First 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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paaiyan
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Fri Feb 09, 2007 12:22 am

OK granted, it's extremely simple and a beginner design, but it's my first try at this. No I haven't tested it yet, working on finding a remote location as I'm not entirely sure what the powers going to be like. I'll put up more pics once I get it painted, right now you can still see the pvc glue and all.

Edit: The ignition system is something of my own design. I'll get a couple of pictures of how i did it tomorrow and post them. I think it's kinda cool myself but that's just me.
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It's just a couple inches shy of 10 feet long.  The chamber is 2 1/2 feet of 4-inch pvc and the rest is 2-inch.  I'll be using Static Guard as fuel, if anyone can give me a rough estimate about how far it may shoot I'd appreciate the input.
It's just a couple inches shy of 10 feet long. The chamber is 2 1/2 feet of 4-inch pvc and the rest is 2-inch. I'll be using Static Guard as fuel, if anyone can give me a rough estimate about how far it may shoot I'd appreciate the input.
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frankrede
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Fri Feb 09, 2007 2:49 am

Wow thats pretty massive, you might want to consider installing a chamber fan. A rough estimate on range would be well over 100 yards, maybe twice that.
Current project: Afghanistan deployment
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Insomniac
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Fri Feb 09, 2007 5:15 am

That thing is a BEAST!!!!!
The C:B ratio doesn't look very good, it would probably be a good idea to cut some of the barrel off. But thats just me, I could be wrong.

Anyways, very nice gun!
I wonder how much deeper the ocean would be without sponges.
Right now I'm having amnesia and deja vu at the same time. I think I've forgotten this before.

Add me on msn!!! insomniac-55@hotmail.com
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paaiyan
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Fri Feb 09, 2007 8:41 am

Well as for the C:B ratio, I really don't remember what I used because I'm just cool like that, but I did use the one that gave me the most barrel. That way's safer because you can always cut some off should the need arise. It's a pain in the butt to add more.
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jrrdw
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Fri Feb 09, 2007 9:03 am

I'll guess at the range with that set up -- 75 yards tops. If the barrel was 1" in diameter, i'de guess 200/250 yards. It seems that when rule of thumb is followed, 200 yards seems to be the standered distance for most of common combustions.
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paaiyan
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Fri Feb 09, 2007 9:26 am

Alright I realized I have 3-inch on the chamber instead of 4. Redid the math and my C:B ratio is look just about .8:1. I remember looking around for a bit to see what everyone thought was good and that seemed to be pretty well accepted. And it's apparently only 8.5 feet long, I was assuming that the ceiling in my garage was the same 10 feet as in my house. Yes I know, I should know all this stuff but I actually built it a couple months ago and had since forgotten the specs.
fom
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Fri Feb 09, 2007 6:21 pm

LOL

a .8:1 ratio would be best for propane/mapp gas but since you using static guard cut some of the barrel off, I dont know how much, someone smarter than me should know.

Edit: I just remeber a 1.5:1 ratio is best for aresols.
SpudBlaster15
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Fri Feb 09, 2007 10:15 pm

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