Propane problems

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.
jsefcik
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Mon Jul 16, 2012 2:41 pm

shield personal defense,you should do a multiple spark gaps, its awesome!!!
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MrCrowley
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Mon Jul 16, 2012 3:05 pm

Well it definitely sounds like your mixes are off. Either you're not venting the chamber properly, the fuel isn't get mixed properly or you've done the calculations wrong. I'm almost certain it's one of those three problems.
Recoiled_monsteR
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Tue Jul 17, 2012 8:33 am

I used the spud tool from ultimate spudgun and By the calculations, the meter is way too big and there is no ignition of propane. I will try adding a chamber fan and see if that helps.
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jackssmirkingrevenge
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Tue Jul 17, 2012 8:53 am

care to share your dimensions (meter, chamber etc.) and fill pressures?
hectmarr wrote:You have to make many weapons, because this field is long and short life
Recoiled_monsteR
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Tue Jul 17, 2012 9:54 am

11" 3" sch 40 chamber, Approximately 50" 1-1/2" sch 40 barrel minus the air ram.
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jackssmirkingrevenge
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Tue Jul 17, 2012 10:10 am

air ram?

What's your meter volume and what pressure do you fill it to?

You know, with that volume you can simply use a 50mL syringe...

http://www.spudfiles.com/forums/how-to- ... 22301.html
hectmarr wrote:You have to make many weapons, because this field is long and short life
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jimmy101
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Tue Jul 17, 2012 12:13 pm

8tonsemi wrote:for 10-20 bucks get a stungun! =)
Stun guns aren't legal in alot of places.
And a stun gun won't help performance at all (especially since the gun is igniting with the sparker).

To tell if a fan will help, without actually installing a fan, just load ammo, fuel, then let the gun sit for ten minutes or so. Assuming your ammo is air tight (like a spud generally is) then the long wait will insure that the fuel and air are fully mixed. If the performance goes up with the long wait then you need a fan. If the performance doesn't improve then your mixture is wrong.
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Recoiled_monsteR
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Tue Jul 17, 2012 2:49 pm

I have an air ram on it to simulate the recoil of a field gun. Its hard to describe. Look at this : http://www.spudfiles.com/forums/ways-to ... rt,15.html
It pushes the whole barrel and chamber backwards upon firing on a set of tracks with elastic bands to return it to original pre-fired position.
I am not sure, but my cannon is the first one I have seen with an airram on it, but it works great.........if I can get a good combustion.
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MrCrowley
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Tue Jul 17, 2012 2:56 pm

Recoiled_monsteR wrote:I have an air ram on it to simulate the recoil of a field gun. Its hard to describe. Look at this : http://www.spudfiles.com/forums/ways-to ... rt,15.html
It pushes the whole barrel and chamber backwards upon firing on a set of tracks with elastic bands to return it to original pre-fired position.
I am not sure, but my cannon is the first one I have seen with an airram on it, but it works great.........if I can get a good combustion.
So you use the combustion gases to help recoil the system? Perhaps you should upload some pictures or a diagram.
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jackssmirkingrevenge
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Tue Jul 17, 2012 3:10 pm

A medium combustion on a low friction rail firing a reasonably heavy projectile shouldn't need boost to recoil nicely...

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hectmarr wrote:You have to make many weapons, because this field is long and short life
Recoiled_monsteR
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Tue Jul 17, 2012 5:44 pm

This is exactly what I did in a nut shell
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jimmy101
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Tue Jul 17, 2012 6:18 pm

Looks to me like that setup would (1) make the recoil worse, (2) waste energy in making the gun recoil and (3) not return the gun to the starting position after firing.
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jackssmirkingrevenge
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Tue Jul 17, 2012 11:49 pm

jimmy101 wrote:Looks to me like that setup would (1) make the recoil worse, (2) waste energy in making the gun recoil and (3) not return the gun to the starting position after firing.
I think he wants to boost recoil for an artillery effect.

Still, I'm confused, that looks like a ball valve pneumatic but we're talking about a combustion :?
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Crna Legija
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Wed Jul 18, 2012 3:05 am

What is the thing in the middle between the chamber and barrel?
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jackssmirkingrevenge
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Wed Jul 18, 2012 3:49 am

hectmarr wrote:You have to make many weapons, because this field is long and short life
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