Spotlight: Spud GunsHello everyone, today I'm starting a new feature - PotatoTech! This feature will spotlight various aspects of potatoes and their use in technology. For this first one, I'm going to highlight something everyone's probably heard of, but you may not know much about - the Spud Gun (aka Potato Cannon). Check it out after the jump:
The construction of a spud gun is sort of like a right of passage for potato enthusiasts. Just as a Jedi must construct his own lightsaber, a potato enthusiast must at some point plan and build a potato cannon.
They're pretty much the same
Potato cannons, besides being fun, are also educational devices - they teach the user valuable physics knowledge, such as kinematics of objects in motion and in free fall. One can learn to calculate exactly how far a potato will fly based on the amount of pressure produced at launch and the angle of the cannon (this is known as the potato's trajectory).
This animation from Wikipedia shows three potatoes launched at the same angle but at differing speeds. As you can see, the distance traveled is proportional to the start velocity.
There are two primary types of potato cannons: pneumatic and combustion-based. A pneumatic cannon relies on compressing the air inside the chamber and then releasing it all at once using a valve. A combustion cannon works by igniting an aerosol inside the combustion chamber, which then expands and produces hot gasses tha generate the pressure to launch the potato.
Although both rely on the same basic principle (that is, high pressures are produced which accelerate the potato towards the lower pressure atmosphere), their construction designs differs significantly, and pneumatic cannons are generally considered to be the more dangerous of the two, because they can launch potatoes at extremely high, even lethal, speeds. The combustion type of course ejects a flame, but in general the amount of pressure generated is much lower, and therefore the tube is less likely to experience structural failure (aka BOOM). Additionally, pneumatic cannons are harder to construct. So in the potato cannon community, a combustion cannon is usually the "beginner" step, and you would advance to more sophisticated, pneumatic cannons.
Here's a video (not mine) of a pneumatic cannon in action. The raw power of these devices in shown in this video.
Compare this to a video of a combustion cannon (again not mine). Although this cannon is louder, as you can see it is.... oh...... oh god... that had to hurt... Watch the recoil on these things!
The last thing I'd like to touch on is safety. (As always, safety last! wait...) These cannons can be fun and educational if used in a safe manner. It is legal to shoot potato cannons for personal use in most states and counties (at least in the United States), but often the laws are written such that as soon as you do any damage or harm anyone, the potato cannon is treated as a firearm in the ensuing arrest and trial. So BE CAREFUL and make sure you look into these laws before attempting to build or use a spud gun.
Finally, here's mine! (Note, this was before I wrapped the entire thing with Gorilla Tape to minimize damage if it ever fails) Doesn't look like much, and it's not too powerful, but it's LOUD and fun!
Well that's it. Anyone have anything to add? Anyone here built one of these things? Leave a comment!