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Electric Aircraft Has Unlimited Range... With A Fleet Of Recharging Planes

 
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It's okay, you've not clicked on "Green Plane Reports", but every so often something from beyond the world of cars catches our attention.

This time, it's electric flight. The concept is nothing new, and it's even been alluded to by people like Elon Musk of Tesla, but for the time being it remains a true flight of fancy, rather than a working concept for passenger transportation.

The video above suggests one such way of making the concept workable. We'll leave you to form your own thoughts, but we can forsee a few disadvantages.


The concept is sound--ensure an electric aircraft can theoretically stay aloft forever, by recharging it in mid air. Think of it as the flying equivalent of inductive charging being built into every road in the land, allowing electric cars to charge as they drive.

And of course, electric planes are a nice idea--there's no issue with how high they can fly as they don't need oxygen to produce thrust, and they'd save millions of gallons of oil per year.

But the concept in the video is a little too Rube Goldberg for us.

We like the range-extending idea of a detachable, flying battery backup, but it seems quite complicated. Imagine if electric cars were always backed up by a recovery truck with a charger on board. Great! Now imagine that truck is also powered by electricity, and constantly has to disappear to be replaced by another truck. Not so great...

And when the concept of electric flight is to cut down on fossil fuel usage and pollution, is sending a fleet of ships, carrying a fleet of recharging aircraft, really the best way of doin that?

Probably not. It's a nice idea, but this might be a case for going back to the drawing board...

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Comments (34)

  1. fb_1001015277 avatar John Briggs Posted: 8/21/2012 11:11am PDT

    The earth rests on the back of a turtle.

    Sure, I know what you are thinking, what does the turtle rest on. Well it is turtles all the way down.
     
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  2. fb_1559222512 avatar Xiaolong Li Posted: 8/21/2012 11:24am PDT

    "electric planes are a nice idea--there's no issue with how high they can fly as they don't need oxygen to produce thrust, "

    When there is no oxygen, there is also very little air for lift or generating thrust....

    Another sign that you lack basic understanding of physics...
     
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  3. fb_1001015277 avatar John Briggs Posted: 8/21/2012 12:14pm PDT

    Right, I didn't understand it. Don't both jets and props move themselves forward by pushing air backwards? If we run out of atmosphere, how do we propel the plane.
     
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  4. fb_61206378 avatar Antony Ingram Posted: 8/21/2012 12:55pm PDT

    Sorry, I should really have clarified John: Specifically oxygen is required for combustion, such as in a jet.

    Oxygen makes up only a fifth of our atmosphere, so engines suffer from a lack of it much sooner than an electric prop would be able to provide thrust or generate lift.

    In other words, you need air for lift, but you need specifically oxygen to run an engine :)
     
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  5. fb_61206378 avatar Antony Ingram Posted: 8/21/2012 12:40pm PDT

    Quite the contrary, Xiaolong. I'm well aware that there's less air for lift higher in the atmosphere, but that point is significantly higher than the point at which there isn't enough oxygen for an engine.

    Oxygen is only a relatively small proportion of the atmosphere, hence you run out of it a lot quicker than you run out of other air molecules for lift...

    I'd also kindly ask that if you're now reading my articles solely for the purpose of picking fault with them, contrary to my comments on the other article I'd very much appreciate you not reading anything I write. You're clearly incapable of being civil, a task managed quite easily by other commenters.
     
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  6. fb_1559222512 avatar Xiaolong Li Posted: 8/21/2012 1:28pm PDT

    "Oxygen is only a relatively small proportion of the atmosphere, hence you run out of it a lot quicker than you run out of other air molecules for lift..."

    If they are in proportion, then you run out of them at the same rate. Turbo charging can always compensate somewhat for the lack of oxygen. You can't compensate for lack of air for lift without thrust...

    "You're clearly incapable of being civil" I am being quite civil here. No nasty words, just facts to show your writings lack scientific foundation... But I don't respect your writing. When you improve them, I will start to respect you...
     
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  7. fb_61206378 avatar Antony Ingram Posted: 8/22/2012 12:35am PDT

    Curious how you don't have a problem with my writing in articles where I'm being kind to the Chevy Volt.
     
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  8. fb_1559222512 avatar Xiaolong Li Posted: 8/22/2012 10:06am PDT

    "being kind" has nothing to do with anything.

    "Being factual" or "scientific", then I have no problem with you.

    Reporting "some famous" people liking the Volt is NOT really a "scientific" article. It is more like a popularity reporting...
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  9. fb_1559222512 avatar Xiaolong Li Posted: 8/21/2012 1:33pm PDT

    Also, you can also compensate the lack of oxygen with other method. But when you run of air, the electric fan blades got nothing to push for. Also, the higher you go, the less efficient the propeller based thrust will be. Not to mention that you are also speed limited...

    I am you thought of those before you wrote this article too...
     
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  10. fb_61206378 avatar Antony Ingram Posted: 8/22/2012 12:29am PDT

    As Elon Musk mentions in the article I link to, the reduction in air resistance compensates for the lack of speed from thrust. So yes, I thought of that too.

    Electric fan blades develop their thrust from air in general, not purely oxygen, so a lack of oxygen isn't as much as a problem as it is for an engine that needs to burn something.
     
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  11. fb_1559222512 avatar Xiaolong Li Posted: 8/22/2012 10:07am PDT

    Like others and I have pointed out, Lacking Oxygen is NOT a problem. Lacking Air is the problem.
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  12. Bret F. avatar Bret F. Posted: 8/21/2012 12:38pm PDT

    I'm thinking a big solar panel would be a lot simpler and more effective than following a drone around with an aircraft carrier full of charging UAVs.

    Oh wait, the solar plane has already been developed.
     
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  13. fb_61206378 avatar Antony Ingram Posted: 8/21/2012 12:57pm PDT

    Agreed. The challenge now is making one suitable for carrying passengers, rather than it simply being an unmanned aircraft!
     
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  14. Bret F. avatar Bret F. Posted: 8/21/2012 1:59pm PDT

    Sorry Antony, when I saw Unlimited Range in the title, I was thinking about unmanned aircraft. Carrying passengers is a much larger challenge than flying a solar drone.

    I still think the recharging UAVs are an impractical idea, especially over water. And, they could crash into the plane during chraging, taking out the passengers.

    But, there are some technologies that could help make electric passenger planes a reality. Higher density batteries, more efficient solar panels and fuels cells could meet the energy needs within the next couple of years.
     
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  15. fb_1559222512 avatar Xiaolong Li Posted: 8/21/2012 4:22pm PDT

    Have you considered the fact that there aren't enough solar energy to keep the plane flying and batteries need to be as energy/power dense as hydrocarbon fuels...
     
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  16. Bret F. avatar Bret F. Posted: 8/22/2012 12:41pm PDT

    Xiaolong,

    Yes, I have considered this and I think about it a lot. My brother has electric remote controlled planes he can fly safely in public areas and they fly great. They are very quiet, which is a big complaint about traditional aircraft.

    Lithium air batteries are as dense as fuel and may or may not be available in 5-10 years. Fuel cells can also achieve similar densities. The problem with solar panels is their low efficiency, which Boeing has solved by using a prism and three substrates. This makes them 45% efficient, instead of the common 15%. On top of all this, electric planes will be more efficient, just are EVs are compared to ICE.

    Yes, I do think we will see electric flight soon, likely with a range-extender for safety.
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  17. fb_1559222512 avatar Xiaolong Li Posted: 8/22/2012 2:00pm PDT

    @1KW-1.5KW per M^2, solar energy on the airplanes are pipe dreams...

    As far as batteries that are as dense as fuel goes, show me a source where ANY batteries that have the power, energy density of a fossil fuel. Same goes for fuel cells... The powerdensity of fuel cells are terrible.
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  18. fb_61206378 avatar Antony Ingram Posted: 8/22/2012 12:32am PDT

    To be fair Bret, I think the example in the video is mainly referring to an unmanned aircraft so you're right - but naturally the focus in future will be on the sort of aircraft we hop into to fly from place to place. Current solar designs aren't really suitable for people.
     
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  19. fb_100001816865740 avatar Vitaly Vinogradov Posted: 8/21/2012 3:50pm PDT

    "there's no issue with how high they can fly as they don't need oxygen to produce thrust"
    This is bs. Props do have very limited ceiling. Compare to jets.

    And while it is possible to make "jet like" electric engine, to archive higher speed and ceiling... Such engine would have similar problems as jet designed for higher altitude/speed. It would be long and heavy, because more air compression stages are needed.

    But overall, oxygen content have nothing to do with either design.

    Not consuming oxygen would not help. Jet engines are limited by number of compressing stages to reach ignition and propulsion. And Electric should have similar compression to reach same speed. Without speed there would be no altitude.

    PS.Im aware of Elon's remark.
     
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  20. fb_1559222512 avatar Xiaolong Li Posted: 8/21/2012 4:24pm PDT

    Well, our "technical" writer would disagree with you.

    What is the point of making it a "jet like" electric engine if the compression doesn't gain you any additional thrust and there is a lot loss in the compression itself?
     
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  21. fb_100001816865740 avatar Vitaly Vinogradov Posted: 8/21/2012 6:57pm PDT

    Compression leads to higher Isp ( http://en.wikipedia.org/wiki/Specific_impulse ). Which allow aircraft to reach much higher speed. And thus higher altitude.

    And Isp is a reason behind as to why jets fly faster/higher then props.

    Or may be you can point me toward the way of achieving high delta V of exhaust without using high compression & staged design?

    Plasma & magnetic fields(railgun like)??? No kidding? Any design that use electric propulsion but theoretically could be practical... Besides, to make plasma out of the ambient air you would need very high temperatures and thus most likely would need crazy levels of compression. Anything else?

    PS. I know compression mean huge energy losses because of resulting temperature gradient.
     
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  22. fb_1559222512 avatar Xiaolong Li Posted: 8/22/2012 12:52am PDT

    Yes, I understand that work in a "jet engine". But explain to me how that is going to work with an electric motor powered by battery or solar energy??

    In order to generate those impulse which produces thrust, the electric motor would have to work at a very high RPM with huge torque. The power to weight ratio of that motor will be pretty poor. Not to mention the power required for that to work.

    If you are using "electric" energy to generate plasma or any kind of magnetic field, it will be terrible efficiency. I don't see how any of them would keep the object flying at high atitude with electricity generated from battery or solar...
     
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  23. fb_100001816865740 avatar Vitaly Vinogradov Posted: 8/22/2012 5:55am PDT

    One more time, I repeat myself: claim of the author of this article: "there's no issue with how high they can fly as they don't need oxygen to produce thrust" IS A BS AND A PIPEDREAM.

    And from the context he mentioned it, we are talking about Musk's SUPERSONIC electric plane, one that fly even higher then jets.

    I have explained that even best probable design of electric plane propulsion wont let plane to reach higher altitudes then jets. Even if you imagine invention of almost weightless motors with high RPM/power.

    But you still arguing with me, claiming that Antony Ingram is correct, and higher speeds/altitudes are reachable for EPlane. See quote. How? HOW?

    "electric motor powered by ... solar energy??"
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  24. fb_1559222512 avatar Xiaolong Li Posted: 8/22/2012 10:03am PDT

    What? I have "NEVER" claiming that Antony Ingram is correct. I have been arguing with him about how his writing is "baseless"...

    You and I are agreeing on the fact that what he wrote was "B.S."...
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  25. fb_1001015277 avatar John Briggs Posted: 8/22/2012 5:09am PDT

    So there is a lot of good input here, but I still don't understand the oxygen issue. I guess there are two issues.

    1) oxygen is needed for traditional power plants in planes (not for EVs) but traditional power plants seem to manage OK? or is that part of their height ceiling?

    2) Air is used for propulsion of all planes, but it sounds like reduced air at higher elevations means less lift, but also less drag. So do those factors cancel each other out? Would we want to fly higher if we could, for efficiency reasons.

    Lastly, I was surprised to find that prop planes have recorded speeds of 530 mph. Grumman F8F Bearcat, the Rare Bear.
     
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  26. fb_100001816865740 avatar Vitaly Vinogradov Posted: 8/22/2012 6:07am PDT

    1) Limiting factor for ceiling for jets is how much air could go into combustion chamber. Since air is less dense, you need more compression stages. Look at Concord vs Boeing. Look at fighter jets, thier engines are long compare to business jets engines that fly low.

    2) "Air is used for propulsion of all planes, but it sounds like reduced air at higher elevations means less lift, but also less drag."
     
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  27. fb_100001816865740 avatar Vitaly Vinogradov Posted: 8/22/2012 6:17am PDT

    To some degree. But to fly higher you will need heavier/more expansive engines. And there is a problem of supersonic boom. Overall industry choose to go subsonic for airliners. And Concord was not really fuel efficient. Proposed SuperConcord designs also were comparing purely to common airliners.
     
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  28. fb_1001015277 avatar John Briggs Posted: 8/22/2012 11:59am PDT

    Vitaly, thanks for the added input.
    So does this validate Antony's original claim that there is a benefit to EV aircraft because they don't need to consume oxygen?
     
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  29. Mikenorthwest avatar Mike Fink Posted: 8/22/2012 12:18pm PDT

    Volta Volaré GT4 Airplane. With one moving part, the hybrid electric EViation Drive requires minimal maintenance and offers TBO times up to ten X of an ICE.
     
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  30. Mikenorthwest avatar Mike Fink Posted: 8/22/2012 12:26pm PDT

    Supersonic Biplane shown in several magazines and news reports March 2012 produces no sonic boom and is quieter, more fuel-efficient.
     
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  31. fb_1001015277 avatar John Briggs Posted: 8/22/2012 5:46pm PDT

    Having read up on this a little more, I think Antony has a point but the statement was over reaching.

    http://www.askacfi.com/3062/just-how-high-can-it-fly.htm

    It perhaps would have been better said that electric motors have an advantage in not suffering from oxygen reduction as altitude increases. As for the maximum flight ceiling, well that is a more complex question having to do with peak thrust and something called "coffin corner".

    Interestingly, humans seem to be the biggest limitation on how high we want to fly :). Our blood boils if we get up too high.
     
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  32. dgatewood avatar Don Gatewoood Posted: 8/23/2012 3:30pm PDT

    Check out a plane I was once associated with, the SR71 which had jet engines, relied on lift, passed mach 3.2, and reached 89,500 feet on one test flight. The two man crew wore space suits.How does this fit the oxygen and drag limits? By the way they are all in museums now.
     
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  33. georgepolowick avatar george kiekens Posted: 8/25/2012 10:09pm PDT

    One example could be a voyager.
    In the first instance here, there could be the electric plane acting a a modified cross between a weather balloon and a space capsule going into LEO. The weather balloon gas would slowly (key work and word being slowly) bring the electric plane up to the mist in near space, while the solar powered engines would provide distance. Even the mist and turbulence to push against would be enough.Then using a space sail, of a thin gas filled sail, like a thin balloon, the electric plane could 'sail' near space, through the mist that separates the atmosphere from space. Then the plane could drop slowly with the electric engines giving distance and the sun giving power, unlimited power at that altitude.
     
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  34. john_v avatar John Voelcker Posted: 8/26/2012 9:27am PDT

    @George: This is your friendly site moderator here. I have removed three out of your four comments because they make blanket and insulting assertions about an ethnic group (the Chinese in this case) and a commenter in particular.

    You're welcome to resubmit the comments without those elements.
     
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