A potato cannon, also known as a potato gun or potato launcher, is a pipe-based cannon that uses air pressure (pneumatic), or combustion of a flammable gas (aerosol, propane, etc.), [1] [2] [3] [4] to fire projectiles, usually potatoes. [5] A simple design consists of a pipe sealed on one end, with a reducer on the other end to lower the diameter of the pipe, which has the corresponding lower-diameter pipe attached to it, called the barrel. Generally, the operator loads the projectile into the barrel, then utilizes a fuel or air pressure (or sometimes both) to propel the projectile out of the cannon.
The potato cannon can trace its origin to the World War II-era Holman Projector, which was a shipboard anti-aircraft weapon. [6]
Combustion powered potato cannons typically have the least complex designs; the four basic elements of which are:
In order to fire, the operator loads a projectile into the barrel, adds fuel to the combustion chamber (for example aerosols or propane), and triggers the ignition source (often using a piezoelectric barbecue igniter). The fuel-air mixture then ignites, creating hot expanding gases which force the projectile out of the barrel. The range of the cannon depends on many variables, including the type of fuel used, the efficiency of the fuel/air ratio, the combustion chamber/barrel ratio, and the flight characteristics of the projectile. Common distances vary from 100–200 meters (330–660 feet), and there is a reported case of a cannon exceeding 500 meters (1,600 feet) of range. [7]
The range of pneumatic cannons is more variable than the range of combustion potato cannons 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 (3,300 ft). [8]
In order to fire, the operator first readies the pressure-triggered valve then injects several times the normal amount of fuel and appropriately more air. When the ignition source is triggered, the pressure from the combustion causes the main valve to open and propels the projectile out of the barrel with the released combustion gases. The hybrid is capable of higher velocities than a combustion or pneumatic potato cannon because the pressure generated is higher than that in a combustion gun (for most fuels), and the shock wave moves faster than it can in a pneumatic (for most gases), due to the higher temperature. Projectiles fired by a hybrid have broken the sound barrier. [9]
The oldest examples simply involve dropping pieces of dry ice into a tube closed at one end and sealing the other end by jamming the projectile in. When the pressure of the carbon dioxide from the subliming dry ice builds high enough, the projectile will be blown out of the tube. [10]
Alternate designs have also been used which use a sharp projectile to puncture the burst disk, like a mortar [15] or using a manual puncturing device to trigger failure of the disk. [16]
It is rare for a potato cannon to be powerful enough to break the sound barrier, although there are some cases of this happening using specialized designs. The potato cannons used are typically hybrids; but some pneumatic cannons have achieved the feat, either by using a special low-density gas, such as helium, [19] or high pressures combined with a fast valve. [20] There is also one reported case of a combustion design achieving super-sonic velocities. [7]
The highest projectile speed recorded from a potato cannon is 933.3 m/s (3,060 ft/s) (approximately 2.7 times the speed of sound) with a 16.6-gram (256 gr) 20 mm plastic slug from a hybrid using a 20 MPa (2,900 psi) pre-ignition mixture of air and propane. [21]
Supersonic velocities have been obtained using the related vacuum bazooka with a de Laval nozzle. This also relies on significantly lowering the density of the gas. [22]
Although potato cannons are created and used for the purpose of recreation there are other devices which work on identical principles in many other fields with more serious uses.
Potato cannons by nature are hazardous and can present safety issues if poorly constructed or used. Projectiles or failing guns can be dangerous and result in life-threatening injuries, including cranial fractures, enucleation, and blindness if a person is hit. [25]
A bullet is a kinetic projectile, a component of firearm ammunition that is shot from a gun barrel. They are made of a variety of materials, such as copper, lead, steel, polymer, rubber and even wax; and are made in various shapes and constructions, including specialized functions such as hunting, target shooting, training, and combat. Bullets are often tapered, making them more aerodynamic. Bullet size is expressed by weight and diameter in both imperial and metric measurement systems. Bullets do not normally contain explosives but strike or damage the intended target by transferring kinetic energy upon impact and penetration.
An air gun or airgun is a gun that uses energy from compressed air or other gases that are mechanically pressurized and then released to propel and accelerate projectiles, similar to the principle of the primitive blowgun. This is in contrast to a firearm, which shoots projectiles using energy generated via exothermic combustion (detonation) of chemical propellants, most often black powder or smokeless powder.
Recoil is the rearward thrust generated when a gun is being discharged. In technical terms, the recoil is a result of conservation of momentum, as according to Newton's third law the force required to accelerate something will evoke an equal but opposite reactional force, which means the forward momentum gained by the projectile and exhaust gases (ejectae) will be mathematically balanced out by an equal and opposite momentum exerted back upon the gun.
Gas gun may refer to:
A gun barrel is a crucial part of gun-type weapons such as small firearms, artillery pieces, and air guns. It is the straight shooting tube, usually made of rigid high-strength metal, through which a contained rapid expansion of high-pressure gas(es) is used to propel a projectile out of the front end (muzzle) at a high velocity. The hollow interior of the barrel is called the bore, and the diameter of the bore is called its caliber, usually measured in inches or millimetres.
The J-2, commonly known as Rocketdyne J-2, was a liquid-fuel cryogenic rocket engine used on NASA's Saturn IB and Saturn V launch vehicles. Built in the United States by Rocketdyne, the J-2 burned cryogenic liquid hydrogen (LH2) and liquid oxygen (LOX) propellants, with each engine producing 1,033.1 kN (232,250 lbf) of thrust in vacuum. The engine's preliminary design dates back to recommendations of the 1959 Silverstein Committee. Rocketdyne won approval to develop the J-2 in June 1960 and the first flight, AS-201, occurred on 26 February 1966. The J-2 underwent several minor upgrades over its operational history to improve the engine's performance, with two major upgrade programs, the de Laval nozzle-type J-2S and aerospike-type J-2T, which were cancelled after the conclusion of the Apollo program.
Smokeless powder is a type of propellant used in firearms and artillery that produces less smoke and less fouling when fired compared to black powder. Because of their similar use, both the original black powder formulation and the smokeless propellant which replaced it are commonly described as gunpowder. The combustion products of smokeless powder are mainly gaseous, compared to around 55% solid products for black powder. In addition, smokeless powder does not leave the thick, heavy fouling of hygroscopic material associated with black powder that causes rusting of the barrel.
A pneumatic weapon is a weapon that fires a projectile by means of air pressure, similar in principle to the operation of pneumatic tube delivery systems. The term comes from a Greek word for "wind" or "breath" (πνεῦμα).
A piston valve is a device used to control the motion of a fluid or gas along a tube or pipe by means of the linear motion of a piston within a chamber or cylinder.
The light-gas gun is an apparatus for physics experiments. It is a highly specialized gun designed to generate extremely high velocities. It is usually used to study high-speed impact phenomena, such as the formation of impact craters by meteorites or the erosion of materials by micrometeoroids. Some basic material research relies on projectile impact to create high pressure; such systems are capable of forcing liquid hydrogen into a metallic state.
The Super High Altitude Research Project was a U.S. government project conducting research into the firing of high-velocity projectiles high into the atmosphere using a two-stage light-gas gun, with the ultimate goal of propelling satellites into Earth orbit. Design work on the prototype space gun began as early as 1985 at the Lawrence Livermore National Laboratory in California and became operational in December 1992. It is the largest gas gun in the world.
The Holman Projector was an anti-aircraft weapon used by the Royal Navy during World War II, primarily between early 1940 and late 1941. The weapon was proposed and designed by Holmans, a machine tool manufacturer based at Camborne, Cornwall. A number of models were produced during the war years, but all worked on the principle of a pneumatic mortar, using compressed air or high pressure steam to fire an explosive projectile at enemy aircraft.
A paintball marker, also known as a paintball gun, paint gun, or simply marker, is an air gun used in the shooting sport of paintball, and the main piece of paintball equipment. Paintball markers use compressed gas, such as carbon dioxide (CO2) or compressed air (HPA), to propel dye-filled gel capsules called paintballs through the barrel and quickly strike a target. The term "marker" is derived from its original use as a tool for forestry personnel to mark trees and ranchers to mark wandering cattle.
Model warship combat is an international club activity, in which participants construct radio-controlled scale models of actual warships, most commonly those built by various nations prior to 1946, such as the USS Des Moines or the German battleship Bismarck. The models are armed with pneumatic cannons, and fight against one another on ponds and lakes. Model warship combat is sometimes considered to be a form of Naval Wargaming, but can also be considered a water-based version of Robot Combat, since much of the internal systems and concepts are the same as radio control electronics, and in some cases possess similar pneumatic systems.
A bamboo cannon is a type of home-made firecracker which is popular during the Eid season in Malaysia and Indonesia, as well as during New Year's Eve celebrations in the Philippines.
A combustion light-gas gun (CLGG) is a projectile weapon that utilizes the explosive force of low molecular-weight combustible gases, such as hydrogen mixed with oxygen, as propellant. When the gases are ignited, they burn, expand and propel the projectile out of the barrel with higher efficiency relative to solid propellant and have achieved higher muzzle velocities in experiments. Combustion light-gas gun technology is one of the areas being explored in an attempt to achieve higher velocities from artillery to gain greater range. Conventional guns use solid propellants, usually nitrocellulose-based compounds, to develop the chamber pressures needed to accelerate the projectiles. CLGGs' gaseous propellants are able to increase the propellant's specific impulse. Therefore, hydrogen is typically the first choice; however, other propellants like methane can be used.
Pneumatic cannon may refer to:
A gun is a device designed to propel a projectile using pressure or explosive force. The projectiles are typically solid, but can also be pressurized liquid, or gas. Solid projectiles may be free-flying or tethered. A large-caliber gun is also called a cannon.
A ram accelerator is a device for accelerating projectiles or just a single projectile to extremely high speeds using jet-engine-like propulsion cycles based on ramjet or scramjet combustion processes. It is thought to be possible to achieve non-rocket spacelaunch with this technology.
A vacuum bazooka is a pipe-based cannon which uses a vacuum pump to reduce pressure in front of the projectile and therefore propel a projectile as a result of the air pressure acting on its reverse. The concept was originally proposed by Neil A Downie in 2001 but many variations have been built since.
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