page_title: Potato cannon
section_title: Pneumatic launchers
hierarchical_section_title: Potato cannon / Launcher types / Pneumatic launchers
caption_attribution_description: English: Spud gun Summary The projectile is loaded in the muzzle (not pictured), and the muzzle is attched to the gun (at 2). The air reservoir (3) is filled to 120 PSI using the schrader valve (4). Upon opening the solenoid valve (1), the air from the reservoir is transferred to the projectile, which is fired out of the muzzle.
context_page_description: A potato cannon is a pipe-based cannon which uses air pressure, or combustion of a flammable gas, to launch projectiles at high speeds. They are built to fire chunks of potato, as a hobby, or to fire other sorts of projectiles, for practical use. Projectiles or failing guns can be dangerous and result in life-threatening injuries, including cranial fractures, enucleation, and blindness if a person is hit.
  The potato cannon can trace its origin to the World War II-era Holman Projector, which was a shipboard anti-aircraft weapon.
context_section_description: Pneumatic launchers are considered a little more difficult to build due to the need of a completely airtight construction. These cannons have four basic components:
  A filling valve
  An air chamber
  A pressure release valve
  A barrel
  In a pneumatic spud gun, air is pumped into the pressure chamber. After the desired chamber pressure is reached, the pressure release valve is opened, allowing the gas to expand down the barrel, propelling the projectile forwards.
  The filling valve is usually a commonly available type such as a Schrader or Presta valve but other assemblies to pressurise the cannon such as quick release connections with ball or check valves have been used.
  The pressure release valve is often one of a variety of commercially available types such as a plumbing ball valve, an irrigation sprinkler valve or a quick exhaust valve. Experienced builders often make their own valves for this purpose to gain greater flow and faster actuation. The most common custom design used is the piston valve. Multiple valves arranged to be triggered together are occasionally used as an alternative to a single larger valve.
  The range of pneumatic cannons is more variable than the range of combustion spud guns due to the increased variation possible in the components. Typical ranges are slightly higher because of the greater power, but the maximum range of some high power pneumatic cannons has been said to be over 1,000 metres (1,100 yd).
  Pneumatic spud guns are generally more powerful than combustion spud guns. A typical combustion gun generates average chamber pressures of about 30 psi (210 kPa) with peaks of around 70–100 psi (500–700 kPa), while the average pneumatic gun can operate at pressures in the vicinity of 100 psi (700 kPa). In recent times, it has become increasingly common for metal pneumatic launchers to use even higher pressures, sometimes up to 500 psi (3.4 MPa) or higher.
caption: A large pneumatic design: The projectile is loaded in the muzzle (not pictured), which is then attached to the cannon (at 2). The air reservoir (3) is filled to 120 psi (0.83 MPa) using the Schrader valve (4). Upon opening the solenoid valve (1), the air from the reservoir is transferred to the projectile, which is fired out of the muzzle.
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