Grumman F7F Tigercat

The Grumman F7F Tigercat is a heavy fighter aircraft that served with the United States Navy (USN) and United States Marine Corps (USMC) from late in World War II until 1954. It was the first twin-engined fighter to be deployed by the USN. While the Tigercat was delivered too late to see combat in World War II, it saw action as a night fighter and attack aircraft during the Korean War.

Designed initially for service on Midway-class aircraft carriers, early production F7Fs were land-based variants. The type was too large to operate from older and smaller carriers, and only a late variant (F7F-4N) was certified for carrier service.

Based on the earlier Grumman XP-50 that was eventually canceled, the company developed the XP-65 (Model 51) further for a future "convoy fighter" concept. In 1943, work on the XP-65 was terminated in favor of the design that would eventually become the F7F. The contract for the prototype XF7F-1 was signed on 30 June 1941. Grumman's aim was to produce a fighter that outperformed and outgunned all existing fighter aircraft, and that had an auxiliary ground attack capability.

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Grumman F7F Tigercat on kaksimoottorinen raskas yhdysvaltalainen tukialuksilta käytettävä hävittäjälentokone. Tigercat on kuuluisan ”kissa-sarjan” jatkaja, Grummanin valmistamat laivaston hävittäjäkoneet olivat cat-päätteisiä.

Tigercat oli Yhdysvaltain laivaston ensimmäinen nykyaikaista laskeutumistelinettä käyttänyt konetyyppi. Prototyyppi lensi ensilentonsa joulukuussa 1943. Konetyyppi ei ehtinyt toiseen maailmansotaan, mutta sitä käytettiin Korean sodassa. Sodan syttyessä nämä koneet olivat tukeutuneita Japaniin.

Kaksi turboahdettua Pratt & Whitney -ruiskutusmäntämoottoria tuottivat kukin 2 100 hevosvoiman tehon. Huippunopeus oli suunnilleen sama kuin P-51 Mustangin, 700 km/h. Siivet olivat trapetsista muotoa: etusiipi tasan suora, mutta jättöreuna kapeni rungosta siiven kärkeen päin.

Aseistuksena koneella oli neljä 20 mm tykkiä siipien tyvissä ja neljä 12,7 mm konekivääriä eturungossa. Kaikki tuliaseet ampuivat eteenpäin. Rungon alle sekä siipiripustuksiin voitiin liittää lisäpolttoainesäiliöitä, pommeja, rakettiaseistusta tai torpedo.

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Armament was heavy: four 20 mm cannons and four 12.7 mm machine guns, as well as underwing and under-fuselage hardpoints for bombs and torpedoes. Performance met expectations too; the F7F Tigercat was one of the highest performance piston-engined fighters, with a top speed well in excess of the US Navy's single-engined aircraft 71 mph faster than a Grumman F6F Hellcat at sea level. 

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General characteristics

Crew: 2 (pilot, radar operator)

Length: 13.8 m

Wingspan: 15.7 m

Height: 5.1 m

Wing area: 42.3 m²

Empty weight: 7,380 kg

Max. takeoff weight: 11,670 kg

Powerplant: 2 × Pratt & Whitney R-2800-34W Double Wasp radial engines, 2,100 hp (1,566 kW) each

Maximum speed: 740 km/h

Range:  1900 km

Service ceiling: 12,300 m

Rate of climb: 23 m/s

Armament: 4 × 20 mm cannon and 4 × 12.7 mm M2 Browning mg

Bombs: 2 × 450 kgbombs under wings or 1 × torpedo under fuselage

Avionics: AN/APS-19 radar

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CAPT Fred M. Trapnell, one of the Navy's premier test pilots, opined that: "It's the best damn fighter I've ever flown." The Grumman F7F was originally named the "Tomcat" but this name was rejected as it was considered too suggestive, at the time. The name would much later be used for the Grumman F-14.

All this was bought at the cost of heavy weight and a high landing speed, but what caused the aircraft to fail carrier suitability trials was poor directional stability with only one engine operational, as well as problems with the arrestor hook design.

The initial production series was therefore used only from land bases by the USMC, as night fighters with APS-6 radar. At first, they were single-seat F7F-1N aircraft, but after the 34th production aircraft, a second seat for a radar operator was added; these aircraft were designated F7F-2N.

The next version produced, the F7F-3, was modified to correct the issues that caused the aircraft to fail carrier acceptance and this version was again trialled on the USS Shangri-La. A wing failure on a heavy landing caused the failure of this carrier qualification too. F7F-3 aircraft were produced in day fighter, night fighter and photo-reconnaissance versions.

A final version, the F7F-4N, was extensively rebuilt for additional strength and stability, and did pass carrier qualification, but only 12 were built.

Marine Corps night fighter squadron VMF(N)-513 flying F7F-3N Tigercats saw action in the early stages of the Korean War, flying night interdiction and fighter missions and shooting down two Polikarpov Po-2 biplanes. This was the only combat use of the aircraft.

Most F7F-2Ns were modified to control drones for combat training, and these gained bubble canopies over the rear cockpit for the drone controller. An F7F-2D used for pilot transitoning also had a rear sliding, bubble canopy.

In 1945, two Tigercats, serialled TT346 and TT349, were evaluated, but rejected, by the British Royal Navy, who preferred a navalized version of the de Havilland Hornet.