Boeing-Stearman Model 75

Model 75 "Stearman"
Kaydet
Boeing Stearman N67193 in USN markings
Role Biplane Trainer
Manufacturer Stearman Aircraft / Boeing
Introduction 1934
Number built 9,800
Unit cost $11,000

The Stearman (Boeing) Model 75 is a biplane used as a military trainer aircraft, of which at least 9,783 were built in the United States during the 1930s and 1940s.[1] 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 USAAF, as a basic trainer for the USN (as the NS & N2S), and with the RCAF as the Kaydet throughout World War II. After the conflict was over, thousands of surplus aircraft were sold on the civil market. In the immediate post-war years they became popular as crop dusters, sports planes, and for aerobatic and wing walking use in airshows.

Contents

Design and development

The Kaydet was a conventional biplane of rugged construction with large, fixed tailwheel undercarriage, and accommodation for the student and instructor in open cockpits in tandem. The radial engine was usually uncowled, although some Stearman operators choose to cowl the engine, most notably the Red Baron Stearman Squadron.

Distinctive sound

Because the design of the Stearman's propeller is unusual, reaching the speed of sound in normal operation, the sound of the plane stands out from other, similar aircraft, and is considered something of a trademark.

Operational history

Post-War usage

After World War II, the thousands of PT (primary trainer)-17 Stearmans were auctioned off to civilians and former pilots. Many were modified for cropdusting use, with a hopper for pesticide or fertilizer fitted in place of the front cockpit. Additional equipment included pumps, spray bars, and nozzles mounted below the lower wings. A popular approved modification to increase the maximum takeoff weight and climb performance involved fitting a larger Pratt & Whitney R-985 engine and a constant speed propeller.

Variants

The US Army Air Forces Kaydet had three different designations based on its power plant:

PT-13, with a Lycoming R-680 engine. 2,141 total all models.[2]
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 modified for instrument flying.
PT-13D PT-13As equipped with the R-680-17 engine. 353 delivered.
PT-17 With a Continental R-670-5 engine. 3,519 delivered
PT-17A 18 PT-17s were equipped with blind-flying instrumention.
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 fitted with blind-flying instrumention.
PT-27
Canadian PT-17. This designation was given to 300 aircraft supplied under Lend-Lease to the RCAF.

The US Navy had several versions including:

NS
Up to 61 delivered. powered by surplus 220 hp (164 kW) Wright J-5 Whirlwind.[3]
N2S Known colloquially as the "Yellow Peril" from its overall-yellow paint scheme.
N2S-1 R-670-14 engine. 250 delivered to the US Navy.
N2S-2 R-680-8 engine. 125 delivered to the US Navy.
N2S-3 R-670-4 engine. 1,875 delivered to the US Navy.
N2S-4 99 US Army aircraft diverted to the US Navy, plus 577 new-build aircraft.
N2S-5 R-680-17 engine. 1,450 delivered to the US Navy.
Stearman 70
(a.k.a. X70) The Wright Field XPT-943 based on the Stearman 6 Cloudboy.
Stearman 73
Civil production of the NS and PT-13.
Stearman 75
(a.k.a. X75) Evaluated by the 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
(a.k.a. X90 & X91) Productionised metal framed version becoming 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.[4]

Operators

 Argentina
Argentine Navy
 Bolivia
 Brazil
 Canada
Royal Canadian Air Force
 Taiwan
Republic of China Air Force
 Colombia
 Cuba
 Dominican Republic
 Greece
 Guatemala
 Honduras
 Iran
Imperial Iranian Air Force
 Israel
Israeli Air Force
 Mexico
Mexican Air Force
 Peru
Peruvian Air Force
 Philippines
Philippine Army Air Corps
Philippine Air Force
 United States
US Army Air Corps/US Army Air Forces
US Marine Corps
United States Navy
 Venezuela

Survivors

A considerable number of Stearmans remain in flying condition throughout the world, as the type remains a popular sport plane and warbird.

Brazil
Israel
Peru
Mexico
United States

Specifications (PT-17)

Data from United States Military Aircraft since 1909[7]

General characteristics

Performance

See also

Aircraft of comparable role, configuration and era

References

Notes

  1. ^ National Museum of the United States Air Force gives the figure 10,346.
  2. ^ NMUSAF fact sheet: Stearman PT-13D Kaydet. Retrieved 18 May 2010.
  3. ^ Bowers 1989, pp.252-253.
  4. ^ Taylor 1965, p. 178.
  5. ^ United States Air Force Museum 1975, p. 21.
  6. ^ http://www.ae.msstate.edu/rfrl/pages/stearman.html
  7. ^ Swanborough and Bowers 1963, p. 443.

Bibliography

  • Avis, Jim and Bowman, Martin. Stearman: A Pictorial History. Motorbooks, 1997. ISBN 0-76030-479-3.
  • Bowers, Peter M. Boeing Aircraft since 1916. London:Putnam, 1989. ISBN 0-85177-804-6.
  • Phillips, Edward H. Stearman Aircraft: A Detailed History . Specialty Press, 2006. ISBN 1-58007-087-6.
  • Swanborough, F.G. and Peter M. Bowers. United States Military Aircraft since 1909. London:Putnam, 1963.
  • Taylor, John W. R. Jane's All The World's Aircraft 1965–66. London: Sampson Low, Marston & Company, 1965.
  • United States Air Force Museum. Wright-Patterson AFB, Ohio: Air Force Museum Foundation. 1975. 

Videography

  • Stearman, Lloyd. Stearmans, You Gotta Love Them. Lap Records, 2005. (NTSC Format)

External links