The Bearcat concept began during a meeting between Battle of Midway veteran F4F Wildcat pilots and Grumman Vice President Jake Swirbul at Pearl Harbor on 23 June 1942. At the meeting, Lieutenant Commander Jimmie Thach emphasized one of the most important requirements in a good fighter plane was "climb rate", which connoted "power." After intensively analyzing carrier warfare in the Pacific Theater of Operations for a year and a half, Grumman commenced designing the F8F Bearcat, and the first prototype flew on 31 August 1944. Prior to the F8F Bearcat, F6F Hellcats had been tasked with the primary missions of fighting exceptionally long range and highly maneuverable late-model Japanese fighter aircraft such as the A6M5 Zero; a later role was defending the fleet against incoming airborne kamikaze attacks.
Work on the Grumman G-58 Bearcat began in 1943 with the specifications calling 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, range was sacrificed.
Compared to the Vought F4U Corsair, the initial F8F-1 Bearcat series was marginally slower but was more maneuverable and climbed more quickly. Its huge 12 ft 4 in Aeroproducts four-bladed propeller required a long landing gear, giving the Bearcat a "nose-up" profile. The hydraulically operated undercarriage used an articulated trunnion which extended the length of the oleo legs when lowered; 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 from the initial version of an all-new airframe design for a production U.S. Navy fighter, a bubble canopy offered 360° visibility.
The target loaded weight of 8,750 lb/3,969 kg 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 included 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 possibility that only one wingtip would break away with the possibility of the aircraft crashing. This was replaced with an explosives system to blow the wing tips off together, which also worked well, but 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).