small but rather beastly 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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FishBoy
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Tue May 27, 2008 3:06 pm

barrel 1- 3/4" x 24"
barrel 2- 1/2" x 24"
chamber- 2" x 12"

all i can say is that small, powerful cannons are loads of fun! :D :D

also, if you have ideas for ammo, i've tried many things but i'd love suggestions
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the little beast
the little beast
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bob-a-lu
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Tue May 27, 2008 5:40 pm

you can put a paintball ina square of toiletpaper and roll the end and that can be shot out of the 3/4".
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FishBoy
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Tue May 27, 2008 5:51 pm

thanx, i'll try it
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starman
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Tue May 27, 2008 6:29 pm

LikimysCrotchus5 wrote:No need for 2 topics on the same cannon.

Mod please. :roll:
Believe it or not it's a different cannon. I'll give you one thing Fish...you get a plan and stick to it.. :wink:

Same comments apply here as the 3" model you posted. You could have just posted these together.
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FishBoy
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Tue May 27, 2008 6:48 pm

thanks starman, do you have any tips for building a larger combustion cannon? (i'm planning on having a 4" x 21" chamber & a 2" x 5' barrel)

also, i'll probably get a tb barrel for it
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mega_swordman
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Tue May 27, 2008 6:56 pm

A 4" cannon is going to cost a bundle, but there isn't really anything to terrible different about building one in comparison to a smaller cannon. One thing to look into though would be getting some sort of fan in the cannon to help mix the fuel. A propane meter also wouldn't do any harm. :wink:
"Never tell people how to do things. Tell them what to do and they will surprise you with their ingenuity." George S. Patton
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FishBoy
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Tue May 27, 2008 7:05 pm

what if i didn't want to use propane?
mainly, if i still wanted to use hairspray or rightguard or whatever, would a chamber fan still help?
Last edited by FishBoy on Tue May 27, 2008 7:08 pm, edited 1 time in total.
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ammosmoke
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Tue May 27, 2008 7:06 pm

Oh yeah, and staying away from bell reducers wouldn't hurt either :wink:. Not saying you used it on this one or anything..
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starman
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Tue May 27, 2008 8:23 pm

FishBoy wrote:thanks starman, do you have any tips for building a larger combustion cannon? (i'm planning on having a 4" x 21" chamber & a 2" x 5' barrel)

also, i'll probably get a tb barrel for it
I have lots of tips, but you will be better served if you take some time to browse the cannon showcase for ideas and methods. We want to see you come up with answers on your own for these things. The answers are out there, trust me.

Having said that, your c:b is coming in around 1.4 which is pretty good...you'll want to keep that in the .8 - 1.5 range for best efficiency. .8 is the ideal ratio. You might consider taking an inch or 2 from the chamber just for some weight savings and handling ease.

Oh and...avoid the duct tape next time.... :wink:
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SpudUke5
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Tue May 27, 2008 8:27 pm

starman wrote:
LikimysCrotchus5 wrote:No need for 2 topics on the same cannon.

Mod please. :roll:
Believe it or not it's a different cannon. I'll give you one thing Fish...you get a plan and stick to it.. :wink:

Same comments apply here as the 3" model you posted. You could have just posted these together.
Really?, i could've sworn it was the same cannon but in a different background.

O well, you have my condolences FishBoy

But anyway, why paint them identically (along with the tape), dont you want them to be unique?
Its nice for a starter gun though.
4SPC, My 4" piston 3" porting cannon
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Fix up copper cannon
Fix up 4SPC
Start Stirrup pump
Start Toolies piston bazooka
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mega_swordman
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Tue May 27, 2008 9:58 pm

FishBoy wrote:What if i didn't want to use propane?
Also, if I still wanted to use hairspray or Rightguard, would a chamber fan still help?
There is no problem with your preference in fuel, i was simply suggesting something that would make fueling the cannon much easier. In regards to the chamber fan, it does in fact help with the efficiency of the cannon. By making the mixing the air and fuel better, it allows for a more even blast instead of a dense area of fuel. This isnt the best of explanations though, someone else may have a better way of saying it.

tl;dr Yes it will help

(Side note: Speaking of efficiency, I haven't seen JSR on the forum lately. That's a shame.)
"Never tell people how to do things. Tell them what to do and they will surprise you with their ingenuity." George S. Patton
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