In late 1933, Stearman engineers Mac Short, Harold W. Zipp, and J. Jack Clark took a 1931 Lloyd Stearman design, and added cantilever landing gear and adjustable elevator trim tabs, to produce the Model 70. Able to withstand +12g and -9g, the aircraft was powered by a 210-hp Lycoming R-680, first flew on 1 January 1934, before flight tests were conducted at Wright Field, Naval Air Station Anacostia, and Pensacola. The Navy then requested a similar model built to Navy specifications, including a 200-hp Wright J-5 engine. The resultant Model 73, was designated NS-1 by the Navy, of which 41 were ordered, including enough spares to build another 20 aircraft.[3]
In the summer of 1934, Stearman engineers refined the Model 73 into the Model X75. The Army Air Corps evaluated the plane that autumn, powered by a 225-hp Wright R-760 or a 225-hp Lycoming R-680. In July 1935, the Army Air Corps ordered 26 with the Lycoming engine, designated the PT-13A, while the navy ordered an additional 20. In August 1936, the Army ordered an additional 50 PT-13As, followed by another 30 in October, and another 28 in December. Simultaneously, the company received orders for its primary trainer from the Argentinian navy, the Philippine Army Air Corps, and the Brazilian Air Force. In January 1937, the army ordered another 26 PT-13As.[3]
On 6 June 1941, the U.S. government issued Approved Type Certificate No. 743 for the civilian version of the Model 75. Designated the Model A75L3 (PT-13) and Model A75N1 (PT-17), about 60 were sold to civilian flights schools such as Parks College of Engineering, Aviation and Technology, and for export.[3]:148
On 15 March 1941, the company delivered the 1000th trainer to the Army, and the 1001st trainer to the Navy. Then on 27 August 1941, the company delivered the 2000th trainer to the Army. On 27 July 1944, the company delivered its 10,000th primary trainer.[3]:145–148,168
The Kaydet was a conventional biplane of rugged construction, with a large, fixed tailwheel 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.
Post-war usage
After World War II, thousands of surplus PT-17s were auctioned off to civilians and former military pilots. Many were modified for crop-dusting 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 Wasp Junior engine and a constant-speed propeller.
Data from: United States Navy aircraft since 1911,[4] Boeing aircraft since 1916[5] 8,584 Model 70s, 75s and 76s were built, with additional "spares" bringing the number up to the sometimes quoted 10,346.[1]
USAAC/USAAF designations
The U.S. Army Air Forces Model 75 Kaydet had three different designations, PT-13, PT-17 and PT-18, depending on which type of radial engine was installed.
PT-13
Initial production version with Lycoming R-680-B4B engine, 26 built in 1936
PT-13A Model A75 with R-680-7 engine, 92 delivered from 1937 to 1938.
PT-13B R-680-11 engine, 255 delivered from 1939 to 1941.
PT-13C Six PT-13Bs modified for instrument flying.
PT-13D Model E75 with R-680-17 engine, 793 delivered
PT-17A 136 PT-17s modified with blind-flying instrumentation.
PT-17B Three PT-17s modified with agricultural spraying equipment for pest control near army bases.
PT-17C Single PT-17 conversion with standardized Army-Navy equipment.
PT-18
Version with Jacobs R-755-7 engine, 150 built. Further production was cancelled as the engines were needed for other types of trainers.
PT-18A Six PT-18s modified with blind-flying instrumentation.
PT-27
USAAF paperwork designation given to 300 D75N1/PT-17 aircraft supplied under Lend-Lease to the Royal Canadian Air Force. The last example built, FK108, had a canopy installed.[a][6]
Republic of China Air Force received 150 PT-17s under Lend-Lease,[17] and 104 refurbished aircraft post war in Taiwan. The ROCAF used them until 1958.[18]
T5-1556 – PT-17 is airworthy with Erling Pétur Erlingsson in Hafnarfjörður, Capital Region. It is the oldest airplane in Iceland. It was brought to the country in 1941 by the aircraft carrier USSWasp and damaged in an accident in 1943.[40][41][42]
PT-17 on display at the Fundación Infante de Orleans in Cuatro Vientos, Madrid.[61]
Switzerland
75-5436 – PT-13D is airworthy, registered as HB-RBG, and based at the Fliegermuseum Altenrhein.[62] Built in 1943 and restored to airworthiness in 1989 after sustaining considerable damage during an emergency landing in the grounds of the Stadler Rail factory in Altenrhein due to engine failure.[63]
An iconic movie image is a Stearman cropduster chasing Cary Grant across a field in North by Northwest (the airplane that chased Grant was actually a Naval Aircraft Factory N3N Canary; the plane that hits the truck is a Stearman).[citation needed]
A heavily modified PT-17 variant was used as the Tornado in the Sonic The Hedgehog 2 Film.
Bowers, Peter M.; Swanborough, Gordon (1990). United States Navy aircraft since 1911. Annapolis, Md.: Naval Institute Press. pp.494–495. ISBN0870217925.
Núñez Padín, Jorge (2000). "BOEING STEARMAN N2S KAYDET". Fuerzas Navales (in Spanish). Jorge N. Padín. Archived from the original on 17 May 2014. Retrieved 16 May 2014.
"2012 Annual Report"(PDF). PacificAviationMuseum.org. Pacific Aviation Museum. Archived from the original(PDF) on 5 September 2015. Retrieved 25 April 2015.
Nordeen, Lon. Fighters Over Israel. London: Guild Publishing, 1991.
Phillips, Edward H. Stearman Aircraft: A Detailed History . Specialty Press, 2006. ISBN1-58007-087-6.
Sapienza, Antonio Luis (May 2001). "L'aviation militare paraguayenne durant la seconde guerre mondiale" [Paraguayan Military Aviation During the Second World War]. Avions: Toute l'Aéronautique et son histoire (in French) (98): 30–33. ISSN1243-8650.
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)