Aerospace Notebook: Boeing brainstorm could save jet fuel

Some of The Boeing Co.'s Phantom Works researchers got together with airport directors and airline officials and put the question to them. Was there something Boeing could do that would mutually benefit both airlines and airports?

"This idea just popped up," recalled Jim Renton, director of technology integration for Phantom Works, Boeing's research and development arm.

Instead of using a commercial jetliner's engines to move the plane around at airports and on those long taxiways, why not power the jet using an electric motor attached to the nose gear? With fuel prices high, airlines would save a lot of money across their fleets.

Not only would airline costs be reduced, but such a system, if widely used, also would reduce airport emissions and eliminate the need for some airport equipment -- those ubiquitous tow tugs that push airplanes back from the gate.

Pilots would have more control over their planes. They could leave the gate when they wanted and not have to depend on a tow tug. That would help reduce the time needed to turn a plane, as measured from when it arrives at a gate until it leaves. Low-cost airlines do everything they can to turn their planes as quickly as possible.

"The pilots could (using the nose-wheel motor) go out to the end of the taxiway, allow time to warm up the engines and take off," said Renton, who divides much of his time between Boeing's operations in Everett and its developmental center across from Boeing Field.

But was such a system feasible?

Recently, at a remote location in the Southwest, Boeing successfully tested a motorized system attached to the nose wheel of a twin- engine 767 that was supplied by Air Canada.

It worked, although there are still some technical issues that must be resolved, Renton said. Now, it's up to top Boeing executives who must decide if this research project goes any further.

"The decision is at the senior management of the company as to what we will do next and how do we proceed," Renton said yesterday. "Once they give us guidance, I'll know how fast the team can go ahead ... and when we might have something to put on an airplane."

He estimated that it would take years before such a system could be designed, built, certified by the Federal Aviation Administration and then be ready for commercial jets.

One of the unresolved issues is weight. Adding weight with a nose-wheel motor would mean that the plane would burn more fuel in flight, even if the fuel burn were reduced while the plane was on the ground.

Renton said the weight of the motor would depend on the type of plane. The bigger the plane, the bigger, and heavier, the electric motor.

For the recent tests, Boeing used an off-the-shelf motor developed by Chorus Motors, which is working with Boeing on the project. Advances in electric motor technology -- "power density," as Renton called it -- have made such a system feasible, he said. Essentially, electric motor researchers have found a way to package significantly more power into a smaller and lighter motor.

A motorized nose-wheel system for a 767 probably would weigh hundreds of pounds, Renton said. Cockpit controls also are required.

But he said researchers at Phantom Works believe that the system can be built to be "weight neutral," meaning that as much weight could be removed from the plane as the system would add. For example, less fuel would be needed, and that would produce a significant weight savings.

There are other issues, too. The system would have to be fail-safe so that the motor's gears would disengage and the plane's nose wheel turn freely if the motor failed.

Renton envisions that the motor could be used to power a jet from when it is ready to leave the gate until a few minutes before it is ready to take off. How long a jet's engines need to run before takeoff depends on how warm the engines already are. A hot or warm engine might need only a couple minutes of run time before the plane was ready to take off. A cold engine would require a longer warm up.

Boeing said the recent tests were performed under various conditions, with the Air Canada 767 being maneuvered on slopes, at ramp temperatures exceeding 120 degrees Fahrenheit and at loads up to 94 percent of the plane's maximum takeoff weight.

The Air Canada pilots who took part in the demonstration like the concept.

"Powered nose wheels have very positive benefits, and I am quite impressed with the potential of the electric motor technology," said Capt. Hugh Campbell, director of pilot qualifications for Air Canada.

Aerospace Notebook is a Wednesday feature by P-I aerospace reporter James Wallace. He can be reached at 206-448-8040 or jameswallace@seattlepi.com.

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