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Consolidated Vultee B-24D or PB4Y Liberator
|Crew||8 to 10|
|110’ x 66’4” x 17’11"
33.53m by 20.22m by 5.46m
|1048 square feet
97.4 square meters
|303 mph at 25,000 feet.
488 km/h at 7620 m
|Cruise speed||200 mph
Rate of climb
|16.5 feet per second
|4 1200hp (895 kW) Pratt & Whitney
Twin Wasp 14-cylinder two-row radial engines driving
|10 0.50 machine guns in dorsal, ventral, and tail turrets, in the nose, and in waist bulges.|
|2 bomb bays of 4000 lbs (1814 kg) each or 2 4000 lb (1814 kg) external bombs|
|2100 mi (3380 km) at 190 mph (306 km/h) with 5000 lbs
(2270 kg) of bombs
2850 miles (4586 km) maximum.
||British Lend-Lease models were
equipped with ASV
Mark II radar by the time war broke out in the
An American version of ASV Mark III radar was available for aircraft produced after 1942-3.
|Total built: 19,203. 1716 built for the Navy as PB4Ys. At
Consolidated Vultee Aircraft Corporation,
San Diego, CA and other plants:
252 early models
260 Liberator III
739 PB4Y Privateer
The B-24C was the first variant with power turrets and turbocharged engines, closely resembling the D but produced in very small numbers.
The first version produced in quantity
was the B-24D with increased fuel and armament.
The main production versions were the
G, H, and J which differed from each other only in minor
details. The G standardized the powered nose turret, which
had been a field and depot modification of the original
three flexible nose guns of the D.
The PB4Y-2 Privateer replaced the twin stabilizers with a single vertical stabilizer and added a flight engineer station. The ventral turret was replaced with an ASG radome.
The C-87 (RY-1, -2, and -3 in Navy service) was a transport version carrying up to twenty passengers with a crew of give. Over 280 were built.
The F-7 was a photoreconnaissance
version that saw service in the Pacific.
A tanker version, the C-109, was
converted from other models and capable of carrying 2900
gallons (11,000 liters) of fuel, of which about 200 were
built. This version was nicknamed the "C-One-Oh-Boom",
though it did not in fact suffer excessive operational
losses. On the other hand, it was not particularly
successful, perhaps because its intended role
(transporting fuel to China for the B-29s) was an exercise
The B-24 was intended as the successor to the legendary B-17 and incorporated a number of advanced technologies. It was rather clumsy in appearance due to the placement of the low-drag Davis wing high on the fuselage. However, this avoided running the engine spar through the bomb bays, allowing a very large bomb capacity, and the Davis wing gave the B-24 excellent range and speed. It was somewhat less rugged than the B-17 and could not fly as high. In some ways it was a disappointment, being a slight improvement at best on the B-17, in spite of being conceived five years later, and being much more complex and expensive.
The design dated to 1939, when the Air Corps suggested
to Consolidated that they open a second line for manufacturing
B-17s under license. Consolidated chose instead to rush
development of its own heavy bomber design, using the Davis
laminar flow wing and tail assembly from the earlier Model 31 flying boat proposal. The
wing spars were widely spaced to accommodate large fuel tanks and
ease of manufacture was an important consideration in the design.
The proposal was accepted on 30 March 1939 and the prototype first
flew on 29 December 1939.
The Davis wing was an unusual design that promoted
laminar flow over more of the surface of the wing than more
conventional designs. This allowed a high angle of attack for
greater lift and minimized drag, giving an aircraft using the wing
a greater range. Beginning with the B-24G, the wing was equipped
with a heated deicing system, which also provided heat to most of
the crew stations. Unlike the B-17, whose earliest versions
entered combat without adequate nose or tail armament, the first
mass-produced Liberator model, the B-24D, was well-armed, with
electrically powered twin-gun tail, ventral, and dorsal turrets,
in addition to pairs of waist guns and nose guns. The flexible
nose guns were replaced with a powered turret as a field and depot
modification and became a standard feature beginning with the
The most remarkable aspect of the B-24 was its massive
scale of production. Ford’s Willow Run aircraft factory, which
applied true mass production techniques to aircraft manufacture,
produced a B-24 every 50 minutes once the assembly line was up and
running. As a result, more B-24s were produced during the war than
any other aircraft. This was enough to supply every U.S. combat
theater and still have aircraft left over for Lend-Lease to 15 Allied nations. The B-24
was the only heavy bomber deployed in some theaters, including China and Burma, until superseded by the
very heavy B-29 Superfortress.
Production was also sufficient to support an unusual variety of
special versions, such as reconnaissance, tanker, and transport
versions. The C-109 tanker was meant to transport gasoline across the Himalayas to the
B-29 airfields in China, but proved unsuccessful in this role.
The British equipped their Lend-Lease B-24s with ASV radar from the very start, for use in antisubmarine warfare in the Atlantic, and it is likely that the U.S. quickly copied this. The Liberator closed the "air gap" in the Atlantic and thus ensured victory in the U-boat war. In the Pacific, far-ranging Navy PB4Ys took a substantial bite out of the Japanese Merchant Marine and did their part to wreck port facilities. The PB4Y was still under development when the ASG radar was coming into production, and became the first aircraft purposely designed with space for a radar set.
The reputation of the B-24 as less rugged than the B-17
may have been largely a matter of perception. Actual loss
statistics do not support the claim. On the other hand, the
reputation of the B-24 for having a cramped nose area for the
navigator and bombardier, compared with the B-17, seems to have
had some basis in reality. The greater popularity of the B-17 may
simply be a matter of aesthetics: Most aircraft enthusiasts
considered it a beautiful aircraft, while the B-24 was boxy and
its high wing placement looked awkward.
About a third of all B-24s were deployed to the Pacific,
where their long range made them more suitable than the B-17. A
number were allocated to the Navy as PB4Y search planes.This made
the B-24 the backbone of the American heavy bomber force in the
Pacific until the introduction of the B-29 late in the war.
Hess et al. (1998)
Museum of the USAF (accessed 2014-2-19)
Sharpe et al. (1999)
Alley (accessed 2008-9-12)
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