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. Adapted versions of the Bearcat have broken speed records for piston-engined aircraft. Today, the Bearcat is popular among warbird owners and air racers.
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".[1]
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 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.
In 1943, Grumman was introducing the F6F Hellcat, powered by the Pratt & Whitney R-2800 engine, which provided . The R-2800 was the most powerful American engine, 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 5feet shorter than the Hellcat, and was cut down vertically behind the cockpit. 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 7feet 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 13feet, three-bladed Hamilton Standard propeller. A slight reduction in size was made by moving to a 12feet 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.[2]
The design team had set the goal that the G-58 should weigh 8750lb 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. Weight-saving measures included restricting the internal fuel capacity to 160usgal and limiting the fixed armament to four .50 cal Browning M2/AN machine guns, two in each wing.[2] (later 183usgal)[3] 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 kamikaze attacks.[4] Compared to the Hellcat, the Bearcat was 20% lighter, had a 30% better rate of climb, and was 50mph faster.[5]
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 230lb.[6]
The design was completed in November 1943 and an order for two prototypes was placed on 27 November 1943 under the BuAir designation XF8F-1. The first prototype flew on 21 August 1944, only nine months after the design effort started.[7] [8] The initial flight test demonstrated a 4800ft/min climb rate and a top speed of 424mph. Compared to the Vought F4U Corsair, the Bearcat was marginally slower, but more maneuverable and climbed more quickly.
Testing demonstrated a number of problems, notably a lack of horizontal stability, an underpowered trim system, landing gear that could be extended only at slow speeds, an unreliable airspeed indicator, and a cramped cockpit. The test pilots also requested that six guns be installed. The stability problem was addressed on the second prototype by adding a triangular fillet to the front of the vertical stabilizer. The extra guns could not be incorporated due to weight and balance considerations.
The Navy placed a production contract for 2,023 aircraft based on the second prototype on 6 October 1944. On 5 February 1945, they awarded another contract for 1,876 slightly modified aircraft from General Motors, given the designation F3M-1. These differed primarily in having the R-2800-34W engine and a small increase in fuel capacity.
Deliveries from Grumman began on 21 May 1945. The end of the war led to the Grumman order being reduced to 770 examples, with the GM contract being cancelled outright. An additional order was placed for 126 F8F-1Bs replacing the .50 cal machine guns with the 20 mm M2 cannon, the US version of the widely used Hispano-Suiza HS.404. Fifteen of these were later modified as F8F-1N night fighters with an APS-19 radar mounted under the starboard wing.
An unmodified production F8F-1 set a 1946 time-to-climb record (after a run of 115feet) of 10000feet in 94 seconds (6383abbr=onNaNabbr=on). The Bearcat held this record for 10 years until it was broken by a jet fighter (which still could not match the Bearcat's short takeoff distance).
In 1948, Grumman introduced a number of improvements to produce the F8F-2. Among the changes were a modified cowling design, taller vertical fin, and the slightly more powerful R-2800-30W engine producing 2240hp. In total, 293 F8F-2s were produced, along with 12 F8F-2N night fighters and 60 F8F-2P reconnaissance versions. Production ended in 1949, and the first units began to convert off the type that year. The last Bearcats were withdrawn in 1952.
The F8F prototypes were ordered in November 1943 and first flew on 21 August 1944, a mere nine months later. The first production aircraft was delivered in February 1945 and the first squadron, Fighter Squadron 19 (VF-19), was operational by 21 May 1945, but World War II was over before the aircraft saw combat service.
One problem that became evident in service was the snap-off wingtips not working as expected. While they worked 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, a possibility arose that only one wingtip would break away with the possibility of the aircraft crashing.[9] This was replaced with an explosives system to blow the wingtips off together, which also worked well, but this ended when a ground technician died due to an accidental triggering. In the end, the wings were reinforced, and the aircraft was limited to 7.5 g.
Postwar, the F8F became a major U.S. Navy and U.S. Marine Corps fighter, equipping 24 fighter squadrons in the Navy and a smaller number in the Marines. Often mentioned as one of the best-handling piston-engined fighters ever built, its performance was sufficient to outperform some early jets. Its capability for aerobatic performance is illustrated by its selection as the second demonstration aircraft for the Navy's elite Blue Angels flight demonstration squadron in 1946, replacing the Grumman F6F Hellcat.[10] The Blue Angels flew the Bearcat until the team was temporarily disbanded in 1950 during the Korean War and pressed into operational combat service. The F9F Panther and McDonnell F2H Banshee largely replaced the Bearcat as their performance and other advantages eclipsed piston-engined fighters.
The first combat for the F8F Bearcat was during the French Indochina War (1946–1954), when nearly 200 Bearcats were delivered to the French forces in 1951.
When the war ended in 1954 and French forces withdrew, 28 surviving Bearcats were donated to South Vietnam, and served with the Republic of Vietnam Air Force from 1956.[11] The Vietnamese Bearcats were retired from 1960 onwards, replaced with Douglas A-1 Skyraiders and North American T-28 Trojans as the Vietnam War (1957–1975) continued.[12] [13] [14] [15]
F8Fs were also supplied to Thailand during the late 1940s.
Bearcats have long been popular in air racing. A stock Bearcat flown by Mira Slovak and sponsored by Bill Stead won the first Reno Air Race in 1964. Rare Bear, a highly modified F8F owned by Lyle Shelton, went on to dominate the event for decades, often competing with Daryl Greenamyer, another famous racer with victories in his own Bearcat (Conquest I, now at the Smithsonian's National Air and Space Museum) and holder of a piston-engined aircraft world speed record in it. Rare Bear also set many performance records, including the 3 km World Speed Record for piston-driven aircraft (528.33mph), set in 1989, and a new time-to-climb record (3000m (10,000feet) in 91.9 seconds (6425.9abbr=onNaNabbr=on), set in 1972, breaking the 1946 record cited above).[16] [17] [18]