Here we cover the evolution of the World War II era Grumman F4F Wildcat specifically US variations of the fighter.

Some background, I've researched the Pacific Theater of World War II for the past 15 years.

Some references for specifics:
The Grumman F4F Wildcat http://www.airvectors.net/avwcat.html
F4F Wildcat vs A6M Zerosen: Pacific Theater 1942 Author Edward M. Young
https://www.amazon.com/F4FWildcatA6...

Photos:
All photos public domain or photos with no known copyright restrictions