Bell X-16

The Bell X-16 was a high-altitude reconnaissance jet aircraft designed in the United States in the 1950s, and the X-16 designation was a cover intended to hide its true mission from the Soviet Union. In the second half of 1953 Fairchild, Bell and Martin made design studies for the Air Force under project MX-2147, and the Bell Model 67 and the Martin design that became the B-57D were chosen for further development. The X-16 was meant to fly 3,000 miles unrefueled at 69,500 feet and was built as light as possible, with a wingspan of almost 115 feet and two Pratt and Whitney J57 turbojets. A full-scale mock-up was completed and 28 aircraft were ordered, but none were finished: the first was about 80 percent complete when the Air Force cancelled the program in 1956 in favor of the Martin RB-57.