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Elon Musk's Next Great Idea? Electric Air Travel (bgr.com)
An anonymous reader writes with this excerpt from BGR: Elon Musk is changing the world one idea at a time. First, with Tesla, the man so many people call the real life Tony Stark has done an incredible job of bringing electric vehicles to the mainstream. Second, Musk has been doing an impressive job over at SpaceX in the realm of space travel. And third, Musk's effective rough draft of a high-speed transportation system known as the Hyperloop is being contemplated and conceptualized in a very real way by some extremely smart people. So where does Musk go from here? Why, Mars of course. Recently, Musk said that he plans to unveil SpaceX's Mars roadmap next September. But on another front, Musk has also been thinking about developing an electric airplane capable of taking off and landing vertically. While answering a few questions during a Q&A session at the SpaceX Hyperloop Pod Award Ceremony last week, Musk was asked what his 'next great idea' was. The answer? Electric-powered air travel.
for this to work!
ELON MUSK SPEAKS!!
An electric airplane sounds like an interesting idea, especially for short hop flights...
It also seems like it would be a nice case for fuel cells because you have a much more limited need for fueling stations (basically just airports) and it would be easier to store enough energy for a moderately long flight.
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Batteries do not have the energy density of jet fuel. The primary thing that matters here is energy density, which has two forms, energy per mass and energy per volume. https://en.wikipedia.org/wiki/Energy_density Both need to be much better than they are today for electric airplanes to have any chance (lifespan and and number of cycle uses also need to improve but that's in some ways less of a barrier.) Energy density of batteries by both metrics batteries has increased by 5%-10% a year depending on the exact metric and choice of examples https://www.quora.com/Is-it-true-that-battery-energy-density-improves-5-8-per-year which is exponential growth ( but with a much slower doubling time than something like Moore's Law. One has a doubling about once every 8 or 10 years.) Jet fuel has an energy density of around 45 MJ/kg, The most efficient batteries have a little under 1 MJ/kg. So one needs at least about 5 doublings before batteries can reasonably compete which will start to occur if they have an energy density of around 32/ MJ/kg. Similar remarks apply to energy density measured by joules per volume. However, there are technical reasons to think that batteries will stop doubling before that (see theabove quora link for details which argues that we can't make batteries much than four times as efficient before we start running into serious theoretical limits). At around 20 MJ/kg, one maybe could run planes practically but they would be much less convenient and practical than today's jets and that would be at the very upper end of the plausible limits just from a straight energy density estimate.
However, the situation is even worse than that. When you use jet fuel, you use it up. Depending on the type of airplane, at take off fuel is generally 25% to 50% of the mass of the plane. So one gets serious savings that one doesn't have to move all the used fuel the entire way. That doesn't work with batteries: they are the same mass and volume whether or not they are charged, and dumping them would defeat most of the point. It might be possible to do some sort of staging approach where one uses some set of batteries to nearly empty and then have them break off in a modular plane that returns to the ground site. But that itself would lead to all sorts of additional problems.
So it is likely that we will still see fossil fuels used for jets for the next 40 or 50 years. Indeed, it is likely that they will be the very last use of fossil fuels.
The Department of Defense thanks you for your suggestion of the solar powered electric submarine. Unfortunately, our calculations indicate that it would be unable to dive deeper than 6 inches, while still receiving sufficient power. Also, it would need sufficient surface area for solar collectors that it would be unable to turn around in a space smaller than the Mediterranean Sea. For these reasons, we believe it is impractical at this time. Sincerely.
I doubt very much he will ever make an electric fan that can pull an aluminum (or even composite) tube through the air at supersonic speeds. Propulsion tech is going to have to take a pretty dramatic leap for it to happen. Find a way to move air using electrostatic force, maybe...
“He’s not deformed, he’s just drunk!”
Does anyone actually refer to Elon Musk as "the real life Tony Stark", other than some fanboys here on Slashdot? Because this is the only place I ever see it - although you can certainly rely on it happening here, every flipping time he's mentioned.
#DeleteChrome
When your EV costs more than 18 months worth of the average American's salary pre-tax? That's not mainstream by a longshot.
I appreciate Musk for what he does but let's be honest about who these toys are for. They're not for the mainstream.
Who hasn't had that idea? Making it work is what counts. Some hubris is helpful, but this is a very difficult problem which can't be solved by just throwing money at it and combining existing state of the art technology. He'll probably end up redefining what he means by "air travel" to some specific niche application. It will be a long time before someone crosses an ocean in an electric plane that isn't a proof of concept which is fragile in more than one way.
The only practical application of an electric airplane within the near future would be lug around batteries. Which may come handy to Elon with his gigantic battery factory. Stuff the "plane" with fully charged batteries and fly it to the nearest sea port or distribution center.
Well, you see the problem: it doesn't fit in the subject line.
Next time you reference Him, I suggest you use the proper enneagrammaton for The Man Known As The Real Life Tony Stark: TMKATRLTS.
I have discovered a truly marvelous proof of killer sig, which this margin is too narrow to contain.
Musk knows that the his company needs all the hype that it needs, including promoting his persona, especially when the booboisie can't spot his electrically heated air.
As I posted below, it seems pretty obvious you would use fuel cells instead of batteries for an electric aircraft... from your energy density link compressed hydrogen has an even better energy density (142 MJ/kg) than jet fuel (46 MJ/kg)!
The cost of hydrogen production is estimated to become close to gasoline production over the next decade or so, but there is a huge pollution benefit to using fuel cells which could drive adoption quicker.
The currently very low cost of oil is probably the main thing that would keep airplanes from going electric soon.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
No batteries used for initial take off. Drop the extension cord and go forward.
Musk is at one of Stark's parties and he quips to Stark that he has an idea for an electric jet. Tony's busy but tells him to give him a call or something...
This is a really good point, and it might be that planes are one of the few contexts where hydrogen really is the way to go.
As I posted below, it seems pretty obvious you would use fuel cells instead of batteries for an electric aircraft... from your energy density link compressed hydrogen has an even better energy density (142 MJ/kg) than jet fuel (46 MJ/kg)!
The cost of hydrogen production is estimated to become close to gasoline production over the next decade or so, but there is a huge pollution benefit to using fuel cells which could drive adoption quicker.
The currently very low cost of oil is probably the main thing that would keep airplanes from going electric soon.
It is still a complete mess in terms of storage, especially when cryogenic, and when you combine it with some carbon to make it easier to store we're back at methan (which also works in fuel cells) or some other kind of jet fuel.
I don't really see any use for pure hydogen systems, beside upper stages of rather short lived rockets (and even there they are developing methan based engines, because of the problems with pure hydrogen).
He keeps recycling old ideas, and the media keeps claiming he's inventing something new. (They should really do at least 3 minutes of research before jumping to such false conclusions.)
It seems his real talent is to convince people to go back to old ideas that didn't take off before. That's neither good nor bad, but stop overhyping them.
A plane takes off and lands horizontally because it's safer. They can glide to a landing if something goes wrong. Vertical takeoff and landing seems unnecessarily risky to me, unless Musk wants them to be able to take off from and land just about anywhere. Fine, make that an option, not the primary means of takeoff and landing.
Seriously, he needs to keep this to his company while he focuses on the other 3, along with his hyperloop. If SpaceX was to work on this behind the scene for the next 2-3 years, then announce it, he could make a world of changes. ,
I prefer the "u" in honour as it seems to be missing these days.
See
Molten Salt Reactor
Aircraft Nuclear Propulsion
Batteries don't store a lot of energy. The power density of a typical battery is very poor, and even a super-advanced battery is 24 *times* as weak as an equal mass of gasoline. Note that on the same chart, Jet Fuel is properly described as kerosene, and has a higher density than gasoline. The better option would go to a *more* energy dense fuel, rather than go to a *less* energy dense fuel (tritium batteries, plutonium batteries, thorium batteries, uranium batteries). Stupid people let their 'social conscience' get in the way of real progress. There are a *crapload* of SJW's floating around lately who are very savvy politically, but don't know jack shit about science. They try to push their agendas, but *sonofabitch!* hard physics gets in the way. And suddenly "but I want it to do this!" gets them replies like "you are a dumbass" and "I wanna pink unicorn too! gimmie gimmie gimmie".
Well that sure escalated fast.
and even more efficient would be skipping storage all together for the take-off and landing and simply beaming the energy.
I prefer the "u" in honour as it seems to be missing these days.
The way I see it you could use electricity for the rotation of the ceramic disk of a Podkletnov device, which would solve your weight problems and also allow you to reach supersonic speeds with just a small jet engine using very little fossil fuel.
Violence is the last refuge of the incompetent. Polar Scope Align for iOS
Ideas are a dime a dozen, I had three this morning. When are we going to start *seeing* any of these grandiose visions of yours?
I've barely seen a Tesla on the road, and you're already planning the Hyperloop transit to your electric airport!
And *who* is going to PAY for this? People are poor, idiot!
Yes, I'm kidding.
---- The above post was generated by the Turing Institute. Maybe.
No idea how Elon Musk feels about it, but I think it's not quite appropriate.
The fictional Tony Stark made his money with dubious weapons business.
Frankly Elon Musk is the better man.
NASA has been researching electric aircraft for quite a while. They do have some advantages, although they're not ready to commercialize yet.
http://www.nasa.gov/centers/ar...
http://www.nasa.gov/aero/testi...
http://aero.larc.nasa.gov/file...
http://ntrs.nasa.gov/archive/n...
http://ntrs.nasa.gov/archive/n...
http://www.geoffreylandis.com
Yes, they still do that, though in developed areas it's often flying for longer to burn the fuel rather than just dumping it.
I don't read AC A human right
Actually hydrogen has great specific energy (energy per unit mass), but lousy energy density (energy per unit volume). Even ignoring the massive weight of a vessel capable of holding hydrogen at >5000 PSI (needed for it to stay liquid at room temperature), liquid hydrogen has only on the order of 1/10 the density as compared to jet fuel (70.85 g/L vs ~800g/L).
The first electric plane to cross the English channel was in 1981.
On July 7, 1981, the aircraft flew 163 miles from Pontoise – Cormeilles Aerodrome, north of Paris, France to Manston Royal Air Force Base in Manston, United Kingdom, staying aloft 5 hours and 23 minutes, with pilot Stephen Ptacek at the controls. Currently the plane is owned by the Smithsonian Institution's Air and Space Museum.
And the Solar Impulse series can charge it's batteries enough during the day to fly to the next dawn. It did a non-stop flight from Japan to Hawaii.
And Airbus has a jump on them as well.
"Transparent" is a shit show that trades on every stereotype going. A man in drag is NOT a transsexual.
All this new tech is fantastic, but it is very frustrating when you have the cash to spend on it and the companies that resell his tech (in Australia) will not bother to take on jobs that are more complex than a "plug it in and walk away" type install.
I really wish Elon Musk would give them a boot up the ass about that attitude because big problems don't get solved by only accepting easy and routine tasks.
Studies have been done on liquid hydrogen airplanes, and LNG turns out to have many advantages. Airplanes will be the last holdout of hydrocarbon fuels, along with infrequently driven cars. I know it sounds weird, but even Fischer Trop using wind turbine hydrogen will be economically competitive (around $10/gallon). Boeing, GE, and ununionized labor are THAT good. I guess it could face competition from battery swap buses.
I think the easiest solution is for people to stop driving SUVs, and rent them instead.
Not surprising he wants batteries everywhere
"...the man so many people call the real life Tony Stark has done an incredible job of bringing electric vehicles to the mainstream."
Errr, not to quibble, but a base model Tesla costs over $100,000....that's not exactly "mainstream" by any standard I'm aware of.
Just cruising through this digital world at 33 1/3 rpm...
Error 53.
SOP for rubycodez
Pain is merely failure leaving the body
Flint is not "White" enough for Musk!
Ha ha
-1 Stupid.
You're forgetting that 60-75% of the energy in hydrocarbon fuel is wasted in the form of heat when you burn it in a combustion engine. Conversion losses for electricity are a tiny fraction of this.
There is always the option of synthesizing jet fuel chemically, possibly from renewable such as biomass or even some purely atmosphere+electricity kind of facility should the technology make it possible / efficient. We have nuclear power plants with ridiculous capacity, we just need to figure a way to store that energy into chemical bonds, and then we can replace fossil fuel with a non-fossil version, with all the energy density. That reaction already exists actually, the Fischer–Tropsch process.
Why don't we make electric cargo ships first?
Cargo ships release a huge amount of CO2, the only reason we don't complain is because they are efficient per ton moved. But switching them over would greatly reduce CO2 consumption. I think it would make sense to do them first since the ship designs are much much less sensitive to mass and volume relative to airplanes. Further, we have had ship based electric propulsion in the form of submarines for a very long time. Once the prise of batteries comes down I'd like to see high voltage lines to the major ports on hand to re-charge ships while the are being unloaded. Since they don't need to be charge 24/7 they would make a great place to dump excess capacity when solar/wind are producing at their maximum.
Going OT as Musk does electric cars and rockets, some years ago a documentary on engineers that worked at Los Alamos talking about one time when they took a drive into a town to get loaded at the saloon. Obviously they could never say what they really do so they start talking out loud about "electric rockets." This engineer went on to describe where they were talking real loud of electric rockets, others in bar were ignoring them. Engineer then said he grabbed one guy by the shirt yelling at him, "we're building electric rockets!" but this guy was really drunk, probably had no idea what was going on. Of course that was way back when concept of electric rockets was science fiction.
mfwright@batnet.com
Nope. Batteries don't have the energy density of gasoline, either, but electric cars have twice the performance, and a quarter of the range of gasoline powered cars now. There's no reason electric planes can't also have twice the performance, and a quarter of the range of planes, now. The thing about jet fuel being used up is also comparable to autos.
I don't respond to AC's.
He was in Iron Man 2 and he's got a lot of good engineers trying to push the limits of current tech. Yes, there's a lot of PR along with it, but he's popular with engineering types because they see him trying to build awesome things and they want in on it. I'm sure there are a lot of problems for them to overcome, but these would only be ordinary projects if they were so easy anyone could manage it and he's trying to raise the bar. And you won't find many people here who think that's a bad thing.
So no, I don't care that you don't like the hype. And I do know that much of it is hype. But I also know that he's going to gather a lot of skilled engineers and TRY to do awesome things in a way that not a lot of companies will. So yeah, I want him to succeed. I know there's a good chance some of this will fail. And I really don't give a single damn about the people trying to tear him down. Seriously, you're wasting your breath, I don't even care one damn bit whether you like it or not. You can't even try to do awesome things without people like you showing up, so it's just like whatever. Yeah there's hype. We know. Deal with it.
The problem with hydrogen is storage. Even in liquid form it is only 70kg per m3 compared to about 800kg/m3 for jet fuel. And that is at 20K which is really really really really cold and complicates tank design a lot. other forms of hydrogen storage have massive weight penalties.
If information wants to be free, why does my internet connection cost so much?
Elon who made his money on the completely unethical paypal and has since used it to prop up several cool albeit financially lame businesses?
Airplanes are not cars.
A full sedan-sized gas tank is about 55 kg, and comprises 4% of the weight of the whole car.
The Tesla Model S battery pack is 540 kg, and comprises 28% of the weight of the whole car.
A fully-fueled long-haul passenger jet may be as much as 50% fuel by weight.
There is simply no weight margin available to devote to multiplying the weight of the energy storage system by 10x; attempting to do so leaves you with something too heavy to fly at all.
Moreover, even if it could get off the ground, a miraculous all-electric plane that was 100% battery by weight would still lack the energy required to carry the weight of the battery, alone, at 600 mph across the Atlantic Ocean using wings and ducted fans. (This assumes present-day resuable battery tech; I am not suggesting that future battery tech couldn't do better.)
Additionally, most of the factors that make electric cars more efficient than hydrocarbon-powered ones (like regenerative braking) don't really apply to airplanes.
There's no reason electric planes can't also have twice the performance,
Well, yes there is. You have to push against the air. You can push twice as hard against pavement for twice the effort, you can't push twice as hard against air under the same terms. Also, liquid fuel goes away as you use it. A battery stays the same weight when you deplete it.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
The little problem with this option and with the current international laws at sea is that after about 30-40 years ship wrecks are often sunk at some place nobdoy looks at.
No, there isn't. The system efficiency of hydrogen (from production, to compression/liquefaction, transport and to the fuel cell) is about 20%.
Whatever your original energy source is, converting it to hydrogen multiplies its pollution by 5.
As pointed out above the best lithium ion batteries are around 1/30th the energy density of hydrocarbon fuel like gasoline. Further though it would require a battery with high power density as well, you couldn't use a technology incapable of discharging it's full actual capacity in an hour. Finally you would need a reliable battery that would keep working over many charge discharge cycles and not die prematurely for purely financial and practicality reasons which is why there are no lithium air batteries helping extend electric car range today.
The little problem with this option and with the current international laws at sea is that after about 30-40 years ship wrecks are often sunk at some place nobdoy looks at.
Yeah, you would have to put some serious controls on the system. It isn't going to happen any time soon. Under current systems you'd basically have to have the military operate such vessels.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Podkletnov device
Podkletnov is a well-known crackpot and scam artists: https://en.wikipedia.org/wiki/... Mod parent down for promoting crank pseudoscience!
"Politicians and diapers must be changed often, and for the same reason."
The only possible advantage is that they are lightest when they require the most power - take-off.
This is patently false, as maximum landing weight for all commercial aircraft is lower than maximum takeoff weight. Next time don't post about things you obviously known nothing about!
"Politicians and diapers must be changed often, and for the same reason."
Where does Hydrogen come from? Electrolysis of water, or incomplete combustion of a fossil fuel (natural gas).
Where does electricity come from? Fossil Fuels or Wind/Solar/Hydro
What is also created when making Hydrogen from Natural Gas? CO2/CO
So it looks to me like Hydrogen fuel cells on a plane is not really a way to reduce pollution.
Major aircraft manufacturers have been working on this for years. Airbus has made no secret they want to get an electric commercial passenger aircraft into production and from what I've read over the last few years, they've been making steady progress. Smaller GA aircraft companies are also taking a serious look at electric, particularly for the light sport class which has regulatory restrictions on size, weight, top speed, and number of passengers and typically do not have the same range/endurance needs. Electric passenger aircraft will happen, maybe not next week, but sooner than many expect, if for no other reason than there's a lot of money being thrown at it...
I'm beginning to get sick of the Elon worship. Apparently, like Steve Jobs, an idea isn't a good idea until it comes from his mouth.
All you smart people and nobody thought about multi-stage (or just 2 stage) takeoff?
With drone technology where it is today, it is easy to envision booster stage or mothership arrangement that brings the entire aircraft up to cruising altitude then detaches and flies itself back to the airport to recharge (or swap batteries) and assist the next plane that needs to take off. This is similar in concept to what The SpaceShip company is doing, but could be used for commercial air flight.
There's lots of advantages here.
First, a commercial airliner burns between 1,000 and 6,000 pounds of fuel getting to cruising altitude. That equivalent energy would no longer need to be stored on the actual plane. It would be in the drone's batteries, reducing the weight of the plane. The drone would continually recharge the main plane during the ascent stage, so the plane will start with 100% batteries at cruising altitude. The booster could hang around longer and push the plane longer, but the further it flies from the origin field, the longer it will take to get back so you start to lose efficiency at some point. Also the booster's wings would be optimized for lift, not high altitude cruise. Ideally the booster would use variable pitch propellors for maximum efficiency during the ascent.
Second, you could envision a battery "tanker" rendezvous performing in-flight recharging. Not so great from transoceanic travel, but a New York to Tokyo flight could top-off the batteries over Seattle.
Third, thrust required by the plane during cruise is much lower than what is needed during takeoff, and since the plane no longer needs to takeoff by itself, the plane's engines could be smaller and lighter, further saving weight and drag. There are some safety issues here that would need to be addressed--extra engine power is a safety feature, but in all likelihood there would be savings from being able to better optimize the plane for cruise operation.
You could also see a drone rendezvous scenario for landing, but you can't fully optimize for that scenario because the plane needs to still be able to land in case of a missed rendezvous.
This type of system could even work in tandem with a normal jet airplane, saving thousands of pounds of fuel on every flight.
Seems to me like the way to do this is to develop a gel based hydrogen fuel (ie a viscous liquid that's safe) and then power a hydrogen fuel cell fed by a syphon to generate the electricity, with the hope that the gel itself breaks down into water vapor and/or some other inert environmentally friendly byproduct.
Is if you use a beefed up APU to provide a shit ton of electrical power. Then you'd still use fuel etc. But you'd have enhanced functionality by all electric propellers in essence. You'd be using an electric motor to spin the turbines around.
See subject & keep RUNNING from a simple fair question "JustAnotherForrest" -> http://slashdot.org/comments.p...
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With your tax dollar support ... except maybe make profits
Hydrogen is a tiny molecule that can leak through just about anything, including solid metal. It's also very explosive and has pretty low specific energy (energy/volume).
If you're set on using hydrogen (e.g. maybe in the distant future it can be economically produced via electrolysis from abundant renewable energy sources) then it's probably better to convert it to a more easily stored and higher specific energy liquid form (like gasoline for ICE engines or ammonia for fuel cells) using the Fischer-Tropsch process or Haber-Bosch process.
As a good /. citizen - I didn't read the article. But did he say "batteries?" Vertical takeoff yes.
How about a Railgun? Just shoot the &$#-ers into the sky and let it glide to its destination?
The damn barbarians were good at heaving big rocks long distances via different catapults - and they didn't use batteries. Well - the giant weight and sling arm I suppose stored up energy...but not a battery in the modern sense.
-1 Stupid.
You're forgetting that 60-75% of the energy in hydrocarbon fuel is wasted in the form of heat when you burn it in a combustion engine. Conversion losses for electricity are a tiny fraction of this.
Partially true. Essentially all of the formulas assume you *could* discharge to an absolute zero heat sink and calculate efficiency that way. Needless to say that is ludicrous as if you had one of those you could deplete the surface temperature of the earth for essentially fuel free unlimited energy. It's far more realistic to assume the low temperature heat resovoir to be the ambient air temperature and then the efficiency with respect to the maximum achievable efficiency isn't nearly that bad.
and a quarter of the range of planes
You said:
600 mph across the Atlantic Ocean
Reading comprehension fail.
"If you have nothing to hide, you have nothing to fear." - Every fascist, ever
If it were anyone else, I would be a bit skeptical...
We are talking about the guy who owns the largest electric car company, is about to own the largest battery factory (employing many battery chemists and other specialists), and owns the most successful of the private space launch companies.
I think he is well aware of the tyranny of the rocket equation (as well as how it applies to aircraft as they burn their fuel), the limitations of a battery, and the differences between theoretical maximums and what you get in practice. More importantly he is advised by those who really are experts, and past success suggests that he does listen and understand.
Tripling battery density would make it viable on shorter flights, perhaps even cost effective. If anyone is in a position to make that happen, he is.
I'm a signature virus. Please copy me to your signature so I can replicate.
No reason this couldn't be done with traditional aircraft as well - think of the launchers on aircraft carriers. Getting from 0 to take-off speed and more with a nice electric launcher would save on fuel as well.
He said:
and a quarter of the range of planes
You said:
600 mph across the Atlantic Ocean
Reading comprehension fail.
Math (or research?) fail. What I wrote squares 100% with that:
New York to London is 5570 km. This is one third of a 777-200LR's max range, BUT that was the goal I set for "a miraculous all-electric plane that was 100% battery by weight".
If a physically impossible 100% battery plane can't go even a third of the range, then a realistic 50% battery plane certainly cannot go a quarter of the range.
As to the 600 mph part (approximately the normal cruise speed of a jet liner) - the OP said "twice the performance" and the article suggests a supersonic battery-powered airplane, which would require even more power just to break the sound barrier.
If it were anyone else, I would be a bit skeptical...
My main point was that JoshuaZ is correct that "The technical problems with this are immense." That doesn't mean it could never, ever work - but it does mean that this statement is completely wrong: "There's no reason electric planes can't also have twice the performance, and a quarter of the range of planes, now."
There are good reasons it can't be done with current technology (for large, high speed planes like Musk was talking about). If this changes, it will be because of one or more major technical breakthroughs.
Tripling battery density would make it viable on shorter flights, perhaps even cost effective.
No, it wouldn't. Recharging will be very expensive and hard to do safely.
Even if you succeed in solving the recharging problem, there is simply no significant advantage to using pure-battery power, to make up for the massive disadvantages. (Hybrid systems like the Terrafugia TF-X could make sense, though.)
If you want an alternative to fossil fuels for full-sized passenger and cargo planes, synthetic fuels are a far more sensible direction to explore.
Is no on paying attention? http://www.solarimpulse.com/
you know, heating the exhaust isn't entirely a loss in this application
Thanks for the reply. I'm not forgetting that at all. The difference is that hydrocarbon fuel just needs to be dug up and refined and it already has the energy potential. There is no energy investment on the part of humans. To charge a battery, you have to acquire the energy from elsewhere, much of the time that means.... burning hydrocarbons.
hmm i think you don't quite understand why jet planes are so popular for long haul. it's more efficient than you think clearly.
world was created 5 seconds before this post as it is.
Now you're moving the goalposts. Your original post was only about charging and discharging losses, which have nothing at all to do with where the energy is acquired from in the first place, and is an argument concerning the viability of using batteries as a power source on a plane rather than burning hydrocarbons. And you're making conversion losses out to be something major, when in fact they're extremely minor. Losses in the batteries are relatively small, and losses in the motors are nearly negligible. ICEs have huge losses because of the thermal cycle, so it doesn't matter that hydrocarbons have so much more energy since much of it is wasted.
As for acquiring the energy, because electric propulsion doesn't have a thermal cycle, you don't need to generate as much energy to charge them to do the same amount of work. Due to the significantly higher efficiencies of large-scale power plants, you end up saving energy that way, and that's ignoring the fact that you can easily switch your generation to something else like solar or nuclear which doesn't cause global warming.
It has nothing to do with losses in charging batteries, I can tell you that, and that's what this discussion is about, not about absolute efficiency.
Jets are popular because they're big, and that gives them economies of scale in moving people. Go look up the burn rates of small corporate/private jets and calculate the per-passenger fuel efficiency of those things: it's absolutely atrocious. Big commercial jets do much better because they cram so many people in and use much larger planes. Efficiencies of scale change everything.
The Tony Stark comparison goes deeper in Iron Man 2.
Hammer's factory is really Elon Musk's SpaceX facility. The people walking in the background are actual employees even though filming there took place at night.
According to the January 2012 Air And Space magazine, Tony Stark's character was also inspired by South African born SpaceX (and PayPal co-founder), Elon Musk. A statue of Iron Man, complete with company ID, "stands guard" at SpaceX along with a Battlestar Galactica (2004) Cylon.
I can't find the exact quote, but before the Monaco racing scene Elon says something to the effect of, "Hey Tony, I've got an idea for an electric jet!" Tony replies, "Great, we'll make it work!" and walks off.
Well, if it is volume energy density you want to be looking at, the real measure you need to use is MJ/L. In this, jet fuel is about 3.5 times better than liquid hydrogen. At the same time, though, hydrogen is about 3.5 times better than jet fuel in MJ/kg, so the situation is closer than you make it out to be. It is true that liquid hydrogen requires way more consideration in storage than jet fuel, which would increase total aircraft mass. At the same time, though, fuel cell/motor combos should be lighter and simpler than jet engines, which would not only decrease aircraft mass but also contribute to decrease in maintenance on the ground. (Note that this latter benefit also applies to electric planes, perhaps at an even greater level.)
One problem I glossed over in the previous paragraph is that liquifying hydrogen is quite energy intensive--up to 50% of the chemical energy in the hydrogen. The heat generated during liquefaction can be partially recovered and used for something else (like air conditioning at the airport), but I wonder if there is much use for the massive cooling effect of LH2 aboard an aircraft, beyond cooling the fuel cell itself. Compressed H2 is comparatively less energy intensive, but you lose a lot of space efficiency that way.