XF4U-3C Vought Corsair (*)
On 14th June, BuAer asked Vought a proposal for making a high altitude version of the Corsair.
With the Vought project VS-331,Vought created the F4U-3 being a high speed, high altitude version of the Corsair fitted with a 2stage turbo supercharger from Rudolph Birmann of TEC from Trenton.
Plans were made in March 1942 for two proto types and a third was ordered in December 1942, to be converted from F4U-1 existing airframes and also decided mid 1943 to evaluate the Pratt & Whitnev XR-2800-16 "C"-series engine with a 2stage Birmann turbosupercharger of 1009A type. The change to this powerplant necessitated the use of a four-blade Hamilton Standard propeller with blades of 6501A-0 type.
F4U-1, BuNo. 02157, was the third aircraft converted to the XF4U-3C proto type based upon the XF4U-3 standards, but it was subsequently destroyed in a crash and did not participate in the program.