double combustion (2 stage)

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.
tarmann_90
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Sat Apr 21, 2007 1:17 am

ive always wondered if this would work, or just make more fire. Line up 2 combustion chambers and link them together with the barrel and shaved bushings. have the first chamber resemble a normal one, but the second one should have slits in the top and bottom of the barrell towards the ends of the chambers. when ignited the potato should go up, but allow the flame to spread into the second chamber, and cause a second ignintion. I think that as long as the projectile is already moving it should have plenty of time to get past the second set of holes before much air can get out.
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jackssmirkingrevenge
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Sat Apr 21, 2007 1:21 am

have a look at this thread :wink:
hectmarr wrote:You have to make many weapons, because this field is long and short life
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hi
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Sat Apr 21, 2007 1:26 am

I dont think it would do much as proformance goes. infact you would propably loss range because the gas would go into the second chamber. I think it would ignite, i have seen 1 foot muzzle flashes on my cannon. But the problem is that all it would do is make a big bang and not very much range.

i think it would be a bang, followed by another bang about a second later. I think this would be a good noise maker. maybe if you put a union aafter the second chamber and a burst disk in it would be really loud.

a really good adition would be a check valve between the first and second chamber, that way the gas didnt go back in.

its a good idea, but wouldnt boost proformance if thats what you want.
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Matheusilla
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Sat Apr 21, 2007 9:06 am

This concept reminds me of something I've heard people doing back in the hayday of combustions. What they would do is build their canon out of several old steel beer cans. Instead of cutting the whole top and bottom out of the cans to stick them together, they would just cut out a portion, like a semi-circle. They would then assemble them with the cut open portions alternating from one side to the other so as to make something resembling a muffler. The idea was that when ignited from the bottom can (uncut on the very bottom) the explosion would travel upwards towards the muzzle and slightly compress the air/fuel in each consecutive "chamber" created by the baffles. Someone I know made one wit heavy steel pipe, about 3" diameter. They had the baffles about 6" apart and alternately placed. the whole thing is maybe 4' long. He uses several drops of gasoline for fuel. It is the loudest cannon I've ever heard.
Juicey
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Sat Apr 21, 2007 9:43 am

By having slits in the second chamber, wouldn't this cause the barrel to fill with fuel as well and be lost through the muzzle?
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SleekZ
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Sat Apr 21, 2007 9:57 am

hehe "shaved bush(ings)" .......sorry I'm not usually smutty! It won't happen again, but I just couldn't help myself! :oops:
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frankrede
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Sat Apr 21, 2007 10:51 am

why not have 2 chambers sideXby side and have them both lead to a barrel using elbows and a T.
gave ignition on both.
and have a union on the barrel for a performance increase.
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lukemc
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Sat Apr 21, 2007 10:55 am

i would think it wouldnt work because some of the explotion would get by the potat just that tiny bit would innite the other gasses in front of the potato doing nothing for performance
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