A place for general potato gun questions and discussions.
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Benny
- Corporal 4

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Sat May 20, 2006 2:11 am
FiveseveN wrote:1. Would you people ever stop giving advice without having solid info on the issue?
Par example... where the HELL did sgort get the idea that H2 is the most powerful fuel ever? Seventh grade chemistry tells us the oxyacetylene torch can yield 3480 °C, while oxyhydrogen only 2200 °C. Practical experiments on Brainiac also show acetylene to clearly be a better explosive.
And as I've said a few times before, I've seen a dozen "carbide cannons" made from drain PVC that held up the pressure, but eventually got contorted because of the heat.
2. What the hell does combustion pressure have to do with anything? It refferes to the pressure at which the gas spontaneously detonates, so unless you plan on containing H2 at 500 PSI inside a tank without porous material inside you're pretty safe. Containing H2 is an issue of its own.
So in a nutshell, H2 is probably more powerful. But you'll have to generate it on the go, since it's difficult to contain.
Propane is pretty inexpensive and easily available. I use butane because it's even more available.
because, he was obviously refering to a combustion so i was givveng him an idea of the pressure that it generates.

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boilingleadbath
- Staff Sergeant 2

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Sat May 20, 2006 12:08 pm
Indeed sgort... I origionaly had [schooled id = " sgort87 "] but apparently it lopped off the id part.
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yuandrew
- Private 2

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Sat May 20, 2006 4:50 pm
Pure hydrogen actually has less energy density than the same volume of a hydrocarbon based fuel (like propane) Hydrogen is more of an energy storage than a fuel; you have to reform some other fuel or use electricity to split water.
Being that I'm into alternative fuel vehicles as well, I'm learning a little about hydrogen fueled vehicles. After all, a potato cannon and an internal combustion engine are very closely related.
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boilingleadbath
- Staff Sergeant 2

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Sat May 20, 2006 11:02 pm
Yuandrew, geussing from your interestin the 'alternative' vehicals (and not to step on your toes, but hydrogen is dumb... long live batteries) you are talking abouth the density in storage.
While it is true that pressurized - or cyrogenic - hydrogen has less energy content/volume than other hydrocarbons, that doesn't apply directly to air-fuel mixtures. It's true but misleading, if that makes any scence.
As I said, though, hydogen does provide less energy/volume of air-fuel mix. Releases it a bit faster, but less energy - and a higher porportion of water is formed. (water, having more vibration modes than CO2, takes more energy to heat up and thus we have another reason for it to be less powerfull.)
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Rambo
- Corporal

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Sun May 21, 2006 1:33 am
The H2+O2 mix is lighter then propane and O2 mix>it gives less energy but bouth of the mixes burn at about 3000 C> when they burn they give the same amount of gases>the presure is the same for bouth of the mixes.
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Benny
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