Why battery-powered aircraft will never have significant range

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Aesquire

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After all this time, I think I can confidently say the Thread Title is Wrong.

It's probably Right, today, depending upon your definition of significant.

I'm going to propose using the Olde idea of airplane range.
New York/Philadelphia/D.C. Urban corridor to Chicago.

DC-3 range. There's a reason Chicago is the Air Transport Hub. Inertia. That's a 1930s system, and it won't change as long as Illinois has Senators. No one today would pick a crud weather location for a hub.

But that early airliner range gives us a fair metric for useful flight distances.

For commercial use!

Recreational flying doesn't have the time constraints, the urgency, nor the time bound schedule aspects, usually.

It's not a big change in customer inconvenience to get off a plane at gate 6 & trot to gate 2. The airplane you just ran away from can then get sanitized, cleaned, and restocked with stale pretzels in tiny bags, while it's recharged/refueling. The hours of downtime the Airline has to factor into their schedules can be transparent to customers. ( except in ticket price )

I'll point out that if the plane will spend 4 hours on the charger, there's no excuse NOT to pay a team to vacuum & wipe up & deodorize. I'd argue a dirty E-Bus airline can't be trusted to care about your health in smells or maintenance.

But private flying you aren't swapping airplanes at lunch and urination breaks. You are in the same quandary as Tesla owners. You need to go from charger to charger. And wait.

Or leave the plane/wait while a paid service person drives a truck with a diesel generator to your plane. ( or car ) Rich people can do that. They can also pay to have precharged cars/planes waiting for them. I'm not on that Venn diagram. But if you consider Bugattis as impulse buys, you enjoy.

I'll speculate that until an Electric airliner, ( Fokker size, not 747 ) has the range to do JFK-ORD they'll be boutique toys for self absorbed virtue signalling. I'll be less rude about private pilots with Electric light planes. You might be just a fellow tech nerd with money. ( unlike me, who doesn't ) And I'm all in favor of electro -fleas and Black Fly and motor glider applications.

In time, things will change.

On a theoretical question. We talk energy density. Btu/watts/etc. per Pound/Kilo.

But what if they develop a battery with, say, 3 times the Kwh per Kilogram of a current ( Tesla/phone ) chemistry battery, but 3 times the Volume? Not Aerogel light, but much less than gasoline or Lithium Polymer?

I'd think you'd try to fill the wing or the front 1/3 with battery.
 

PMD

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But what if they develop a battery with, say, 3 times the Kwh per Kilogram of a current ( Tesla/phone ) chemistry battery, but 3 times the Volume? Not Aerogel light, but much less than gasoline or Lithium Polymer?
To be competitive with wildly inefficient turbines, you would need more like 30 times the current energy density - something that is simply not feasible. To be competitive with the ONLY logical light airplane power (i.e. diesel) make that something like 50x.

In a world where good and bad design is measured in ounces, adding TONS of ultra-polluting, explosively unstable garbage to a light airplane is somewhere beyond daft.
 

Saville

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“ I will believe in them when I see them“
Isn’t that what people said to Morse when he said he could send messages through the sky?
I don't know I wasn't there..were you?

And because one person did one thing that some thought was impossible does not mean that all such attempts will succeed.

And of course I include the seemingly obligatory line that I'm not saying it's forever impossible; not saying I don't want it; not saying it oughtn't be researched etc. etc. etc.
 

Aesquire

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To be competitive with wildly inefficient turbines, you would need more like 30 times the current energy density - something that is simply not feasible.
Competitive in energy density, yes. But competitive in overall performance is a bigger picture. Why aren't small turbines used in Cubs, Kitfoxes, and trikes? Fuel burn. ( and scale effects ) The IC engine rules at our scales, the small light 1-2-4 seater. A RV-10 was flying with a turboprop. So the 4 seat segment is possible, but expensive. In multiple ways.

Much like electric.

For our purposes fuel costs are typically a small percentage of costs. I've seen some Rocket and other fast light planes brag of Prius or typical car miles per gallon efficiency, but that's unusual.

Today's & Tomorrow's fuel cost rise is political mostly, and the causes beyond our concern, here, but the facts of fuel cost is our concern.

If it's just a $10-40 recharge then the cost of fuel @ $20 gallon starts to offset the high price of batteries.

If your ability to get that electricity is rationed by the State, that also changes the equation. See California. It's not yet to the point of "third world" dystopian post apocalypse neo-aristocracy hells where only the rich enclaves get power . Yet. ( unlike the partially completed, and then stopped water system ) And the politics of that best not discussed, lest it inflame bowels.

The point is that a Single factor is seldom the only reason for engineering compromises. There may be one dominating factor.

And my Question was an Engineering one, low mass density ( but higher power to weight ratio ) energy storage. What would You Do with that change?

It's hypothetical today, but might be important next year. We don't know which technology will succeed.

Cars ALSO have packaging issues. The extra bulk and lower efficiency of the air conditioning system that used air & not phase change fluids kept that potential advance from catching on in cars. Better, but bulkier, batteries would give you more minivan or pickup truck designs to compensate.

How does that change affect planes?
 

PMD

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Competitive in energy density, yes. But competitive in overall performance is a bigger picture. Why aren't small turbines used in Cubs, Kitfoxes, and trikes? Fuel burn. ( and scale effects )

How does that change affect planes?
Incremental differences affecting range, weight, performance, etc. are things IMHO that exist in practical terms in single digit percentages. When we are talking thousands of percentage points difference in energy density, it is time to stand back and realize that virtue signalling has no place in engineering. Sadly, it IS the world of politics and junk-pop-media, so it WILL affect aviation - and in an extremely negative way.

The question of turbines in little airplanes is "what is the MISSION?" It it is to bore holes in the sky, have some jollies and you've got the cash, then there certainly is a place for such things in E/AB 1-4 place world. One of my friends has built an 8 place Walter 601D powered E/AB, but it's required range is only a hundred and some-odd miles from bush cabin near road to bush cabin near absolutely nothing but a lake. The net payload it can lift works out very well with 900HP and a combined weight of not much fuel and a very light engine/prop. IF you are actually hauling people or cargo any distance, my rule of thumb is that a turboprop comes on par with a diesel at about 4 hours total mission length. If you do very long range flights in little airplanes (my personal passion) then turbines are impossible. Now, back this up into an electric propulsion system, and the same considerations apply, but the range/endurance for parity becomes laughably short.

Then, of course, there is the outside influence. Being forced into Lithium Ion batteries by the virtue signalling crowd, you are putting a TON of garbage into a little airplane that in a POUND or so can easily burn down a 777. Worse yet, THE MOST POLLUTING thing we do in the world of transportation is mine lithium. Finally, the whole idiotic trend to carbon demonization with nothing practical as a replacement means turning to truly stupid solution of an extremely dangerous, expensive and polluting material that has no where near enough known or expected reserves to come anywhere NEAR the political idiotic goal of converting everything to battery power.

It is IMHO our absolute obligation as people able to think clearly enough to design and build flying (driving and floating) machines to stand up to the absolute idiocy of the whole lithium culture.
 

tspear

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For commercial use!

It's not a big change in customer inconvenience to get off a plane at gate 6 & trot to gate 2. The airplane you just ran away from can then get sanitized, cleaned, and restocked with stale pretzels in tiny bags, while it's recharged/refueling. The hours of downtime the Airline has to factor into their schedules can be transparent to customers. ( except in ticket price )

I'll speculate that until an Electric airliner, ( Fokker size, not 747 ) has the range to do JFK-ORD they'll be boutique toys for self absorbed virtue signalling. I'll be less rude about private pilots with Electric light planes. You might be just a fellow tech nerd with money. ( unlike me, who doesn't ) And I'm all in favor of electro -fleas and Black Fly and motor glider applications.
I believe you are wrong. The two types of electric planes that are the most advanced in both production or development are commercial only.
One side is lead by Pipestrel focused on flight training, charge time goal in that market is one for one. one minute of charging for one minute of flying, They have already attained a solid 1 hour performance which is viable for pattern and other basic training. They only need to double the battery capacity to cover the super majority of flight training. In you go back through the thread, you will find where Pipetrel videos show they are not even using the latest tech in the current battery cells. So this is viable in a few years.
Second is lead by multiple companies looking at short haul; the target customers are Cape Air, fedEx, and UPS. These flights are less then 200 miles, with the majority less than 100. Turn time is just a few flights a day. When you look at Magnix (I think that was the name), they are well along on the fedEx/UPS side. On the commercial airliner, you see this: Cape Air Prepares To Operate Eviation's Alice Electric Commuter

I see personal aircraft much further behind these fixed operations. Because there is a lack of a charging network.

Tim
 

Dan Thomas

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I had a look at that. They call it a "revised" design of the original Alice. Wow, is it revised. The original thing had so many drawbacks it wasn't funny. Props on wingtips; imagine crosswind takeoffs or touchdowns. A prop behind the tailwheel, chewing up debris flicked up by the tire. Conversion from trike to tailwheel?? CG problems from more batteries, maybe? It caught fire and was destroyed before it ever flew.

Original:
1627665549460.png


"Revised:"

1627665615528.png
 

Dan Thomas

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Yeah, I thought the original design was a solution looking for a problem.

Tim
It would have found more than one problem, for sure. Achieving electrified flight is difficult enough without introducing a bunch more stupid risks.
 

John.Roo

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I had a look at that. They call it a "revised" design of the original Alice. Wow, is it revised. The original thing had so many drawbacks it wasn't funny. Props on wingtips; imagine crosswind takeoffs or touchdowns. A prop behind the tailwheel, chewing up debris flicked up by the tire. Conversion from trike to tailwheel?? CG problems from more batteries, maybe? It caught fire and was destroyed before it ever flew.

Original:
View attachment 113669


"Revised:"

View attachment 113670
Original design has been used to attract investors. I have been told many times that "investors are looking for something new". I totally agree that previous design has been looking for many problems, but new design is too "normal". I definitely prefer the "new" version, however do you think that "new" version looks like something special? Two engines, "T" tail...
But who cares - anyway is just a new nice rendered drawing :cool:
 

Pilot-34

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Most of me is in IL but my hearts in Alaska
Another thread let me to the study of flying submarines
Now it seems like Electric propulsion would be the perfect match for James Bond in his new flying submarine car.
Just think of the specifications
200 miles of road range just enough to get from the airport to the casino.
25 miles of flight just enough to get away from the bad guys.
10 miles of underwater travel just enough to sneak into the bad guys lair.
 
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