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Preloaded Cartridge Prototype

Built a pneumatic cannon? Then post it here! This section is for completed, finished cannons that you have built. Please include pictures and information.
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Unread postAuthor: Davidvaini » Sun Oct 05, 2008 5:17 pm

oh sometimes they are just kinda hard to get off... rocking the coupling back and fourth really helps in taking it off.. The other method is twisting but that is a little more difficult at times.

oh and btw thanks!

:D
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Unread postAuthor: covey12 » Wed Oct 08, 2008 1:41 pm

how do you fire this, i cant figure it out, plz post a how to make
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Unread postAuthor: Demon » Wed Oct 08, 2008 1:45 pm

how do you fire this, i cant figure it out, plz post a how to make


Do you actually know what is an burst disk?


http://www.spudfiles.com/spud_wiki/index.php/Burst_disk
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Unread postAuthor: Davidvaini » Thu Dec 04, 2008 12:15 pm

update: I have been working on multiple ways to make these shells more efficient. One of the major ways you can make these shells more efficient is by rounding the edges slightly on the pipe.. that way when you push on the coupling it doesnt tear.


Another is to remove the actual shreader valve in the back of the stem.. If you are just overloading pressure into these then the shreader valve is just restricting airflow.

More to come.
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Unread postAuthor: mark.f » Thu Dec 04, 2008 1:24 pm

Couldn't you make the air chamber shorter and up the pressure?

It only seems logical to me since you are going for an airsoft/paintball gun type weapon. They all use small chamber volume coupled with high pressure.
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Unread postAuthor: Davidvaini » Thu Dec 04, 2008 1:30 pm

I could but I would have to find a tougher burst disk material.. Reason I went with this material is because for its width it is extremely strong.. holds about 60 psi. I would love to make it small volume high pressure but untill I find a suitable burst disk material they will have to be around this size..

I did make a smaller shell and painted it black and gold.. this is it:

Image
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Unread postAuthor: mark.f » Thu Dec 04, 2008 1:34 pm

Ah. Didn't see that.

As for the material, why not install some sort of gasket on the male end of the catridge so that you can use conventional burst disks such as pop can aluminum or multiple layers of aluminum foil?
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Unread postAuthor: Davidvaini » Thu Dec 04, 2008 1:46 pm

space requirements to fit in the appropriate size tube.

Besides these babies perform perfect for airsoft.
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Unread postAuthor: SP00K » Thu Dec 04, 2008 3:33 pm

I was making a grenade launcher and was referred to this page about your preloaded cartridges. I really love the concept of the shells being allready to fire. How do you fire them out of the tribarreled gun?

Also, I read that you had some sort of way to mechanically trigger the burst disks instead of just waiting for tehm to break while standing there. (how exactly does that work?)

You had the said that these shells would be made for airsoft, but I don't see the economical fashion of standing there while filling a shell with air pressure in the middle of a close range firefight.

I apologize if I sound like I am trying to find folly in your design, but I do like all of your ideas and figure you have a good answer for my que's.
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Unread postAuthor: mark.f » Thu Dec 04, 2008 6:51 pm

The delay is probably minimal. I used my air compressor to fire off a rather large burst disk cannon (chamber volume wise) and the delay was only a second or two.

I imagine with the high pressure of the CO<sub>2</sub> inflator and the relatively small "chamber" volume, the delay is very small, perhaps negligible.
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Unread postAuthor: Davidvaini » Thu Dec 04, 2008 6:55 pm

when you press the trigger to fill them its almost instant.

So as soon as you press the trigger it fires..
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Unread postAuthor: SP00K » Fri Dec 05, 2008 10:13 am

Yeah, when I wrote that post ^^^, I hadn't realized, people used c02 inflators as triggers to fill spud guns. :roll:
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Unread postAuthor: conman817 » Sun Dec 14, 2008 3:49 pm

thank for this design i made a shell thats more like a rocket launcher out of 1/2" pipe my friends love it thanks but i use alufoil cause im cheap and 4 layers of it holds about 80psi thanks
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Unread postAuthor: ROB » Tue Dec 30, 2008 10:55 pm

I think I have found an improvment, or atleast for my purposes, of this design.

I have been developing a gun based around this preloaded cartridge. (hopefully I will show you all in the near future, Im pretty excited about it)

Anyway I have been fiddling around with the preloaded cartridge, and thought of putting a reducer that went from 1 1/4- 1/2. I then put a half inch tube from the reducer out. well obviously it turned into a crude cannon...of sorts. I got bored with this, and started seeing way's to improve.


I wanted to see what was the best burst-disk meterial. After trying alot of crap. I always came back to ALUMINUM FOIL.(not so much the tape.)
So I wanted to see how much I could put on, before the coupler would not fit. I ended up putting on 8. The coupler flew off and hit the side of my deck(over 20ft away). I was astounded. I then whipped out my hammer....puting 12 layers on this time, I pounded the crap(pardon) out of the coupler. I not only managed to get it on ,but also all the way down.
Shot it (and because of the half inch tube) made a welding rod dart, go through my cedar fence at over 150ft away (the tube was only 2ft long).

as of right now, I am happy with this improvment (even if it is slight).
The cannon I am working on right now is based off of this.

just thought I would share this....

P.S- I can't get the coupler off after this.....to many layers
(beleive me I have tryed)....just be aware if you try this.
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Unread postAuthor: Davidvaini » Thu Feb 26, 2009 11:36 pm

New project that incorporates my 3/4" shells:

Image

link to the thread:

http://www.spudfiles.com/forums/viewtop ... tml#232938
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