I didn't bother to post earlier, but F7F was my guess too. My uncle was sent to MIT to become an aeronautical engineer under the Navy's V12 program during WW II, and after the war went to work for Grumman. I'm sure he was involved with that generation of post-war aircraft, the F7F, F8F, and F9F. He took me to a couple of air shows at Grumman. My son is named after him.

Paul

Stupidity has its way, while its cousin, evil, runs rampant.