Aviation Naval Warfare Land Systems Small Arms By Flag By Year By Tag

Bell XV-15

1977 COLD WAR X-PLANE

History of Bell XV-15

Since the dawn of helicopters providing vertical to horizontal flight (the first operational models appeared during World War II), aerospace engineers have been looking for ways to incorporate better online performance. This led to countless experiments during the Cold War as companies tried to find suitable solutions.

For a while, "thrust" propellers seemed to be the future, while other designs relied on complex turbojet configurations combined with traditional helicopter blade configurations. Over time, the technology behind the "tilting" cabin improved, giving rise to the concept of a "pitch-rotor" aircraft??a craft that was both a helicopter and an airplane.

Over time, Bell worked hard to bring his XV-3 prototype to life, which followed the a priori "Model 1-G" and "Model 2" molds. The Type 1-G was the first flying tiltrotor in aviation history, powered by a reciprocating engine sunk in the fuselage, driving the tiltable wingtip rotors through a shaft.

The subsequent XV-3, an evolution of the Model 1-G and Model 2, took to the air with a similar concept in 1955, and the aircraft earned the distinction of being the first tiltrotor to go from vertical to horizontal flight, This paved the way for the subsequent development of the refined XV-15.

The XV-15 is a complete redesign of the same tiltrotor approach, but with its engines relocated to tiltable nacelles placed in the wingtips. There is a common driveshaft between the two engines, which can be relied on if one engine fails - the other can maintain the workload.

The XV-15 project was officially launched in 1971.

The basic layout of the XV-15 has been established and is emulated today by the U.S. military's combat V-22: the fuselage has a helicopter-like shape, the side-by-side cockpit accommodates two crew members, and the tail section is tapered. Above the roof are common wing components, topped by sloping engine nacelles that drive large, thick rotor blades around an oversized spinner.

The fuselage is supported on the ground by a retractable tricycle unit, and the stern contains a biplane rudder configuration placed on a common horizontal plane.

The XV-15 first flew on May 3, 1977, and is itself the ancestor of the Boeing V-22 Osprey family described elsewhere on this page. The Boeing V-22 was the first tilt-rotor aircraft to enter service in 2007.

The U.S. government commissioned a pair of airworthy prototypes to continue the program, with Boeing, Grumman, and Sikorsky joining Bell in the race. For NASA, Bell's submission of the Model 301 ended up winning when it competed with Boeing (which offered the Model 222). Bell then produced two prototypes, the N702NA and N703NA.

These were then extensively tested at the Ames Research Center in Mountain View, California, and then airborne in Dryden (NASA, Edwards AFB). It made its public debut at the 1981 Paris Air Show and was well received by the public.

The N702NA later crashed (no casualties) during a test flight and its wreckage is being rebuilt for the simulator character. The N703NA survived the flight and is exhibited first at the National Museum of the United States Air Force in Dayton, Ohio, and later at the Udvar-Hazy Center Aviation Museum near Washington, D.C.

After running out, the XV-15 series was completely phased out in 2003.

Bell worked with Boeing to develop the V-22 series, a larger version of the XV-15 with more power and capability.