Big Red

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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PCGUY
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Sat Feb 12, 2005 10:57 pm

<div align="center">BIG RED

Provided By - pedoo

Two 4"x18" chambers elbowed to a 2"x5' barrel. Ignition comes from electronic BBQ igniter, with duel sparkers. ( expensive BBQ's with side burners ) both igniters spark at the exact same time. They sell these electric igniters with the other igniters at local hardware stores.

<img src="http://www.spudfiles.com/official_pics/red1.jpg">

In each chamber mount 1 igniter to a 2" ring and bolt to wall, use that screw to carry current. A second screw must be drilled on each chamber right next to the ring for the wire to complete the cirrcut.

<img src="http://www.spudfiles.com/official_pics/red2.jpg">

<img src="http://www.spudfiles.com/official_pics/red3.jpg">

Provided By - pedoo</div>
Last edited by PCGUY on Sat Jul 29, 2006 12:07 am, edited 1 time in total.
Yes, I am the guy that owns & operates SpudFiles (along with our extremely helpful moderators).
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theexp
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Sun Feb 13, 2005 7:52 pm

Really original ignition system, but i bet it adds alot of power. I have never seen i cannon like that. I like it tho. Is is awkward to shoot at all tho?
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drac
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Tue Jun 14, 2005 6:33 pm

I like the cannon, but I like the Foster's Lager shirt even more. Very nice cannon.
Tommy_TreeTop
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Tue Jun 14, 2005 6:37 pm

What type of propellant do you use? And how good does it work? how far cna your cannon shoot?
darthtator
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Mon Jul 25, 2005 2:19 pm

having two seperate chambers, do you ever have a bad mix in one chamber and only have one fire? I would also like know how far it shoots and basically the above questions.
Your hands can't hit what your eyes can't see, float like a butterfly sting like a bee. *Ali*
spudshot
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Mon Jul 25, 2005 7:54 pm

that seems like it would be a problem to me, though it could be cleared up by using metered propane with an injection point in each chamber
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darthtator
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Tue Jul 26, 2005 12:08 pm

ya thats true I just didn't see any schrader valve or on board injection so I thought I"d ask.
Your hands can't hit what your eyes can't see, float like a butterfly sting like a bee. *Ali*
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Rambo
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Tue Jan 17, 2006 2:16 pm

I thik that if the ignition is write in the middle of the chamber, the fuel will burn faster.And the best shape for the chamber is spfere.Why you people arent using oxigen.Better small and storng chamber with power fuel then bigger wich can't stand a great preshure.And lower preshur means....... the god given air is far from a good fuel
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Lucas_Pukas
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Tue Jan 17, 2006 4:11 pm

Rambo wrote:I thik that if the ignition is write in the middle of the chamber, the fuel will burn faster.And the best shape for the chamber is spfere.Why you people arent using oxigen.Better small and storng chamber with power fuel then bigger wich can't stand a great preshure.And lower preshur means....... the god given air is far from a good fuel
Hooked on foniks...look into it!
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boilingleadbath
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Tue Jan 17, 2006 6:06 pm

"If the ignition is in the center, then the fuel will burn faster"
True, but not to an extent where it's worth drasticaly modifing your system.

"The best shape for the chamber is a sphere"
True, and we'll start using them when you find an inexpensive source for spherical pressure vessles.

"Why arn't you people using oxegen-enriched atmospheres?"
Because we'd need to get (somewhat pricy) oxegen regulators and storage containers, and it increases the burn front velocity which can lead to DDT... which is bad, even with steel pipe.

"It's better to use a small, strong chamber with a more powerfull fuel than a larger chamber with lower-powered fuel."
The pressure spike will not increase lineraly with the generated pressure... the increase in mass caused by the thicker chamber will not be countered by the higher generated pressure.
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Rambo
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Wed Jan 18, 2006 3:39 pm

You mean that the oxigen will cause an explosive burning.Or detunation.The preshure should be about 10 atnospfears.Wich isn't more then the preshure in a good hibrid.The ignition will be more relaible if you use a spark of two elektrodes toching each other.I use 650000mf capasitor.The spark i huge.By the way my new gun is with 3,5L chamber and it cost me 10 levs= about 7$.The guns in internet are more then 100$.Looks like the americans envaliuate their work very high.
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boilingleadbath
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Wed Jan 18, 2006 6:01 pm

7$ for a 3.5L gun? Wow! I wana move to Bulgaria too!
Yeah, an oxegen enriched fuel mix will be more likely to detonate. That doesn't mean it will, but if it does, the shockwave is likely to do bad things to the chamber walls.
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Rambo
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Thu Jan 19, 2006 8:45 am

My gun is made only by two paipes-125mm and 40mm. the wall of the pipe is 2mm.I made the diametar reduser by stitupor (I hope that's the word for it) and the sealing is also hand made .The ignition caused me some problems but I'll fix them.(the spark i about 2mm.)I'll use the other capasitor.
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boilingleadbath
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Thu Jan 19, 2006 6:37 pm

...ah, I see. Yeah, the fittings are the parts that get you - a single 4" (~100mm) fitting costs me 6$!
SPUDDY6
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Tue Aug 01, 2006 7:34 pm

do any of you guys live in california?
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