operated 0.50-inch machine guns firing through a floor hatch. From September 1943 onward, most B-24Js destined for the Pacific had their ball turrets removed at modification centers in the US before being dispatched to the front. In Europe, the ball turret was discarded during the spring of 1944, when the increased availability of long-range escort fighters made the danger of Luftwaffe fighter attacks from below less likely.
in the United Kingdom, the 492nd Bomb Group used B-24H and J Liberators for nighttime supply dropping and agent insertion missions over occupied Europe. These planes were painted entirely black and usually had their nose turrets removed and their noses faired over.
In the European theater, several B-24Js were fitted with H2X blind-bombing radar in place of the ventral ball turret. The H2X was the US version of the RAF's H2S.
86 B-24Js were modified with three nose and three bomb bay camera installations and were redesignated F-7A. 92 other B-24Js were modified with all six cameras in the bomb bay as F-7Bs. All the armament was retained. These planes were used primarily in the CBI theater and in the Philippines.
208 B-24J and L models were converted to unarmed fuel transports under the designation C-109. All armament and bombardment equipment was removed and both the forward and aft turrets were removed and faired over with sheet metal. The waist windows were retained. Eight fuel tanks were installed inside the fuselage that could carry 2900 US gallons. An early plan called for ten B-29 groups to be stationed in China for operations against Japan, and these bombers were to be supported by no less than 2000 C-109s operating with the 20th Air Force flying in supplies of aviation gasoline over the Hump from India. This plan was dropped when the B-29 Supoerfortress operations were relocated from China to the Marianas, from where they could be better supported by US Navy seaborne tankers. In late 1944, the C-109s were transferred to the Air Transport Command. Some limited use of the C-109 was made in Europe.
Some 15th Air Force B-24J lead planes had their noses altered so that the lead bombardier and navigator had much improved visibilities. The nose turret was removed and a perspex structure was installed in its place. A single hand-held machine gun was incorporated for use by the navigator.
One of the more remarkable examples of a modified B-24J (serial number 42-73130) was one upon which was grafted the complete nose of a B-17G in an attempt to improve the forward visibility. Only one such example was produced.
A total of 6678 B-24Js were built. 2792 were built by Convair/San Diego, 1558 by Convair/Fort Worth, 1587 by Ford/Willow Run, 536 by North American/Dallas, and 205 by Douglas/Tulsa. Ford actually built 1849 B-24Js, but they delivered 205 of these to Douglas/Tulsa and 57 to Convair/Fort Worth. Most of the Fort Worth B-24J production was devoted to Lend-Lease, and much of the US Navy Liberator patrol bomber allocation came from San Diego production.
The B-24J was replaced on the production lines at Ford and Convair/San Diego by the B-24L in September of 1944. During mid-1944, the USAAF had decided that Convair/San Diego and Ford/Willow Run would by themselves be able to meet all future needs for Liberator production, and ordered that assembly of the Liberator at Douglas, North American, and Convair/Fort Worth be discontinued. The last B-24J rolled off the line at Douglas in July of 1944. However, production of the B-24J at North American and Consolidated/Fort Worth continued until November and December of 1944 respectively, mainly fulfilling contracts for Lend-Lease to Britain.
Although thousands of B-24Js were manufactured, most were scrapped shortly after the end of the war and very few of them survive today. I am aware of only five. An ex-Indian AF B-24J-85-CF (44-44052) is with the Bob Collings Foundation. It is one of the few Liberators still flying. It has carried various markings throughout the years of its operation as a flying museum. Another flyable B-24J (B-24J-95-CF) is 44-44272, now with Yesterday's Air Force of Liberal, Kansas. B-24J-20-FO 44-48781 is on display at the Eighth Air Force Museum at Barksdale AFB in Louisiana. It bears the name *Laiden Maiden*, and carries 486th BG markings. B-24J-90-CF 44-44175, an ex-Indian Air Force machine (HE877), is with the Pima County Air Museum of Tucson, Arizona. B-24J-90-CF 44-44213 is with the Indian Air Force Museum at Palam, India.
Serials of the B-24J Liberator:
42-50452/50508 Consolidated B-24J-401-CF Liberator 42-50509/50759 Ford B-24J-1-FO Liberator 42-50760/51076 Ford B-24J-5-FO Liberator 42-51226/51292 Douglas-Tulsa B-24J-1-DT Liberator 42-51293/51395 Douglas-Tulsa B-24J-5-DT Liberator 42-51396/51430 Douglas-Tulsa B-24J-10-DT Liberator 42-51431/51610 Ford B-24J-5-FO Liberator 42-51611/51825 Ford B-24J-10-FO Liberator 42-51826/52075 Ford B-24J-15-FO Liberator 42-52076 Ford B-24J-20-FO Liberator 42-64047/64141 Consolidated B-24J-1-CF Liberator 42-64142/64236 Consolidated B-24J-5-CF Liberator 42-64237/64328 Consolidated B-24J-10-CF Liberator 42-64329 Consolidated B-24J-CF Liberator 42-64330/64346 Consolidated B-24J-15-CF Liberator 42-64347/64394 Consolidated B-24J-20-CF Liberator 42-72964/73014 Consolidated B-24J-1-CO Liberator 42-73015/73064 Consolidated B-24J-5-CO Liberator 42-73065/73114 Consolidated B-24J-10-CO Liberator 42-73115/73164 Consolidated B-24J-15-CO Liberator 42-73165/73214 Consolidated B-24J-20-CO Liberator 42-73215/73264 Consolidated B-24J-25-CO Liberator 42-73265/73314 Consolidated B-24J-30-CO Liberator 42-73315/73364 Consolidated B-24J-35-CO Liberator 42-73365/73414 Consolidated B-24J-40-CO Liberator 42-73415/73464 Consolidated B-24J-45-CO Liberator 42-73465/73514 Consolidated B-24J-50-CO Liberator 42-78475 North American B-24J-2-NT Liberator 42-78476/78794 North American B-24J-1-NT Liberator 42-95504/95628 Ford B-24J-1-FO Liberator 42-99736/99805 Consolidated B-24J-15-CF Liberator 42-99806/99871 Consolidated B-24J-20-CF Liberator 42-99872/99935 Consolidated B-24J-25-CF Liberator 42-99936/99985 Consolidated B-24J-55-CO Liberator 42-99986/100035 Consolidated B-24J-60-CO Liberator 42-100036/100085 Consolidated B-24J-65-CO Liberator 42-100086/100135 Consolidated B-24J-70-CO Liberator 42-100136/100185 Consolidated B-24J-75-CO Liberator 42-100186/100235 Consolidated B-24J-80-CO Liberator 42-100236/100285 Consolidated B-24J-85-CO Liberator 42-100286/100335 Consolidated B-24J-90-CO Liberator 42-100336/100385 Consolidated B-24J-95-CO Liberator 42-100386/100435 Consolidated B-24J-100-CO Liberator 42-109789/109838 Consolidated B-24J-105-CO Liberator 42-109839/109888 Consolidated B-24J-110-CO Liberator 42-109889/109938 Consolidated B-24J-115-CO Liberator 42-109939/109988 Consolidated B-24J-120-CO Liberator 42-109989/110038 Consolidated B-24J-125-CO Liberator 42-110039/110088 Consolidated B-24J-130-CO Liberator 42-110089/110138 Consolidated B-24J-135-CO Liberator 42-110139/110188 Consolidated B-24J-140-CO Liberator 44-10253/10302 Consolidated B-24J-30-CF Liberator 44-10303/10352 Consolidated B-24J-35-CF Liberator 44-10353/10374 Consolidated B-24J-40-CF Liberator 44-10375/10402 Consolidated B-24J-45-CF Liberator 44-10403/10452 Consolidated B-24J-50-CF Liberator 44-10453/10502 Consolidated B-24J-55-CF Liberator 44-10503/10552 Consolidated B-24J-60-CF Liberator 44-10553/10602 Consolidated B-24J-65-CF Liberator 44-10603/10652 Consolidated B-24J-70-CF Liberator 44-10653/10702 Consolidated B-24J-75-CF Liberator 44-10703/10752 Consolidated B-24J-80-CF Liberator 44-28061/28276 North American/Dallas B-24J-5-NT Liberator 44-40049/40148 Consolidated B-24J-145-CO Liberator 44-40149/40248 Consolidated B-24J-150-CO Liberator 44-40249/40348 Consolidated B-24J-155-CO Liberator 44-40349/40448 Consolidated B-24J-160-CO Liberator 44-40449/40548 Consolidated B-24J-165-CO Liberator 44-40549/40648 Consolidated B-24J-170-CO Liberator 44-40649/40748 Consolidated B-24J-175-CO Liberator 44-40749/40848 Consolidated B-24J-180-CO Liberator 44-40849/40948 Consolidated B-24J-185-CO Liberator 44-40949/41048 Consolidated B-24J-190-CO Liberator 44-41049/41148 Consolidated B-24J-195-CO Liberator 44-41149/41248 Consolidated B-24J-200-CO Liberator 44-41249/41348 Consolidated B-24J-205-CO Liberator 44-41349/41389 Consolidated B-24J-210-CO Liberator 44-44049/44148 Consolidated B-24J-85-CF Liberator 44-44149/44248 Consolidated B-24J-90-CF Liberator 44-44249/44348 Consolidated B-24J-95-CF Liberator 44-44349/44448 Consolidated B-24J-100-CF Liberator 44-44449/44501 Consolidated B-24J-105-CF Liberator 44-48754/49001 Ford B-24J-20-FO Liberator
Specification of B-24J Liberator:
Four Pratt & Whitney R-1830-65 Twin Wasp fourteen-cylinder air-cooled radial engines with General Electric B-22 turbosuperchargers rated at 1200 hp at 2700 rpm for takeoff and maintaining this power as a military rating up to 31,800 feet. Performance: Maximum speed 300 mph at 30,000 feet, 277 mph at 20,000 feet. Maximum continuous speed 278 mph at 25,000 feet. Usual combat operating speed was 180-215 mph at between 10,000 and 25,000 feet. Initial climb rate 1025 feet per minute. At a takeoff weight of 56,000 pounds, an altitude of 20,000 feet could be reached in 25 minutes. Service ceiling 28,000 feet at 56,000 pound takeoff weight. Range and endurance with a 5000-pound bombload was 1700 miles in 7.3 hours at 25,000 feet (all-up weight of 61,500 pounds) with 2364 US gallons of fuel. Landing speed 95 mph (light)-125 mph (loaded). Weights: 38,000 pounds empty, 56,000 pounds combat, 71,200 pounds maximum overload. Dimensions: Wingspan 110 feet 0 inches, length 64 feet 2 inches, height 18 feet 0 inches, wing area 1048 square feet. Fuel: 2364 US gallons in main tanks, plus 450 gallons in auxiliary wing tanks and 800 gallons in extra tanks fitted in bomb bay if required. Accommodation: Crew was normally ten (pilot, copilot, bombardier, nose gunner, navigator, radio operator, ball turret gunner, two waist gunners, and tail gunner). Armament: Ten 0.50-inch Browning machine guns in nose, upper ventral, and tail turrets and in waist positions. Maximum internal bomb load was 8000 pounds. Two 4000 pound bombs could be carried on external racks, one underneath each inner wing. Maximum short range bomb load was 12,800 pounds (by using underwing racks), but normal offensive load was 5000 pounds.