Simple Air Cannon

For Christmas this year, I was given a copy of Backyard Ballistics. Now all of the information in the book is widely discussed on the internet but there is value in having it pulled together in one place. And, with a genuine vacation from work, I was determined to make use of the information immediately since I knew I wouldn’t get to it later.

The chosen project was a PVC cannon powered by compressed air. One sprinkler system install gave me all the PVC experience I’ll probably ever need and since explosives always drive down the wife acceptance factor, compressed air seemed like the way to go. The heart of it is just a large diameter PVC pipe to act as the chamber and then an electronically controlled sprinkler valve to let it loose in a burst. Since internally these valves have a large disk diaphragm, once the switch is thrown, a large volume of water (or air) can flow by quickly. So after a quick rummage through my box of PVC leftovers and a trip or two to Lowe’s I had everything I needed.

After some very cautious testing of the tank (which went up to 60PSI without any sign of stress) I started launching things for real. My chosen projectile was a left over wrapping paper tube, slit down the side and tightened around the outside of the barrel. A leftover end cap taped to the tip gave it the right front heavy weighting.

The effect was mighty impressive, at least to me. Shooting at 20psi the arrow flew across the street to the neighbor’s gutter. You can’t follow the arc, but you get the idea from this clip.. Bumping it up to 30psi sent the arrow very close to the neighbor’s red pickup you can see in the driveway here.

Eventually the paper got too weak and the back side ripped out during a shot. Still, it was loads of fun and I’m sure it will come in handy some day for…uh…baseball practice?