In 1962, the United States Navy announced their request for two prototype aircraft with V/STOL capability, powered by four ducted fan nacelles, they consulted Bell Helicopters, a world-renowned company that was then exploring this innovation.
Bell Helicopters already had extensive experience with VTOL aircraft and was able to utilize an already developed test mockup. In 1964 the prototype, internally referred to by Bell as Model D2127, was ordered by the Navy and received the X-22 designation. It was unveiled at an event in Niagara Falls in May 1965.
With the team's ever-pioneering spirit, Bell was already developing a similar prototype. This aircraft flew with three blade propellers mounted on four wings connected to four gas turbines which, in turn, were mounted in pairs on the rear wings. Maneuvering was achieved by tilting the propeller blades in combination with control surfaces (elevators and ailerons), which were located in the thrust stream of the propellers.
During takeoff, the propellers would tilt upwards or at 45 degrees, demonstrating a new type of aircraft movement that could handle short runways. This revolutionary vehicle - the best of its time - was known as the Bell X-22.
In contrast to other tilt-rotor craft (such as the Bell XV-3), transitions between hovering and horizontal flight succeeded nearly immediately.
The second X-22 first flew on 26 August 1967. Early that year, it was equipped with a variable flight control and stabilizer system from Cornell Aeronautical Laboratory, which improved flight performance.
The second prototype was moved to Cornell Aeronautical Laboratory for further testing; the last flight occurred in 1988. Although the ducted fan propellers were considered usable, they were not used again on a US military aircraft until the F-35B.
The Bell X-22 model continued successful flights into the 1980s, even though the original program was canceled. It is currently on display at the Niagara Aerospace Museum in New York. As for the technology, its concept lives on through our Bell Nexus 4EX, another vehicle that demonstrates the possibility of duct and propeller technology. Exploring new ways of enhancing vertical take-off and landing aircraft is a journey our teams have embarked on since our very beginning. Today, this mission carries on.
Although not on display, the only currently remaining craft, 151521, is currently stored by the Niagara Aerospace Museum, New York.