How to incorporate a Hydrogen fuel cell into an electric aircraft for Homebuilders?

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PMD

Well-Known Member
First of all, sorry to be late to the party. Catching up on a lot of things here and there.

5.2 SYSTEM DESCRIPTIONS (from fuel cell information presentation)
5-2 5.2.1 AIR SYSTEM.....................................................................................................
5-2 5.2.2 FUEL STORAGE SYSTEM ...................................................................................
5-4 5.2.3 FUEL DELIVERY SYSTEM ...................................................................................
5-9 5.2.4 HUMIDIFICATION SYSTEM ................................................................................
5-11 5.2.5 STACK COOLING SYSTEM................................................................................
5-12 5.2.6 BUS COOLING SYSTEM ...................................................................................
5-14 5.2.7 HVAC SYSTEM ..............................................................................................
5-17 5.2.8 LUBRICATION SYSTEM.....................................................................................
5-18 5.2.9 HYDRAULIC SYSTEM .......................................................................................
5-19 5.2.10 ELECTRICAL SYSTEM ......................................................................................
5-20 5.2.11 CONTROL SYSTEM..........................................................................................
5-23 5.2.12 LEAK DETECTION SYSTEM...............................................................................
5-24 5.2.13 FIRE SUPPRESSION SYSTEM............................................................................

The less informed that seem to think saving the world is their mission - using mostly total BS based on junk science or things very profitable to the proponents - seem to think fuel cells are simple little things that feed unicorn farts into one end and get rainbows out of the other. Now, I am seldom the smartest guy in the room, but more of a techno-geek Forest Gump who just happens to meet a lot of extremely bright people who sometimes share some really interesting information. A research project that we had some work with was planning to build a very high altitude, relatively long duration aircraft that was to use hydrogen fuel cells to stay aloft. The bulk, complexity and COOLING REQUIREMENTS (very difficult with extremely low density of the stratosphere) took so much power that it was far simpler to just feed the hydrogen to a piston engine - as the amount of power needed to cool was almost what it took to stay aloft. Now, that was no big surprise, but what was unique was the technology for them to transport liquid hydrogen. That I can't discuss, but let's just say it is practical and relatively simple. Also the energy density of liquid H2 is a fair bit better than Jet A or ULSD - even when the storage medium is included. So: why are we screwing around with these fuel cells? They are almost as stupid as Li ion batteries (but not quite). IMHO, if there is any real place for modern aviation power in the "green" world, it would be using liquid hydrogen or burning bio-fuels. Of course, diesels are the right way to do that, as they are truly multi-fuel engines that will tolerate almost ANYTHING that can be burned.

Didn't want to go down the carbon and nuclear rat holes, but - while I wouldn't go so far as to say there is no anthropomorphic damage to the atmosphere from our carbon use, but what I WILL say is that if we weren't killing off the plankton and the oceans - they EASILY HAD the capacity to absorb the level of CO2 we emit to within a sustainable level. The killoff has been at the rate of about 1% a year and we are nearing the tipping point by a few decades. When that goes to its logical destination, not much of anything else we are doing or will do will matter at all. An intelligent race of animals would fix what can kill us all instead of chasing red herrings that are making/will make a few people very rich.

I am a big fan of thorium, and "we" (i.e. Canada) make a fair number of thorium fuel bundles - but they need to be seeded with uranium. The problem is that a thorium reaction can go flat very easily so the much more reliable decay of Uranium isotopes is need to make a stable reaction. When I say stable, I don't mean as in "won't run away" but "won't stop tunning at all". Still some work to do before it is the ultimate reactor fuel (and by that, I mean in sub-critical mass, gas cooled reactors).

Aesquire

Well-Known Member
Darn you! now I'm very curious about the liquid storage technology you can't tell us about! DAng It! ( please take this with good humour! I understand proprietary restrictions & classifications )

For maximum power density, you use Hydrogen slush. It's very... not done... here, on Earth, because the easy way to make it is to fill up a tank with liquid hydrogen at the coolest cryogenic temperatures you can, then valve some off into a hard vacuum. Some turns to "snow" in the tank, and you refill, vent, refill, vent etc. With plenty available for refueling ( rare ) and in orbit, or on the Moon, ( also rare ) where the hard vacuum is free ( except all the costs to get there in the first place ) it's a valid technique. Provided you are going to immediately burn it off. The reason for that is Hydrogen, H2, has 2 forms, Ortho & Para.

And one decays into the other, releasing heat. which both complicates storage and transport, and may be responsible for several explosions, including bubble chambers at universities.

There has been research into practical ways to convert the Hydrogen before use. So it's not a "deal breaker" just another thing on the long list of safety items you have to be sure of before using.

.

Aesquire

Well-Known Member
Oh, by the way, I found I CAN get hydrogen locally. Repairs are long since completed on the Hydrogen facility at the Airport that exploded some years back.

and GM closed the research plant... unrelated to the explosion.

Aesquire

Well-Known Member
But back to the OP question.

Expensive and heavy, but possible. The availability of automotive hardware makes it an attractive experimental idea. Just like electric cars and batteries do with battery powered planes.

Efficiency and weight are conflicting and sometimes synergistic in propulsion design. How much does a fuel cell system weigh compared to a turbine and generator? An IC engine and generator? And how efficiently does each convert fuel to sparks? What will be those numbers tomorrow?

And remember, a high efficiency light weight system that runs on unavailable or very expensive energy/fuel isn't practical, even if possible.

Otoh, practical isn't necessarily the only metric for decision making. Lots of folk enjoy windsurfing. Few commute that way.

wsimpso1

Super Moderator
Staff member
Log Member
Moderator Mode ON:

I just cleared 56 posts, mostly in the class of major thread drift, some in politics, and frequently a combination of the two.

This thread is about implementing hydrogen fuel cell power in an airplane. I left posts that got into related practicality issues. Let's remember, this forum is about little airplanes that we build and maintain ourselves.

If you want to talk about energy generation and distribution, you gotta find someplace else to do it.

Moderator Mode OFF

Aesquire

Well-Known Member
Apology for indulging in/allowing myself to be baited into... Religious heresy discussion. My bad.

I'll be very interested to see when someone disassembles a ( name brand ) Hydrogen car drive train so we can see how much it weighs and how complex the control and cooling systems.

With modern IC car engine conversion a while back the concern was primarily the PSRU, and now the additional challenge of computer controls. The Raptor show is a perfect example of the promise and challenges.

For a common automobile engine that is popularly hot-rodded, ( GM LS series ) there are aftermarket computers allowing tuning past automotive pollution restrictions, and probably more important, to operate the engine without trunk light sensors, windshield washer fluid level, and other inputs a stock computer demands. ( one does everything vehicle computer and bus instead of discrete systems is cheaper and aids maintenance diagnosis. )

If your target car for airplane conversion isn't a popular hot-rod engine source, the aftermarket computers just don't exist. V-8 pickup, yes, common junkyard hot rod donor. Certain Toyota, Nissan, etc. Performance cars, yes. Others? No demand, so no joy. You'll need to make work around gizmos so the engine will run properly without wheel slip sensors, etc.

So keep your eyes open for the hot rod mad scientist who wants to NASA up a Slingshot ( 3 wheeler ) or other economy vehicle, ( jetski?) with fuel cells.

Marc Zeitlin

Exalted Grand Poobah
I'll be very interested to see when someone disassembles a ( name brand ) Hydrogen car drive train so we can see how much it weighs and how complex the control and cooling systems.
I was peripherally involved in an electric V-TOL project that used the Mirai automobile fuel cell system as the basis for the powerplant. You can find almost all the info you ask for here:

It IS complex, and it's definitely heavier than a comparable powered IC engine, but far less than the batteries required for the same range.

blane.c

Well-Known Member
HBA Supporter
The NEXO fuel cell weighs around 196lbs for 95kw. Add battery 40kw for a total of 135kw and its weight and the motor etc. But stand alone 196lb for 95kw.

Vigilant1

Well-Known Member
The NEXO fuel cell weighs around 196lbs for 95kw. Add battery 40kw for a total of 135kw and its weight and the motor etc. But stand alone 196lb for 95kw.
? The battery should be rated in kilowatt hours (energy), not kilowatts (power). The fuel cell, like a motor, can be rated in kilowatts (power).

Adding 95kw to 40kwh wouldn't give us 135kw. We can't add them at all, it doesn't mean anything.

HBA Supporter

Martin W

Active Member
Some folks like to live in the land of make-believe
Here is a good video comparing electric batteries to hydrogen fuel
eg: .... TESLA 3 ................ $12 to recharge ............... 500km range .............. 2.4 cents per km ......... TOYOTA MIRIA ....$85 fill with hydrogen .... 480 km range ........ 17 cents per km.

more here:

BBerson

Light Plane Philosopher
HBA Supporter
...... 2.4 cents per km
......... TOYOTA MIRIA .... \$85 fill with hydrogen .... 480 km range ........ 17 cents per km.
The 17 cents per km was for the expensive onsite production by electrolysis. Industrial production is cheaper.
At the end he said hydrogen makes sense for aviation. It works regardless of the fuel cost.
The real solution will be reforming liquid hydrocarbon fuels into hydrogen for the fuel cell.

Vigilant1

Well-Known Member
The real solution will be reforming liquid hydrocarbon fuels into hydrogen for the fuel cell.
That seems a lot more practical. Or store the hydrogen as ammonia. Something in liquid form that is convenient and packs a lot of energy per liter/kg.
"Pure" hydrogen (cryogenic liquid or high pressure compressed gas) has a lot of baggage. It's important to factor in the energy costs of compressing/cooling that stuff and hauling around the heavy tanks when extolling its purported virtues.

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BBerson

Light Plane Philosopher
HBA Supporter
Or store the hydrogen as ammonia
Yep. Toxic ammonia for those anti carbon extremists.

Aesquire

Well-Known Member
You can find almost all the info you ask for here:
Ok, could be my hand cranked browser, but I don't find any answers as to weight of the parts. This is the second time you told me the same company site & the fourth time I've looked. Do you have a link to the information I'm apparently too ignorant to find?

As I've said, I'd buy a fuel cell car, if I could refuel it in rural... Anywhere in the region. NYC I avoid like the Plague, because... Plague. And traffic, cost, crowding, and this last year, very little open that interests me. That's all related to personal preference and politics not relevant to the thread.

And a 5-7 hour drive to fill the fuel tank of a vehicle that doesn't have the range to get there!

So me getting a Hydrogen fuel cell automobile is like a guy in the New Guinea jungle buying a Tesla. Pretty, but can't use it.

Ditto the hypothetical fuel cell plane. Or an engine that runs on any fuel I need to pay to deliver to me that doesn't have ANY commercial delivery system. If I buy an engine that runs on pure Heptane, I have to pay absurd amounts to get any delivered by a hazmat licenced driver to where I need it. Bill Gates can afford that. Great if you can, I don't have the money.

Doesn't mean Heptane or Hydrogen, or Virgin spit, is a terrible thing. Just not affordable outside a very geographically limited area. ( good luck )

Decades ago, a group of guys flew ultralights across the country, on alcohol. Publicity stunt, and they needed a van running with them to carry the fuel, and a sponsor to deliver the fuel to where the team could refuel their refueling vehicle. Decades later, to do the same flight, you need to replicate that fuel delivery system. Van, crew, contract

Martin W

Active Member
Ok, could be my hand cranked browser, but I don't find any answers as to weight of the parts. This is the second time you told me the same company site & the fourth time I've looked. Do you have a link to the information I'm apparently too ignorant to find?

As I've said, I'd buy a fuel cell car, if I could refuel it in rural... Anywhere in the region. NYC I avoid like the Plague, because... Plague. And traffic, cost, crowding, and this last year, very little open that interests me. That's all related to personal preference and politics not relevant to the thread.

And a 5-7 hour drive to fill the fuel tank of a vehicle that doesn't have the range to get there!

So me getting a Hydrogen fuel cell automobile is like a guy in the New Guinea jungle buying a Tesla. Pretty, but can't use it.

Ditto the hypothetical fuel cell plane. Or an engine that runs on any fuel I need to pay to deliver to me that doesn't have ANY commercial delivery system. If I buy an engine that runs on pure Heptane, I have to pay absurd amounts to get any delivered by a hazmat licenced driver to where I need it. Bill Gates can afford that. Great if you can, I don't have the money.

Doesn't mean Heptane or Hydrogen, or Virgin spit, is a terrible thing. Just not affordable outside a very geographically limited area. ( good luck )

Decades ago, a group of guys flew ultralights across the country, on alcohol. Publicity stunt, and they needed a van running with them to carry the fuel, and a sponsor to deliver the fuel to where the team could refuel their refueling vehicle. Decades later, to do the same flight, you need to replicate that fuel delivery system. Van, crew, contract
This may change your mind ..... it is a 38 minute video full of pertinent information .... Mr Cadogan is a bit rude and crude with language but his science is good. Very informative.

Nevermind

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Aesquire

Well-Known Member
"Spectacularly Retarded".

Yep.

Obviously you get I'm talking fuel cell automobile, which I can't legally fuel on most of the planet.

( out of curiosity, I checked NYDOT regulations, and fueling your car with unapproved, well, anything, is illegal. Mostly the idea is to keep idiots from carrying Molotov cocktails ( glass containers full of gasoline ) but subsection (c) of rule googleplex ( iirc) requires Hydrogen filling stations to be licensed by a bureaucratic process that actually doesn't exist yet, since with only 2 stations in the entire state it was easier to grant exemptions than write the rest of the procedure down. Much like FAA multicopter rules. Actually that's not as stupid as it sounds. Why create reams of paperwork, when, A. It might never be needed, if the fad passes... And since GM closed their research down ( presumably after cashing in the tax advantage ), it has. Or B. It turns out the bureaucrats in charge don't know anything about highly flammable pressurized gas handling. Or C. The people building the filling stations change their mind on how to do it best, but Can't, because changing a regulation is like shoveling out the Augean stables. )

Thanks for the video. Very informative!

Aesquire

Well-Known Member

Only one mention of Hydrogen in airplanes. Royal pain to build the much larger fuel tanks into a plane to get the same range as, say, JetA. And that ignores the problems mentioned above that affect a turbine as well as IC engines. So... Hydrogen in fuel cells is the logical use, aside from Airships, and for some reason there's a lot of reluctance to build hydrogen filled airships. ( cough, Hindenburg, cough )

I'll assume that fuel cells will be further developed to improve safety, and perhaps the ability to use less pure fuel than today. I'm very skeptical of how much the storage and transport problems can be improved. Really hope that works out.

The Biofuel Problem part of the Energy Problem is both political and engineering. I urgently caution that the side effects of politically mandated technology be carefully studied to avoid disasters like the revolutions, wars, mass migration, and starvation/malnutrition that converting a sizable percentage of farm land into fuel production has already caused.

Aesquire

Well-Known Member

Still looks like a fuel cell is a better idea than IC for Hydrogen. We need an Alchemist to develop a direct replacement for gasoline & Jet fuel that has none of the drawbacks of fossil fuels, and is completely renewable and eco friendly. but with my luck it'll be a byproduct at the Soylent factory.