Fueling A 6ft 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.
rustlerdude987
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Sun Jun 24, 2012 4:35 pm

Recently i have made a tennis ball cannon that is 6ft with a 201 ci chamber and mostly have been shooting it with stater fluid but i am looking for something a bit more reliable. i was thinking Syringe fueling because it is simple but i think that it is mostly for smaller cannons so some advice would be great and im not sure if i want go with propane because of the complications with having to change my cannon greatly.
Last edited by rustlerdude987 on Sun Jun 24, 2012 5:57 pm, edited 1 time in total.
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Labtecpower
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Sun Jun 24, 2012 4:59 pm

A 201 ml chamber will only take about 7cc of butane, or 8 cc of propane, so you should be okay with syringe fueling :wink:
rustlerdude987
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Sun Jun 24, 2012 5:48 pm

could you tell me how you got that because i think im confused about it and im sorry that is in cubic inches the real chamber is 3307.974 cc
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Technician1002
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Sun Jun 24, 2012 6:06 pm

Check your math. 200 cc is a pretty small combustion chamber for a 6 foot long tennis ball launcher.

edit; I see someone noticed while i looked for a pic..
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rustlerdude987
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Sun Jun 24, 2012 6:18 pm

yeah my bad so back to the question how would i fuel a 3307.974 cc chamber properly?
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pneumaticcannons
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Sun Jun 24, 2012 8:06 pm

About 109 cc's of butane should do the trick... Three shots from one of those big 30 cc syringes seems like a lot of butane though... You might be better off with propane+ a proper meter. either way, you will still need a good chamber fan considering that your chamber is only just under 2" ID

Here is an excellent tutorial on the subject:
http://www.spudfiles.com/forums/how-to- ... 22301.html
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jimmy101
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Sun Jun 24, 2012 9:19 pm

The biggest syringe I've seen that the average Joe can buy is 70cc. They usually have them at any store that sell horse supplies and medicines.

So that'll be nearly two syringe fulls for the 3310cc chamber. If you find the syringe in a store usually they'll have needles as well. Try to get a long blunt needle (don't need that razor sharp point, it'll only end up getting jabbed into your finger).

For reliability the fuel ratio is important, but so is proper mixing. A chamber fan + syringe will get nearly 100% of the performance that a particular gun is capable of. And, more importantly in my view, the gun will be much more consistent. You won't have one shot go 50 feet and the next one go 300 feet. Every shot will go 300 ft.
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jsefcik
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Sun Jun 24, 2012 9:26 pm

go with air powered my friend!!!, fuel is alot easier!!!
rustlerdude987
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Sun Jun 24, 2012 10:07 pm

I found this will it work


and what is the ratio for propane because butane is just useless for my amount if i can only get about two shots out of a 8 oz bottle
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pneumaticcannons
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Sun Jun 24, 2012 10:59 pm

Holy shite! Thats a big syringe! :lol:
and what is the ratio for propane
[spoonfeed] 4.2% [/spoonfeed]
i can only get about two shots out of a 8 oz bottle
How do you figure that? To me, that just sounds like an extreme under estimation...
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rustlerdude987
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Sun Jun 24, 2012 11:15 pm

[/quote]How do you figure that? To me, that just sounds like an extreme under estimation...[/quote]




these say they are 8 oz cans 8 US fluid ounces = 236.588237 cc and each shot is about 109cc thats just about 2 shoots or maybe i am just over thinking this

overall i am just trying to find a more reliable way to shoot and really need a walk through on how i should convert my advance spray and pray into something more reliable.
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pneumaticcannons
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Sun Jun 24, 2012 11:24 pm

The fact that the cans say 8 oz on them means that they contain 8 oz of liquid butane :lol:
liquid butane expands to thousands its original volume once in gas form @ atmospheric pressure.
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rustlerdude987
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Sun Jun 24, 2012 11:33 pm

That makes so much more but were the he'll am I going to get a 110 cc syringe!
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pneumaticcannons
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Mon Jun 25, 2012 12:37 am

That syringe you linked probably actually holds a bit more than 100 cc's. It's ok if you have a slightly lean mix. If all else fails, throw some crap in the chamber to lower it's volume lol.
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rustlerdude987
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Mon Jun 25, 2012 12:42 am

Yeah you know with the chamber fan I'm adding I wil probably be fine.
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