Advanced Hydrogen Mini Combustion Cannon

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
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FeLeX
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Thu Feb 07, 2008 9:44 am

Whats your power source? If you hook it up to a car battery I bet it would go alot faster than 15s/mL
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rcman50166
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Thu Feb 07, 2008 5:57 pm

I saw you recommend that for another thread. I don't imagine you know much about electricity. A car battery has about 6000 watts (volt-amps really) of power in it. (for a comparison a wall outlet only has 1850 watts) If I were to just hook it up to a fuel cell that small the production rate would equal zero. That is because there would no longer be a fuel cell to produce hydrogen. This particular cell can, maybe, tolerate half a watt of power. Any more the conductor grid will fail.
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FeLeX
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Thu Feb 07, 2008 7:30 pm

Oh ok. Cuz I definetly didn't just do practically the same thing in my ELECTRONICS class.
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rcman50166
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Thu Feb 07, 2008 7:44 pm

I'm majoring in electromechanical engineering...
Will anyone help me on this one? It's not the same as an electrolysis machine. Take a nine volt to steel wool. That's exactly what happens.
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FeLeX
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Thu Feb 07, 2008 10:00 pm

Poser. Oh yea and message too short ;)
jon_89
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Thu Feb 07, 2008 11:05 pm

I will share my idea with you. This would be totally awsome if you had something similar to Jacks pen gun and incorprated this all into a hot glue gun case.
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rp181
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Thu Feb 07, 2008 11:32 pm

i dont quite get this, i thought fuel cells take hydrogen and produce water and electricity. How does this produce gas? And yes, that high current with totally kill it. Why do you think car battery cables are so thick, yet flybacks so thin(you will say that flybacks are think, most of it is insulation)?

Edit: If this produces hydrogen and oxygen, why have metering? its already the perfect ratio.
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rcman50166
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Fri Feb 08, 2008 4:03 pm

jon_89 wrote:I will share my idea with you. This would be totally awsome if you had something similar to Jacks pen gun and incorprated this all into a hot glue gun case.
But I need my glue gun... :cry:
Anyway, I saw his little gun and I'm not sure I can build something so compact. Even if I did the fuel cell would be a big eye sore.
rp181 wrote:i dont quite get this, i thought fuel cells take hydrogen and produce water and electricity. How does this produce gas? And yes, that high current with totally kill it. Why do you think car battery cables are so thick, yet flybacks so thin(you will say that flybacks are think, most of it is insulation)?

Edit: If this produces hydrogen and oxygen, why have metering? its already the perfect ratio.
This is a reversible fuel cell. It is designed to take water and turn it into hydrogen and oxygen when a current is run through the cell. It's kinda like how a motor can use electricity but if the motor is mechanically spun it will put out electricity. As for the metering, I'm not using the produced oxygen for fear of chamber failure. If I was I would still need to meter it so when the fuel is injected it displaces all of the air that is in the chamber.
jon_89
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Fri Feb 08, 2008 8:55 pm

so the volume of hydrogen and oxygen is the same volume as the chamber?
Drop that Sound
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Sat Feb 09, 2008 12:10 am

I bet that kit would work good on a gas powered nitro RC car.
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rcman50166
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Tue Feb 12, 2008 4:35 pm

jon_89 wrote:so the volume of hydrogen and oxygen is the same volume as the chamber?
Yes. The volume of H2 would most nearly need to be the same as the chamber. The volume of the chamber would be 2 parts hydrogen and one part oxygen. (by volume)
Drop that Sound wrote:I bet that kit would work good on a gas powered nitro RC car.
It could feasably work on a nirto engine but the problem, even with real sized cars, has always been hydrogen storage. A hydrogen based internal combustion engine would, to be practical, need Hydrogen stored in liquid form. The trouble is hydrogen has a pressure of up to 10,000 PSI in liquid state; most tanks can't hold that type of pressure safely. with the atmospheric pressure container I'm using, the most run time on a nitro gas engine is probably around 5-10 seconds.
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rcman50166
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Wed Mar 12, 2008 4:38 pm

Eureka! :idea: It works! After tinkering with the fuel mixture I got it to what is pretty damn close to the golden ratio. The gun is a monster! It tears through soda cans (a baseline test for me) and shatters the bbs upon impact. I figured out that adding oxygen to the mix made it too rich and wouldn't combust. Using atmospheric air the oxygen percentage is less making it closer to ideal combustion mixtures. The only thing I need to improve now is make the chamber smaller. This will make it so that I can use pure oxygen in the chamber instead of having half the chamber filled with atmospheric air. There is bad news, however, which is I currently don't have a working digital camera so vidoes and pictures are currently out of the question. :cry:
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microman171
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Wed Sep 17, 2008 2:17 pm

I have one of those generators (off one of those cars). But I think the HHO gas is easier as it has the perfect mixture (dont know why yours doesnt work in tha respect...) I will try out this spudgun when i can find some good solid chamber and barrel marerial.
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ramses
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Wed Sep 17, 2008 2:39 pm

flamerz14 wrote:OR... go build a hybrid with that fuel cell. i mean, come on, you have hydrogen and oxygen. Just need a little bit of metering thats all :twisted:
metering wouldn't even be necessary if he used the oxygen, as they are conveniently produced in exactly the right proportions. All he has to do is take the output, mix them and suicidally feed them into the intake of a fridge compressor or shock pump. Maybe not as suicidally with the shock pump, but I don't want to compress H2+O2 in a metal tube located "conveniently" between my legs. Possible, but risky.

For air, I still wouldn't compress it, but he would need a meter. (keep the syringe and go get a crap-tasic gauge for the air :D
microman171
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Wed Sep 17, 2008 11:40 pm

Yeah I was thinking about the pressure too Maybe if you kept them seperate before injection... The hydrogen would have no oxygen to burn and the oxygen would have no fuel to oxidize. When they were metered into the chamber you have the right air to fuel ratio.
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