The final version of the Wildcat was produced by General Motor’s Eastern Aircraft Division. It was based on the Grumman prototype XF4F-8 aircraft, designed to be a light weight version of the Wildcat. A great deal of effort went into reducing the weight of the airframe, which went down by 500 lbs. The engine was changed to a 1350 HP Wright R-1820-56 Cyclone air cooled radial engine, giving more power at the same weight.
These changes significantly improved the overall performance of the aircraft, especially at altitude. Compared to the F4F-4, the FM-2 had a higher service ceiling and produced its maximum speed of 320 mph at 28,000 feet (the F4F-4 could reach 318 mph, but at only 19,400). The FM-2 restored much of the performance lost when the folding wings were added to the F4F-4. Finally, the more powerful lighter aircraft could take off in a shorter length than earlier Wildcats.
The FM-2 Wildcat carried the same four .50 calibre machine guns as the FM-1. The last 1,400 FM-2s also had the capacity to carry six rockets under the wings.
The FM-2 entered production in the autumn of 1943. 310 aircraft were built that year. In total 4,437 FM-2s and 340 Wildcat VIs for British use were built before production ended in May 1945, accounting for well over half of all Wildcat production.
At first glance it seems odd that the most numerous version of the Wildcat entered production after the aircraft had been superseded by the F6F Hellcat and the F4U Corsair. However, the FM-2 Wildcat could operate easily off the smaller escort carriers, while the newer, larger aircraft were better suited to use from the fleet carriers. The FM-2 was used on escort carriers in the Atlantic, where they played a major role in the anti-submarine warfare that won the battle of the Atlantic. In the Pacific the FM-2 was used to provide close support during the island hoping campaign.