The first B-24A to be lost to enemy action was at Hickam Field on December 7, 1941; it had been fitted with cameras and three guns for a secret mission to photograph Japanese mandated islands in the Pacific. Four more were lost in Australia by March 19, 1942. The Liberator II, built on the LB-30 contract with R-1830-S3C4G engines and Curtiss (instead of the usual Hamilton) propellers, was the first model with a longer nose and provision for two 850-pound power-operated gun turrets, along with 14 .303-caliber guns. Four were in the Boulton Paul top turret, four in the tail turret, two in each waist window, one at the tunnel hatch, and another in the nose. Except for test examples, the armament was to be installed in Britain.
Seven crewmen with a Sperry bombsight and twelve 500-pound bombs were the standard load, which could be carried 3,020 miles. The first LB-30 (AL503) was flown May 26, 1941, but was destroyed by a fatal crash on June 2. Another 139 were delivered from August 8 to December 31, 1941.
Most Liberators had been flown by American pilots to Montreal, where British pilots took them across the Atlantic. The AAF’s own Ferry Command next undertook to fly them across the South Atlantic and Africa to an RAF bomber squadron in Egypt, and the first five began that pioneering flight on November 21, 1941. The first raid by one of these RAF Liberator IIs was on Tripoli on the night of January 10, 1942.
When the United States entered the war, there still were no Liberators with AAF bomber squadrons, so the remaining 74 LB-30s were taken over by the Air Force. Two days after the Pearl Harbor attack, provisions for British armament were ordered to be replaced by eight .50-caliber guns, including two hand-operated guns on posts at the tail and waist openings, with single guns in the nose and tunnel positions. Instead of the Boulton Paul turret on top behind the rear wing spar, a two-gun Martin power turret, like that of a B-26, was installed at the Tucson modification center.
Twelve of these LB-30s were flown by 7th Bomb Group crews to Java, six via the South Atlantic and Africa, and the others across the Pacific via Hawaii, various islands, and Australia. The first three to arrive flew the first Air Force Liberator combat sorties on January 17, 1942.
Seventeen others were rushed to the Canal Zone in March/April 1942 to fill out the 6th Bomb Group, and that summer were fitted with ASV Mark II radar. The 30th Bomb Group had LB-30s at March Field and sent six to Hawaii and three to Alaska in time to fly a few sorties in June 1942. Others served the AAF as transports, but 23 Army LB-30s were returned to British control in 1942, to bring the RAF LB-30 total to 88, less four lost en route. Most went to RAF squadrons in India.
Turbosupercharged 1,200-hp R-1830-41 Wasps in elliptical cowls, like those of the XB-24B, were used on nine B-24Cs, the first flown October 14, 1941. Seven .50-caliber guns and 2,900 rounds of ammunition were carried, two guns in a 954-pound Consolidated armored hydraulic-powered tail turret. A swing of 122-degrees sideways and 111-degrees up and down gave the B-24 a much better arc of fire than the B-17E’s tail guns. Another pair was in a Martin power turret behind the pilots’ cabin, two more were in a retractable Bendix belly turret behind the bomb bay, and one hand-held gun remained in the nose.
Rearranged crew stations moved the navigator’s table into the nose, as it was assumed he would operate the bombsight, while the radio operator now sat behind the co-pilot, instead of behind the bomb bay. Eight B-24Cs were accepted from December 20 to 31, 1941, but the last was delayed to February 10, 1942, as it was a test bed for the General Electric remote-control turrets planned for the B-29.
The first mass-production Liberator version was the B-24D, first flown on January 12, 1942, which was similar at first to the B-24C, except for R-1830-43 engines. While the first 26 replaced the early Liberators given to the RAF, Consolidated had received orders for 56 more on August 16, and for 352 on September 20, 1940.
The Lend-lease program contracted on May 12, 1941, for 700 more Liberators for Britain, and as later contracts were added for the AAF, a production pool of five factories was established. These included a new Consolidated factory at Fort Worth, a Douglas factory at Tulsa, and an enormous Ford plant at Willow Run, Michigan, that produced both complete B-24E aircraft and KD (knock-down) sub- assemblies for the Fort Worth and Tulsa factories. North American joined the pool when it received a letter contract in January 1942 to build 750 at a new Dallas factory.
The first 26 B-24Ds accepted at Consolidated’s San Diego factory from January 22 to February 12, 1942, had seven guns and lacked the astrodome in the nose common to all later models. Their specified weight was 33,822 pounds empty and only 41,000 pounds design gross. This unrealistic low loading would permit a 316-mph top speed, claimed the Model Specification dated February 1, 1942.
Liberator weight would rise due to operational requirements. The top Martin power turret and a Consolidated power turret in the tail remained with two .50-caliber guns each, but the Bendix belly turret with its awkward periscope sight was removed from the first 287 B-24Ds. Most remained in the United States, beginning with the 44th BG which first trained crews for new units. Aircraft sent overseas, beginning with the HALPRO unit, added three hand-held .50-caliber guns. These were mounted at each waist window and at the bottom camera door behind them, as planned for early models.
A system of block numbers and letters was adopted to identify the numerous changes and factory of origin, starting with the B-24D-1-CO accepted at San Diego on June 30, 1942. Beginning with the B-24D-20-CO and Fort Worth’s B-24D-1-CF model, outboard 450-gallon wing tanks could augment the normal 2,364 gallon fuel capacity. Another 780 gallons could be provided in bomb-bay ferry tanks when bombs were not needed.