The XF6F-1 went through three conversions during its career. Shortly after its first flight its R-2600 engine was replaced with an R-2800 and it became the second XF6F-3. Following the initial test program, it was converted into the XF6F-4 in late 1942. It remained in this configuration until 1944, when it was converted to a more or less production F6F-3 and delivered to the Navy. I have seen two photographs of the -4. One shows it in the 1943-4 tricolor scheme. The other was taken in late 1942. It was taken from above and to the rear of the aircraft. Given the lighting conditions, it is unclear whether the -4 still retained the bare metal of the -1 or whether it had been painted non-specular intermediate blue. One clue may be that the fusilage insignia are smaller and placed further aft than on the
-1. Another feature I noticed in the photo is that the plexiglas in the top of the canopy appears to have been painted, perhaps to create some kind of sun shade. Can anyone shed light on either of these points?