The F6F continues to remain the largest single-motor piston fighter and the most popular carrier- borne fighter. Each and every aircraft of the index was manufactured at the same Grumman plant based on Long Island. Changes in the construction of the aircraft over the 10 years of its life were very slight: only five prototypes were issued, and only two models went into serial production. This unusual production history might reflect the fact that the designers of the aircraft were far from being “cabinet warriors”. Although the contract on the two prototypes was granted to Grumman as early as on June 30, 1941, the project gained full speed only in February 1942, when Grumman had finished studying the field reports on the Wildcat battle performance. They decided to rid F4F of its shortcomings and augment its advantages. The principal change entailed the installation of the most powerful US engine available. In combination with the enlarged wing area and thick bearing structure, the aircraft was expected to demonstrate high maneuverability, good take-off and landing characteristics, and an increase in speed and climb rate. The XF6F-1 with the 1600-hp Wright R-2600-16 engine flew on June 26, 1942, showing good results but suggesting inadequate power. The third prototype was fit with the 2-level 18-cylinder Pratt-Whitney Double Wasp R-2800-10 beauty with a two-stage supercharger delivering 2000 hp at take-off. The XF6F-3 flew on July 30, 1942 and soon went into serial production. The XF6F-1, refit with a R-2800-10 and four 20-mm Ford-Temko (Hispano М2) cannons, was redesignated the XF6F-4 and put through tests on October 3, 1942. US arms specialists could not solve the cannon-jamming problem. The sleeve came apart in the cartridge chamber, and the tape greasing froze at high altitudes, making the guns impossible to use in aircrafts. The problem was that the F6F-5 specifications included arms compartments designed to accommodate either 12.7-mm machine guns or 20-mm cannons.

Pilots of F6F-3’s from aircraft carrier Lexington after a combat mission in which they shot down 17 out of 20 enemy bombers heading to Tarawa Island, November 1943. [11]	An F6F-3 on aircraft carrier Yorktown, November 1943. (Photo from ‘KOKU-Fun’ magazine, 1975, #6)

Manufacture of the F6F-3 started up in October 1942, and the first aircraft in the series was shipped to the carrier Essex on January 16, 1943. Well over 2500 aircrafts were delivered during the first year, the later batches equipped with the R-2800-10W engine which allowed for a short (up to 5 minutes) injection of water-methanol solution, forcing engine capacity and lowering heat return. By April of 1944, when the Long Island plant switched over to manufacture of F6F-5 aircrafts, a total of 4402 F6F-3s were built. Their number included 167 F6F-3E and F6F-3N night fighters with APS radar mounted in a pod beneath the starboard wing. The design of the F6F-3 was very advanced for its time and featured large components assembly, overlapping welding of the bearing duralumin fuselage covering, and multilevel protection of fuel tanks, power plant and cockpit. To improve the sight and take off/landing characteristics, the engine axis had to be shifted 3 degrees downward and the cockpit lifted to create the trademark “hunchback” silhouette. The powerful engine required a larger propeller and, consequently, longer chassis racks. In spite of this, the chassis turned out to be very durable and allowed for a considerable groove which together with the high carrying ability of the wings at low speeds made the aircraft easy to land. Large slot-hole flaps released automatically at speeds below 315 km/h. With the growth in speed, the deviation angle decreased, enabling skilled pilots to stand up to the latest Zero models in maneuverable fight. Mounted in the wing pods of the F6F-3 were six 12.7-mm machine guns, each of which held 400-450 rounds of ammunition. The wings featured a hydro-drive folding mechanism, similar to that of the Wildcat. To enlarge the flight range the aircraft had a 568-liter disposable tank under the fuselage. Later models were fit with two additional standard 220-liter tanks or bombs.

Cockpit of an F6F ‘Hellcat’

The F6F-3 underwent its first test in battle on August 31, 1943 when a batch of the Hellcats from the carriers Lexington, Essex and Independence assaulted Marcus Island. The next day two F6F-3s downed a Kavanishi H8K Emily hydroplane. The first encounter with the Zero took place much later in December 1943 when a group of 91 Hellcats ripped into a hundred of the Japanese aircrafts. In the ensuing battle, 28 of the 50 Zeros were destroyed at a total loss to the F6F-3 of 3 planes. The Hellcat pilots used their advantage in speed to deliver fast diving strikes and left the battle by turning over and diving as soon as the enemy tried to use their favorite tactics of maneuverable battle. As the numbers of the Japanese fighters dwindled, the Hellcat became widely used for land strikes. This led to the development of a new F6F-5 model in April of 1944. This model had reinforced wings and armed cabin, two optional 20-mm cannons which could replace the internal 12.7mm machine guns, underwing attachments for 6 127-mm rockets, and center-section pylons for up to 453-kg of bombs.

An F6F-5 during testing, 26 March 1945. Six 5-inch HVAR rockets and two 11.75 inch ‘Tiny Tim’ rockets are visible [11].	Torpedo-bombers ‘Avenger’ and F6F-5’s on the deck of carrier Monterey, 25 March 1945. [12]

By autumn of 1944 the carrier borne F6F-5 was replaced by the F6F-3. On June 19, 1944 in “The Great Marianas Turkey Shoot”, as the aerial Battle of the Philippine Sea is known, the 5th Fleet Hellcats managed to counter every attack of the Japanese fighters, downing 300 of them while losing only 30 aircrafts. While defending the Lexington in a F6F-3, Lieutenant Alexander Vrachu, who had already accounted for 12 kills, in a single fight downed six Yokosuka D4Y1 Judy dive-bombers, firing about 60 12,7-mm rounds on each. This achievement was repeated on October 10, 1944 by Commander David McCampbell, who piloted a F6F-5 while downing six Japanese aircrafts in combat over the Philippines. It is not for nothing that the Hellcat received the name of “ace factory.”

Projections, armaments and protection systems of F6F-5. NAVAER report, 1945 [5]. The standard weapon systems are indicated as two 20mm cannons and four 0.5 inch machineguns.

The Hellcat remained the main US carrier-borne fighter till the end of war but engaged in fewer and fewer battles as the enemy receded. Assault missions were being taken over by a different fighter plane – the Chance-Vote F4U Corsair. The latest Grumman “cats” – the F7F Tigercat and the F8F Bearcat – did not get to fight at all.

Carrier-based interceptor F8F-1 (front) and night fighter F7F-2N, end of 1945. [11]	The F4U-1A of Captain Ira Kepford with 14 victory markings, VF-17 “Skull and bones”, New Georgia, February 1944. [11]

The Chance-Vote-Sikorsky company was awarded the contract for the development of a fast and high-altitude carrier-borne fighter on June 11, 1938. The aircraft was supposed to be designed especially for the experimental 1800-hp Pratt-Whitney Double Wasp XR-2800 engine. The designers, Rex Basel and Igor Sikorsky, developed a very compact aircraft with the most powerful 2-level 18-cylinder engine of the time. The round section fuselage was riveted to the engine diameter. The effort to minimize the length and weight of the main chassis racks, providing at the same time sufficient backslash under the large propeller, resulted in the “turned seagull” wing type. Compact chassis racks were placed in the central section, near the oil radiator and the supercharger air inlet. Wing machine guns and integrated fuel tanks were brought out to the wing pods which could be folded up over the cockpit by hydraulic drive. The design used advanced electric welding technology.

Flight tests of the XF4U-1 began on May 29, 1940. The designers confronted serious problems. The wheel trimmers collapsed, the experimental engine overheated and failed, and the forward centering promoted toppling of the aircraft during landing and complicated extrication from spins. In course of the operational development, the armament of the aircraft was supplemented. The front machine guns were removed, while the number of underwing machine guns changed to four. However, high climb rate (22 m/c at the ground level) and horizontal speed (651 km/h) triumphed over all the disadvantages: this prototype was the first US battle aircraft to exceed the “magic” figure of 400 mph. The contract for the manufacture of 654 F4U-1 fighters was awarded on June 30, 1941. It stipulated a vast set of modifications. The serial model was to be fitted with the 2000-hp Double Wasp R-2800-8 and the fuel tanks removed from the pods and replaced by three 12.7-mm Colt-Browning guns on each side (two guns with 400 round ammunition capacity and one 375-round gun). The now protected fuel tank was to be placed in the fuselage above the wing, and the cockpit shifted 91 cm backwards. The weight of the armored cockpit, engine, oil and fuel tanks increased, and the range of flight and the climb rate fell. The long hood and wings completely blocked the pilot’s sightlines in the front and to the sides. The rear line of sight, in spite of glass panels and a periscope above the windshield, was also far from perfection. Take-off and battle maneuverability were facilitated by flaps with angle reduction mechanism that worked independently of the hydraulic release cylinders on the speed meter. A large disposable fuel tank was mounted under the fuselage.

Cockpit of a F4U ‘Corsair’.

A small batch of F4U-1s was put through field tests on land and aboard the carrier Sangamon in July of 1942. High landing speed, large lay angle, poor sight and rigid chassis racks called for superior skill on the part of the pilot when landing on board the carrier, as the aircraft tended to “jumpjack” and topple. For this reason, from September 1942 on, Corsairs began to be delivered to the US Marine Corps. The first battle test came on February 13, 1943, when the aircraft, manned by VMF-124 pilots, saw action over Guadalcanal. On February 14 the aircraft had its first battle against 50 Zeros. The encounter came to be known as the “St. Valentine’s Day Massacre”. The mixed group of Lockheed P-38 Lightning, Curtis P-40 Hawk and Corsairs, which was supposed to cover the Consolidated B-24 Liberator bombers, allowed two of them to be downed. The US lost two Corsairs, two Hawks and four Lightnings, while the Japanese lost only four Zeros. During the first two weeks of their battle history, eight Corsairs were destroyed and another five suffered crash landings. However, the hard-earned experience proved to be invaluable: during the next two months the VMF-124 pilots downed 68 Japanese aircrafts, losing only four F4U-1 and three pilots.

During the next half-year Corsairs were delivered to seven Marine Corps squadrons. By August, a thousand aircrafts had already been manufactured. Due to the large distances between the islands, unprotected tanks were brought back into the pods. The problem of poor visibility which had complicated take-off and landing was resolved with the appearance of F4U-1 Number 689. This model received the index F4U-1A in 1944. The pilot’s seat was lifted up by 229 mm, the sight raised by 127 mm, the pedals and handle lengthened and the three-section convex part of the cockpit enlarged. The first models tended to topple at low speeds. This problem was resolved by addition of the turbulizing patch to the starboard on the wing front pad. The Brewster and Goodyear plants, having already mastered the manufacture of F4U-1, shifted the production line to this improved version, indexing it as F3A-1A and FG-1A (with solid wings). Field workshops fitted the fuselage and pods with bomb pylons (for up to 453 kg). The standard fuselage pylon for large bombs was invented by Brewster – which happened to be the company’s sole contribution to the development of this model. The Navy revoked its contract with this company as it managed to manufacture only 735 models of F3A-1A и F3A-1D by June of 1944. As for Goodyear, by the end of war it accounted for the manufacture of 35% of all the Corsairs, issuing mainly FG-1A and FG-1D models.