The Boeing P-12/F4B was an American pursuit aircraft that was operated by the United States Army Air Corps , United States Marine Corps, and United States Navy.
P-12s were flown by the 17th Pursuit Group at March Field, California, and the 20th Pursuit Group at Barksdale Field, Louisiana.
Older P-12s were used by groups overseas, the 4th Composite Group in the Philippines, the 16th Pursuit Group in the Canal Zone, and the 18th Pursuit Group in Hawaii.
The P-12 remained in service with first-line pursuit groups until replaced by Boeing P-26s in 1934–1935.
Survivors were relegated to training duties until 1941, when most were grounded and assigned to mechanic’s schools.
23 P-12Cs, P-12Ds and P-12Es were transferred to the Navy for use as advanced trainers.
These aircraft were redesignated as F4B-4As
One prototype with spreader bar landing gear and 425 hp Pratt & Whitney R-1340-8 engine, later designated XF4B-1 for Navy evaluation.
One prototype with split axle undercarriage and provision for a 500 lb bomb on ventral rack, later designated XF4B-1 for Navy evaluation.
Model 102, U.S. Army Air Corps version of the F4B-1 with a 450 hp R-1340-7 engine.
Model 101, 10th built P-12 with NACA cowl a 525 hp R-1340-9 engine and shorter undercarriage, one built.
Model 102B, as P-12 with larger main wheels and improvements tested on XP-12A.
Model 222, as P-12B with ring cowl and spreader bar undercarriage.
Model 234, as P-12C with a 525 hp R-1340-17 engine.
Model 234, as P-12D with semi-monocoque metal fuselage, redesigned vertical tail surfaces, some were later fitted with tail wheels instead of skids.
Model 251, as P-12E with a 600 hp R-1340-19 engine.
P-12B modified with a R-1340-15 engine with side-type supercharger, one converted.
P-12D modified with a GISR-1340E experimental engine, one converted.
P-12E modified with a 575 hp R-1340-23 engine, and special bomb sight, one conversion.
P-12E and P-12J re-engined with a fuel injected SR-1340E engine, seven temporary conversions.
YP-12K temporary fitted with a F-2 supercharger, one converted.
Designation for proposed use of P-12 as a radio-controlled target drone
Designation given to two prototypes for Navy evaluation, the former Model 83 and the former Model 89.
Boeing Model 99 for the United States Navy, split-axle landing gear and ventral bomb rack.
One F4B-1 converted to unarmed executive transport for the Assistant Secretary of the Navy, fuel tank moved to upper wing centre section.
Boeing Model 223, spreader bar landing gear, Frise ailerons, tail wheel replacing skid.
Boeing Model 235, as F4B-2 but with semi-monocoque metal fuselage and equipment changes.
Boeing Model 235, as F4B-3 but with redesigned vertical tail surfaces, 550 hp R-1340-16 engine, under wing racks for two 116 lb bombs, last 45 built had an enlarged headrest, this housed a life raft, 92 built and one built from spares.
23 assorted P-12 aircraft transferred from USAAC for use as a radio controlled target aircraft.
Civil version of the F4B-1 with upper wing tank.
Two-seat civil version for Howard Hughes, later converted to a single-seater, one built.
One Model 100 temporary used as a P-12 demonstrator.
Export version of the P-12E for the Siamese Air Force, two built,
One later transferred to the Japanese Navy under the designation AXB.
One civil variant of the P-12F sold to Pratt & Whitney as an engine test bed.
Prototype of the P-12E/F4B-3 variant, after evaluation sold to the Chinese Air Force.
Export version of the F4B-4 for Brazilian Navy
Export version for Brazil with an F4B-3 fuselage and P-12E wings