In article ,
(B2431) wrote:

Corsair had a 4 bladed prop. A 3 bladed prop may have been big enough to
irritate the Seabees who had no sense of humour when it came to prop blades
chewing up their runways.

The F4U had a three-blade prop from the XF4U-1. The F4U-4 introduced the
four-blade prop on production Corsairs. (The XF4U-3 had a four-blade
prop, but didn't go into production, and the prototypes were returned to
their F4U-1 initial state.)