Following the modifications at field airfields, the introduction of reinforced defensive weapons at factories began. Emerson was preparing a new stern turret for the B-24. But, due to the primary need, she was asked to modify the turret to be placed in the bow of the Liberator. Emerson engineers, together with Consolidated specialists, hastily adapted the installation to the new location. The turret blueprints were sent to Willow Run, where a wooden model was quickly made. The nose of the aircraft was redesigned in accordance with it. The Air Force headquarters took only three and a half months to fine-tune the turret, test and mount it on the bomber.

The installation of the new Emerson A-15 turret required 56 changes to the airframe design. In fact, the entire nose was redone. The bombardier's cockpit has completely changed. The landing gear niche doors began to open outward, not inward. The A-15 turret added about 100 kg to the vehicle's weight. This had a positive effect on the alignment of the aircraft. Previously, the Liberator was "heavy on the tail" and flew with a slightly raised nose. The change in the position of the center of gravity leveled the machine.

The new version was designated B-24N. It also differed from the previous modifications by the improved A-6B turret at the rear. She had a much larger glass area on the sides, which improved the view of the shooter. A Martin A-3D turret was mounted on top. Before that, they put A-ZA, and then A-ZS, outwardly almost indistinguishable from it. The new A-3D had an enlarged transparent hood. This was also dictated by the requirements for better visibility. Onboard installations (also of a new type, K-6 pivots) were screened. The side windows near the lower turret were eliminated as unnecessary - the shooter in the "ball" could look almost anywhere. The navigation lights above and below the wing were replaced with one light at the tip of each wing.

Due to the large number of changes made, the implementation of the B-24N has fallen behind the planned schedule. But already in March 1944, the Ford plant produced a new bomber every 100 minutes. Separate components from the V-24N were also supplied to enterprises in Fort Worth and Tulsa. A total of 3100 aircraft of this modification were produced. They were delivered to England as "Liberator" VI. There, the aft turret on them was usually changed to their own Boulton Paul.

From the H-20 series, the onboard installations were spread along the length so that the arrows did not interfere with each other. Approximately in the middle of the production of the H type, a color change took place. More precisely, they stopped painting them altogether. The Liberators now gleamed with polished aluminum.

At the beginning of January 1944, six new bombing groups were transferred to North Africa on the B-24N. On January 19, one of them, 449th, “plowed” the enemy airfield in Perugia, where the air reconnaissance officers were based. This contributed to the achievement of surprise in the Allied landing at Anzio four days later.

Advanced bombers were produced not only by Ford. After the manufacture of 25 B-24Gs in Dallas, they switched to the assembly of B-24G-1 machines. Despite the retention of the letter designation, these aircraft no longer corresponded to Type D, but to Type N. They almost completely corresponded to the aircraft from Willow Run, including the Emerson A-15 turret. The first B-24G-1 was handed over to representatives of the Air Force on November 3, 1943, three months after the start of production of the B-24N. At first, the Dallas planes were slightly heavier than the Willow Run planes, but things quickly improved. A total of 430 new B-24Gs were manufactured. Early series were camouflaged, but starting with the G-10 series, the aircraft ceased to be painted.

Most of the bombers of this type entered the Mediterranean theater of operations, the 15th Air Force.

It was obvious that the A-15 turrets would not be enough for all factories. Therefore, San Diego modified the A-6A stern turret to be installed in the bow of the Liberator. In August 1943, the first aircraft with such weapons was handed over to the Air Force. The modification was designated B-24J. The installation of two A-6A turrets made the Type J the longest bomber modification. The rest of the armament was retained as the B-24D. In San Diego, the spaced-apart onboard mounts and the A-3D upper turret of the B-24N were not implemented.

But the B-24J was distinguished by an improved C-1 autopilot, a new M-type bombsight and an improved petrol system. In Fort Worth, the release of the J modification was mastered in September 1943.

At the beginning of 1944, the Air Force command ordered to install new scopes and autopilots on all production Liberators, designating them B-24J. Willow Run switched to such aircraft from April 1944, North American factories in Dallas and Douglas factories in Tulsa - from May. For the first time, all businesses made cars under the same designation. But the planes were not the same. By the spring of 1944, the supply of A-15 turrets had grown so much that they were also installed in Fort Worth and San Diego instead of A-6B. In San Diego, the transition took place from the 181st B-24J, in Fort Worth from the 41st. Now all the factories were making practically the same bomber. The B-24J became the most massive modification of the Liberator.

Gradually, many of the innovations inherent in the B-24H were implemented on the B-24J. We removed the side windows at the lower turret, introduced single navigation lights on the wing. All these changes were made at different plants at different series. Aircraft of later releases received thermal de-icers. They were first tested on the XB-24F, a converted B-24D.

Some episodes seemed to fall out of the general course of evolution of the "Liberator". Thus, 122 aircraft of the J-165 series received an M-6A aft turret with a hydraulic drive. It also carried a pair of 12.7 mm machine guns. Fort Worth produced 57 B-24J-40s, which were actually B-24Hs, assembled from units brought from Willow Run. These were the only B-24Js with A-3D turrets on top and shielded onboard mounts.

Despite the external similarity, the five factories still made "Liberators" a little differently. Their nodes were often not interchangeable. Ford's planes were different from North American and Convair (Consolidated merged with Valty to form Consolidated-Valty Aircraft, or Convair for short).

Lack of standardization was a constant problem for suppliers and repairers, who were forced to select and store parts and assemblies of numerous subspecies of B-24.

Modification J aircraft were delivered to Great Britain. A total of 1,200 aircraft of this type were sent there.

RECENT MODIFICATIONS In mid-1944, the Air Force decided that two factories, in San Diego and Willow Run, were sufficient to meet the need for Liberators. Production at Douglas and North American was ordered to cease. The Fort Worth plant continued to operate, producing the B-24J, until the end of 1944, mainly for export to the UK under the Lend-Lease program.

The enrichment of the equipment and the strengthening of the armament have significantly increased the weight of the B-24J compared to the previous modifications. Flight data fell accordingly, especially at high altitudes. In order to reduce takeoff weight, in the Pacific theater of operations, crews removed the Sperry ball turret and replaced it with a pair of 12.7 mm machine guns firing through a hatch in the floor. When, by the spring of 1944, the capabilities of fighter cover over Europe had significantly expanded, they began to do the same there.

In an attempt to make the Liberator easier, the Convair specialists at the Taxon plant have developed several new feeding options. The new M-6 Stinger turret saved about 100 kg compared to the standard A-6B. She was easier to control and had a large field of fire. By August 1944, the San Diego and Willow Run factories had switched to a lightweight modification of the bomber called the B-24L. Due to the introduction of the M-6 turret and some other measures, the weight has decreased by more than 450 kg. On the L type in San Diego, the K-5 onboard installations with shielded hatches were finally introduced. Later, on the L-5 series, the bombardier's cockpit glazing area was increased and a trimmer was introduced on the left aileron, on the L-15 series - a device for removing static charge. 417 B-24Ls were assembled in San Diego, and 1250 in Willow Run.

On July 10, 1944, the Air Force headquarters ordered not to install aft turrets at the factories, but to mount them in the Air Force modification centers, depending on the needs of each theater of operations. "Liberators" without tail units in San Diego still went as B-24L, and in Willow Run they were renamed B-24M. The latter designation did not last long, and the Air Force soon renamed 115 vehicles produced at Willow Run as B-24L.

On several aircraft, named RB-24L, remote-controlled turrets were mounted to train the shooters of the latest B-29 bombers. To train navigators, training TB-24Ls with radar stations were also made for them.

In December 1944, both plants switched to production of "real" V-24Ms. This was the last serial modification of the Liberator. On it, feed installations were again installed in factories. Only one type was mounted - a lightweight version of the A-6B turret. From the V-24M-20 series, a completely modified pilot's cockpit canopy with improved visibility was introduced.

The release of the "Liberators" was completed in June 1945. In San Diego, 916 B-24Ms were manufactured, and in Willow Run - 1877. Some new aircraft, after the official termination of contracts, went straight to scrap metal.

There were a few more modifications that remained only in prototypes or were purely experimental. The XB-24R was a flying laboratory of the Sperry Gyroscope Company ", the XB-24Q tested a tail turret with a radar sight, later modified for the B-47 jet bomber. In June 1944, a B-24J appeared with a nose part from the "Flying Fortress" B-17G, but this "mutation" was unsuccessful. In 1943, Ford converted one B-24D to the XB-24K with a single fin. In April 1944, it was concluded that this improved the stability of the aircraft. For military trials, seven YB-24Ks were built, and they wanted to launch this model into series. But all the "Liberators" were still produced with two-finned plumage. The new high keel was used on PB4Y-2 "Privatur" naval patrol aircraft and its transport modification RY-3.

Photo	Description
	Drawing B-24J Liberator
	"Maulin Mallard" from 93 Bomber Group.
	B-24 groups arriving in England and Italy during the winter of 1943-44 were equipped with the B-24H and J models. These featured improved armament, with a power-operated nose turret and a retractable ball turret. Unfortunately these features and revised equipment raised the overall weight of the Liberator, adversely effecting handling qualities as well as reducing operational altitude when fully loaded. The 701st Bomb Squadron's B-24J 2100404/ MK:S, The Grim Reaper, endured to the end of hostilities despite its forbidding name, although it was transferred to another group following repairs. The ball turret usually remained retracted until over enemy territory due to its drag when lowered; the guns can be seen pointing down from the well. To improve handling, most Eighth Air Force Liberators had their ball turrets removed in the spring of 1944, but the Fifteenth Air Force chose to retain theirs. (USAAF)

Bibliography

• "Encyclopedia of military engineering" /Aerospace Publising/
• "American warplanes of World War II" /under cor. David Donald/
• "RAIDING THE REICH. The Allied Strategie Offensive in Europe" /Roger A. Freeman/