The F4U-4 in World War II

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Development

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Throughout 1943 and 1944, and into the beginning of 1945, Vought continued upgrading the F4U Corsair "1-Series." The F4U-1, 1A, 1D and 1C, however, all shared the same core, and modifications and updates were often implemented in the field on earlier variants as they were introduced in the factory on the later models (for example 1As still in service were retrofit to carry the same wingroot pylons and four rocket tab positions used on the 1C). However the Corsair would soon receive a major upgrade.

 

While the supercharger-equipped XF4U-3 project provided unsatisfactory results, Vought would follow a different path with its contemporary and successor. At the heart of this new variant was an improved Pratt and Whitney R-2800-18(W) radial, replacing the earlier -8(W). This model of the engine would produce 2100 hp on takeoff, and with the use of water-methanol injection could achieve a power rating of 2450 hp. To take advantage of the increased engine power, the three-bladed paddle prop utilized since the 1A was replaced with a massive four-bladed paddle. The result was a significant increase in airspeed, rate of climb, and lateral acceleration.

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The aircraft's cowling was redesigned with a distinctive chin scoop, and in addition to the exhaust stacks on the lower fuselage exhaust was vented from an additional stack on either side of the fuselage above the wings. The curved armored windscreen in most production aircraft would be replaced with a flat screen to reduce optical distortion, and the metal hood on the canopy over the pilot's head would be completely eliminated. The cockpit was completely redesigned. The "floorless" cockpit of the 1-Series Corsairs was eliminated and replaced with a floored version. The instrument cluster was revised, as was the positioning of controls for the engine, landing gear, flaps, and other secondary systems.

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Armament returned to the six Browning .50 cal of the -1, 1A and 1D, bringing to an end the experiment of all-cannon armament in the Corsair until the end of the war. Like the 1D, the aircraft was fitted with two main pylons inboard of the landing gear, and rocket tabs for four 5" HVARs on each wing, for a total of 8. The wing-mounted fuel tanks were eliminated, and even more of the fabric-covered wing surface was replaced with metal.

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The new aircraft, designated the F4U-4, put up monstrous performance numbers. With a top speed exceeding 450 mph at level flight at altitude she was one of the fastest propeller-driven fighters of the war. Acceleration was excellent and rate of climb was boosted to nearly 4000 fpm by the uprated engine and four-bladed propeller. In combat she provided all the strengths of the previous models: excellent rate of roll, exceptional mid and high-speed maneuverability, rugged airframe and superb firepower and ordinance load. She surpassed the P-51 Mustang--widely and often considered America's finest fighter aircraft of WWII--in nearly all aspects of performance. Compared to her chief opponents in the Pacific, she completely dominated the A6M and Ki-43. She was faster than Japan's best fighter, the Ki-84, and cleanly outmatched her in vertical performance. While the "Frank" was highly maneuverable at low speeds, at mid and high speeds the F4U-4 was superior, especially with the Ki-84's tendency to suffer loss of aileron and elevator authority at higher speeds. The F4U-4 was to the best of Japan's late-war designs what the F4U-1 and F6F was to the Zero. 

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Unit Deployment

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F4U-4s began to deploy to the Pacific during the final four months of the conflict, replacing and supplementing the 1Ds and 1Cs already in the theater. However despite her gaudy performance, the F4U-4's limited action against the all but beaten Japanese Air and Naval forces meant she would make little real impact on the Pacific war. It was perhaps this late arrival that has led the "4-Hog" to be relegated by history to a place behind the P-51 Mustang as the greatest American fighter of WWII. By the time the Corsair fought her next war the age of propeller fighters was at an end, and the F4U-4 never had a real chance to truly show her capabilities as an air-to-air combatant.

F4U-4s were deployed to both Navy and Marine squadrons, and operated from carrier decks and land bases. First Corsair ace Kenneth A. Walsh finished out the war in the F4U-4, recording his final victory in the aircraft.