Potato Cannon!

It seems 2004 – 2005 was a a busy year for me. I also started to make a Auto-loading potato/tennis ball cannon.

I already had a manually loading one which could shoot a tennis ball 100+ meters or so. But i wanted to one up it. and in comes the idea of a auto-loading, auto- priming cannon. Now the reason i was using tennis balls was; A, they were a uniform shape; B, the fuzz on the ball enabled it to have a perfectly snug fin in the bore of some PVC Tubing i had. Not too tight that it wouldn’t fire out and/or explode the combustion chamber in my face. Not too loose that it would fall out or into the combustion chamber. In other words “a perfect eggie” (sorry, inside joke, my mates will get it tho).

Probably the best, most fun part of this project was that it involved a bit of automation. Figuring out a logical sequence then the way to do it involving mechanical and electrical methods is that i find challenging and fun. Even if its just a motor, gas supply, and valve, all with a couple of relays which latched or disconnected based on micro-switches. A pretty dumb setup really but that was all it needed and it worked, for the most part anyway. The Gas Supply was on the side of the chamber with a regulator and 12v solenoid gas valve to turn it on and off.

The project got pretty far, to the point where i could load balls at the push of a button and i was testing the combustion mixture. But the mixture tuning became too hard and it needed forced aspiration to stop it melting itself. So after it melted the sealing taper of the chamber i gave up.

check out the video of what it did below: