26 November 2010

Grumman's Biggest Cat in World War II

In early 1941 the United States Navy issued a requirement to Grumman for development of a large twin-engined fighter powered by twin Pratt & Whitney R-2800 Double Wasp engines of 2,100 horsepower each. The Double Wasp was used on the Navy's other two fighters under development at the time, the Grumman F6F Hellcat and the Vought F4U Corsair- two such engines offered a tremendous leap in performance for what the Navy designated the F7F. The fighter would be heavily armed with four 20mm cannon in the wing roots and four 0.50-caliber machine guns in the nose with provision for carrying a torpedo under the fuselage or two 1,000 lb bombs under the wings. The large fighter would form the nucleus of the air wing of the new 45,000 ton Midway class aircraft carriers then under proposal. On 30 June 1941 the Navy authorized Grumman to begin work on the Tigercat. Two prototypes designated XF7F-1 were ordered on that day. As an interesting historical sidenote, five weeks earlier the US Army Air Force ordered two aircraft as well which were to be designated XP-65 but had lighter Wright R-1820 engines that would have been turbosupercharged to give the XP-65 even better peformance than the F7F. However, the differing specifications of the Navy and the Army were at odds as the USAAF wanted a lighter fighter than what the Navy desired. As a result, what might have been the first American joint-service fighter died quietly when the Army bowed out due to concerns about the design becoming overweight to meet Navy requirements. 

With the first F7F-1 Tigercats rolling off the Grumman production lines in April 1944, the Navy took the unusual step of having the Tigercat only operate with land-based squadrons of the US Marine Corps and skip  what promised to be a lengthy carrier qualification series of tests as the Navy had not previously operated large twin-engined fighters off its flight decks. The aircraft carrier it was intended for, the USS Midway, was still under construction at the time. At that point in the Pacific War the Navy felt that its fighter needs were being satisfied with the F6F Hellcat and the F4U Corsair. The Marines could operate the Tigercat as a fighter bomber which the Navy brass felt was more suited to the aircraft's design. Plans were set in motion to equip twelve Marine Corps fighter squadrons that were operating the Corsair at the time to re-equip with the Tigercat. The Corsairs would then be passed back to the Navy to meet fleet requirements in the Pacific. 

Production of the F7F-1 Tigercat came to sudden halt in December 1944 after only 35 aircraft were built. By this point in the war the Navy's carrier battle groups were gearing up for their first raids on the Japanese Home Islands themselves (Task Force 58 in February 1945) as a diversion for the assault on Iwo Jima. The Navy had a different role in mind for the Tigercat and the third F7F-1 was converted into the prototype XF7F-2N night fighter with an AN/APS-6 radar set in the nose, displacing the four 0.50-caliber machine guns, and a second seat for the radar operator over the wing behind the pilot. More powerful versions of the R-2800 radial were used to compensate for the increased weight of the second crewman and the additional radar equipment. However, changing requirements and technical issues meant that the F7F-2N was only an interim type, with only 65 being produced between December 1944 when F7F-1 production was stopped in favor of the night fighter and August 1945. Several of the -2Ns did go to sea, though, but for a series of comparison tests aboard the USS Antietam and the USS Shangri-La with the North American PBJ-1 Mitchell (the Navy version of the B-25 Mitchell). Both were being evaluated as night fighters by the Navy in April 1945 but it was soon found that both the Tigercat and the Mitchell were too large for the Essex-class fleet carriers and the Navy settled on radar-equipped variants of the F6F Hellcat and F4U Corsair instead. 

Only one Tigercat squadron made it to the Pacific before the end of the war with the Japanese surrender. Marine Corps squadron VMF(N)-533 was one of three Marine Corps night fighter squadrons established in 1943 operating the night fighter version of the Hellcat, the F6F-5N. Based in Okinawa at the time, the squadron was to convert to the night fighter Tigercat in theatre, but their new mounts arrived the day before the Japanese surrender. Patrols were made over China and Japan, but no operational engagements took place in the months following the Japanese surrender. Interestingly, the Royal Navy evaluated two F7F-2N Tigercats in the night fighter role, but decided to adopt the De Havilland Sea Hornet instead for the role. 

The most famous and most-produced version of the Tigercat, the F7F-3 and -3N, didn't arrive until March of 1946, too late for service in the Second World War. This variant was never carrier-qualified as well and by the time the Midway class carriers it was intended for were operational, the Navy's standard fighter was the Grumman F8F Bearcat and jets were just over the horizon. The F7F-4N was fully carrier capable and fully qualified unlike the previous versions, but only 14 of this model were built. In the Korean War, night fighting Tigercats in the hands of the Marine Corps finally drew blood and achieved fame that had eluded it during the Second World War. 

Source: United States Naval Fighters of World War II in Action by Michael O'Leary. Blandford Press, 1980, p136-141.

1 comment:

  1. What type aicrcarft and its configuration on the night Butch OHaire was shot down?