 Further aerodynamic improvements were made to an F3F-2 (BuNo 1031) based on wind tunnel studies in the NACA Langley 30' x 60' full-scale wind tunnel and became the XF3F-3.It featured a larger-diameter propeller, and a complete revision of the fuselage skinning forward of the aft cabane strut in order to improve aerodynamics and reduce carbon monoxide intrusion.On 21 June 1938, the Navy ordered 27 F3F-3s, as new monoplane fighters like the Brewster F2A and Grumman's own F4F Wildcat were taking longer to develop than had been planned.