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Two cylinder gear-less twin aircraft

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pictsidhe

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Hydrogen is hard to store. Solutions are heavy, except large scale cryogenic storage. That has safety issues should the cooling fail. It also needs great care during refill. It has an extremely wide flammability limit and unusually low ignition energy. That makes it far more dangerous than gasoline or propane. As for being green, you need to look at how it is made. Yes, we all know it can be made from solar or wind power, but it never is...
 

pictsidhe

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If only this planet had scientists and engineers.

Oh well.
I take it that you haven't looked into the hydrogen storage that has so far been devised or proposed by scientists and engineers?
The big problem is it's very low density. Known storage solutions have a small tare fraction. They are also bulky. No good for aircraft or long range anything. Yes chemical storage sucks too.

Anyone who suggests making it in flight from solar power is going straight on my ignore list.
 

Hot Wings

Grumpy Cynic
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Zack: "Agree to disagree. That’s what I love about science, there’s no one right answer."

Humor from the Big Bang Theory that really isn't so funny. :(

My wife Wife calls me Shellard. :confused:
 

DaveK

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I don’t think anybody has mentioned having electric boost for takeoff, but having the IC provide all cruise power. This might work out if the battery and electric weights aren’t too high. Something like the Rotax 912 with 60hp electric motor to supplement for 2-5 minutes for climb out. The rest of the time the IC would directly power prop. Could be configured to slowly charge battery on cruise or use regenerative braking on windmilling prop when descending to top battery off incase of a go around. Wouldn’t work for continuous touch and goes, but on a clean airframe it could potentially increase climb rate in a useful way while keeping a reasonable cruise speed. Could also allow for a short continuation of flight if the IC failed if configured correctly. I believe a Spanish university was investigating this approach a few years back,
 

PagoBay

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Company promises 300 mile range later this year.

 

crashdog

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I did a workup on a 1IC-> 2EM hybrid. It can work, particularly if the IC is one of several high performance motorcycle engines. Is it efficient - not particularly? It does have advantages in that E propulsion can be more effectively located. But it is not a simple solution, and neither is it inexpensive.

For fuel cells, think of a move away from pure hydrogen (storage) and toward the NH3 (ammonia) cycle. That is the future of transportation fuels. Although, to be honest, if you are going to use electrochemistry to manufacture NH3, surely other forms of synthetic fuels would be more readily workable in the near term.
 

Topaz

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No kidding, but then, so is 100LL. And lets not even talk about hydrogen...
No, let's.

100LL is easy and safe to handle if done in an open space and you control ignition sources. We have about a century of experience handling, dispensing, and storing gasoline in a variety of environments. It's handled very casually with a minimum of training.

Pressurized gaseous hydrogen is even safer to handle - no worse than welding gases, and the same precautions. The main issue is pressure-vessel safety. Hydrogen doesn't "explode" - we're not talking Hindenburg here. Long-term issues include embrittlement of metals, but that's relatively well-understood.

Ammonia is caustic on touch and an extreme inhalation hazard. It's highly reactive with all sorts of common materials. You'll never see open, casual, pumping of ammonia like gasoline, nor easy gas transfer and storage like hydrogen. Pure ammonia requires special vessels, transfer systems, and *extreme* precautions. It also has an inconvenient boiling temperature, making the choice of liquid or gaseous storage awkward. It's nothing to be casual about.
 

pictsidhe

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The flammability limits of hydrogen are 4% to 75%. It also has an extremely low ignition energy. That no big deal static discharge at a gas station is a far, far bigger deal for hydrogen.
But the big issue with hydrogen in planes that it's just so heavy to store. Find suitably light storage before saying it's the best advance since sliced bread.
 
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