The Stearman Model 75 is a biplane formerly used as a military trainer aircraft, of which at least 10,626 were built in the United States during the 1930s and 1940s.
Stearman Aircraft became a subsidiary of Boeing in 1934.
Widely known as the Stearman, Boeing Stearman, or Kaydet, it served as a primary trainer for the United States Army Air Forces, the United States Navy as the NS and N2S, and with the Royal Canadian Air Force as the Kaydet throughout World War II.
The Kaydet was a conventional biplane of rugged construction, with a large, fixed tail wheel undercarriage, and accommodation for the student and instructor in open cockpits in tandem.
The radial engine was usually not cowled, although some Stearman operators choose to cowl the engine, most notably the Red Baron Stearman Squadron.
Variants
The U.S. Army Air Forces Kaydet had three different designations based on its power plant
Production was 2,141 in total for all models.
PT-13
Initial production, R-680-B4B engine, 26 built
PT-13A
R-680-7 engine, 92 delivered 1937–38, Model A-75
PT-13B
R-680-11 engine, 255 delivered 1939–40
PT-13C
Six PT-13Bs were modified for instrument flying.
PT-13D
PT-13As equipped with the R-680-17 engine, 353 delivered, Model E-75
PT-17
With a Continental R-670-5 engine, 3,519 were delivered.
PT-17A 18 PT-17s were equipped with blind-flying instrumentation.
PT-17B Three PT-17s were equipped with agricultural spraying equipment for pest control.
PT-18
PT-13 with a Jacobs R-755 engine, 150 built
PT-18A Six PT-18s were fitted with blind-flying instrumentation.
PT-27
Canadian PT-17: This designation was given to 300 aircraft supplied under Lend-Lease to the Royal Canadian Air Force.
The U.S. Navy had several versions, including:
NS
Up to 61 delivered, powered by surplus 220 hp (164 kW) Wright J-5 Whirlwind
N2S
N2S-1
R-670-14 engine, 250 delivered to the U.S. Navy
N2S-2
R-680-8 engine, 125 delivered to the U.S. Navy
N2S-3
R-670-4 engine, 1,875 delivered to the U.S. Navy
N2S-4
99 U.S. Army aircraft diverted to the U.S. Navy, plus 577 newly built aircraft
N2S-5
R-680-17 engine, 1,450 delivered to the U.S. Navy
Stearman 70
Original prototype, powered by 215 hp (160 kW) Lycoming radial engine, temporary designation XPT-943 for evaluation
Model 73
Initial production version, 61 built for U.S. Navy as NS plus export variants
Model 73L3
Version for the Philippines, powered by 200 hp (150 kW) R-680-4 or R-680C1 engines
Model A73B1
Seven aircraft for Cuban Air Force powered by 235 hp (175 kW) Wright R-790 Whirlwind, delivered 1939–1940
Model A73L3
Improved version for the Philippines, three built
Stearman 75
Or
X75
Evaluated by the U.S. Army as a primary trainer, the X75L3 became the PT-13 prototype.
Variants of the 75 formed the PT-17 family.
Stearman 76
Export trainer and armed versions of the 75
Stearman 90 and 91
(Or X90 and X91) the metal-frame version, became the XBT-17
Stearman XPT-943
The X70 evaluated at Wright Field
American Airmotive NA-75
Single-seat agricultural conversion of Model 75, fitted with new, high-lift wings
