WC Archive

Essentially, this means that the aircraft can taxi on the power of its APU, with all main engines shut off.  It can also back itself away from a gate.

I've long wondered why nobody did this.  Guess it was just waiting for power/weight to get high enough.

Yes, Engineer-Poet, it runs the plane from the APU ("Auxiliary Power Unit", for those not in the biz) with jet-engines off. And more importantly, as you said, the planes can drive backwards as well as forwards.

Jamais, slight correction to the post: currently all planes have to be pushed backwards by the tow-tug vehicles; their jets can only push them forwards.

And to elaborate, waiting for tugs to come and hook up wastes time; it's possible that if all planes had motorized wheels, airports might get one extra flight per day per gate. (This alone would make the invention financially desireable, even ignoring the other benefits.) The invention's main environmental benefits are that it:
- saves fuel
- reduces air pollution
- reduces noise pollution
- reduces engine wear (there're always little bits of debris on runways that get sucked into the engines.)

And EP, you're right that this would've been done long ago, except that no one else has been able to get the power density that Chorus motors get. At some point we'll have photos up on the website so you can see how small they are.

But presumably wouldn't an extra flight per gate per day result in more pollution being emitted than was originally saved by installing these devices?

This isn't intended to be a nitpicking point, I do understand that more efficient use of existing resources and infrastructure will be part of the solution, but there is a danger that increases in fuel efficiency of any kind just cause us to do more with what we have available i.e. "Great, hybrids. Now we can drive twice as far." or "Wow, with these savings in heating bills, we can afford to attend that trade conference in South Africa." New Scientist just published a very interesting editorial on just this subject, basically arguing that energy saving in itself will not help, if we do not address the question of what is done with the resources that are saved. Still, we have to start somewhere. Does anyone have any thoughts on how we can ensure that great advances in technology like the one posted above result in actual cuts in net emissions, not just greater resource efficiency, and hence more damaging activities? Seems to me that this is where regulatory measures and mandatory limits to emissions come in.

Like every other engineer sitting around hot and bothered in a grounded jet, I have wondered the same thing, why not just put some power to those wheels and drive off? Of course the answer is that the motors were too heavy until now.

But I also bet that a lot of those same folks had a further thought- why not make a network of vacuum filled tubes in which maglevs could skoot from hither to yon in a blink, using almost no fuel relative to these whales pushing a lot of high Mach air out of the way?

This is an old, old idea, even older than I am: I think Goddard started it, and there is much good thinking about it on the web, but as with the wheel motors, the technology just wasn't there until now. But now is now.

Actually, I wondered why air motors (running off APU bleed air) wouldn't have sufficed.

I read the Chorus spec sheet (they're HQ'ed in Gibraltar, a domain I'd never seen before).  What they have is a very clever method for doing what every BSEE knows is possible:  adjusting the number of poles in the motor stator to suit the torque/speed demands of the moment.

Genius consists of looking at what everyone has looked at before, and seeing what no one has seen before.  My hat's off to them.

The other thing I like about Chorus Motors is their parent company, Borealis. They are also developing special Peltier type devices that convert heat energy into direct electricity at 70-80% Carnot efficiencies using quantum electron thermotunnelling on chips. Any heat source can be used to generate electricity, not to mention secondary heat recovery. And recently, they have come up with Photon Chips™, converting sunlight directly into electricty. These guys are phenomenal!

To me, this is sort of a finger in the dike solution. It's a good idea that should be implemented, but it won't resolve the longer term problem that current planes won't be affordable to fly if the price of fuel goes up a lot more. We're gonna need to switch to those blimp-like things that a previous post mentioned.

Although only briefly mentioned in the post, this motor is probably more significant for other applications (transportation and otherwise) where it could make a substantial impact on fuel consumption. I'd like to see a post on the recent innovations in electric motors. I've seen many individual articles but no aggrigation.

Actault fuel is not the most important cost of a flight and people were flying back decades ago when flights cost far more inflation ajusted. Just will mean fewer people will fly.. wich is prolly a damn good thing