Dedicated to all those who served with or supported the 456th Fighter Squadron or 456th Fighter Interceptor Squadron or the UNITED STATES AIR FORCE


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This was the first non-research plane to be assigned an X designation. The use of the letter X was meant to disguise the covert nature of the X-16. 20 X-16s were initially ordered by the USAF, but the program was cancelled before the first unit was completed. No examples are known to exist.

Bell X-16

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The Bell X-16 was an aircraft designed as a high altitude reconnaissance jet aircraft in the United States in the 1950s. A mockup of the X-16 was built, but the project was cancelled in favor of Martin RB-57 before any X-16 aircraft were completed. The designation of X-16 was a cover to try to hide the true nature of the craft from the Soviets during the Cold War.



During the second half of 1953, Fairchild, Bell, and Martin Aircraft conducted high-altitude reconnaissance aircraft design studies for the U.S. Air Force. All three designs used Pratt & Whitney J57-P19 engines. The Bell (X-16) and Martin (B-57D) designs were chosen for further development. The Bell design was designated the X-16. The X-16 project was cancelled by the Air Force in favor of Martin RB-57 in 1956. A full-scale X-16 mockup was completed and one aircraft was partially completed. It was designed as a high-altitude long-range reconnaissance aircraft. A total of 28 aircraft were ordered, but none were completed. The first X-16 was about 80-percent complete when the program was cancelled in 1956.

The X-16 design was breaking new ground with its design. Its wing was extremely long with a high-aspect ratio. It was significantly lighter and more flexible than any in existence at that time. The entire aircraft was made as light as possible to fulfill its mission of a 3,000-mile unrefueled range at a 70,000 foot altitude.

Although no X-16 was ever completed, it made contributions to aircraft design with its lightweight design. It was also a driving force behind the development of the high-altitude J57 jet engine that would later power the U-2 and other aircraft.


Operational History

None completed. Program cancelled in 1956.


Aircraft serial number

28 ordered, none completed.


Specifications ( X-16 As Designed )

General characteristics



Bell X-16

The Bell X-16 was a proposed high altitude photo-reconnaissance aircraft. The X-16 had enormous wings with slight sweep, and a podded engine under each wing. The X designation was used as part of the cover story for the program. The X-16 was the choice of the USAF, but it was later cancelled in in favor of the CIA-sponsored Lockheed U-2 which first flew in Feburary 1955. Only a mock-up was completed.

By 1952 the new generation of turbojet engines, with their inherent high altitude potential, had created an opportunity of matching engine and airfoil to achieve an airplane of low wing-loading capable of higher altitude operation than anything yet conceived. The ideal application for such an airplane was reconnaissance; the high attitude would make detection very difficult and provide protection until effective countermeasures were developed.

By March 1953 the Air Force had developed a set of specifications for preliminary design studies by aircraft manufacturers. Operating conditions selected were an altitude of 21,340 meters or higher, a range of 2,800 kilometers, and subsonic speeds. Propulsion was to be by turbojet or turboprop suitably modified for the high altitude operation. The airplane would carry a crew of one and photographic equipment weighing between 45 and 318 kilograms. No armament or ejection equipment was provided, in keeping with the objective of minimum gross weight and high altitude for protection.

Bell Aircraft, Fairchild Aircraft, and Glenn L. Martin were called in to discuss the studies, and all three were very interested. The Air Force talked to no one else. Contracts to the three were let beginning 1 July 1953 and ran to the end of the year. Bell and Fairchild were asked to design a new airplane; Martin, builder of the B-57 bomber and RB-57 reconnaissance airplane, was asked to study modifications to the RB-57 to meet the more stringent altitude requirements.

Wright Field evaluated the three studies in early 1954 and had the contractors present the study results during the first part of March. Bell proposed a twin-engine airplane [the MX-2147, subsequently designate X-16]; Fairchild submitted a single-engine design [the MX-2147]; and Martin discussed modifications to the RB-57, including a larger wing (the Model 294). All used Pratt & Whitney J-57 engines, modified for high altitude operation and initially designated J-57-P19 (later J-57-P37). The high-altitude B-57D was subsequently built, and the Bell X-16 was initiated but cancelled in mid-1955.




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