General Motors FM Wildcat

With Grumman working on their new carrier fighter the F6F Hellcat but with demand for its predecessor the F4F Wildcat still high, the decision was taken to out-source production of the F4F. This led to a contract being agreed on the 18th April 1942 for 1,800 F4F Wildcats to be produced by General Motors' Eastern Aircraft Division and the aircraft built by General Motors would be known as FM-1. The 1st September 1942 saw the first FM-1 fly although this had been produced from parts which Grumman had already manufactured.

Unsurprisingly the FM-1 Wildcat was the same as the Grumman produced F4Fs with the one change occurring with the aircraft's armament. Whilst Grumman produced aircraft had six 0.50-in machine-guns the FM-1s produced by General Motors only had four, however this was offset by an extra 20% of ammunition.

Development of the Wildcat continued and a pair of Grumman built prototype XF4F-8s would provide the basis for the General Motors FM-2. This new version had its fin and rudder made taller and featured a lighter airframe to help take-off performance. The biggest change was the introduction of the Wright R-1820-56 cyclone engine which featured a turbocharger, indeed later FM-2 production aircraft had a water-injection system.

Serving with the United States Navy a number of General Motors FM Wildcats were provided to the United Kingdom under Lend-Lease. These were originally called Martlets before reverting back to the American name of Wildcat.

With a total of 4,777 aircraft being delivered by August 1945, when production ceased, it meant that over 7,500 Wildcats had been built by Grumman and General Motors Combined.