Boeing P-12

By the late 1930s it was replaced in front-line duty by newer designs, but it was still used for training into the early 1940s.

F4B-1 (Boeing Model 99) The F4B-1 was built using typical construction techniques of the day with a welded truss fuselage with formers and longerons to define the aerodynamic shape.

The Pratt & Whitney R-1340 nine-cylinder radial engine was uncowled and sported prominent cooling fairings behind each cylinder which were later removed in service.

A spreader bar was incorporated between the landing wheels and the tail skid was replaced by a castoring tailwheel.

Some F4B-2s received F4B-4 style vertical fins and rudders to address poor directional stability.

F4B-3 (Boeing Model 235) The F4B-3 represented a significant departure in design from the earlier versions of the F4B.

From the engine mount aft to the rear of the fuel tank bay, the structure was welded steel truss, while the fuselage aft of the fuel tank bay was constructed of stressed skin, semi-monocoque aluminum alloy.

F4B-4 (Boeing Model 235) The F4B-4 was nearly identical to the F4B-3, but incorporated a larger vertical fin to address the directional stability issues that plagued the F4B from its inception.

By direction of MAJ Roy S. Gieger, Officer-in-Charge of Marine Corps Aviation, all VF-10M F4B-4s on strength be transferred to VF-9M at Quantico.

VF-9M based at Brown Field, Quantico flew F4B-4s, starting the transition in September 1932.

Formation of F4B-4 in the 1930s
Row of Army Air Corps P-12s in 1932, of the 17th Pursuit Squadron
Boeing P-12
Boeing P-12 with Captain Ira Eaker
Boeing F4B-1 of VF-5 squadron
Boeing P-12E, trainer aircraft, 25th Bombardment Squadron , France Field , 1933
Boeing 100 NX872H
Boeing 218
P-12E at Planes of Fame, USA
F4B-2 3-view drawing