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Need help with new idea for spudgun.

Post questions and info about combustion (flammable vapor) powered cannons here. This includes discussion about fuels, ratios, ignition systems, safety, and anything else relevant.
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Need help with new idea for spudgun.

Unread postAuthor: Mudbubble » Fri Mar 28, 2008 5:09 am

Hi guys,

This is just a short question and i know there's no need for a new thread.
However its the base of my whole spudgun idea.
If I were to have a spudgun that launches a AA battery (1.4cm/0.55inches) through its barrel, while applying the CB ratio 1:1.5, What would be the ideal spec. for the spud gun i'm about to make? :D

Thank you for your time. :D
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Unread postAuthor: SpudFarm » Fri Mar 28, 2008 5:22 am

make everything as big ass you can afford.
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Unread postAuthor: TurboSuper » Fri Mar 28, 2008 5:40 am

Well you have the ratio backwards, it's 1.5:1 C:B ratio. You can also go with a 0.8:1 ratio. I hear alot of bickering over which is better...1.5:1 is louder, I'll tell you that much.

And it doesn't really matter how big you make it as long as it follows that ratio, although from personal experience having a large diameter chamber works better.
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Unread postAuthor: Jared Haehnel » Fri Mar 28, 2008 8:17 am

spudfarm wrote:make everything as big ass you can afford.


I agree with him...bigger the better...more damage 8)
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My current projects....

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http://www.spudfiles.com/forums/my-new- ... rt,15.html
Still on the drawing board...
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Screen doors for submarines...
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Unread postAuthor: scottcrete » Fri Mar 28, 2008 8:24 am

would would a 3 to 1 cb ratio be like? thats about what my at4 will be... will it have a signifgant kick? will it be loud? that barrel is 1.5 ft long 2 inch.. and the chamber is 2feet 5 inch long with a 4 inch diameter..

all yah.. i added a lasersight
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Last edited by scottcrete on Fri Mar 28, 2008 8:27 am, edited 1 time in total.
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Unread postAuthor: Jared Haehnel » Fri Mar 28, 2008 8:27 am

It will be LOUD... and not that much kick...mostly because of all the wasted energy.
But one the bright side not many members here can brag they have a scale replica of a AT4 that shoots potatoes 8)
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My current projects....

Currently buying part for...
http://www.spudfiles.com/forums/my-new- ... rt,15.html
Still on the drawing board...
C02 tank hybrid
Screen doors for submarines...
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Unread postAuthor: Mudbubble » Fri Mar 28, 2008 10:29 am

Oopsy there, I messed up the CB ratio there. :? 1.5:1 would be better cos louder= more powerful right?
I wouldn't want it too big, it's better for me when its lighter and more concealable.What do you think of a barrel that is 1.3cm/0.5" x 60cm/23.4inches and a chamber that is 2.5cm/1" x 30cm/11.7" ???

Btw wicked ass at4 you have there scottcrete! :shock:
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Unread postAuthor: super spuder » Fri Mar 28, 2008 4:25 pm

louder= less powerful.
the noise is wasted energy. The shorter the barrel, the less time the pressure from the expanding gas has to speed up the projectile. To long of a barrel also reduces velocitys because the projectile will no longer be getting pushed by the gasses, and will be getting slown down from the drag on the inside of the barrel. I still think that a 1.5:1 ratio will be better (not positive though), cause there will be more expanding gas. pretty much just decide on a chamber size, then make a barrel to match... or decide on a barrel and make a chamber to match.
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trying to decide on a new project, probably something small.
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