Design & Development

The Bearcat concept was inspired by the early 1943 evaluation of a captured Focke-Wulf Fw 190 by Grumman test pilots and engineering staff. After flying the Fw 190, Grumman test pilot Robert Hall wrote a report directed to President Leroy Grumman, who then personally laid out the specifications for Design 58, the successor to the Hellcat. Design 58 closely emulated the design philosophy of the German fighter, although no part of the Fw 190 was copied. The F8F Bearcat stemmed from Design 58 with the primary missions of outperforming highly maneuverable late-model Japanese fighter aircraft such as the A6M5 Zero; a later role was defending the fleet against incoming airborne suicide (kamikaze) attacks.

Work on the Grumman G-58 Bearcat began in 1943 with the intention to provide the U.S. Navy with a high performance derivative of the Grumman F6F Hellcat. The specifications called for an aircraft able to operate from the smallest carrier, primarily in the interceptor role. The F6F's Pratt & Whitney R-2800 engine was retained but compared to the Hellcat, the Bearcat was 20% lighter, had a 30% better rate of climb and was 50 mph (80 km/h) faster. To achieve this, the range was necessarily sacrificed.

In comparison with the Vought F4U Corsair, the initial Bearcat (F8F-1) was marginally slower but was more maneuverable and climbed more quickly. Its huge 12 ft 4 in Aero Products four-bladed propeller required a long landing gear (made even longer by the mid-fuselage position of the wing), giving the Bearcat an easily-recognized, "nose-up" profile. The hydraulically operated undercarriage used an articulated trunnion which extended the length of the oleo legs to lengthen when down, much as the earlier Republic P-47 Thunderbolt had done several years earlier; as the undercarriage retracted the legs were shortened, enabling them to fit into a wheel well which was entirely in the wing. An additional benefit of the inward retracting units was a wide track, which helped counter propeller torque on takeoff and gave the F8F good ground and carrier deck handling. For the first time in a production Navy fighter, a bubble canopy offered 360° visibility.

The target loaded weight of 8,750 lb/3,969 kg (derived from the land-based German aircraft) was essentially impossible to achieve as the structure of the new fighter had to be made strong enough for aircraft carrier landings. Structurally the fuselage used flush riveting as well as spot welding, with a heavy gauge 302W aluminum alloy skin. Armor protection was provided for the pilot, engine and oil cooler; weight saving measures include restricting the internal fuel capacity to 160 gal (606 l) (later 183) and limiting the fixed armament to four .50 cal Browning M2/AN machine guns, two in each wing.

As a weight-saving concept the designers came up with detachable wingtips; if the "g"-force exceeded 7.5 "g" then the tips would snap off, leaving a perfectly flyable aircraft still capable of carrier landing. While this worked very well under carefully controlled conditions in flight and on the ground, in the field, where aircraft were repetitively stressed by landing on carriers and since the wings were slightly less carefully made in the factories, there was a chance that only one wingtip would break away with the possibility of the aircraft crashing. This was replaced with an explosives system to blow the wings off together, which worked well, however this ended when a ground technician died due to accidental triggering. In the end the wings were reinforced and the aircraft limited to 7.5 g.

An unmodified production F8F-1 set a 1946 time-to-climb record (after a run of 115 ft/35 m) of 10,000 ft (3,048 m) in 94 seconds (6,383 fpm). The Bearcat held this record for 10 years until it was broken by a modern jet fighter (which still could not match the Bearcat's short takeoff distance).

Wikipedia: Grumman F8F Bearcat