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Weird burst disk spring pistol
Posted: Thu Feb 14, 2008 2:15 am
by Mitchza89
Well I have absolutely no idea If this will work but I don't see why it shouldn't.
After the release clip on the back of the piston is released, the piston is pulled foward extremely quick due to the strong springs pulling it in. At the peak of compression, the burst disk should give out thus sending a wall of compressed air. It's somewhat impracticle but eh....I'll make it and see what happens

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Edit: The ring at the back will be attatched to a trigger mechanism.
Posted: Thu Feb 14, 2008 3:51 am
by Mr. Beaver
I get it, like putting a burst disk in front of a syringe.
Nice idea i think it will opening the valve faster

Posted: Thu Feb 14, 2008 4:00 am
by Mitchza89
Haha I can only hope. Thanks for the comment mate.
Posted: Thu Feb 14, 2008 4:03 am
by jackssmirkingrevenge
It will work, but you need an airtight and low friction piston (a dismantled bicycle pump would be perfect) and a hefty spring if you want decent power. As I always say in these cases, it's not worth the effort.
The only reason I'd see for making a springer is if you need a compact and self contained launcher that is independent of compressors or air tanks.
Posted: Thu Feb 14, 2008 4:06 am
by Mitchza89
Yeah thats exactly right. I came up with that little plan because I want a average power bb pistol, just something I can use to do some can shooting inside with my mates after a few beers (:D Might be dangerous...) Having a mounted shocky even with a small chamber size, just takes too long to pump up...
Posted: Thu Feb 14, 2008 4:11 am
by jackssmirkingrevenge
Cheap airsoft pistols with tiny pistons and sh!tty springs get 250 fps or so, if you can make the construction strong enough (generous use of epoxy recommended) to allow the trigger to restrain a reasonably powerful spring (you can take a few hints from how
commercial springers are built) I'm sure you can double that at least, especually with a burst disk - though the latter would add complexity to reloading, why not just use an o-ring in the breech to retain the projectile while pressure builds up.
Posted: Thu Feb 14, 2008 4:15 am
by Mitchza89
Yeah thats a good plan you got there Jack. An o-ring would be alot easier and cheaper parts wise. I have a couple of springs from an umbrella mechanism, they are decent sized springs....very, very tough. It's all food for thought anyway

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Posted: Thu Feb 14, 2008 4:21 am
by jackssmirkingrevenge
Don't forget that the wider your piston, the less it has to travel, and make sure the barrel volume is not more than the swept volume of the piston.
Posted: Thu Feb 14, 2008 4:24 am
by Mitchza89
I was planning on using a 5in long piece of 1in poly pipe or a long brass nipple. Hmmm... With a decent de-compression of the spring, at it's peak, what would I be looking at for a PSI level? Just a total rough guess..
Posted: Thu Feb 14, 2008 4:27 am
by jackssmirkingrevenge
Without knowing the strength of the spring (that would give you the maximum theoretical psi possible) and the pressure at which the projectile would start moving, it's impossible to give you an estimate.
Posted: Thu Feb 14, 2008 4:29 am
by Mitchza89
Well what's the PSI peak of an airsoft pistol?
Posted: Thu Feb 14, 2008 6:45 am
by Ragnarok
jackssmirkingrevenge wrote:The only reason I'd see for making a springer is if you need a compact and self contained launcher that is independent of compressors or air tanks.
For which, personally, I would prefer to build a gauss/coil gun - easily run off a small battery pack.
It's going to be more complicated and costly, but timed and built well, and preferably with multiple stages, it can put out a lot more energy.
As well as being a lot cooler... I'd much rather say:
"That's my high pressure air cannon, that's one of my combustions, and that one at the end is my advanced gauss gun."
than:
"... and that one at the end is a BB springer."
It's a nice idea, but as I've said many a time, my experience with springers has been decidedly poor.
Posted: Thu Feb 14, 2008 7:04 pm
by Mitchza89
Hmmm just too many idea's are running through the old noggin'

Ehhhh I don't know...
Posted: Thu Feb 14, 2008 7:50 pm
by Leonard
Ragnarok wrote:
For which, personally, I would prefer to build a gauss/coil gun - easily run off a small battery pack..
Do you mean that the coil mecanism will be pushing the piston (thus creating air pressure) or will the coil mecanism be the actual power source? (metalic material being the ammo in this case)?
Posted: Thu Feb 14, 2008 8:32 pm
by jon_89
Looks like a good idea. What kind of spring are you going to use?