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Boeing Working on Fuel Cell Aircraft
Journal written by jdray (645332) and posted by
samzenpus
on Wed Mar 28, 2007 07:40 PM
from the 12,000-AA-batteries-not-included dept.
from the 12,000-AA-batteries-not-included dept.
"Boeing is working with development partners on a fuel cell-based small aircraft. It seems like a logical use of the technology. Now if they can come up with a quiet, personal-sized VTOL craft a la Paul Moller's Skycar (which is anything but quiet), we'll really have something." From the article "A Boeing research director was quoted as saying, "While Boeing does not envision that fuel cells will provide primary power for future commercial passenger airplanes, demonstrations like this help pave the way for potentially using this technology in small manned and unmanned air vehicles."
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Better hurry up... (Score:4, Funny)
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Re:Better hurry up... (Score:5, Funny)
Parent
Skycar (Score:5, Funny)
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As long as that's a requirement, the plane wil
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"The Skycar remains perfectly positioned for the expected invention of antigravity."
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A&P certified mechanics are expensive.
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And to do that we just need to suspend the laws of physics. Unless you know of another way of lifting 2,000 lbs straight up in the air.
giant rubber bands (Score:4, Interesting)
This isn't totally humorous, incidentally. Think of aircraft carriers. You can achieve very short take-off distances without putting the giant (noisy) vertical-flight machinery on your aircraft -- because you can just leave it on the ground behind you. But you must then accept the fact that you can only launch in certain places.
Still, I'd bet there's a market for a cheap skycar that can only launch at certain public facilities but can land nearly anywhere.
Parent
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If you have the launch facility, you also have the landing facility. So we're back to the standard (cheap) Cessna.
Landing 'anywhere' = vertical landing. Loud, dangerous (crosswinds) and expensive on fuel.
Without some uber propulsion type (not fans pushing air), I don't see it happening any time soon.
Re:giant rubber bands (Score:4, Funny)
Parent
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Ratios (Score:2)
ha ha (Score:4, Informative)
You probably mean the external combustion engine, also known as the jet engine. Only small airplanes use pistons and such. And the answer is: of course not. This is yet another PR stunt aimed at the Gasoline Is Eeeeeeevil ninnies of the world who failed freshman chemistry.
If not, what about fuel cell powered dirigibles?
I don't think the problem with dirigibles is how to power them. I think the problem is that there's just about zero demand for a transport service that's about as slow as a ship or train but neither as efficient nor as reliable.
A big cargo ship carrying 70,000 tons of cargo can cruise at 15 knots with its 50,000 HP engines running at 80%. The EPA helpfully estimates [epa.gov] big marine engine fuel consumption as about 250 grams per kilowatt-hour, which lets you work out that a cargo ship consumes about 4 grams of fuel per ton of cargo per kilometer traveled.
Four locomotives pulling a hundred-car freight train at 60-80 MPH, with each car carrying 100 tons of cargo, will burn about 7.5 gallons [bts.gov] each per mile. That works out to 7 grams of fuel per ton of cargo per kilometer traveled.
There's no way any vehicle that flies can ever come close to that kind of fuel efficiency. So who would want cargo delivery that's just as slow, but much more expensive?
Parent
time to educate the masses again... (Score:5, Funny)
Sounds like someone failed basic understanding-of-how-things-work class.
Oh I agree, definitely.
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Re:time to educate the masses again... (Score:4, Informative)
Sounds like someone failed basic understanding-of-how-things-work class.
Oh I agree, definitely.
Somebody failed looking at pictures class. The combustion chamber in a jet engine is quite definitely in the middle of the engine. Combustion takes place inside the engine, between the compressor and the turbine.
Not all ICEs have pistons, nor are all piston engines ICEs.
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More kinetic energy is bad (Score:2)
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I believe that's what they said about the automobile 100 years ago.
Re:More kinetic energy is bad (Score:4, Insightful)
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Considering that 3000 people die per day from car accidents around the world, what we have is a disaster of the proportion of september 11, done daily.
Generally speaking, most countries seek to blame the individual driver. Most airlines seek to fix the system. And when you look at what they have had to do to make planes safe, its pretty clear that few of us really have a right to lift a few tons of metal into the air ove
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Given the relation p = m v, you do the math on that, and couple it with the fact that no non-military building I know of is built to withstand impacts from above. Anyone in a home or apartment that's hit by a falling, fast-moving aircraft is dead meat.
Reliability? (Score:5, Interesting)
Turboprop engines are a good middle ground for mid-sized planes starting at the 12-seat size or so, but are very expensive for the smallest aircraft. (2 and 4 seaters)
Electric motors, other the other hand, can be incredibly reliable. If designed for it, they have just a single moving part, and can run continuously, 24x7x365 for many years without issues. This kind of reliability in a small plane would be just incredible!
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Just as with cars, power density is the sticking point. And even more than cars, weight is an issue. Taking the standard Cessna 172:
Fuel capacity of 42 USG.
Range 790 miles.
Assuming the gas and electric engines weigh the same, and assuming 6lb per gal for Avgas....can we build a battery pack good enough for 790 mile range, with NO loss of power over that range, that weighs 250lbs?
(The Prius battery pack weighs about 1/2 that - 45kg))
Re:Reliability? (Score:4, Interesting)
No, but that may be why they're looking at fuel cells which have different performance characteristics than battery packs.
My guess is that they really want to use it for military/police UAVs where getting rid of the noise from a combustion engine will seriously improve stealth operation modes. Smaller surveillance-oriented versions could perhaps be dropped from a mother ship and have smaller range requirements than you indicate.
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The Wankel engines are much smaller and lighter for the same horsepower than piston engines. Their drawback for automobiles is similar to turbines - they don't like low RPMS (the rotor seals leak at l
Bah. (Score:5, Funny)
Blimps could be quiet (Score:2)
So, engine noise and laminar flow ducted fans? However you do it, flight needs a lot of power and it's going to get all that power to be smooth and quiet.
Use a compressor (Score:2)
Pump the helium (or hydrogen - that wasn't what started the fire on the Hindenber, although it certainly made it worse once it ignited) into tanks to descend. Release it into the gas bag to ascend. Pump it all into your tanks and fold up your envelope to park. Submarines do something like this with air.
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Ultralights (Score:4, Interesting)
I am a hang glider pilot, and I would love to have a small engine for it. There are several manufacturers [doodlebugnorthwest.com] who make small engines [swedishaerosport.se] for them, they are loud, stinky, gasoline engines. Most of them only hold 1-2 gallons of fuel, which is plenty for this type of flight. Wouldn't a fuel-cell engine do the trick?
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An awful lot of that noise is the prop, not the actual engine.
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-Yes, the fuel cell takes in hyrodgen and outputs electricity, which runs an electric motor.
Would it be quieter than a gasoline engine? More reliable?
Yes, and yes. Electric engines are virtually silent, and have far less moving parts than internal combustion engines.
Would there be any odor?
No, the only output from a fuel cell is water vapour.
If so, they would be ideal for ultralights:
Maybe! Your main problem here is fuel density. On the one hand,
Moller (Score:2)
It's not the engines which are noisy (Score:5, Insightful)
See: Overclocked PCs, Helicopters, Jet Engine, extractor fan, air conditioner, Vacuum cleaner...
It wouldn't matter if Moller's thing had fuel cells - it would just as noisy.
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Re:It's not the engines which are noisy (Score:4, Insightful)
You can get cute and use TMD (Tip Magnetic Drive) fan blades, which have no ends (its thought that tip vortex at the end of fan blades is responsible for much of the noise associated with fans and blades) and you could spend millions designing the most efficient blades possible.
Hell, you could even bet that in a few years the next generation of memetic polyalloys (T1000 et al) or "memory metals" will even allow the actual blades to change shape depending on their rotational speed, thus reducing noise still further.
But the fact remains, on a 2000 KG car, you need at least 2000 KG of vertical thrust to keep it in the air, and 2000 KG of thrust is a LOT. Are you seriously suggesting that fan blades can be made as quiet as say - a 5-litre V8 car at 6000 rpms? No way. Not gonna happen. Not ever.
Unless some way can be made to shift large amounts of air, efficiently, with no blades at all, then the Moller thing will never be anything more than a fucking dangerous, extremely noisy experimental demonstrator.
I'm still hanging out for effective anti-gravity. After all, it's such a weak force, that 2 AA batteries should be powerful enough to keep your car airborn for a year or so. Then all you need is some way to move it about, and you only need one engine for that - so it'd be much quieter.
Parent
Electric Aircraft (Score:3, Interesting)
Energy density is getting there. (Score:3, Interesting)
Battery energy density is finally getting good enough for this sort of thing. Electric cars with real performance are at last possible, although the trunk full of laptop batteries still costs too much.
For aircraft, the price point is higher, so this could work. There are lots of little electric-powered unmanned aircraft around, from toys to small military recon units. An outfit called Aviation Tomorrow [archive.org] was making noise about an electric-powered kitplane back in 2002-2005. They got to the point where they'd announced the first flight test in 2005, then disappeared. What seems to have gone wrong is that they originally planned a battery powered plane, which would have worked, then switched to hydrogen and Ballard fuel cells, which didn't.
The embarrassing fact about the fuel cell industry is that almost nobody is shipping a usable product. It's still all prototypes. Five years ago, Ballard was about to launch a commercial product with Coleman, but they couldn't make it work well, and Coleman backed out. APC supposedly sells a fuel cell product for server backup power, but it doesn't really seem to be installed in any quantity. (For one thing, it requires chilled water for cooling, which is a real problem if you need power to chill the water.)
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Have you ever noticed that you never see David Copperfield in the same place as the creator of the Moller Skycar?
The guy is either one of the most deluded inventors, financially incompetent, or a huckster. Or, all of the above.
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It'd be good to know what kind of power delivery
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I guess weight is the major obstacle at the moment.
It is. Current (pardon the pun) PEM fuel cell technology typically uses platinum, AFAIK. Stacks are heavy. The Ballard Mark 1030 [ballard.com] provides about 78 Watts per liter of unit volume and 66 Watts per kilogram. The Ballard Mark 902 [ballard.com], which is used in several fuel cell cars and buses, is much more powerful at 1133 Watts per liter of unit volume and 885 Watts per kilogram, but it's heavy (96 kilos, over 211 pounds). Note that neither of these devices weights
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We'll have flying cars. People just wont be allowed to control them themselves, except for maybe an emergency landing mode.
As a bonus, we could call the central control system 'Skynet'