Spud Cannon
What is a spud cannon?
A spud cannon, or spud launcher, is a device used to fling objects, such as potatoes, at high speeds over large distances. There are three variations of the spud cannon: combustion, pneumatic, and hybrid. Today we will only be going over the combustion variation.
How does it work?
A combustion cannon consists of two main sections. The combustion chamber and the barrel. For this project i used a 3″x2′ PVC pipe for the chamber, and a 1 1/2″x4′ PVC pipe for the barrel. The object is placed in the barrel and pushed down to the front of the combustion chamber. The chamber is then filled by quickly spraying a little bit of propane into it. Remember, if there is too much fuel(propane) there will not be enough oxygen and it will not ignite. Once the combustion chamber is fuled and sealed it is then ignited. Mine is ignited with an inexpensive BBQ lighter that creates a spark in the chamber to ignite the gas. The hot gas greatly expands, creating pressures of up to 60 psi. This is much like what happens in the cylinder of a car. This high pressure created by the explosion forces the object out at high speeds.
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Here is what the igniter looks like on the inside of the combustion chamber. The spark occurs between the peice of wire and the end of the BBQ igniter. |
Here is what the igniter looks like on the outside. I like the Big Red Button look of it. You can see that it was not fully sealed and some of the explosion escaped out and left those brown, charred marks. Future models should be sealed here to improve effeicency. |
Related Books:
Backyard Ballistics
