cartridge combustion - initial test video

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Postby fullmetaljacket » Thu Apr 06, 2006 11:16 am

Following my recent <a href="http://localhost/forums/viewtopic.php?t=12983">experimentation</a> with the practicality of having a combustion launcher that uses a reloadable cartridge which is ejected after firing, I've come up with a design for such a launcher and the cartridge it will use:

<a href="http://www.greatestjournal.com/"><img src="http://pictures.greatestjournal.com/userimg/5865081/512443" width="552" height="386" alt="GreatestJournal Free Photo Hosting"></a>

Cartridge end view, featuring exposed contacts that complete the circuit with the ignitor when touching the bolt face.


<a href="http://www.greatestjournal.com/"><img src="http://pictures.greatestjournal.com/userimg/5865083/512443" width="626" height="389" alt="GreatestJournal Free Photo Hosting"></a>

Launcher oblique view. At rest, the bolt face touches the cartridge base and allows the circuit to be made. On firing, the spring delays the movement of the cartridge, ensuring the projectile would have left the barrel when the breech is out of the chamber. The cartridge will continue to travel backwards until it strikes the ridge in the breech structure that will tip it out towards the side. If a gravity fed magazine is in place, a new cartridge should drop into the breech and be fed into the chamber by the return spring.
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Postby BC Pneumatics » Thu Apr 06, 2006 11:26 am

Looks nice, it would be great if you got it working. Does this alter the legality though? I know, at least in CA, air guns that store the air in a cartrage are illegal, so hopefully something similar doesnt restrict this.
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Postby fullmetaljacket » Thu Apr 06, 2006 12:04 pm

The legality issue was discussed <a href="http://localhost/forums/viewtopic.php?t=10827&SearchTerms=cartridge">here</a> when I first mentioned the idea, since I don't intend to use any finished prototype off my propert and to commit felonies I'm not too worried about legal issues.
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Postby BC Pneumatics » Thu Apr 06, 2006 12:13 pm

Haha, alright. I had missed that thread... just make sure nothing happens ;)
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Postby fullmetaljacket » Thu Apr 06, 2006 1:10 pm

I'm hoping the final result will look something like the <a href="http://www.obscure-reference.com/guns/bfr/BFR_Lahti.jpg">Lahti L-39 anti-tank rifle</a>, not something you'd want to be seen running around with :D
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Postby rsgpit » Thu Apr 06, 2006 2:27 pm

Why the epoxy plug? How about using a PVC plug and drilling the holes for the wires.
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Postby fullmetaljacket » Thu Apr 06, 2006 6:36 pm

<blockquote id="quote"><font size="1" face="tahoma,verdana,arial" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by rsgpit</i>
Why the epoxy plug? How about using a PVC plug and drilling the holes for the wires.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Simply because that's the construction method I'm used to.

And to answer SPG's fuelling question on the other <small>now locked</small> thread, I'm metering 4 ml (3% of the total volume) of butane from an upright lighter refill can into a syringe, which I then inject into the cartridge, the latter being cap quickly adterwards with the projectile.
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Postby fullmetaljacket » Sat Apr 08, 2006 1:38 pm

I built an experimental "cradle" with a spring loaded bolt featuring contacts wired to the ignitor that mate with the base of the cartridge.

Note that the ejector that would tip the cart out sideways is not yet fitted.

<b><a href="http://209.245.59.44/Gimme/46387620/577477401/93017009/B0186649-AE92-422C-B64E-61A52F4D0585/0.473048/2/DSCF1120.AVI" target="_blank">- = combustion cartridge test fire video = -</a></b>

<b><a href="http://209.245.59.44/Gimme/46387620/979616251/93019610/B0186649-AE92-422C-B64E-61A52F4D0585/0.704302/2/DSCF1121.AVI" target="_blank">- = test video #2, with slightly better lighting = -</a></b>

if that doesn't work, here they are on putfile:

<b>http://media.putfile.com/carttest

http://media.putfile.com/carttest2</b>

<small>edit - putfile sucked, uploaded to streamload
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Postby saladtossser » Sat Apr 08, 2006 2:26 pm

putfile does not suck, in fact its way way way better than streamload

<blockquote id="quote"><font size="1" face="tahoma,verdana,arial" id="quote">quote:<hr height="1" noshade id="quote">Download Error

TOO MANY RECENT DOWNLOAD LOCATIONS

The URL you are using to download this file from has been used from too many different locations. Please wait a while before trying again.

Sorry for the inconvenience.

Contact us if you have any questions, and please include the URL of this document in your correspondence.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

anyways, how many cartridges do you plan on making? and how do u vent it? fill it up with water and dump the water?
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Postby fullmetaljacket » Sat Apr 08, 2006 2:50 pm

<blockquote id="quote"><font size="1" face="tahoma,verdana,arial" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by saladtossser</i>
anyways, how many cartridges do you plan on making? and how do u vent it? fill it up with water and dump the water?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

If I manage to get it to eject the fired cart and load a new one, I was planning on a 4 round clip similar to the 40mm bofors cannon:

<img src="http://inert-ord.net/usa03a/usa5/40mm/usn3.jpg" alt="">

The cartridge is very simple and would be easy to make in small quantities.

As regards to venting, I find a 3 second burst of air from my blowgun into the mouth of the cartridge works very well.
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