Why battery-powered aircraft will never have significant range

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Vigilant1

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. I'm not talking about VTOL, that is a power hog. I'm again referring to a conventional STOL airplane somewhere between the size of a Caravan, a Twin Otter, or Dash 7. But using the propwash from the multiple propellers (combined with big DH double-slot flaps) to increase the lift significantly.
Interestingly, the 'challenge' with electric flight is energy density, not power. It's pretty easy and cheap to get a big, short burst of power with electricity (the Tesla acceleration trick is an example, it's just a by-product of the battery size they need for practical range. The bigger motors aren't especially expensive or heavy as a share of the whole vehicle). In this respect, the 'extra stuff" needed for an electric VTOL is less than for an IC VTOL. In either case, the 'V' portion of a trip might only account for a few percent of the flight time, and not even a large percent of the energy use.
I suspect that we may find that there is a business case for a small number of short range, small payload E-VTOL to serve a very limited matket.. Maybe 50 miles, 4 people, backyard to rooftop/100'x100' lot. Land is expensive where there is a concentrated amount of big money, and folks with big money will spend some of it to avoid sitting in traffic. Eventually, if battery tech gets cheaper, the benefits will become more widely available.
 
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Dan Thomas

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It will take a serious breakthrough before electric flight becomes practical for anything other than a short hop. Perhaps there is one being worked on right now, and the inventors are keeping mum on it, which is a wise way to do things. Too many supposedly revolutionary ideas are promoted using nothing more than CGI and big techie words. One grows tired of the endless promises that are never kept.

The one thing that keeps getting ignored in the discussions about electric transportation of any sort: You need electricity to accomplish it, and existing sources are completely inadequate for electrifying anything more than a tiny percentage of the fleet. Even if a huge gain in battery technology happens, we still need a lot more power generation or the gains are mostly useless.
 

Aesquire

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It's pretty easy and cheap to get a big, short burst of power with electricity (the Tesla acceleration trick is an example, it's just a by-product of the battery size they need for practical range. The bigger motors aren't especially expensive or heavy as a share of the whole vehicle). In this respect, the 'extra stuff" needed for an electric VTOL is less than for an IC VTOL.
Agreed, that's why I was saying that you can use a large(r) motor, and a small(er) battery, for serious STOL & fast climb in a motor glider self launch application.

That also applies to winged VTOL craft like Black Fly, but NOT to the multi-copters. Those are brute force and computers, and the first is power hog.
 

Aesquire

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Too many supposedly revolutionary ideas are promoted using nothing more than CGI and big techie words. One grows tired of the endless promises that are never kept.

The one thing that keeps getting ignored in the discussions about electric transportation of any sort: You need electricity to accomplish it, and existing sources are completely inadequate for electrifying anything more than a tiny percentage of the fleet. Even if a huge gain in battery technology happens, we still need a lot more power generation or the gains are mostly useless.
Totally agree.

On the second part, The Political/Religious aspects that aren't relevant here can be very annoying. I often tell people that the "conversion" from IC/Turbine/Steam... fossil fuel, to Electric Utopia Requires more power generation. Lots more. Double? I often get denial and rage. And the assumption I'm anti progress, or a Cthulu worshiper ( insert the cult you hate here )

I'm not a Luddite on the technology, I was using NASA tech in High school.

I freely admit I'm a Luddite on Social Media. ( One of the Tech Gods & Major Players obviously was "free" because they were selling the customer's information. That the company got started so a nerd could get girls to send him pictures without knowing they were I learned later when the Movie came out. Scam from the beginning )

Every BTU or Watt equiv. you replace in Vehicles, no matter how you measure it, has to be replaced by 20%+ MORE power generation to the grid that charges them. That's hard physics, no amount of dreaming or battery breakthrough or aerogel LED technobabble can change that.

But if you accept that, you can do wonders. Small, short ranged, expensive wonders, but still.

In Airplanes we have had the luck to be parallel in time with automobiles. So the liquid fuels are broadly compatible.

For GA size and power density needs, Steam is Assumed to be too heavy. That's true, but small scale vehicle steam engines couldn't compete with the ease of IC. So we don't have a century of refinement. Flash boilers and turbines? Steam Turbines were a game changer in ships. The biggest advantage of Steam ( external combustion, working fluid whatever ) is there is no Octane, etc. need. If you can burn it fast enough, it works. Wood chips, coal, Hydrogen, mammoth patties.

Turbines don't scale well to the low ( 80-300 ) horsepower needs of existing airplanes ( which evolved with IC ) mostly because of fuel consumption. Again, there wasn't pressure to develop light efficient 160 hp turboshaft engines to replace Lycosaurs.

So, in loose lockstep with automobiles, IC became the Norm.

( Time Machine the engine from a SubSonex back to the Wright brothers. They couldn't duplicate it, but what difference it could have made? )
 

EzyBuildWing

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Latest Tesla is ".......absolutely ridiculous" ..... 9.3 seconds quarter-mile, 1.9 seconds to 60...... regulations require a parachute if dragging at local drag-strip.....!!!
Steering "Yoke" has replaced the steering-wheel.......
Battery tech getting better......
Vid certainly worth watching!

 

Dan Thomas

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Latest Tesla is ".......absolutely ridiculous" ..... 9.3 seconds quarter-mile, 1.9 seconds to 60...... regulations require a parachute if dragging at local drag-strip.....!!!
Steering "Yoke" has replaced the steering-wheel.......
Battery tech getting better......
Vid certainly worth watching!

Completely irrelevant. It will never fly. This belongs on a hot-car forum, not HBA.
 

Saville

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Latest Tesla is ".......absolutely ridiculous" ..... 9.3 seconds quarter-mile, 1.9 seconds to 60...... regulations require a parachute if dragging at local drag-strip.....!!!
Steering "Yoke" has replaced the steering-wheel.......
Battery tech getting better......
Vid certainly worth watching!

Dan is right and it has already been explained to you in detail why Tesla drag strip runs are irrelevant for electrical aircraft. So why you keep posting these things is a mystery.
 

Pilot-34

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Dan is right and it has already been explained to you in detail why Tesla drag strip runs are irrelevant for electrical aircraft. So why you keep posting these things is a mystery.
You have to have the imagination to imagine something new to get something new.
Right here is why Tesla dragstrip runs are important
It will take a serious breakthrough before electric flight becomes practical for anything other than a short hop. Perhaps there is one being worked on right now, and the inventors are keeping mum on it,……..
Look at the black fly ,scale it up to eight people and an hour of flight.

Suddenly you have a high-speed commuter from the outlying airports and suburbs to central downtown.

and at less than helicopter costs.
 

Saville

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You have to have the imagination to imagine something new to get something new.
Right here is why Tesla dragstrip runs are important


Look at the black fly ,scale it up to eight people and an hour of flight.

Suddenly you have a high-speed commuter from the outlying airports and suburbs to central downtown.

and at less than helicopter costs.
I can imagine aircraft powered by electric motors. I don't need Tesla dragstrip runs to imagine those. And I know that Tesla dragstrip runs are meaningless with regard to powering cruising aircraft.

And "scaling up the black fly" is right where the performance problems appear. So just "imagining" a scale up isn't practical. That's been discussed a lot in the thread.

There has been voluminous discussion in this thread about:

"high-speed commuter from the outlying airports and suburbs to central downtown."

including costs, infrastructure, whether or not a market exists.....etc.

I'll believe in them when I see them.
 

Aesquire

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Less than helicopter costs....

So what's the price multiplier going from single seat, to eight, in airplanes?

Black Fly claims Luxury SUV prices. That means from $70-120k. Have there been Any sales to show an actual price tag?

Going from 1 to 2 seats shouldn't double, quite, the cost of an airplane. From 1 to 8, ten times? twenty?

So few million dollars for a nice roomy short range substitute to a Cessna 208? That's a 2.45 million dollar plane, so that's quite the bargain. Imaginary craft often are, but once carbon fiber starts getting laid in molds...

I remind myself not to be overly pessimistic. Electric commuter VTOL robotic service and my car's extended warranty might happen!
 

Dan Thomas

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So few million dollars for a nice roomy short range substitute to a Cessna 208? That's a 2.45 million dollar plane, so that's quite the bargain. Imaginary craft often are, but once carbon fiber starts getting laid in molds...
I think the price starts rising even before the layups start, as regulations make themselves felt and lawyers get involved. The price rises steadily until the bugs have finally been worked out of the prototypes and production lines have finally been set up. Then the price rises in smaller jumps as production proceeds, then in bigger jumps as they find that they've priced themselves out of most of the market and they have to make fewer airplanes each deliver more money to cover expenses.

Imaginary airplanes are always affordable.
 

Dan Thomas

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I take great exception to this statement. In today's world we MUST be inclusive. Tesla has indeed earned its place on the HBA forum (i.e. Hot Boat Anchors).
Yup. I found this:

How much does a Tesla weigh? (Model S, Model 3 & Model X) Tesla model S weighs about 4,647 lbs (2,107 kgs). while models 3 and X weigh 3,552 lbs (1,611 kgs) and 5,421 lbs (2,458 kgs) respectively.

Those are empty weights. How well would such a machine fly, even if it had wings and a propeller?
 

tallank

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Latest Tesla is ".......absolutely ridiculous" ..... 9.3 seconds quarter-mile, 1.9 seconds to 60...... regulations require a parachute if dragging at local drag-strip.....!!!
Steering "Yoke" has replaced the steering-wheel.......
Battery tech getting better......
Vid certainly worth watching!

You are confusing power versus energy. The amount of energy a battery can hold is the limiting factor, not the power you can get out of it for 10 seconds.
 

Victor Bravo

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Imaginary airplanes are always affordable.
^^^^^^^

And right there is the name for the new forum category, the official HBA bumper sticker, the T-shirt, the movie/cable/TV/book title, the motivational poster, the radio show, the podcast, the Blog/Vlog/Hog/Frog, the "white paper"", the TED talk, the sound bite, the investment prospectus, the congressional hearing, the lawsuit, and the epitaph on the gravestone.
 
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