SpudFiles

<div align="center">BDMAC

Burst Disc Mortar Air Cannon

Provided By fiebigspudguns - <a href="http://www.geocities.com/fiebigspudguns ... udguns/</a>

This is the BDMAC. It is a burst disc gun set up to perform like a mortar. It is my first burst disc cannon and can be used as a mortar or as a regular cannon.

The idea behind a burst disc gun is to put a disc of some sort (usually made form aluminum foil) in between the barrel and cahmber. You pressurize the gun and when you have put enough pressure in the disc will burst and release all the air. This is much more efficent than any valve because there is very little (if any at all) air restriction from a valve.

The heart of a burst disc gun is the union. A union is a PVC fitting which allows you to seperate the cahmber from the barrel and then screw them together with a bursat disc inside.

As you may know military mortars are used my dropping a shell into the barrel, and when it hits the bottom the shell is launched. This is the exact same, except without explosives of any sort. To use this mortar you pressurize the chamber and drop in a 'shell'. The shell has a shart point which 'prematurely' bursts the disc as it hits, and launches the projectile.

The shells I use are simply short pieces of 1" dowel rod with a nail sticking out of one end. These are very very cheap, simple, and easy to make.

This is just the basic design and could use much improvement, and some people from the Spudtech Forums are already planning more advanced designs.

One problem that the cannon has is being able to efficently puncture the burst disc, this problem is being worked out with new designs.

This is one of the unefficently punctured burst discs (in a normal burst disc cannon the entire center would be blown out)

Provided By fiebigspudguns - <a href="http://www.geocities.com/fiebigspudguns ... /</a></div>

thats pretty cool, Paint it to get rid of the purple stains. Cool mortar type cannon

how far does it shoot/ HOW MUCH DAMAGE

try putting multiple nails in the bottem?

If I were you i would use razor blades angled slightly down in a square shape(four blades) this would be harder but would give the most efficiency.

sharpen the dowel to a point that wiuld take some time but should puncture the burst disk well

Pneumatic and DWV dont mix...

thats cool i agree with BC No DWV but i still love your cannon the mortar things awesome

You could use a file or Dremel tool to sharpen the nail at a more extreme (i.e acute angle), so there would be less surface area on the tip, which in theory SHOULD penetrate the burst disk well.

wouldent the mortar shell be hard to jam in and because of ur design its not possible to ram it in with somethingso therefore the shell should drop in and that means it isnt airtight... sooo then ur shot wouldent be so powerfull. i want to see ur cannon in action it intrigues me

nice mortar! truly ingenious

Very kool but I've an idea. A reconstruction with dual chambers or just a stand to hold it up and a 45* instead of two 90* being that 45* is the angle at which the greastest trajectory is obtained. To puncture the foil better use 4 or 5 nails depending on how many fit in a circular pattern, may take another minute or so to glue em on but the multiple puncuture will weaken the foil which should cause the entire thing to blow out instead of a single hole.

how do you hold in the aluminum foil? can you post pics?

In between the halves of the union: