Help with fueling setup

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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cfb_rolley
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Fri Dec 10, 2010 5:31 am

Yup, it's all well and good if the burst disc breaks, the expanding gases have somewhere to go. But if it doesn't, then the expanding gases will keep increasing the chamber pressure until either it cracks, or until the gases stop increasing in temperature. What I was asking, is what pressure would be produced inside the chamber at that peak point.
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Crna Legija
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Fri Dec 10, 2010 10:40 am

its about 100psi per x
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saefroch
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Fri Dec 10, 2010 7:24 pm

Saefroch wrote:HGDT says 215.4 psi from a 2x mix, generated by 3,600F combustion products. Most PVC is only rated to 240psi, at 73F.
These are the results from HGDT with a propane 2x mix and an intact burst disc at chamber burnout. Recommended that you download that and GGDT.
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cfb_rolley
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Fri Dec 10, 2010 9:24 pm

Ahhh I see. I would, but all I have is my phone atm since my laptop died :(
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Imkindofabigdeal
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Fri Dec 10, 2010 11:15 pm

I'm sorry to interrupt this fine thread, and i understand if my post gets deleted, but are you really that lazy that you cant just type out AT THE MOMENT! seriously you have to abbreviate that! I mean come on now, thats only what 8 more letters then if you were to put atm. Lets grow up here people and start talking like big boys and girls. Its stupid as hell!

Sorry carry on :),
Ben
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cfb_rolley
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Fri Dec 10, 2010 11:17 pm

Normally I do, but I'm using my phone and it's a pain in the ass! Haha
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Moonbogg
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Sat Dec 11, 2010 3:36 am

Don't think a metal chamber won't fail on you. If the punishment is too great and the metal fatigues, it will fail. Pressure vessels begin to form stress cracks on the inside of the chamber first as well, so you'd likely never know a failure was coming as there would be no visible signs. Having a cannon fail while shooting it like a rifle next to your cheek wouldn't be too much fun i'm afraid.
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