Sometime ago there was a big debate over the Grumman F8F Bearcat, and how it's design may or may not have been influenced by the FW-190.
Well, while doing some research the other night, I ran across a very interesting tidbit...seems Kurt Tank may have been very influenced himself by an American design!
The Richard Palmer designed Hughes H-1 racer, which set several speed records in early 1937, has a lot in common with the FW-190V-1 prototype. The H-1 was a radial engine power aircraft with a very similar planform and size to the FW...and given that the FW didn't fly until 1939, it seems very likely that Kurt Tank's design staff was influenced by the Palmer design.
-Smut