Originally published at: FAA Funds Electric Taxi Initiative - AVweb
APU powers electric motors on landing gear wheels
Would be really really good on days when everyone is deicing or there are ground holds. No having to return to the gate for more fuel after exceeding a holdover time. And nice to have some extra weight available for pax and bags.
It makes some sense but seems complex, expensive, and potentially heavy and adds failure points.
Maybe just use tugs? A small diesel engine on the tug would use much less fuel than the jet engines, and probably less than the APU which is also a turbine.
Sure it would save some fuel during taxi. But the additional weight would also cost fuel during flight. And there will be additional maintenance needed for electric motors.
There is no free lunch. Every engineering decision is driven by these tradeoffs. I can’t believe that airplane manufacturers and airlines haven’t already considered such a system.
The motors might not be fast enough, but I wonder if this could also be used to spin the wheels up before landing to help with tire wear?
What added weight? Every upgrade is a failure point. The backup would be to taxi with jet engines.
That’s been researched for decades. The additional weight isn’t worth the small benefits.
Zero is the least of the options.
Right but the point of my comment is that with the system in this article the hardware would already be there to do it.
Incorporating an electric motor large enough to move a 777 or A350 into its main gear would be a major redesign of the gear truck. It might also require changing the size and shape of the gear wells. Definitely not an easy fix. Since tugs are used to move aircraft around the ramp at most major airports anyway, albeit when they are empty of passengers and baggage, that could be easily implemented and requires no modifications to the planes. The biggest issue would probably be during wet or slippery weather where the tugs could have problems getting adequate traction. However, under those conditions, the planes could always revert to engine power.
If one wanted to really go with low emissions, they could design an electric drive tug to move the planes. The added weight of the batteries could actually benefit the tug with regard to getting better traction. Just a thought…
Remote Tug with a link to the Pilots in the cockpit that return back to the charging station with AI Self-Driving Technology wouldn’t cost much and available today. Here’s one of the General Aviation Tug company that could probably do it:
Best Tugs would most likely accept the challenge with a good option also.
Not to Mention the added draw on APU Electrics to supply Power to A/C during Taxi in /out as well as supplying power to Move something like a 777-300
First read about this 20 years ago, French chap designed a motor in wheel system for the nose wheel which he said would not need landing gear changes, and could have own battery so did not even need to fire up APU.
Working prototype (on Aibus 320 from memory) but nothing came of it because it is expensive, and really, solved a problem airlines did not know they had…
Has been worked on before, IIRC for nose gear as it does not usually have brakes.
(Some B727-200s had nose gear brakes, I asked Boeing to produce a kit for 727-100C but their costs were too high as divided by only a few airplanes.
Pacific Western wanted that for gravel runways, as forward CofG due cargo pallets in front of cabin required use of F30 instead of F40 thus landing length performance suffered which limited inbound payload.
(Reversible JATO was not a very feasible notion. :-o)
About 40 years ago, a company came up with the idea of building under-the-taxiways powered slots that would have a mechanism to hook to the nose wheel and tow the plane to the runway. I never heard of the idea afterwards. I came out around the time of the second gas crunch in 1978. Once the price of gas dropped, I guess the reason went away.
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