Why battery-powered aircraft will never have significant range

[Dan Thomas]

They built new stuff, rushed it to market and had cell-phone batteries exploding.

Exactly. They made promises they couldn't keep. We get tired of that. Suppose they'd been building electric airplane batteries?

GPS is so good people have died on obscure roads, or going over incomplete bridges.

That's not a fault of the GPS system. That's a fault of the people programming the maps in the GPS receivers. Aircraft programmers don't make mistakes like that. For one thing, we're not flying on dead-end roads or closed bridges. We're in the air, following a flight plan we programmed into it, and we're supposed to make sure we know where we're going and what terrain might be in the way. Modern systems will warn you of approaching terrain, but you should have known about it anyway. Suppose the GPS had died when you're flying in IMC and approaching terrain? You die if you haven't studied it.

Aluminum/Air batteries are light enough and powerful enough, but they have to be completely recycled.

They have been telling us about aluminum/air batteries for way too long already. From Wikipedia:
Aluminium-powered vehicles have been under discussion for some decades.[2] Hybridisation mitigates the costs, and in 1989 road tests of a hybridised aluminium–air/lead–acid battery in an electric vehicle were reported.[3] An aluminium-powered plug-in hybrid minivan was demonstrated in Ontario in 1990.[4]

No idea about these Lithium/Air batteries, but the potential exists, as long as big money doesn't buy the rights and bury them.

Why would they? There would be far more money in producing them.

That said, you're still griping, demanding proven technology...

Oh. So it's wrong to demand proven technology? What was it you were saying about cellphone batteries rushed to market, then finding that they exploded? Are we supposed to be fine with unproven technology that explodes in your pocket? Or electric airplane batteries that catch fire in flight? Do we want new technology so bad that we're prepared to risk our lives, and those of our passengers, as guinea pigs in experimental machinery?

 

[Pops]

I want new technology. I don't want hollow promises of new technology.

I got my IFR ticket flying the old "steam" gauge panels. That takes a lot of brainpower, interpreting needles and numbers to create a picture in your mind as to where you are and where you are going and what the airplane is doing. When I flew the Garmin glass G1000 stuff, with it all drawn out for you, the workload went way down. Really nice, really expensive, really bad if it quits and you got your ticket on it and now you have to fly the standby gauges.

Fuel injection sure made the engine smoother, too, and eliminated carb ice. LED landing and nav lights made the jobs of both the pilot and mechanic a lot easier. Modern multigrade oils with their anti-scuffing additives sure made the engine last longer and over a wider temperature range.

I'm old enough to have learned to fly in some airplanes that still used vacuum tubes in their radios. Still had generators that didn't generate below 1200 engine RPM so that your lights and radios drained the battery before you got off the ground at night. Navigation was by ADF and VOR instead of GPS. None of that was any fun and I don't miss any of it.

The difference is that they built this stuff, made it work, and sold it to us. They didn't make big promises and make us wait decades for it.

Nothing will make you appreciate modern equipment more than flying IFR with an ADF where you have to fly outbound and do procedure turn back inbound in a strong crosswind. Or trying to taxi in at a larger airport at night time and try to keep the rpm's up high enough to keep the generator on line but trying to keep the speed down with the old weak brakes. If not, tower can't see you because of your dim lights.
Is that some of the things that make it the good old days ?

 

[J.L. Frusha]

Yet people ARE working on the problem and trying to solve many aspects of the overall big picture.
Variable thrust? How about using multiple electric motors, cutting some off at cruising speed with folding props?

Latest NASA design...
~3 ft 8 3/4 in diameter prop disk, yet only ~8 3/4 in diameter pod, when folded...

 

[J.L. Frusha]

How many ways can electronic GPS fail?

Ever watched "The Core"?

 

[Saville]

BOOM! This just blew things the other way...

J.L

I think this is the problem and why you are getting so much pushback from people: Your sentence above.

We've heard THAT zillions of times for decades and nothing came of the zillion pronouncements of game-changing events.

Had you just posted the article and said something without the hyperbole I would have thought - "Interesting
lab experiment. No problem with lithium? Hope it works out". I can't speak authoritatively for the others but I suspect you would not have gotten the strong pushback.

But we've heard "BOOM" too many times, on things that turned out to be vaporware, across decades. So some of us are skeptical of massive claims. Especially when it's a lab experiment and not hundreds of production items coming out the factory door.

I have to tell you that I didn't even bother to read the article because of how you started it.

 

[Sraight'nlevel]

Batteries are lame that is for sure.

Is there any other way to gain range with them ?

How about a dolly launch...or a system with a catapult on a dolly...kinda like shooting the craft first to several hundred meters altitude with great speed ???

Could something be gained with that ?

 

[Saville]

Batteries are lame that is for sure.

Is there any other way to gain range with them ?

How about a dolly launch...or a system with a catapult on a dolly...kinda like shooting the craft first to several hundred meters altitude with great speed ???

Could something be gained with that ?

Yes but how many of these launchers do you imagine would have to be built to satisfy a flight rate equivalent to ICE now?

And how are they powered?

How many per airport will be needed to replicate the takeoff rate at airports?

 

[Sraight'nlevel]

Yes but how many of these launchers do you imagine would have to be built to satisfy a flight rate equivalent to ICE now?

And how are they powered?

How many per airport will be needed to replicate the takeoff rate at airports?

Ok....well how much would the efficiency be bettered...25% ?

 

[blane.c]

Batteries are lame that is for sure.

Is there any other way to gain range with them ?

How about a dolly launch...or a system with a catapult on a dolly...kinda like shooting the craft first to several hundred meters altitude with great speed ???

Could something be gained with that ?

"Battery Barge" semi-buoyant barge filled with batteries and hydrogen gas towed by the aircraft.

 

[Saville]

Ok....well how much would the efficiency be bettered...25% ?

Well you'd have to answer my questions first before you can calculate that. You can't just look at the isolated aircraft and specify a savings and call it a day. You have to analyze the entire system to know if it produces an actual savings.

 

[AllenW]

Yup, just like the carburetor in the 1970’s that, when installed on any 8 cylinder, got 120 miles per gallon. Never available because the gasoline companies bought it and hid it. Yup, just like that.


BJC

I thought it was the carburetor that allowed cars to run on water that got buried. Of course, now that water is more expensive than gasoline in your grocery aisle, they may be bringing it back.....

 

[AllenW]

I’ve been wondering, what would a ‘practical’ electric cross country two-seater look like? To be practical I’ll arbitrarily say it has to be able to go 1000 miles between sunrise and sunset and has to be able to fly when I want, not having to wait for ideal conditions (thunderstorms and icing notwithstanding).

Why limit the time period between sunrise and sunset? See Solar Impulse 2, which has (had?) batteries to allow continued flight in the dark. But....it's a little slower than you want. And more fragile.

 

[Jay Kempf]

Yet people ARE working on the problem and trying to solve many aspects of the overall big picture.
Variable thrust? How about using multiple electric motors, cutting some off at cruising speed with folding props?

Latest NASA design...
~3 ft 8 3/4 in diameter prop disk, yet only ~8 3/4 in diameter pod, when folded...

View attachment 121230

View attachment 121231

Yeah the whole tip propellers are going to counter spin and thereby eliminate the tip vortex thing. Well, those motors out there are considered prime risk to the FAA so what are you going to do when one fails locked rotor instantly? Only the flying pancake every did this successfully. All others that were like that like Alice abandoned the configuration. It doesn't pass the smell test. And all those little props? Sure easier to do with electric than a cross shaft or a bunch of IC but still a whole lot of mechanical overhead and a whole bunch of less than efficient props. And the structural fraction for batteries just keeps going down while the need to feed current to electric motors is going up.


Will it be more efficient at high speeds? NO. Aspect ratio wins always. Aspect ratio with a whole bunch of electric motor pods taking away any drag benefit you get from aspect ratio... NO. And a bunch of other solid NOs.

Just because this project has a NASA label on it doesn't mean it is anything other than a research project.

 

[J.L. Frusha]

The whole premise of this thread, is that electric aircraft will never fly very far is blown, anyway.

E-genius flew from Stuttgart to Milan - 521.2kilometers.

 

[Dan Thomas]

Yet people ARE working on the problem and trying to solve many aspects of the overall big picture.
Variable thrust? How about using multiple electric motors, cutting some off at cruising speed with folding props?

Latest NASA design...
~3 ft 8 3/4 in diameter prop disk, yet only ~8 3/4 in diameter pod, when folded...

View attachment 121230

View attachment 121231

That thing was first posted here more than five years ago. I haven't heard of any test flights yet. Or anything else about it.

 

[Dan Thomas]

Ok....well how much would the efficiency be bettered...25% ?

W don't need 25%. We need 500%. Or more. Airliners would need several thousands of percent more. A Boeing 777 has two 110,000 HP engines. It can fly ten hours at a stretch, easily. How much battery does it need to run 220,000 HP at maybe 75% power for ten hours?

 

[J.L. Frusha]

That thing was first posted here more than five years ago. I haven't heard of any test flights yet. Or anything else about it.

If you were really interested, you would have tried contacting people about, like I've been doing.

 

[Saville]

The whole premise of this thread, is that electric aircraft will never fly very far is blown, anyway.

E-genius flew from Stuttgart to Milan - 521.2kilometers.

That "premise" was never accepted by the very large majority of posters here including me.

So your comment is an attack on a largely non-existent opinion. I cannot recall anyone posting here in, say the last 6 months (more likely a year)who argued that electrict aircraft will NEVER fly very far.

I can't predict the future - neither can you.

 

[jedi]

The whole premise of this thread, is that electric aircraft will never fly very far is blown, anyway.

E-genius flew from Stuttgart to Milan - 521.2kilometers.

Lindbergh flew more than 10 times as far in 1927, about 5527 km.

 

[Dan Thomas]

E-genius flew from Stuttgart to Milan - 521.2kilometers.

It sure did. A motorglider, in the summer, that takes advantages of the various types of atmospheric lift. It didn't not rely entirely on its batteries and motor. That isn't going to work for the average PPL.

I towed gliders in the 1970. Well-acquainted with ridge (orographic) lift, thermal lift, and lift near storms. I had to drag the gliders around to find the best lift, and circle in it until their pilots were satisfied and released. Some of that lift can be mighty powerful. Rough, too. I once took off, and within about three miles, at 70 MPH, less than three minutes, I had gained 3500 feet. That tug, pulling the glider, could never climb like that on its own. Unpowered gliders often fly hundreds of miles on cross-county flights.