A320 Electric Taxing
 

Lufthansa and technology company L-3 Communications have conducted taxi trials with an Airbus A320 equipped with electrical motors on both main landing gears (MLG) as part of a feasibility study to gain initial operational experience and data about a MLG-fitted electrical drive system.

The motors and control units were temporarily installed on the aircraft at Frankfurt International airport earlier this week. They are based on existing industrial components manufactured by L-3's Magnet Motor subsidiary in Starnberg, near Munich, and already in use on other applications such as ground vehicles.

An engineering team comprising staff from Airbus, L-3 and Lufthansa Technik (LHT) replaced the brake assemblies of the inboard MLG wheels with drive units, each one containing a liquid-cooled electrical motor, powered by the aircraft's APU, and planetary gearbox.

Power supply cables and coolant hoses were installed along the rear of the MLG, across the landing flap trailing edge, upper wing surface and through opened passenger windows into the aircraft's interior.

System control and ancillary equipment was installed in the twinjet's aft cargo compartment, which had been fitted with a special door with two large openings for cooling.

Operational controls were fitted on the flight deck and coupled with the nose wheel steering system. The two drive units were synchronized so that if, for example, the nose wheel was deflected to its 75-degree maximum, the motor on the respective inside wheel was stopped.

The pilots reported that the demonstrator system not only handled well, but was more responsive than the main engines normally used for the task, said Christian Mutz, project manager innovation at LHT.

The team trialled a broad range of ground manoeuvres, including sustained taxiing up to a maximum speed of 25kph (13.5kts), a 180-degree turn on a 40m-wide (130ft) taxiway, runs on sloped surfaces, and various self-powered reverse movements.

Approximately 40 test points were covered to assess values such as brake away momentum for taxi start from standstill, acceleration, energy consumption, heat development and tyre deformation in different conditions.

The team varied tyre pressure, switched off one of the two drive units, and trialled taxiing with a fully fuelled aircraft.

Despite strong winds, with gusts up to 70kt, at Frankfurt airport on 7 December, no adverse handling was encountered with the electric taxiing system, said Mutz.

Acceleration values were a key focus particular in regard to crossing runways, for which aircraft usually must have two engines running in case of redundancy.

The flight crew also operated the system while the engines were running. Mutz said that while the powerplants provided sufficient thrust at ground idle to move the aircraft forward, the drive units were still able to reverse the twinjet. This was not only possible along a linear track, but the pilots were able to do S-turns and tight turns, he said.

Mutz added that the team was surprised about how agile and mobile the aircraft had become, and how easily the pilots adapted to the controls.

The test data will now be evaluated and flow in the specification of a potential electric drive system in the future.

L-3 and Lufthansa Technik are planning to design a system which could be retrofitted to in-service aircraft.

Installation of the demonstrator system took two days before tests began on 6 December. The equipment is currently being removed again, and the aircraft (reg. D-AIZF) is due to re-enter passenger service on 10 December


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That's future
 

That's the future..!
Just imagine how much fuel can be saved :ok:

old news I'm afraid see here.

What does the system weigh? How much extra fuel does the APU burn generating the power? And is 13.5 knots the maximum speed? There are some airports where that would hold up the ground traffic.

How much would sector fuel burn be affected as a result of the additional weight? Not to mention additional mx costs.

They stole my idea!
Me on pprune in 2008: avion remorque une fois au sol par de vehicules electriques
They have spies on pprune!!!
:8:8:8

While this is a great idea that will eventually turn to become reality, once the materials, technology etc improve, as well as weight, I just wonder: why is this system based on the MLG? Would it not be as efficient to place it on the Nose Gear instead? There would be much less conversion costs on existing aircraft and most pushbacks and towings are done from the Nose Gear. Of course on a slippery or contaminated surface it would be less than ideal, so there might be cases where engines will have to run anyway.

Maybe this perspective has been looked at before?

Flex

You do realise of course this'll mean yet another QRH or hard
to find FCOM drill when the damn thing decides to run amok.

Dunno what ECAM will be presented but I have no doubt it'll
be unnecessarily complicated.

Don't live in the past!

You realise of course that you are operating a computer, which is awfully more complicated than reading a newspaper? :}

I bet a little computer reset will be the first step, like most of these electric airplanes nowadays.

I can imagine this -

AIRBUS:
Autobrake (if on while taxying)......OFF
Manual braking.........APPLY
This should disconnect all electric wheeling. If not use the
following paper checklist in PRO-SUP-ABN:
Reset Electric Wheel CB on P22 OFF then ON
If electric wheels still operating abnormally:
Reset LGCIU #1
NW Steering switch OFF then ON
Elec blue pump sw.....OFF
Reset Elec Wheel CB
Elec blue pump sw....ON
Green Hyd SW.......OFF then ON
If electric wheels still abnormal:
Bus Tie......OPEN
AC ESS......OFF
GEN SW 1+2......OFF
Attempt whole procedure again using batteries only.
If unable to reset and/or if unable to correct the elec
wheel malfunction:
Parking Brake......SET
Call for maintainence.

BOEING:
Electric Wheel Switch.....OFF
Proceed under engine power.