The Grumman F8F Bearcat is an American single-engined, carrier-based, fighter aircraft introduced in late World War II. It served during the mid-20th century in the United States Navy, the United States Marine Corps, and the air forces of other nations. It was Grumman Aircraft's last piston-engined fighter aircraft.
Modified versions of the Bearcat have broken speed records for piston-engined aircraft. Today, the Bearcat is popular among warbird owners and air racers.
Design and development
Concept
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".
Climb performance is strongly related to the power-to-weight ratio, and is maximized by wrapping the smallest and lightest possible airframe around the most powerful available engine. Another goal was that the G-58 (Grumman's design designation for the aircraft) should be able to operate from escort carriers, which were then limited to the obsolescent F4F Wildcat, as the Grumman F6F Hellcat was too large and heavy. A small, lightweight aircraft would make this possible. After intensively analyzing carrier warfare in the Pacific Theater of Operations for a year and a half, Grumman began development of the G-58 Bearcat in late 1943.
Design
In 1943, Grumman was in the process of introducing the F6F Hellcat, powered by the Pratt & Whitney R-2800 engine, which provided . The R-2800 was the most powerful American engine available at that time, so it would be retained for the G-58. This meant that improved performance would have to come from a lighter airframe.
To meet this goal, the Bearcat's fuselage was about shorter than the Hellcat, and was cut down vertically behind the cockpit area. This allowed the use of a bubble canopy, the first to be fitted to a US Navy fighter. The vertical stabilizer was the same height as the Hellcat's, but had an increased aspect ratio, giving it a thinner look. The wingspan was less than the Hellcat's. Structurally, the fuselage used flush riveting and spot welding, with a heavy-gauge 302W aluminum alloy skin suitable for carrier landings. Armor protection was provided for the pilot, engine, and oil cooler.
The Hellcat used a , three-bladed Hamilton Standard propeller. A slight reduction in size was made by moving to a Aeroproducts four-bladed propeller. Keeping the prop clear of the deck required long landing gear, which, combined with the shortened fuselage, gave the Bearcat a significant "nose-up" profile on land. The hydraulically operated undercarriage used an articulated trunnion that 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.
The design team had set the goal that the G-58 should weigh fully loaded. As development continued, this was found to be impossible to achieve, as the structure of the new fighter had to be made strong enough for aircraft carrier landings. Ultimately, many of the weight-saving measures included restricting the internal fuel capacity to (later ) and limiting the fixed armament to four .50 cal Browning M2/AN machine guns, two in each wing. The limited range due to the reduced fuel load meant it would be useful in the interception role, but the Hellcat would still be needed for longer range patrols. A later role was defending the fleet against airborne kamikaze attacks. Compared to the Hellcat, the Bearcat was 20% lighter, had a 30% better rate of climb, and was faster.
Another weight-saving concept the designers found was detachable wingtips. The wings were designed to fold at a point about out along the span, reducing the space taken up on the carrier. Normally, the hinge system would have to be built very strong to transmit loads from the outer portions of the wing to the main spar in the inner section, which adds considerable weight. Instead of building the entire wing to be able to withstand high-g loads, only the inner portion of the wing was able to do this. The outer portions were more lightly constructed, and designed to snap off at the hinge line if the force exceeded 7.5 g. In this case, the aircraft would still be flyable and could be repaired after returning to the carrier. This saved .