Bell's Huge Tiltrotor Concept Takes
Big Step Forward with U.S. Contract

Bell Helicopter Textron has received a big boost to its ambitions to develop a large tiltrotor that would feature four, rather than the traditional two rotating engines.

The U.S. Defense Department's research organization, the Defense Advanced Research Projects Agency (DARPA), has awarded the company a $400,000 phase one exploratory study contract to further investigate its Quad Tiltrotor concept.

The Quad Tiltrotor would be used for heavy cargo lift and be in the class of a C-130-30, the stretch version of the Hercules. Initial design concepts call for the aircraft to be equipped with four V-22 wings, two each forward and aft. Each wing would have the engines and prop-rotors on the outside of the wing, again mirroring the V-22 approach.

The total value of the potential three-phase program is $6 million, but the actual benefit to Bell of this seed money could be much greater. The commandant of the U.S. Marine Corps, Gen. James Jones, has voiced strong interest in such a system, and has urged the Pentagon to at least investigate the technology.

The Marines are launch customer for the Bell Boeing V-22 Osprey tiltrotor and are interested in transitioning to an all vertical take-off and landing fleet. The Quad Tiltrotor, or another VTOL system, would likely take the place of Marine Corps C-130s.

Another potential candidate is the U.S. Army's Future Transport Rotorcraft program. The Army is making a push to a more mobile and flexible force. But the service is seen as unlikely to be willing to provide enough money pursue such a new technology.

During the first phase of the DARPA contract, Bell will only draft a technology roadmap to lead to an operational system. The second phase, which has been authorized, involves building a 1/14-scale hovering model of the aircraft. DARPA will decide later whether to authorize a third phase, during which wind tunnel modeling would help determine the loads and aerodynamic performance of a full-size aircraft.

So far there is no funding for a full-scale flight demonstration system. However, Bell said that it could build a prototype starting around 2002. The company believes it could have an operational aircraft ready for delivery by 2010. That's based on the assumption it will be able to use much of the V-22 technology.

As with the regular V-22-like tiltrotor technology that Bell-with Agusta as a partner-is spinning off into the commercial market with the BA609, the Fort Worth, Texas-based company sees commercial applications for the Quad Tiltrotor. "The civil Quad Tiltrotor could use existing commercial airports, civil aviation airports, and new inter-city vertiports," Bell said.

By Robert Wall