Bell X-16

The Bell X-16 was a high altitude reconnaissance jet aircraft designed in the United States in the 1950s. A mock-up of the X-16 was built, but the project was cancelled in favor of the 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 aircraft mission from the Soviet Union during the Cold War.

Development
During the second half of 1953, Fairchild, Bell, and Martin Aircraft conducted high altitude reconnaissance aircraft design studies for the United States Air Force under project MX-2147. All three designs used Pratt & Whitney J57-19 engines. The Bell and Martin (B-57D) designs were chosen for further development. The Bell Model 67 design was designated the X-16. A full-scale X-16 mock-up was completed and one aircraft was partially completed. It was designed as a high altitude long-range reconnaissance aircraft.

The X-16 design was breaking new ground with its design. Its wing was long (114.83 feet) with a high aspect ratio (11.9). It was significantly lighter and more flexible than usual jet aircraft wings. The entire aircraft was made as light as possible to fulfill its mission of a 3,000-mile unrefueled range at a 69,500 ft altitude.

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 by the Air Force in favor of the Martin RB-57 in 1956. 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 Lockheed U-2 and other aircraft.