Motor Assist Drive...for Jetliners

1 August 2005

Boeing Company and Chorus Motors have demonstrated the use of an onboard electric motor attached to the nose wheel of a Boeing 767 to allow jetliners to maneuver into and around gates.

If widely deployed, the onboard nose-wheel motor would largely eliminate the use of tow tugs or the airplanes’ own engines for such work, reducing ground fuel consumption and emissions.

The demonstration was the result of a partnership formed last August between Boeing Phantom Works (the advanced research and development unit) and Chorus Motors plc. The Chorus Meshcon (Mesh Connected) Motor, a high-phase-order motor/drive system, offers five times the startup or acceleration torque of a conventional motor and drive of the same rated horsepower and base speed.

The Phantom Works/Chorus Motors team, in cooperation with Air Canada, installed an electric motor drive on an Air Canada 767 and conducted a series of tests. Air Canada pilots performed ground maneuvers on slopes and terrains typical of those at airports around the world, including driving in reverse from a gate and taxiing forward to a runway. Tests also were performed at ramp temperatures exceeding 120º F (48.9º C) and at loads of up to 94% of the maximum takeoff weight for the airplane.

Powered nose wheels have very positive benefits and I am quite impressed with the potential of the electric motor technology.

—Capt. Hugh Campbell, director of Pilot Qualifications at Air Canada

The Chorus Meshcon (a specific application of the broader Chorus Drive concept) utilizes harmonic drive to “spoof” the drive electronics to think they are operating at a higher speed. The net benefit is that the motor drive, which cannot output maximum current and voltage to a 3-phase motor at low speed, is capable of achieving torques exceeding five times that of what can be achieved in a 3-phase machine.

The result is that a much smaller drive can be used for the same load, greatly reducing the cost of the resulting drive. High speed operation is not hampered, so the same motor could be used to start a car engine, and efficiently produce electrical output.

Resources:

• Chorus Technology. Useful animations and more detailed explanations of the electronics.

• WorldChanging: Chorus Motors Partners with Boeing