Electric Airplanes

[ncbill]

On a crash landing this thing looks like it would puree the pilot.

"Will it blend?"

 

[Time2]

I did think the propellers should be a little above the pilots head, rather than right at the same level.

 

[NW-Bound]

While weight is an issue in ground based vehicles (cars, trucks, trains, etc.) it's much more important in aircraft as a HUGE amount of the energy involved in flying is 1) Lifting an aircraft initially to its most efficient altitude and 2) simply holding the aircraft up at all times. In ground based vehicles, weight is a small factor in additional rolling resistance and a bit bigger factor in acceleration...

Yes. With a car, once you are up to speed, weight is not as big a factor as rolling resistance and particularly aerodynamic drag when you are at highway speed.

Here's a concrete example. This Tesla X got its range reduced to about 1/2 when towing a little travel trailer. The car weighs about 5,500 lbs, and even more with the driver and passengers. The bitty travel trailer weighs 1,500 lbs. It takes as much energy to move the trailer as it does the car.

What is important is that the lighter travel trailer has the same aerodynamic resistance as the more streamlined car which is more than 3 times heavier.

Both travel trailers cause roughly the same range reduction. One would have thought that the teardrop trailer would do better, but look is deceiving.

This data came out of a test done by edmunds.com. I provided a link to the original article in a post on the "Electric Vehicle" thread.

See: https://www.early-retirement.org/forums/f27/the-electric-vehicle-thread-101783-10.html#post2616028

 

[BOBOT]

This is a very interesting (and informed) discussion.

I saw the NOVA show and was impressed with the commitment of the entrepreneurs, if not with the technological-or economic-prospects. But remember it wasn't so long ago that electric cars, even without being augmented with advanced autonomous capabilities, was a pipe dream. It seems to me that this technology will eventually make business sense for short-haul commuting.

I took a flyer on one of the companies, bought a few shares, just to stay in touch with what's happening.

 

[ERD50]

... But remember it wasn't so long ago that electric cars, even without being augmented with advanced autonomous capabilities, was a pipe dream. ....

A little history lesson. We've had electric cars for over one hundred years, and for a time they were very competitive with the gasoline car. There were even hybrids back then.

The Baker is one of the more popular ones form that time:

https://en.wikipedia.org/wiki/Baker_Motor_Vehicle

https://en.wikipedia.org/wiki/List_of_hybrid_vehicles#Early_designs:_1899-1917

Early designs: 1899-1917

1899: Carmaker Pieper of Belgium introduced a vehicle with an under-seat electric motor and a gasoline engine.[10] It used the internal combustion engine to charge its batteries at cruise speed and used both motors to accelerate or climb a hill. Auto-Mixte, also of Belgium, built vehicles from 1906 to 1912 under the Pieper patents.[11]
1900: Ferdinand Porsche, then a young engineer at Jacob Lohner & Co. creates the first gasoline-electric hybrid vehicles.[12]
1901: Jacob Lohner & Co. produces the first Lohner Porsche, a series of gasoline-electric hybrid vehicles based on employee Ferdinand Porsche's novel drivetrain.[12] These vehicles had a driveline that was either gas or electric, but not both at the same time.
1905 or sooner: Fischer Motor Vehicle Co., Hoboken, NJ produces and sells a petrol-electric omnibus in the United States and in London, including battery storage.[13]
1907: AL (French car)
1917: Woods Dual Power Car had a driveline similar to the current GMC/Chevrolet Silverado hybrid pickup truck.

-ERD50

 

[NW-Bound]

Yes, electric cars were around in the early 1900s. Here's a photo of a charging station, back in 1910.

It is the lithium battery that brought back the EV, this time with enough energy storage to go a few hundred miles to allow competition with the ICE car. However, as discussed in the Electric Car thread, the EV still trails the ICE car badly for some applications. Another factor of 2x or 3x in battery improvements is needed.

When it comes to airborne applications, the electric plane is at the same stage as the EV back in 1910: barely useable for short distance commute, and that's it.

A huge improvement is needed before we can see the electric plane used for commercial air transport.

As the video in the OP noted, the energy needed by a 737 has to be stored in a battery currently weighing 1.2 million pounds.

 

[NW-Bound]

... In rotary aircraft (helicopters) I think I've heard that as much as 75% of the fuel is used JUST to keep the aircraft at altitude. In conventional aircraft, I'm sure the proportion needed to keep the aircraft aloft is considerably smaller but still WAY more important than weight is in a car/truck/bus, etc...

It may not be common knowledge, but a helicopter takes a lot more power to hover than it does in forward flight.

A small chopper may take 2x as much power to hover out of ground effect compared to when it flies forward at around 70 mph.

When within a few feet of the ground, it takes a chopper less power to hover due to ground effect.

At higher and higher speed, the power requirement goes up again, but the chopper may be flying at 150 mph before it needs the same amount of power as it does at hover.

Many of the electric planes are of the tilt-rotor type, in order to have VTOL (vertical takeoff and landing) capability. With the lift from their wings, they take less power than a helicopter in forward flight, but still need the most power when taking-off or landing.

 

[NW-Bound]

Why do it by air? Or old fashioned rail?

Have we forgotten the Hyperloop?

The Hyperloop is a pipe dream. If people cannot afford a high-speed mag lev track, how do they have money for a mag lev inside a long continuous evacuated tube and all the complexities that come with it?

 

[Koolau]

Yes, electric cars were around in the early 1900s. Here's a photo of a charging station, back in 1910.

It is the lithium battery that brought back the EV, this time with enough energy storage to go a few hundred miles to allow competition with the ICE car. However, as discussed in the Electric Car thread, the EV still trails the ICE car badly for some applications. Another factor of 2x or 3x in battery improvements is needed.

When it comes to airborne applications, the electric plane is at the same stage as the EV back in 1910: barely useable for short distance commute, and that's it.

A huge improvement is needed before we can see the electric plane used for commercial air transport.

As the video in the OP noted, the energy needed by a 737 has to be stored in a battery currently weighing 1.2 million pounds.

Are you suggesting that such improvement IS possible such as to make electrical aircraft possible in the future? I ask this, not to be impertinent. I would simply suggest it IS possible to calculate RIGHT NOW (I can't do it - that's not my area of expertise) if it will EVER be possible to create a battery to power an aircraft on a practical basis. I think it's important to do that calculation NOW (totally theoretical is fine by me - assume everything works, assume no issues with heat, assume it doesn't lose much charge just sitting, on and on - the perfect POSSIBLE battery.) If the theory says "no" then let's put more efforts on other ways to cut FF usage if that's the ultimate goal.

Unless as I suggested above, someone comes up with a practical hydrogen cycle fuel cell (higher rate of electrical production compared to now), it seems unlikely we'll solve the weight issues you mention. I'd like to think I'm wrong but I've done just enough electrochemistry to be dangerous - and skeptical.

I assume that EV proponents DID do the up-fornt calculations and decided it was possible to "get there" in the battery-to-drive-an-EV business. I just want someone to stop and do the electrochemical calculations to see if a battery can be made light enough to power a practical aircraft. I've looked high and low on the net and haven't found a good source that would even suggest it will be possible. Of course, maybe we'll make strides in lightening aircraft with such miracles as carbon fiber EVERYTING.

I found this Forbes article suggesting someone may have discovered the "Holy Grail" of Li batteries. I think it concludes they might theoretically reach a 3X improvement over current technology. And, of course, this if it pans out.

https://www.forbes.com/sites/rrapier/2019/05/16/the-holy-grail-of-lithium-batteries/?sh=65b661773d63

Here is an abstract of a pay article that looks to have done what I want: Calculate the potential energy density of up to 1600+ anode/cathode combinations. The abstract suggest potential energy densities of up to 1000+ AH/kg at 1.5+ volts. I think that's still way too low to create an aircraft battery, assuming one of the combos might prove as good as the theoretical.

https://www.sciencedirect.com/science/article/abs/pii/S240582971931102X

Comments? I'm not against electric aircraft (or electric vehicles in general). I just don't want us think something is possible when perhaps it is not (the battery part, anyway - I'm open minded on fuel cells as potential sources of electricity for (probably) propeller driven aircraft. YMMV

 

[NW-Bound]

Are you suggesting that such improvement IS possible such as to make electrical aircraft possible in the future? I ask this, not to be impertinent. I would simply suggest it IS possible to calculate RIGHT NOW (I can't do it - that's not my area of expertise) if it will EVER be possible to create a battery to power an aircraft on a practical basis...

No, don't get me wrong.

I don't see how it is possible to replace current jetliners with electric planes that can cross the ocean on a single charge, using what we know right now.

But I cannot say what we can or cannot do, simply because I don't know enough about battery chemistry to know the theoretical limit.

Let's say, if in the far future, we cannot find a battery that allows a non-stop flight from LA to London, what we can do easily today, but we can at least do NYC to London, that itself is useful. It will take longer to get there, but when fossil fuel runs out, to be able to get there at all is enough to make one grateful.

So, can we do NY to London with an electric plane? No way with what we know about current battery technology. Maybe in 100 years? I will not live long enough to find out.

In other words, I will not say never, but it's extremely unlikely in one's lifetime.

 

[Redbugdave]

I'm not so sure the rest of the world is ready for this new electric revolution that will bring much more efficiency while saving the planet.

 

[sengsational]

Electric Air "Transportation"

As I mentioned earlier, in R/C flying, ICE has been taken over by electric. I'm seeing the same thing on the horizon for paramotor.

The standard paramotor is two stroke ICE. They're finicky, noisy, and cause more injuries than any other aspect of the sport. The following link has a comparison between traditional and electric power in paramotor: https://openppg.com/compare-top-electric-and-gas-paramotors/

One of the things that's a pain for a paramotor pilot is if they want to fly somewhere in the world, they need to drive themselves there or wash every molecule of fuel out of their engine to (try to) get it shipped. Even then, there have been problems getting paramotors shipped. Shipping batteries can also be trouble, but you might just rent those at your destination. Reminds me of scuba, where you bring all your own gear, but rent tanks.

I think electric air flight will progress from small to large, so saying it take a million pounds of batteries to get a 737 across the Pacific isn't where we are today. We're at the point of having 1 hour in the air instead of 2.5 hours. By the way, the class of "aircraft" that paramotors fit in allows only 14.5 liters of fuel, maximum, so batteries might just catch-up!

 

[Koolau]

No, don't get me wrong.

I don't see how it is possible to replace current jetliners with electric planes that can cross the ocean on a single charge, using what we know right now.

But I cannot say what we can or cannot do, simply because I don't know enough about battery chemistry to know the theoretical limit.

Let's say, if in the far future, we cannot find a battery that allows a non-stop flight from LA to London, what we can do easily today, but we can at least do NYC to London, that itself is useful. It will take longer to get there, but when fossil fuel runs out, to be able to get there at all is enough to make one grateful.

So, can we do NY to London with an electric plane? No way with what we know about current battery technology. Maybe in 100 years? I will not live long enough to find out.

In other words, I will not say never, but it's extremely unlikely in one's lifetime.

Not to put too fine a point on it, but I return to MY main point. I think it would be valuable for "someone" to do that "possible/impossible" in the next 100 years calculation NOW. The chemistry will not change in 100 years. Maybe the weight of the aircraft can change in that time frame, but the POSSIBLE battery chemistry (true battery - charge in - charge out, not "consumables" like H2) will not change.

Suggesting there could be a real "breakthrough" in battery technology is like saying after using petroleum for 100 years in aircraft engines, there will be a breakthrough in liquid fuels and we'll find one that can double the miles flown per pound of fuel. Yeah, I know, liquified H2 would do that and a bit more, but so far, it's only been practical in rockets. What size/weight/issues would you face in a liquid hydrogen fueled aircraft. Reduce it to H2 at 10000 lb/inchsq and you still have weight issues. SO Jet fuel is still safe from any breakthrough liquid fuels - just like (my opinion) it's safe from any theoretical battery - please prove me wrong.

As a non-electrochemist, it appears we are at best about 15X to 25X too heavy for long distance - reasonable velocity electric aircraft right now. We can whack away at that at quite a cost - and end up at maybe 10X to 20X too heavy in 100 years OR we can attack what CAN be done NOW such as improve jet engines, lighten airframes, improve aerodynamics, improve airport designs so aircraft never need to circle for traffic overloading, etc. etc. etc.

If I am right (and I'd be glad to be shown to be wrong) there is no point in even thinking about replacing current flight technology with battery driven airliners. Rather than spend a lot of money on improving batteries that CAN'T work in airliners - ever, why not spend the money on improving jet engine technology for instance. I'm BETTING we have WAY more chance of doubling the energy efficiency of jet aircraft than we have for finding a battery 15 or 25 times lighter/AH than we have now. Doubling jet aircraft efficiency puts them in the same league as current EV "MPG" per seat-mile. And your Tesla only goes 70 mph as it gets its 110 mpge (times how ever many passengers you carry on average) vs an airliner like the 787 which already gets around 100 passenger-mpg. at Mach .8+

If reducing the use of FF (because we're "running out" or because of greenhouse gasses or whatever) is the reason to talk about battery driven airliners, we could simply optimize all future airliners for use with turboprops instead of turbofans. The "penalty" would be that speeds would drop from averages of about Mach .8 to about mach .5. Making turboprops "efficient" and increase to Mach .6 on average would likely be simpler (and cheaper) than increasing current .8 Mach airliners to .9 Mach airliners. Point being, for a penalty of speed of about 25%, we could probably save close to 35% or so on fuel - per mile. How much is your time worth? - I guess that depends on your opinion of greenhouse gasses and global warming. But that's another story.

Going back to that article abstract on potential batteries I posted: The theoretical 1000 Whr battery that just might be possible is roughly 4 times as good as what Tesla uses now if my limited research and limited understanding are correct. SO, an EV might get 600 miles/charge and that's great. It still won't fly a 787 equivalent from NYC to London - even if the aircraft is not carrying passengers and luggage.

So, final stab at making my point. Unless I'm (hopefully) wrong, we can stop NOW fantasizing about battery powered airliners. We can stop getting Fed grants to do "research" on them. Start ups can work on other stuff. We can consider all future "stories" on battery powered airliners as pure click bait. We can get back to "practical stuff" like EVs with decent range AND faster charging stations at more locations, and how the heck are we gonna make enough electricity to replace the other 98% of our ICE cars with battery powered cars.

This editorial writer welcomes responsible (electrochemical) replies with differing opinions since YMMV.

 

[sengsational]

So when all we had were NiCd batteries, possible battery chemistry was what it was. Then NiMH came along, and it was roughly twice as good as NiCd. Then Li-ion came along, and it was roughly three times as good. Each time, more things became possible. The bleeding edge battery tech (not consumer stuff) is better yet. It was incremental then, it will be incremental going forward. I see no justification that supports a claim that humanity has found all possible energy storage methodologies. Breakthroughs are still possible. But nobody will every need more than 640K, that's for sure.

 

[FI FELLOW]

anyone ever use a dropping mercury electrode polarograph - well never mind.

Yes, I have, back in academia; not an instrument much in use in industrial labs these days, at least not the ones I've been haunting. Cool instrument as the mercury droplet creates a fresh new electrode with every new drop. No worries about poisoned, drifting electrodes screwing up the measurements.

 

[braumeister]

I have no doubt that I know less about this than most here, but I can't shake the thought that we don't know what we don't know.

Critics of early steam locomotives thought that humans were not designed to go at 50 mph, and that it would be impossible to survive such speeds.

Thinking about how we went from the advent of heavier-than-air powered flight to walking on the moon in less than 66 years lets me stay optimistic.

 

[ejman]

A couple of thoughts come to mind (previously expressed much better by their original authors)
1) You don't know what you don't know.
2) If an elderly, very distinguished scientist says something is impossible, it is about to happen.

 

[ERD50]

Not to put too fine a point on it, but I return to MY main point. I think it would be valuable for "someone" to do that "possible/impossible" in the next 100 years calculation NOW. The chemistry will not change in 100 years. Maybe the weight of the aircraft can change in that time frame, but the POSSIBLE battery chemistry (true battery - charge in - charge out, not "consumables" like H2) will not change.

Suggesting there could be a real "breakthrough" in battery technology is like saying after using petroleum for 100 years in aircraft engines, there will be a breakthrough in liquid fuels and we'll find one that can double the miles flown per pound of fuel. ... .

Quite a few years back, one of the posters here, a ChemE, did some analysis of the theoretical limits of chemical batteries. Way over my head, but I guess you can figure some maximums based on the energy bands in an element, and its mass and volume. IIRC, the theoretical wasn't something astronomically greater, and of course that doesn't count the support structure, or whether those materials cold stand up in a vehicle environment, or blow up the first time you tried to recharge, or just disintegrate.

So when all we had were NiCd batteries, possible battery chemistry was what it was. Then NiMH came along, and it was roughly twice as good as NiCd. Then Li-ion came along, and it was roughly three times as good. Each time, more things became possible. The bleeding edge battery tech (not consumer stuff) is better yet. It was incremental then, it will be incremental going forward. I see no justification that supports a claim that humanity has found all possible energy storage methodologies. Breakthroughs are still possible. But nobody will every need more than 640K, that's for sure.

Yes, but I think breakthroughs in an area like this are becoming less and less common, and more incremental. We (well, the really bright people among us, not me) have a good understanding of the theoretical limits, and what it might take to get closer. Sure, there can still be surprises, but I wouldn't hold out a lot of hope.

I have no doubt that I know less about this than most here, but I can't shake the thought that we don't know what we don't know.

Critics of early steam locomotives thought that humans were not designed to go at 50 mph, and that it would be impossible to survive such speeds.

Thinking about how we went from the advent of heavier-than-air powered flight to walking on the moon in less than 66 years lets me stay optimistic.

Yes, as I say above - that was a different time and we didn't understand the limits.

...Suggesting there could be a real "breakthrough" in battery technology is like saying after using petroleum for 100 years in aircraft engines, there will be a breakthrough in liquid fuels and we'll find one that can double the miles flown per pound of fuel.

Good point! It really doesn't make sense to apply this hope to only one side!

-ERD50

 

[Koolau]

One of my favorite Lason cartoons is contained in this site:

REMOVED!

It is the way I view the debate on using batteries to operate airliners. I keep mentioning electrochemistry. While it's true we "don't know what we don't know", we DO know the general parameters that govern potential between any one anode and another cathode. Based on that, we can calculate a maximum amount of energy storage that is theoretically possible per pound of said anode and cathode material. I can't do the math, but the site I furnished earlier suggested 1kw/lb is about the theoretical limit. Suggesting that there is some other anode out there waiting for the perfect cathode that will (dare I say it) "magically" provide 20kw/lb is like the cartoon in my opinion. In any case, I wouldn't want to be any place close to the first experiment on these two "miracle" materials when they are brought into close proximity to one another.

My gut says that if we ever DO create an electric airplane, it will NOT be powered by what we would call a "battery." It might be powered by (consumable) hydrogen (a fuel cell) OR perhaps an on-board nuclear reactor. At this point, neither seems very likely, BUT they both DO possess the "theoretical" POTENTIAL energy required to power an airliner. All we need to do is figure a way to up the flow of electricity from current fuel cells OR find ways to shield a nuclear reactor such that it won't weigh more than a current airliner.

By the way, I DO believe in miracles - in the mind of God and the hearts of men. In the physical world of chemistry and physics. I gave up on miracles back when I earned my living as a scientist. Of course, you're free to believe in electrochemical (or other physical) miracles since YMMV.

 

[REWahoo]

^ Anyone else getting virus warnings from this link?

 

[Koolau]

^ Anyone else getting virus warnings from this link?

No, but apologize if my Apple and Norton missed it.

If mods want to kill it, I'll just say the cartoon simply shows a couple scientists studying a set of equations. In the middle of the equations is the statement (something like) "then a miracle occurs." One scientist suggests the other scientist may want to add a bit more detail. YMMV

I removed it just in case. See above summary of the cartoon.

 

[ncbill]

Solid-state (electrolyte) batteries should deliver twice the capacity at less cost than today's liquid electrolyte batteries, plus fast-charge in half the time...still at least 5 years away, but expected to be commercialized.

 

[stephenson]

Here's quick Wiki link for the A330 - pretty typical long haul aircraft - https://en.wikipedia.org/wiki/Airbus_A330

Max Take Off Weight is shown at: 533,000 pounds with about 240,000 pounds of fuel.

Think about batteries ....

So, airships, anyone? MIGHT work since solar arrays could be made to be conformal enough to keep batteries powered.

 

[Koolau]

Here's quick Wiki link for the A330 - pretty typical long haul aircraft - https://en.wikipedia.org/wiki/Airbus_A330

Max Take Off Weight is shown at: 533,000 pounds with about 240,000 pounds of fuel.

Think about batteries ....

So, airships, anyone? MIGHT work since solar arrays could be made to be conformal enough to keep batteries powered.

I've often wondered if airships might be a good fit for SOME air freight applications. At well less than 100MPH I doubt they would be much more than a "curiosity" for passenger service. While it's true that airships have a fairly large surface area that might be amenable to collecting solar power, I'm guessing it would only extend battery range - not truly "recharge" on the "wing" so to speak. I'm guessing NW-Bound could give us a good estimate on this concept.

Airships do have issues other than being slow. They're much more susceptible to the winds aloft and especially "bad" weather. I once watched the INDY 500 and was truly amazed as I watched the GoodYear blimp. Going one direction, it fought the wind for the better part of half an hour to traverse the track. Turning around and heading the other way, the blimp barely got turned around before it was at the opposite end and fighting to turn back around into the wind. I'd guess the return trip was 3 minutes or so.

I actually experienced a fairly similar flight in a Cessna 150 which had a true airspeed around 105MPH. Going to my destination should have taken about 25 or 30 minutes. But a huge frontal system was coming in and the headwinds were so strong that the flight took almost an hour. The return took 15 minutes. It was breathtaking. Slower moving aircraft are very susceptible to winds but YMMV.

 

[LastOfTheBoomers]

The first impact will be general aviation- your basic Cessna 172 engine with all the associated hoses, etc weighs about 390 pounds and makes 150HP. A Tesla motor weighs 70 lbs and makes 375HP. A British company makes a 300HP motor that weighs 20 lbs - still experimental though.

One advantage is charging the batteries during decent. I’ve also thought that there might be some sort of super capacitor used for take off and dropped at the end of the runway - or wireless charging along the runway.

Very exciting to watch this technology take-off! (Pun alert)