Bell Boeing Quad TiltRotor

The Bell Boeing Quad TiltRotor (QTR) was a proposed four-rotor derivative of the Bell Boeing V-22 Osprey that Bell Helicopter and Boeing studied jointly as a contender in the United States Army's Joint Heavy Lift program. Bell had developed its model D-322 as a quad tiltrotor concept in 1979, and the two companies disclosed a design in 1999 for a C-130-size V/STOL transport with a payload of up to 25,000 pounds in a hover and about half its parts in common with the V-22. A tandem-wing layout put a V-22 type engine and a 50-foot rotor at each of four wing tips, with a cargo bay that could carry 110 paratroopers or 150 passengers. A 2005 Army contract funded a conceptual design study, and a one-fifth-scale model was tested in the NASA Langley Transonic Dynamics Tunnel in 2006. The study ended in May 2007, but the Department of Defense did not pursue development.