In February 1938, the US Navy Bureau of Aeronautics published a requests for proposals (RFP) for both a twin-engined and a single-engined fighter. For the single-engined fighter the Navy requested the maximum obtainable speed, and a stalling speed not higher than 70 mph (113 km/h). A range of 1,000 miles (1610 km) was specified. The fighter had to carry four guns, or three with increased ammunition. Provision had to be made for anti-aircraft bombs to be carried in the wing. These small bombs would, according to thinking in the 1930s, be dropped on enemy aircraft formations.

An unusual element of the RFP was that the Navy vowed to consider designs with liquid-cooled engines, in contradiction with a policy settled in 1927 that required air-cooled engines for shipboard aircraft. From the viewpoint of naval aviators, liquid cooling systems had serious disadvantages: They were heavier, more vulnerable, and more difficult to maintain. But in the late 1930s, there was a growing conviction in international aviation circles, that radial engines presented a too high drag penalty. Liquid-cooled engines with their smaller frontal area could be installed in a more streamlined fuselage. Hence the option to accept a fighter built for such an engine, in practice the Allison V-1710.

This engine was indeed chosen by Bell for their entry in the competition: The Bell Model 5 Airabonita, virtually a P-39 Airacobra with tailwheel landing gear, a slightly larger wing, and a stronger structure. As in the P-39, the engine was placed amidships, over the wing. The pilot sat in front of the engine, with a long extension shaft passing between his legs to drive the propeller up front. A 23 mm Madsen cannon or a 12.7 mm (0.50 in) machine-gun and two 7.62 mm (0.30 in) machine-guns were installed in the nose, the cannon firing through the hollow propeller hub.

There was more choice in radial engines: The older Pratt & Whitney R-1830, and the new the Wright R-2600 and Pratt & Whitney R-2800. These air-cooled radial engines had a larger frontal area than the V-1710, and thus generated more drag. For the R-2600 and R-2800 this was compensated for by their power: While the V-1710 was hoped to deliver about 1,150 hp (858 kW), the R-2800 was expected to generate 2,000 hp (1492 kW) and more, and the R-2600 1500hp. Radial engines were chosen by Brewster, Grumman, Vought and Curtiss. Grumman proposed a development of the F4F Wildcat, that would be powered by the R-2600 engine. Brewster, manufacturer of the F2A Buffalo that had been the US Navy's first monoplane fighter, offered designs with the R-2600 or R-2800. Curtiss proposed developments of the P-36 Mohawk, powered by either the R-2600 or the older R-1830 engine.

A Chance-Vought F4U-1D of VMF 124 U.S. Marine Squadron flown by Major Greg Boyington - New Guinea 1943

In April 1938, Vought proposed its two designs to the US Navy. One, called V-166A by Vought and "Vought A" by the USN, was powered by the R-1830. The other, the V-166B or "Vought B", was designed around the new Pratt & Whitney R-2800 Double Wasp radial engine. This was an 18-cylinder, two-row air-cooled radial. This engine would later also be installed in the competing Grumman F6F Hellcat and in the Republic P-47 Thunderbolt for the USAAF, but the new Vought fighter was the first to use this engine. The R-2800 later acquired a reputation as a powerful and very reliable engine. But it was also very bulky, and aircraft powered by it tended to be big.

In May 1938, the Bureau of Aeronautics evaluated the proposals. The "Vought B" was deemed to be the best one, with a merit figure of 86.4 on a scale from 0 to 100. Hence on 11 June, a contract was given for development of the Vought V-166B, the fighter that would become famous as the F4U Corsair.

The evaluation committee also recommended that the "Brewster A" proposal, rated third best, should be developed because of its alternative R-2600 engine. Because of the management difficulties of Brewster, this never happened. Grumman received a contract to develop to F4F-3 version of the Wildcat, and won the simultaneous competition for a twin-engined fighter with F5F Skyrocket. Their R-2600 engined fighter was rejected, but in June 1941 the Navy would nevertheless order two prototypes of the F6F Hellcat, which switched to the R-2800 during development. The Navy was also sufficiently intrigued by the Bell proposal to order a prototype, named the XFL-1. But the Bell fighter, ranked sixth of the competitors, was obviously not destined to enter production, and Bell was very reluctant to invest time and money in its development. The history of the Airabonita would be an unhappy one.

The engineers of Grumman and Republic both selected to install the R-2800 in a fuselage with an egg-shaped cross-section, deeper than was strictly required by the R-2800. This created room for a bath with ducts under the engine. For the P-47, the determining factor was the installation of the turbo supercharger in the aft fuselage, which required air and exhaust ducts in the lower fuselage. The considerations of Grumman may have been similar, because a version of the F6F with a turbo supercharged R-2600 engine was offered to the US Navy. Vought's Chief designer Rex B. Beisel instead opted for a fuselage of circular cross-section, of a diameter matching that of the R-2800. The oil cooler and supercharger air intakes would be installed in the wing leading edges. He also avoided the hump-backed upper fuselage of the Grumman F4F and F6F, that was designed to give the pilot a better forward visibility over the engine. Hence, the forward fuselage was of cylindrical shape. Construction was all-metal, and streamlining was improved further by using a new spot-welding technique that gave a very smooth finish.

A very large propeller was required to convert the power of the R-2800 into forward thrust. A three-bladed propeller with a diameter of 13.25 ft (4.04 m) was chosen. Sufficient propeller clearance could have been achieved by designing a long and stalky landing gear, or by making the fuselage deeper again, thus moving the wing downwards relative to the engine. Instead, the Vought team adopted an inverted gull wing: the wing started with strong anhedral, i.e. a downwards slope toward the wingtips, and then curved upwards to strong dihedral. The landing gear was installed at the lowest point of the bend. Such a construction was not uncommon, though usually associated with fixed landing gear, such as on the German Junkers Ju 87 "Stuka" dive bomber. Inevitably, the weight of such a construction is higher than that of a straight wing. But apart from keeping the landing gear short and simple, it offered the advantage that the joint between wing and fuselage was made at the ideal angle. In that way a wing root fairing could be avoided. The entire construction contributed to the purposeful ugliness of the design, but it was efficient.

The wing had integral leading edge fuel tanks, which were unprotected. For storage aboard carriers, the wing folded upward outboard of the main landing gear legs. The wheels folded backwards, turning through 90 degrees while retracting, so that they were stored flat within the wing. The entire trailing edge inboard of the ailerons was provided with flaps. The outer wing panels were covered with fabric aft of the wing spar.

The pilot sat in a large cockpit over the wing trailing edge. The view straight forward over the engine cowling was poor, even more so than common in single-seat fighters of the day. View too the sides was reasonable, although the cockpit canopy was heavily framed. No concessions were made to rearward view, the aft of the cockpit being faired into a gently sloping fuselage decking. The tailplanes and fins had rounded tips, and the control surfaces were fabric covered.

Armament consisted of one 12.7 mm (0.50 in) machine-gun in each wing, a 12.7 mm (0.50 in) machine-gun and a 7.62 mm (0.30 in) machine-gun in the engine cowl decking. There was also room for 20 small anti-aircraft bombs, stored in the wings.
 

In June 1938 the USN signed a contract for a prototype, the XF4U-1, BuNo 1443. After mock-up inspection in February 1939 construction of the XF4U-1 went ahead quickly. First flight of the XF4U-1 was made on 29 May 1940, by Lyman A. Bullard Jr. The XF4U-1 was powered by a XR-2800-4 engine, rated at 1,805 hp (1347 kW). The first flight was not uneventful. A hurried landing was made when the elevator trim tabs failed because of flutter.

Early testing encountered a serious setback when project pilot Boone T. Guyton ran out of fuel during the fifth test flight and made an emergency landing on a golf course. The XF4U-1 was badly damaged, but not beyond repair, and Chance Vought rebuilt it.

On 1 October the XF4U-1 made a flight for Stratford to Hartford with an average ground speed of 404 mph (650 km/h). It was then the first US fighter to fly faster than 400 mph. The XF4U-1 also had an excellent rate of climb. On the other hand, the testing of the XF4U-1 revealed that some of the requirements of the US Navy would have to be rewritten. In full-power dive tests speeds of up to 549 mph (885 km/h) were achieved, but not without damage to the control surfaces and access panels, and in one case, an engine failure. The spin recovery standards also had to be relaxed, as recovery from the required ten-turn spin proved impossible without recourse to an anti-spin chute.

Much time was spent trying to improve the handling of the XF4U-1. Numerous changes were made to the ailerons, with success, as these were later known to be very effective. However, the low-speed handling characteristics left much to be desired. The F4U had a troubling tendency to drop a wing when it stalled. And this was a critical factor for a shipboard fighter, which would have to make dangerous deck landings. 

The Pilots
The most flamboyant, outspoken and highest scoring Marine Corps fighter pilot of WWII was Colonel “Pappy” Boyington, VMF-214 the “Black Sheep”. As Squadron Leader. He operated out of Vella Lavella in the South Pacific. Pappy’s total was 28 enemy aircraft downed. Upon his release from 20 months as a prisoner of the Japanese he was ordered to Washington to receive the nations highest award the Medal of Honour from President Harry S. Truman.

Lt. Robert Hanson ( The Terror of Rabaul) VMF-215 flying out of Vella Lavella Bouganville for a short period, VMF-215 was moved to a new base at Torokina closer to Raboul. Lt. Robert Hanson shot down 25 enemy aircraft in just 3 months and 20 in 17 days in just six missions. This was an accomplishment that was never equalled by any other WWII Allied Pilot. VMF-215 produced 10 aces during the campaign against Rabaul and shot down 137 enemy aircraft in just 18 weeks.

Ensign Ira Kempford (“Blackburns Irregulars”) VF-17 they lived up to their name They disrupted many country social events buzzing race tracks, official ceremonies, farmers , local citizens and were known to run vehicles off the road while inverted. The Navy was happy to transfer them to the South Pacific.They compiled some amazing statistics, 8,557 combat hours, 156 enemy aircraft shot down, five ships sunk, and produced more aces than any other Navy unit, and all this was accomplished in just 76 days. Kempford became the fifth highest scoring Navy ace of WWII with an official score of 17 Japanese aircraft shot down.

Lt. Alvin J.Jensen VMF-214 after getting lost and caught in a very severe storm he came out of the storm in a spin and inverted, after he managed to regain control, he realized that directly below was a Japanese airfield. He immediately attacked the airfield and in doing so destroyed 24 aircraft, four Vals, eight Zekes and twelve Betty’s before returning to Vella Lavella. This was described as the greatest single-handed feat of the Pacific War. For this he was awarded the Navy Cross.

Nicknames: Bend-Wing Bird; Bent-Wing Ensign Eliminator; Bent-Wing Monster; Whistling Death; Horseshoe; Super Stuka; U-Bird, Hose Nose; Hog Nose; Sweetheart; Hog.

Specifications (F4U-1A):

Engine: 2,000hp Pratt and Whitney R-2800-8 radial piston engine
Weight: Empty 8,980 lbs, Maximum Takeoff 14,000 lbs.
Wing Span: 41ft. 0in.
Length: 33ft. 4in.
Height: 16ft. 1in.

Performance:
Maximum Speed at 20,000ft: 420 mph
Cruising Speed: 185 mph
Service Ceiling: 37,000 ft.
Initial Climb Rate: 3,100 feet/min.

Armament:
Six 12.7mm (0.50 in) machine guns, wing-mounted.

Number Built: 12,571

Number Still Airworthy:  ~28