Corvette-Size Electric Motor Seen Changing How Jets Taxi
 

Corvette-Size Electric Motor Seen Changing How Jets Taxi - Bloomberg

As fuel prices continue to soar, airlines are studying new technology that may save more than $200,000 per jet every year. The breakthrough only sounds mundane: It’s all about how planes taxi.
Travelers are familiar with the sight of low-slung airport tugs pushing aircraft away from the gate so the main jet engines can crank up safely. Thrust from the kerosene-slurping turbofans then powers planes into position for takeoff.
Now, equipment makers such as Honeywell International Inc. (HON) are devising electric motors that weigh about as much as V-8s in Chevrolet Corvettes yet pack enough torque to move 180,000-pound (81,650-kilogram) jets, letting pilots taxi without relying on main engines or diesel tractors.
“You could have tug-less airports,” said Ian Davies, chief of engineering and maintenance for EasyJet Plc (EZJ), Britain’s largest discount airline. “It might fundamentally change how we operate in airports.”
Taxiing on electric power is an example of how technology, in this case motors so small they fit in the hub of a jet’s nose wheel, can revolutionize something as routine as an airliner’s journey between the terminal and the runway.
“It’s a simple concept, but it’s complex to integrate into an aircraft,” said Olivier Savin, chief of Safran SA (SAF)’s Green Taxiing System Joint Venture with Honeywell. “Integration is the key to success.”

Airbus, EasyJet

The prospect of annual savings topping $200,000 a jet from lower fuel use and less ground time has stirred interest from planemaker Airbus SAS and airlines such as EasyJet and Alitalia SpA. The first new aircraft with electric-taxi technology may be in production in as few as three years, and older planes may get the gear as soon as 2013.
Airlines face the highest sustained prices ever for jet kerosene, the industry’s largest cost, based on data compiled by Bloomberg. United Continental Holdings Inc. (UAL), the world’s biggest carrier, says it burns $25,000 of fuel a minute. Jet fuel for immediate delivery in New York Harbor has averaged $3.12 a gallon in 2012, more than four times as much as a decade ago.
Taxiing on one engine has become a common fuel-saving practice for twin-engine jets in recent years, and planes already make electricity when they’re at the gate by running small turbine engines known as auxiliary power units.
What’s new today is the convergence of airlines’ hunger for more efficiency and recent advances in miniaturizing electric motors to propel a plane at the 20 miles (32 kilometers) per hour it may need for taxiing.
How Heavy?
The Honeywell-Safran team estimates its unit would weigh a maximum of 880 pounds, while startup WheelTug Plc said its electric-taxi technology is only about 300 pounds. Another entry, a venture between L-3 Communications Holdings Inc. (LLL) and Crane Co. (CR), isn’t commenting on the heft of its system.
WheelTug’s motor fits in the hub of a jet’s front wheel and is just 5 inches wide, Chief Executive Officer Isaiah Cox said. That’s half as broad as two years ago, when the Gibraltar-based company still had to attach the motors outside the hub, he said.
“It’s like packaging an elephant into the nose wheel of an airplane,” Cox said.
That would eliminate the cost of a push-back from a tug, which runs $50 to $150, and the consumption of about 55 gallons of fuel taxiing before and after takeoff, based on average burn rates and ground times at U.S. airports, Cox said.
WheelTug says its system may save about $500,000 a plane annually, including benefits such as less wear on engines.

Eliminating Tugs

Honeywell and Paris-based Safran say the savings may exceed $200,000 per plane a year by paring fuel use and ground time, and eliminating charges for tugs’ services. Stamford, Connecticut-based Crane also says taxiing on electricity would cut noise, reduce emissions and shrink the risk of having a jet’s main engines ingest tarmac debris.
Meshing small electric motors and new cockpit controls won’t be the only challenge for Morris Township, New Jersey- based Honeywell and its rivals.
Suppliers will have to convince airlines that the savings will make up for the extra fuel burned in flight from the equipment’s added weight, said Tim Campbell, president of St. Paul, Minnesota-based Mountain Vista Consulting and the former chief of regional operations for Northwest Airlines Corp.
Airport tugs also would need to be on hand in case a plane’s APU fails, Campbell said in a telephone interview.

Boeing, Airbus

Boeing Co. (BA) isn’t “actively pursuing” electric taxi, Terrance Scott, a spokesman, said in an e-mailed response to questions.
Airbus is talking with “potential suppliers” for an electric taxi system, Martin Fendt, a spokesman, said in a telephone interview, without identifying them. “It’s certainly something we’re keen to see where the potential is.”
WheelTug’s focus is to fit its electric-taxi system to existing jets, and it has installation agreements with Alitalia and El Al Israel Airlines Ltd. (ELAL) The company has a target of late 2013 to get the first units onto planes.
The Honeywell/Safran and L-3/Crane groups are concentrating instead on persuading planemakers to adopt the technology for new aircraft. Their systems drive the main landing gear. Honeywell and Safran expect to run trials with a Safran-owned Airbus A320 by mid-2013. L-3 and Crane tested their team’s unit in December on a Deutsche Lufthansa AG (LHA) A320.
Airlines have powerful incentives to act, said Scott Whitfill, who oversees about 70 tugs as North America maintenance director for Worldwide Flight Services.
‘Not Cheap’
“If airplanes were able essentially to back themselves out and I didn’t have to supply a push-back tractor, that would impact the cost of my handling for the airline,” Whitfill said in a telephone interview. “Push-backs are not cheap.”
Savings from the electric motors would be greatest on single-aisle jets such as the A320 and Boeing’s 737, whose frequent short-haul flights mean more time taxiing. Wide-bodies land and take off less often because they fly longer routes.
“It’s huge,” said Rick Jones, vice president of Crane’s aerospace unit. “It’s looking to us like it’s going to be a compelling value proposition for the airlines.”
Davies of Luton, England-based EasyJet is convinced. The carrier’s 215-plane fleet consists entirely of jets from the A320 family. That makes it one of the airlines that would benefit from electric taxi, and it’s preparing to test the Honeywell-Safran system.
“There’s no doubt to me that the technology is there. It will work,” Davies said. “Let’s say 40 years from now, maybe all aircraft will have this.”

I think this is definitely a way forward to reducing pollution at airports.

Not sure whether built-in taxi systems are the answer siince you need to lug them round the sky, or if different ground vehicles would be a better solution - perhaps something which groundcrew attach at the gate and remove at the threshold is the answer?

Put a lot of people out of a job too. :(

Like this perhaps...

Mototok

Lufthansa has already tried out a system fitted within the main wheel hub of an A320.

We'll still need people to lug around and load bags, food, ladders, fuel, poop ....

*poop, unload (I hope! :eek:)

Hi,

In some time .. the cost of electricity (or any energy other than human or animal) will be so high .. they will use horses or oxen for taxi :sad:
And this will give some new airports jobs :ok:

Any airline that elects to carry 880lb of dead weight around is going to want to save a lot more than $200K in annual DOCs per aircraft.

It might put drivers out of a job, but it will create many more jobs in the engineeing sector designing, building and fitting these things, plus the jobs needed to maintain them. Overall no less jobs, just jobs in different places.

:)

The Mototok is exactly what I was thinking of, but if it were controllable by the pilot (or followed a pre-set route from runway to gate) then so much the better. No need to carry around all that drive weight, yet silent and emmission free.

The advantage is in eliminating the collateral structure in the tug itself, and placing its motive power in the wheel of the a/c. So we save carting around the frame and wheels of the tug. For this benefit we pay mightily for developing and certifying a small and exotic engine to carry around the sky.

There is NO free lunch. Energy is costly, and whether it comes from being stored in petroleum or battery (solar generated, or petrol), the cost cannot be eliminated from the equation.

Find the thread elsewhere in this website for the done to death ramifications of toting a million dollar motor around the skies to eliminate diesel power on the ground.

You make the call.

They run off the APU power mostly; so no additional exotic engine needed I think.

880lb sounds about 4 lost PAX that could have flown. How much does an average seat bring in per-year on a typical short-haul fleet (with more landings / take offs I think that's the target market) these days?

Hi ross

We speak "wheel tug" yes? APU is power, the engine is in the truck (wheel) of the a/c. It will be electric, of course.

I see you are a partisan. Let me direct you to an electric motor that produces three hp per pound of engine weight.

You will need symmetrical motive power, so at least one engine per side, but better would be one engine per wheel, sixteen on a 747.

No problem, the wheel is the armature, the brake disc the rotor, easy peasy.
Old technology, proven, and expensive.

Where is it? The problem is not the technology.

Your problem is to demonstrate cost/benefit. No mean feat. Two 880 pound systems would cost an airline four thousand dollars a day.

All the best.

Well if you look at it that way, a very rough calculation for a loco doing 4 sectors per day, 365 days/year would give you a break even price point of 200k/(365*4*4)=34.25 USD per seat/sector.

Then again are these sort of locos constrained by aircraft MTOW? (Especially when charging for registered and cabin luggage). Guess you would need to consider the incremental fuel burn resulting from the additional induced drag of hauling the 880lb.

years ago, I seem to remember a similar concept, to spin up the wheels before landing to reduce wear on the tires....

Instead, why not accelerate the runway to ground speed...

i would definitvly prefer to see a real corvette V8 and not an electric motor on the main gears !

with sidepipes !

You also have to factor in the fuel saving from the engines not running for as long.
For example on a 747 Classic the standard start-up & taxy allowance is 1400 kg. If you could halve then then are pretty neutral with weight. For sure there's a few airports where you don't burn the full 1400 kg but also more than a few where you do. (LAX, Amsterdam, etc.)

A taxi test or 2 is nice for marketing, but does not necessarily prove suitability for operational use.

Even 300 lb is significant in the nose gear. The retraction mechanism may be stressed by it, causing premature failures. One air turnback caused by a hydraulic failure would offset a LOT of tug time...

While it may be less of an impact on a 747 main gear, it is also likely that more/larger units would be required. Electric load would be substantial, and the APU generators may not be able to drive all that plus the standard "house load." Load shedding starts in the galleys, which would not be appreciated by the flight attendants.

Finally, nosewheel mounting would not likely work very well on slippery ramps, i.e., in snowy climates in the winter. Mounting on the main gear would be significantly more complex, since it would also have to withstand brake heat, and prove to NOT interfere with brake operation or heat dissipation.

That 880lbs figure stated in the article clearly won't be the weight of the final product when and if implemented, there are electric motors now a days producing amazing torque at very low weight, there was also a 330lbs figure given in the article, take it to pilots to run with the worst case scenarion:rolleyes: also the weight of the device won't be in addition to the brake assembly for that tire, it will be in lieu off since an electric motor can be utilized as dynamic braking just like it is used today in large trucks and trains, you don't need to install it in all the tires of an A/C as someone suggested that you will need to install 16 in a 747, 3 will be enough, the hardest part for the motors will be the initial break away torque needed, once the weight is rolling the inertia of the mass itself will help along. If this system is used in both the departure and arrival stages, it could be huge savings:ok:
Who said anything about the nose gear?

Sounds like a thread with a lot of people who have no idea of what they're talking about.

Regarding using electric motors in lieu of brakes, have any of these "it's easy" experts ever actually seen the brake energy figures for large commercial aircraft and compared them to the dynamic braking capacity of an electric motor that would fit? :ugh:

"Worst case scenarion (sic)"?!? I used a 300# figure in my assessment!

What will be the cost of certifying electric motors as replacement brakes in EACH TYPE of airplane? How practical is it in a 737 or A320, where 2 motors (asymmetric braking as a "normal" condition is untenable) represent 50% of the braking power? Will the motor mfgr/vendor do it? Where will the energy generated by that motor be stored or dissipated? There aren't any batteries in ANY commercial airplane capable of taking that kind of charge rate, so any additional batteries, cabling, and/or heat sinks will be additional weight.

Nose gear? You didn't read the OP's reference very closely:

FOD crew following taxiing airplanes around with shovels?