Cessna T - 37 Tweet The Cessna T - 37 Tweet ( designated Model 318 by Cessna ) is a small , economical twin - engine jet trainer - attack type aircraft which flew for decades as a primary trainer for the United States Air Force ( USAF ) and in the air forces of several other nations . 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 . 1 , 269 Cessna T - 37s were built , with 419 still serving in the United States Air Force in 2006 . Between 2001 and 31 July 2009 the USAF phased out the T - 37 in favor of the T - 6 Texan II . Development . Origins . 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 United States Air Force ( 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 of " 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 4 . 3 m ( 14 ft ) . It first flew on October 12 , 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 a hundred access panels and doors . An experienced ground crew could change an engine in about a half hour . The XT - 37 was aerodynamically clean , so much so that an air brake was fitted behind the nosewheel door to help reduce speed for landing . 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 k N ) thrust each . The engines had thrust attenuator s 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 - round " in case something went wrong . Empty weight of the XT - 37 was 2 . 27 tonnes ( 5 , 000 lb ) . Tests showed the XT - 37 had a maximum speed of 628 km / h ( 390 mph ) at altitude , with a range of 1 , 505 km ( 935 mi ) . The aircraft was unpressurized , and so limited to a ceiling of 7 . 6 km ( 25 , 000 ft ) 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 . Production . The production T - 37A was similar to the XT - 37 prototypes , except for minor changes to fix problems revealed by the flight test program . The first T - 37A was completed in September 1955 and flew later that year . The T - 37A was very noisy , even by the standards of a jet aircraft . The intake of air into its small turbojets emitted a high - pitched shriek that led some to describe the trainer as a " Screaming Mimi " , and it was referred to as the " 6 , 000 pound dog whistle " or " Converter " ( converts fuel and air into noise and smoke ) . The piercing whistle quickly gave the T - 37 its name : " Tweety Bird " , or just " Tweet " . The Air Force spent a lot of time and money sound - proofing buildings at bases where the T - 37 was stationed , and ear protection remains mandatory for all personnel when near an operating aircraft . The Air Force ordered 444 T - 37As , with the last produced in 1959 . During 1957 , the US Army evaluated three T - 37As for battlefield observation and other combat support roles , but eventually procured the Grumman OV - 1 Mohawk instead . The Air Force liked the T - 37A , but considered it to be underpowered ; consequently they ordered an improved version , the T - 37B , with uprated J - 69 - T - 25 engines . The new engines provided about 10 % more thrust and were more reliable . Improved avionics were also specified for the new variant . A total of 552 newly built T - 37Bs were constructed through 1973 . All surviving T - 37As were eventually upgraded to the T - 37B standard as well . Due to a series of accidents caused by bird strike s between 1965 and 1970 , all T - 37s were later retrofitted with a new windscreen made of Lexan polycarbonate plastic 12 . 5 mm ( ½in ) thick , which could tolerate the impact of a 1 . 8 kg ( 4 lb ) bird at a relative speed of 460 km / h ( 288 mph ) . In 1962 Cessna suggested the T - 37B as a replacement for the North American F - 100 Super Sabre as the primary aircraft for the USAF aerobatic demonstration team , the Thunderbirds , but the USAF was satisfied with the F - 100 . The T - 37A and T - 37B had no built - in armament and no stores pylons for external armament . In 1961 Cessna began developing a modest enhancement of the T - 37 for use as a weapons trainer . The new variant , the T - 37C , was intended for export and could be used for light attack duties if required . The prototype T - 37C was a modified T - 37B . The primary changes included stronger wings , with a stores pylon under each wing outboard of the main landing gear well . The T - 37C could also be fitted with wingtip fuel tanks , each with a capacity of 245 l ( 65 US gallons ) , that could be dropped in an emergency . A computing gunsight and gun camera were added . The T - 37C could also be fitted with a reconnaissance camera mounted inside the fuselage . The primary armament of the T - 37C was the General Electric " multi - purpose pod " with a 12 . 7 mm ( 0 . 50 caliber ) machine gun with 200 rounds , two 70 mm ( 2 . 75 in ) folding - fin rocket s , and four practice bomb s . Other stores , such as folding - fin rocket pods or Sidewinder air - to - air missiles , could be carried . The changes increased the weight of the T - 37C by 650 kg ( 1 , 430 lb ) . As the engines were not upgraded , this reduced top speed to 595 km / h ( 370 mph ) , though the wingtip tanks increased maximum range to 1 , 770 km ( 1 , 100 mi ) . T - 37 production ended in 1975 . The list of exports above amounts to 273 T - 37Cs . Adding this to the 444 T - 37As and 552 T - 37Bs gives a total of 1 , 269 aircraft built . Concept aircraft . Cessna proposed a number of innovative variants of the Tweet that never went into production . In 1959 , Cessna built a prototype of a light jet transport version of the T - 37 , designated the Cessna Model 407 , which was stretched 61 cm ( 2 ft ) to accommodate a four - place pressurized cockpit with an automobile - type configuration . Only a wooden mockup of the " Model 407 " was constructed . The project was canceled due to insufficient customer interest . The company also proposed a similar four - place military light transport , the " Model 405 " , with a big clamshell canopy , but it was never built . In response to a United States Navy " Tandem Navy Trainer " ( TNT ) requirement , Cessna proposed a T - 37 with a modified fuselage featuring a tandem cockpit . The Navy selected the North American T - 2 Buckeye instead . Cessna proposed various other trainer derivatives for the US Navy and Air Force , including a vertical takeoff version based on the TNT configuration and incorporating lift - jet pods in the wings , but none of them got to the prototype stage . Operational history . The T - 37A was delivered to the U . S . Air Force beginning in June 1956 . The USAF began cadet training in the T - 37A during 1957 . The first T - 37B was delivered in 1959 . Instructors and students considered the T - 37A a pleasant aircraft to fly . It handled well and was agile and responsive , though it was definitely not overpowered . It was capable of all traditional aerobatic maneuvers . Students intentionally placed the aircraft into a spin as part of their pilot training . The Air Force made several attempts to replace the T - 37 ( including the T - 46 ) , but it remained in service with the USAF until it was phased out in favor of the Beechcraft T - 6A Texan II between 2001 and 2009 . The T - 6 is a turboprop aircraft with more power , better fuel efficiency and more modern avionics than the Tweet . The final USAF student training sortie by a T - 37B aircraft in the Air Education and Training Command ( AETC ) took place on 17 June 2009 . The last USAF operator of the T - 37B , the 80th Flying Training Wing ( 80 FTW ) , flew the sortie from its home station at Sheppard AFB , Texas . The last T - 37B was officially retired from active USAF service on 31 July 2009 . Former Operators . T - 37s , including both new - build and ex - USAF aircraft , were supplied to a number of countries , including :