Category Archives: PNEUMATICS

Range Testing Theory for Spud Guns (Or any Projectile)

Going through my files, I came across this discussion that I wrote about the science behind spud guns (For actual guns that I’ve built, check out this mini-bolt-action model or this double-barrel pneumatic air cannon). If you’re interested in calculating the range of a projectile thrower of any kind, this discussion may be of some use to you.  I don’t recommend building a spud gun, and this whole discussing was written while I was still in college, so keep that in mind (also, where you see: “X^2” or “V0^2” etc that means X or whatever variable squared):

Spud Gun Testing and Ballistics

One thing that applies to both pneumatic and combustion spud guns is that the range of your cannon is related to the muzzle velocity or velocity at the end of the barrel. When a potato –or your choice of projectiles- is shot from your cannon, it has a certain velocity. This gives the potato some kinetic energy which hurls it away from the earth. Unfortunately, Read more »

The Double-barrel Pneumatic Air Cannon

After restoring my mine bolt-action potato cannon, I decided that the double-barrel cannon that resided in my garage would be interesting to get working again.  It hadn’t been fired in several years, and one of the valves no longer worked.  Additionally, it leaked badly, so I had my work cut out for me.  Here’s a picture of the gun partially restored before any sort of leak testing or firing (Read on for another video at the end):

double barrel PAC on ground

The principle behind this gun, or most pneumatic air cannons, Read more »

The Miniature Bolt-Action Pneumatic Potato Gun: Part 3 – Putting Everything Together

So I’ve gone over the mechanical design of the bolt mechanism as well as the pneumatics involved.  However, I didn’t really go over putting everything together.  This device was actually constructed a few years ago and sat around in my garage since then.  It’s been a very popular post so far, so I’m glad I dug it up.

mini pneumatic potato cannon being assembledBefore recently, all the components just sat around together and were fired that way.  To make it really work, I needed some sort of stock to hold everything together.  After some thought, I used a 9 inch piece of 2 x 4 drilled out with hole saws to accommodate the different sizes of pipe.  I also cut a hole in the side to allow for better gripping.

Besides the grip hole, Read more »