What is a Potato Launcher and How do they Work?
A potato launcher as the name implies, is a launcher or gun, that shoots (propels) a potato, in much the same way as a firearm shoots a bullet, but at a much lower velocity (speed), and uses a different type of ignition and propulsion. You will hear them called many things: spud gun, air cannons, air launchers, potato launcher, potato gun, spud cannon, spudzooka, pneumatic guns, and the list goes on.
Potato launchers come in a variety of shapes, sizes, and configurations. The number of projectiles that can be shot from a potato launcher-spud gun, is only limited by a matching barrel size and your imagination. All spud guns share one thing in common, they all rely on a "rapidly expanding volume of gases" to move the projectile down the launcher barrel. Most launchers are made from pressure rated PVC piping, but many people have made them from ABS, aluminum, steel, iron, or other materials.
NEVER build or use a potato launcher unless it was built with a pressure rated piping. Typical ratings are 220psi and above. You will get hurt. There are 2 basic types of potato launchers:
The Combustion Potato Launcher:
The Combustion Potato Guns function is similar to the "Air or Pneumatic Launcher" but a flammable gas is used instead of air. There are 4 basic components needed for a combustion launcher to work:- A combustion chamber for the gases to reach a high pressure
- A barrel for the projectile (the gas pressure pushes this out)
- A firing device either manual or electronic
- A flammable fuel source that will create the gases
The combustion potato launcher or (spud gun)is typically the simplest and the cheapest type of launcher to build. This is a great first potato launcher if your thinking of building one.
A proper chamber to barrel ratio is essential not just for safety, but for launcher performance. A 1:1 ratio is typical, but moving up to 1.5:1 will not just increase performance, but give you a louder BANG! Because you are dealing with a fuel that is being ignited, you must exercise proper safety precautions or you can and will get hurt.
The Air/Pneumatic Potato Launcher:
The Air/Pneumatic Potato Guns function is a little simpler and usually safer. The "fuel source" is simply compressed air which can be from an air compressor or a regulated tank. There are 4 basic components needed for a pneumatic launcher to work:- An air chamber for the gases to reach a high pressure
- A barrel for the projectile (the air pressure pushes this out)
- A fast valve to dump the air either manual or electronic
- A compressed air source that will create the gases (air is a gas)
The pneumatic potato launcher or (spud gun)is typically a little more costly then the combustion type launcher, but worth the performance increase.
The chamber to barrel ratio is much more flexible with a pneumatic gun, since they are typically used for various activities such as T-shirt launching or other marketing products. Antenna launching, tennis balls, golf balls, and PVC rockets just to name a few. The performance required for a PVC rocket will not be the same as needed to launch a T-shirt into a crowd of people, therefore the flexibility with ratios. Air/Pneumatic launchers typically are greater performers then the combustion launchers and the only real limitation is your imagination. Because you are dealing with a very high pressure, relief valves are typically used to prevent possible ruptures in your launcher, and to stay within the launcher materials pressure ratings. You must exercise proper safety precautions or you can and will get hurt.
There are many ways to charge or pressurize an air gun. Portable air tanks in various sizes, a direct air line connection to a compressor, and even as simple as a bicycle pump for low pressure pneumatic guns. Air guns are more expensive to build then combustion guns, so if cost is your main concern, stick with a basic combustion launcher.