The Electric Airplane Is Coming

An anonymous reader writes "The electric car is so yesterday; electric airplanes are coming. A battery electric-powered ultralight aircraft has been flying for the last year. A series-hybrid motor glider and a concept for an all-electric, 50-seat passenger plane were introduced at the Paris Air Show."

Comments

First post from an electric airplane!

[GameboyRMH]

Writing from my Alienware laptop while running Crysis, powered by the cig. port! This is so much fu^H^H NO CARRIER

Amazingly fantastic batteries!

[localman57]

A battery electric-powered ultralight aircraft has been flying for the last year.

Flying FOR A YEAR? Crap. My Volt only goes 35 miles then I have to charge it or burn gas. I want one of those airplane batteries!

Storage capacitor manhattan project

[xtal]

We need this more than any other technology right now, and it's a solvable problem.

Want something to stimulate the economy? That'd do it.

Re:Storage capacitor manhattan project

[Jeng]

We need this more than any other technology right now, and it's a solvable problem

Is it in the same category of solvable problems that Fusion is in?

Re:Storage capacitor manhattan project

[MrEricSir]

The ghost of Osama Bin Laden is wetting his pants over this idea.

Re:Storage capacitor manhattan project

[Teancum]

What will be the one little thing that makes the difference?

Considering that the entire Tokamak concept is a blind alley and needs to be abandoned completely in terms of fusion research. There are some interesting scientific discoveries that are happening with that research and it isn't completely going to waste, but I would be completely shocked if somehow a Tokamak-derived fusion reactor ever became a practical device.

It was a very good idea to try out the ideas to see if they worked, and it wasn't a completely poor choice in terms of thinking it could work. But the sad thing is that after billions of dollars have been spend on that approach at the exclusion of any other potential technology or even philosophical concept that might achieve fusion, it needs to be left in the dustbin of history like the airship. Technological progress is filled with stuff like that, and sometimes it is hard to tell when to call it quits on one philosophy and then try to go another direction.

Not in any practical sense

[jpmorgan]

Not in any practical sense. Weight is critically important in aviation, and kerosene has an order of magnitude higher specific energy than the best batteries.

http://en.wikipedia.org/wiki/Energy_density#Energy_densities_ignoring_external_components

Re:Not in any practical sense

[lyml]

While what you're saying is true (that todays batteries are not energy dense enough). There are other advantages to a purely electric battery system making energy density not the only factor.

1. Higher efficiency of electric motors
2. Lower cost of fuel
3. Lower weight of electric motors

In fact, the article mentions that before it would be feasible to replace fuel with batteries for heavy aircraft battery capacity needs to increase by a factor of 4. When it does the switch-over would be fast due to the very high costs of flying air-planes.

In the meantime, we will have to settle for ultra-light airplanes using battery systems and watch as it becomes feasible for heavier and heavier aircrafts over time.

Re:Hovering Vehicle

[JustinOpinion]

What you're describing will not work. You're trying to violate the laws of physics, similar to proposals of perpetual motion machines. It's a neat thought experiment, in order to identify the problems, but it won't work in the real world.

From basic Newtonian mechanics, we know that for every force there will be an equal and opposite reactive force. A closed system will not be able to achieve motion without an external force: either a force applied to other objects (e.g. pushing against the ground, or pushing against (a.k.a. 'blowing') a fluid like air or water) or by ejecting matter (as in a rocket).

Specifically regarding your design: As I understand it, you basically want an object where internally forces are applied to inclined planes, in order to push the planes 'upwards'. You imagine that this can be done in a way where there is no corresponding opposing force also pushing the object downwards. You try to get around this problem by imagining a decoupling where internal masses are momentarily not touching the main mass: so you have one piece that fires a 'bullet' horizontally, which hits the inclined plane (pushing it upwards). You imply that this means there is no corresponding opposing force. However you mention offhand that you will recover the 'bullets' and reuse them. But if the bullet hits the inclined plane, and pushes it upwards, then the bullet will be correspondingly deflected downwards. When the bullet hits the recovery mechanism, it will impart to it a downward force equal and opposite to the upward force that the inclined plane felt. The two forces will cancel out: the plane is pushed up, the recover mechanism is pushed down.

You can imagine putting the recovery mechanism further away from the inclined plane. But, at best this just creates a time lag between when the inclined plane is pushed upwards, and the bullet-recovery mechanism is pushed downwards. So the vehicle will jolt up-down but on average will stay in the same place and thus will not hover against the constant force of gravity. This is inescapable since the planes and the recovery mechanism are mechanically coupled to one another. The only way to solve this is to remove the recovery mechanism, and let the bullets shoot out the bottom of the object, so that the planes are pushed upwards and the opposing force is carried away by the bullets, out of the object. Of course 'flying' by shooting a gun downwards is generally inefficient, which is why we've invented things like helicopters, which push air downwards instead. That way you don't have to carry around a bunch of bullets; you just use the mass and hydrodynamic properties of the fluid you're flying through.

Slow down.

[MaWeiTao]

Of all the modes of transport available to humans, air travel would be hit hardest by a true fuel shortage. If we were to run out of oil in the next few years the we'd just transition to electric cars. Many, if not most, trains already run on electricity. There are alternatives for shipborne travel, coal, wind, nuclear and possibly even electric. There is, however, no viable alternative for air travel except for dirigibles. Unless, I suppose, someone were willing to give nuclear-powered aircraft a shot. Needless to say, intercontinental travel would get significantly slower for quite a while.

Re:Slow down.

[Grishnakh]

Many, if not most, trains already run on electricity.

No, they don't. They run on oil, just like everything else (diesel to be precise). They merely use a series-hybrid system so they can run the engine constantly and get much more torque than the diesel engine can generate. There's no batteries there. These systems have been in locomotives for many decades now, along with most large construction equipment.

Of course, since the actual propulsion is electric, you could power them from something else theoretically, but what? You need something to generate electricity. Batteries are out, because they don't store nearly enough energy to run a locomotive across the country. Mr. Fusion hasn't been invented yet. So you're stuck with some kind of ICE engine, running on either fossil fuel or biodiesel. Fossil fuel is much cheaper since you don't have to grow it, it's already made for you and waiting for you to pump it out of the ground. I suppose you could use coal somehow, but that isn't as energy-dense as fossil fuel, and it's quite dirty.

There are alternatives for shipborne travel, coal, wind, nuclear and possibly even electric.

Again, you have no idea what you're talking about. Many ships now are indeed electrically-propelled. But where do they get the power from? Diesel engines. Take away diesel and what are you going to use? Nuclear has only been used on one commercial ship in history, and it was a failure due to cost. There aren't exactly a lot of nuclear engineers out there willing to be paid peanuts to babysit nuclear reactors on commercial ships, and that isn't something you want some uneducated guy to be running; think about it: the people who serve as crews on ocean ships aren't usually normal middle-class people you'd trust with a multimillion dollar nuclear reactor where an accident means an environmental catastrophe (remember Japan just a couple months ago?), they're either guys with some screws loose, or desperately poor uneducated people from third-world countries. Nuclear power only works on military ships because the dynamics are completely different: rigorous training, unmatched benefits, the threat of court-martial if you screw up, a nation with the world's largest economy willing to spend a ridiculous sum of money on its military, etc. Nimitz-class carriers aren't cheap to operate.

If we ran out of oil, a lot of things would be very different, and I'm afraid it'd basically be like going back to the Dark Ages in many ways, unless some severe changes were made in time. Perhaps they'd build more nuclear power plants, and power the trains with overhead electric lines the way they do with light-rail systems, but that wouldn't help cars and ships much. They could probably use coal for ships somehow, though that would suck environmentally. They could probably do electric for cars, and everyone would just have to get used to a 50 or 75-mile range and recharging every night. If these things were put in place in time, disaster could be avoided, and we'd just have to make some adjustments to our lifestyles until new technologies (such as orbital solar power generation) could come online to give us cheaper and cleaner energy. However, seeing how political units work, I have little hope that they could avoid disaster.

Re:Slow down.

[bertok]

Sure, energy is fungible.

The problem is that all such methods add a substantial overhead in terms of % loss of energy and as a significant infrastructure expense. For example, it's surprisingly hard to expose microbes to sunlight without fouling issues, or contamination from other microbes. A lot of trivial demonstrations have been done, but a small, short-term project that isn't intended to make a profit is a far cry from doing this on an industrial scale, where the people operating the system are poorly educated country folk.

On top of that, the low overall efficiency means that enormous areas would have to be paved over with the growth medium of these things. It's doable in some places like Australia, Spain, or the United States, but is not viable in many European countries. They're already using that space to grow food!

Bad title

[bigsexyjoe]

The linked article does describe the efforts to create but it emphasizes that they need many advances to make it happen and that it isn't coming for at least twenty years.

Re:So does this mean I can stop seeing those ads

[Grishnakh]

The chain electricity->synthetic jet fuel->combustion engine is about one tenth as effective as electricity->battery->electric engine.

So while battery tech might not be quite there yet, even if wide scale synthesis of jet fuel was already existing, there would still be a drive force towards electric airplanes.

The entire problem is battery tech, and it's not looking like this is going to change any time soon. The efficiency problem really isn't that important, because our crappy battery tech simply makes it completely infeasible to have real electric airplanes: they weigh too much for the amount of energy they store, whereas liquid fuels (whether kerosene/JP1, diesel (yes, there's airplanes that can run on diesel), or a vegetable-derived version of one of these) have a much, much higher energy density, making them useful for aviation. Because an aircraft has to use its power to lift itself up in the air, against the force of gravity, along with its powerplant and its fuel supply, things are a little different than with ground-based vehicles. Powerplants with a high power-to-weight ratio are very important, as is fuel with a high energy density. It's even worse in helicopters.

Right now, there's already a big desire to start moving to electric cars and away from fossil fuels there. However, again, battery tech is the limiting factor. Everything else is a solved problem; high-performance electric motors are no problem, and there's electric accessories available (A/C compressors, power steering, etc.). But we're still a ways from having good battery tech for cars that'll make fossil fuel engines obsolete, and our best electric cars don't even have a 100-mile range it seems, plus the recharge time is a big problem. And electric cars don't come close to matching the comfort or performance of midsize, average regular cars. The battery tech needed for electric aircraft will be another order of magnitude or two better than what electric cars need, so we're really a long way from this goal.

Battery technology that's an order of magnitude or two better than what we have now would literally change the world, as all the other pieces are in place to have electric vehicles. It's the only thing holding us back. But there's no way to know how far away this revolution is. Someone might invent something much better in 10 years, or it might take 200.

Re:SMES

[bwayne314]

You also didn't take into account that the jet-fuel payload decreases throughout the duration of the flight as it is burned up, typically by the end of the flight most of the fuel is gone and the plane is much lighter, resulting is better fuel efficiency. While batteries can't be dumped out of the plane after they are discharged.

Re:LOL

[Grishnakh]

Don't be dumb; there's an infinite number of molecules out there that can be made from the elements on the periodic table. For instance, carbon nanotubes have only been discovered relatively recently, and have all kinds of interesting and useful properties, yet carbon the element has been known since ancient times, and is probably one of the first elements named and understood by scientists when they first invented chemistry. More recently, it's been discovered that you can make nanotubes with boron and boron nitride, which have very different properties from the carbon variety (BN tubes are insulators, whereas carbon tubes are conductors).

http://www.newscientist.com/article/dn13143-boron-nanotubes-could-outperform-carbon.html

This is just the tip of the iceberg. There's an untold number of "metamaterials" out there waiting to be discovered, things which don't occur in nature in any significant quantity, have all kinds of amazing properties, and are made from simple elements that we've known about for ages (boron and nitrogen aren't exactly new discoveries).

Re:Every pound counts

[vijayiyer]

A typical aircraft economy cruise is 55% of peak power. Fast cruise is 75% power. 1 kW would not go all that long of a ways towards powering the aircraft. Also, while the 140 is a beautiful aircraft, it's not exactly a speed demon.

Re:A storage technologyt is not needed.

[wagnerrp]

Kerosene is around 6.7 pounds per gallon, meaning that 50000 gallons of fuel weighs around 335000 pounds, not 34000 pounds. Over 40% of the aircraft's loaded weight is spent in fuel.

How can you say the stupid things you posted? How can you not be bothered to check basic facts?

Re:SMES

[fluffy99]

When you start using units like 'megawatts per hour' to describe energy, nothing else you say engineering related has any credibility.

Huh? When you're talking about electricity *storage* you have to say how long a device can supply the stated power for.

Methinks YOU'RE the one who just dashed your credibility on the rocks of /.

Try megawatt x hours, not megawatts/hour. Using the wrong units hinders your credibility.

Re:SMES

[wagnerrp]

The truth is that a 1 MW/h SMES weighs about as much as a horseshoe.

MW/h. You keep using that word. I do not think it means what you think it means.

none of which I bothered to take into account, because they only help my case.

Nothing can help your case if you can't keep your god damned units straight. It makes you look like someone who is just regurgitating crap they read off some internet webring, without understanding any of its implications.