Republic XP-72 Superbolt - Was Designed Around the Pratt & Whitney R-4360 Wasp Major 28-Cylinder Air Cooled Radial Engine with a Supercharger Mounted Behind the Pilot and Driven by an Extension Shaft from the Engine – Armament: 6 x .50 cal Wing Mounted Machine Guns and Two Underwing Racks for 1,000 lb Bombs - With the Advent of the New Turbojet-Powered Interceptors Only 2 Were Built (2)
Kuznetsov NK-12 - Google Search
P-47 variant, testing the V 16 Chrysler engine with hemispheric chambers-Very ugly,very powerful,very fast, 501 mph.
P-75 Fisher Eagle. 1943. Built by Fisher Body Div. of GM. Powerplant: Allison V-3420 counter thrust props. Designed to be an interceptor.