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Even before the Grumman F4F Wildcat had fully entered service, Grumman was working on a successor. The initial contract had been signed on 30 June 1941, well before the attack on Pearl Harbor. However, the design of the new fighter was greatly influenced by the events of December 1941 and early 1942, when the Mitsubishi Zero proved itself to be superior to every allied fighter. The experience gained at great expense in the Pacific gave Grumman a chance to custom built their new fighter to kill the Zero.
The new Grumman fighter physically resembled the earlier Wildcat in many ways – most obviously the shape of the fuselage and cockpit and in the method chosen to fold the wings. However, the F6F was a completely new fighter, not a modification of the older aircraft. Grumman’s design philosophy with the F6F was to produce as good a fighter as possible without making any radical changes. This contrasts to Chance-Vought’s attitude to the Corsair, a much more innovative fighter. The result was that the Corsair was a superior aircraft, but was slower to produce, and took much longer to enter full service. The F6F was easier to produce, and from the very first production model was ready for carrier operation. The aircraft went from contract to service in only eighteen months! The many similarities between the F4F and the F6F made it much easier to switch production to the more advanced aircraft.
The F6F featured a lower wing than the Wildcat. The landing gear could retract fully into the wing (it rotated through 90 degrees then folded backwards into the wings), rather than partly into the fuselage as in the Wildcat. This allowed the wheels to be much farther apart (wider wheel base), which made it much easier to land on carriers. The F6F Hellcat had the largest wing area of any American single engined fighter of the Second World War. With the increased wing area came an increase in the size of the control areas. The Wildcat was a very manoeuvrable aircraft.
Unlike the Corsair, the Hellcat was designed to maximise visibility, with a high cockpit and pilot position and a sloping engine cowling. The new design had more armour than the Wildcat and more firepower. The F6F carried six .50 calibre Browning machine guns, three per wing, with 400 rounds per gun (the Wildcat could only carry 240 rounds per gun when equipped with six guns).
XF6F-1
The first complete prototype was the XF6F-1 (No. 02981), which flew on 26 June 1942. It was powered by the Wright R 2600-16 engine, giving 1,600 hp. The prototype out-performed the F4F Wildcat, but not by as much as the Pratt and Whitney powered XF6F-3.
XF6F-3
The first XF6F-3 (No. 02982) first flew on 30 July 1942. It was powered by the Pratt and Whitney R2800-10 Double Wasp engine, giving 2,000 hp. Grumman quickly converted the XF6F-1 to use the same engine, and re-designated it as a second XF6F-3. The resulting aircraft could reach a maximum speed of 380 mph, sixty miles per hour faster than the standard F4F-4 Wildcat. The XF6F-3 was accepted for production as the F6F-3.
XF6F-2
The original design contract for the F6F had included provision for work on a turbo-charged version. The success of the XF6F-3 sidelined this project until 1943. As first built the XF6F-2 had a Wright R-2600-6 engine and a Birmann turbo-supercharger. Performance was not great, and so the engine was replaced by a Pratt & Whitney R-2800-21. This version first flew on 7 January 1944, but the performance did not improve significantly. The project was soon abandoned and the test aircraft rebuilt as a F6F-3.
XF6F-4
This was a further development of the original Hellcat prototype (No. 02981). The engine was changed again, to the Pratt & Whitney R 2800-27, and the machine guns were replaced by four 20mm cannon, with 200 rounds per gun. This version first flew on 3 October 1942, but was not accepted for mass production. The aircraft itself was finally rebuilt as a standard F6F-3 in 1943.
XF6F-6
Two XF6F-6 prototypes were developed in 1944. They used the Pratt and Whitney R2800-18 engine, with a four blade propeller. The first prototype flew on 6 July 1944. This model reached a top speed of 417 mph, significantly faster than the 380 mph of the production versions. The design was accepted by the Navy, and planning began for mass production, but before that could begin the war ended, and in August 1945 the contract was cancelled.
Prototypes - F6F-3 - F6F-5 - Combat Record - Statistics