Based On 30 Years Of Research

Bell's MAPL tail fan demonstrator made its first flight last week at Bell's new XworX research center in Arlington (TX).

On Thursday July 15th, the aircraft lifted into a hover, performed some low-speed maneuvers including pedal turns, and landed. The demonstrator will be used to explore the flight characteristics of this protected, low-noise anti-torque device intended for use on Bell's new MAPL line of light helicopters (the Modular Affordable Product Line.)

Bell CEO Mike Redenbaugh said in a statement to ANN, "This is an extension of protected anti-torque development at Bell that started in the 1970s with small-scale testing and includes the Ducted Tail Rotor demonstrations done ten years ago. We are developing a tail rotor for our customers that will be quieter, more effective, and more reliable with lower operating costs."

After the flight, pilot Jim McCollough said, "This aircraft is easy to fly. The workload in hover is very low." Observers described the tail fan as practically inaudible. "You can occasionally hear a purring sound," said one. The demonstrator is an experimental Bell 407 with a forty-inch diameter fan and duct, which replace the sixty-five inch diameter tail rotor. The tail fan incorporates technology developed during bench testing completed earlier this year, many features of which are covered by new patent disclosures. It has been designed to allow testing in multiple different duct configurations, to provide information on their performance and acoustics in hover and forward flight. The test program will be conducted at the XworX facility and at Leadville, Colorado to obtain high-altitude performance data.

The tail fan is only one of many new technologies being developed specifically for the MAPL family, including an advanced rotor demonstrator planned to fly later this year. The first aircraft in the MAPL family is expected to be available in 2008, although some of these new technologies are mature and are being incorporated in Bell's 427i announced at HAI earlier this year.

FMI: www.bellhelicopter.textron.com