Editing Grumman F8F Bearcat (section)

==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 [[John Thach|Jimmie Thach]] emphasized one of the most important requirements in a good fighter plane was "[[climb rate]]".<ref>Ewing 2004, pp. 182, 308.</ref>

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 [[Aircraft carrier|carrier]] warfare in the [[Asiatic-Pacific Theater|Pacific Theater of Operations]] for a year and a half, Grumman began development of the G-58 Bearcat in late 1943.

===Design===
[[File:Grumman F6F-3 Hellcat of VF-1 in flight over California (USA), in 1943 (80-G-K-605).jpg|thumb|The Bearcat was influenced by the larger [[F6F Hellcat]].]]

In 1943, Grumman was introducing the [[F6F Hellcat]], powered by the [[Pratt & Whitney R-2800]] engine, which provided {{convert|2000|hp}}. 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 {{convert|5|ft|abbr=on}} 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 {{convert|7|ft|abbr=on}} 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.<ref name="Scrivner 1990, p.4."/> Armor protection was provided for the pilot, engine, and oil cooler.

The Hellcat used a {{convert|13|ft|1|in|abbr=on|adj=on}}, three-bladed [[Hamilton Standard]] propeller. A slight reduction in size was made by moving to a {{convert|12|ft|7|in|abbr=on|adj=on}} 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 strut|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.<ref name="Scrivner 1990, p.4.">Scrivner 1990, p. 4.</ref>

The design team had set the goal that the G-58 should weigh {{convert|8750|lb|-1|abbr=on}} 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 {{convert|160|usgal|L}} and limiting the fixed armament to four [[.50 cal]] [[M2 Browning machine gun|Browning M2/AN]] machine guns, two in each wing.<ref name="Scrivner 1990, p.4."/>(later {{convert|183|usgal|L|disp=sqbr}})<ref>Scrivner 1990, p. 7.</ref> The limited range due to the reduced fuel load meant it would be useful in the [[interceptor aircraft|interception role]], but the Hellcat would still be needed for longer range patrols. A later role was defending the fleet against ''[[kamikaze]]'' attacks.<ref>[http://broadcast.illuminatedtech.com/display/story.cfm?bp=92&sid=7974 "F8F Bearcat."] {{webarchive|url=https://web.archive.org/web/20061007060602/http://broadcast.illuminatedtech.com/display/story.cfm?bp=92&sid=7974 |date=2006-10-07 }} ''U.S. Naval Air Museum''. Retrieved: 18 August 2010.</ref> Compared to the Hellcat, the Bearcat was 20% lighter, had a 30% better rate of climb, and was {{convert|50|mph|-1|abbr=on}} faster.<ref>Swanborough and Bowers 1991, p. 241.</ref>

Another weight-saving concept the designers found was detachable wingtips. The wings were designed to fold at a point about {{frac|2|3}} 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&nbsp;g. In this case, the aircraft would still be flyable and could be repaired after returning to the carrier. This saved {{convert|230|lb|abbr=on}}.<ref>Meyer, Corwin W. [http://findarticles.com/p/articles/mi_qa3897/is_199808/ai_n8826530/pg_1 "Clipping the Bearcat's wing."] ''Flight Journal'', August 1998, p. 1. Retrieved: 18 August 2010.</ref>

[[File:Grumman XF8F-1 Bearcat 1945.jpg|thumb|An XF8F-1 prototype at the [[National Advisory Committee for Aeronautics|NACA]] Langley Research Facility in 1945]]

===Prototypes===
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.<ref>Gunston 1988, p. 48.</ref><ref>Francillon 1989, p. 243.</ref>{{efn|One account states the first flight on 13 August.<ref>{{cite book |first=Richard |last=Thruelsen |title=The Grumman Story |publisher=Praeger |year=1976 |page=213}}</ref>}} The initial flight test demonstrated a {{convert|4,800|ft/min|abbr=on}} climb rate and a top speed of {{convert|424|mph|abbr=on}}. 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.

===Production===
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]]' [[Eastern Aircraft Division]], 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&nbsp;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 {{convert|115|ft|abbr=on|disp=sqbr}}) of {{convert|10000|ft|0}} in 94 seconds ({{convert|6383|ft/min|m/s|abbr=on|disp=sqbr}}). 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 {{convert|2,240|hp|abbr=on}}. 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.