01/15/2019. Remarks by Johan Visschedijk: "The F4B-3 was the USN production equivalent of the P-12E with the semi-monocoque metal fuselage, and 21 were ordered on April 23, 1931, together with 92 F4B-4s, the latter differing only in having enlarged vertical tail surfaces, and life raft stowage in an enlarged streamlined headrest on the last 45 examples. Both were designated Model 235 by their manufacturer.

The first F4B-3 was delivered on December 24, 1931, but delivery of the F4B-4s did not commence until July 21, 1932 as the US Navy agreed to the first fourteen airframes being diverted after modification to Brazil under the designation Model 256. Nine essentially similar fighters, using F4B-3 fuselages, tails and landing gears married to P-12E wings, were subsequently delivered to Brazil as Model 267s. Armed with two 0.3 in (7.62 mm) machine guns and having provision for two 116 lb (52.6 kg) bombs on underwing racks, the F4B-4 was powered by a 550 hp Pratt & Whitney R-1340-16 engine and remained first-line equipment until 1938."