page_title: Cessna T-37 Tweet
section_title: Origins
hierarchical_section_title: Cessna T-37 Tweet / Development / Origins
caption_attribution_description: The U.S. Air Force prototype Cessna XT-37-CE Tweety Bird (s/n 54-716), the first originally designed USAF jet trainer. It first flew in 12 October 1954.
context_page_description: The Cessna T-37 Tweet is a small, economical twin-engined jet trainer type which flew for decades as a primary trainer for the United States Air Force and in the air forces of several other nations. The T-37C was additionally capable of some light attack duties if required. The A-37 Dragonfly variant served in the light attack role during the Vietnam War and continues to serve in the air forces of several South American nations.
  The T-37 served as the U.S. Air Force's primary pilot training vehicle for over 52 years after its first flight. After completing Primary in the Tweet, students moved on to other advanced Air Force, Navy, Marine Corps or Allied trainers. With a total of 1,269 Cessna T-37s built, the USAF retired its last T-37 in 2009.
context_section_description: The Cessna Aircraft Company of Wichita, Kansas, provided the United States Army during World War II and the Korean War with utility, light transport, and observation aircraft, particularly the "O-1 Bird Dog" series.
  In the spring of 1952, the USAF issued a request for proposals for a "Trainer Experimental (TX)" program, specifying a lightweight, two-seat basic trainer for introducing USAF cadets to jet aircraft.
  Cessna responded to the TX request with a twin-jet design with side-by-side seating. The USAF liked the Cessna design, which was given the company designation "Model 318", and the side-by-side seating since it let the student and instructor interact more closely than with tandem seating. In the spring of 1954, the USAF awarded Cessna a contract for three prototypes of the Model 318, and a contract for a single static test aircraft. The Air Force designated the type as XT-37.
  The XT-37 had a low, straight wing, with the engines buried in the wing roots, a clamshell-type canopy hinged to open vertically to the rear, a control layout similar to that of contemporary operational USAF aircraft, ejection seats, and tricycle landing gear with a wide track of 14 ft (4.3 m). It first flew on 12 October 1954.
  The wide track and a steerable nosewheel made the aircraft easy to handle on the ground, and the short landing gear avoided the need for access ladders and service stands. The aircraft was designed to be simple to maintain, with more than 100 access panels and doors. An experienced ground crew could change an engine in about half an hour.
  The XT-37 was aerodynamically clean, so much so that a speedbrake was fitted behind the nosewheel doors to help increase drag for landing and for use in other phases of flight. Since the short landing gear placed the engine air intakes close to the ground, screens pivoted over the intakes from underneath when the landing gear was extended, to prevent foreign object damage.
  The XT-37 was fitted with two Continental-Teledyne J69-T-9 turbojet engines, French Turbomeca Marboré engines built under license, with 920 lbf (4.1 kN) thrust each. The engines had thrust attenuators to allow them to remain spooled-up (i.e. rotating at speeds above idle) during landing approach, permitting shorter landings while still allowing the aircraft to easily make another go-around in case something went wrong. Empty weight of the XT-37 was 5,000 lb (2,300 kg).
  Tests showed the XT-37 had a maximum speed of 390 mph (630 km/h) at altitude, with a range of 935 mi (1,505 km). The aircraft had a service ceiling of 35,000 feet (10,700 m) but was unpressurized so was limited to an operational ceiling of 25,000 feet (7,600 m) by USAF regulations.
  The initial prototype crashed during spin tests. Later prototypes had new features to improve handling, including long strakes along the nose, and an extensively redesigned and enlarged tail. After these modifications, the USAF found the aircraft acceptable to their needs, and ordered it into production as the T-37A. Production aircraft remained tricky in recovering from a spin; the recovery procedure was complex compared with most aircraft.
caption: The XT-37, circa 1954
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