Gunpowder has long been the propellant of choice to launch a projectile from a weapon. But the fine gray powder does have three major limitations:
- Gunpowder must be carried with the projectile, making the entire round heavier.
- Ordnance based on black powder is volatile, and so difficult to handle and transport.
- The muzzle velocity of projectiles propelled by gunpowder is generally limited to about 4,000 feet (about 1,219 meters) per second.
Is it possible to overcome these challenges? One solution is the electromagnetic rail gun, or rail gun for short. Using a magnetic field powered by electricity, a rail gun can accelerate a projectile up to 52,493 feet (16,000 meters) per second. And while current Navy guns have a maximum range of 12 miles, rail guns can hit a target 250 miles away in six minutes.
How many games have you played that featured a railgun as a weapon? I’m guessing just a few under a thousand. From Halo to Stargate to the movie Eraser, railguns are just as much a part of the sci-fi genre as bad acting and large-chested blue aliens. Now however, railguns are no longer science fiction. They are a reality for the US Navy.
The Navy demonstrated its new toy at the Naval Surface Warfare Center. The weapon uses electromagnetism to propel non-explosive projectiles to high speeds. The new weapon should increase the range of US Navy vessels as well as decrease the cost. The railgun is expected to replace the expensive Tomahawk missile saving the Navy a lot of money. Because of the speed of the projectile launched from such a weapon, it might be a cheap and efficient way to shoot down incoming missiles.
“It’s pretty amazing capability, and it went off without a hitch,” said Capt. Joseph McGettigan, commander of NSWC Dahlgren Division. He continued, “The biggest thing is it’s real–not just something on the drawing board.”
According to Wikepedia, “A Railgun is a type of Magnetic Accelerator Gun (MAG) that utilises an electromagnetic force to propel an electrically conductive projectile that is initially part of the current path.”
Don’t look for a hand-held model anytime soon. The full version, meant for Navy destroyers, will require an enormous amount of electrical energy to fire. The next generation of Navy destroyers are built to be all electrical, allowing for energy to be diverted from the engines to the railgun as needed. The gun would be able to fire a 40 pound projectile up to 6 times a minute, no faster because of the weight of the projectile and the amount of energy required. The projectile would actually leave earths orbit and reenter under satellite guidance. The force of the impact would destroy targets with no chemical explosive needed. Three main parts are required;
The power supply is simply a source of electric current. Typically, the current used in medium- to large-caliber rail guns is in the millions of amps.
The rails are lengths of conductive metal, such as copper. They can range from four to 30 feet (9 meters) long.
The armature bridges the gap between the rails. It can be a solid piece of conductive metal or a conductive sabot — a carrier that houses a dart or other projectile. Some rail guns use a plasma armature. In this set-up a thin metal foil is placed on the back of a non-conducting projectile. When power flows through this foil it vaporizes and becomes a plasma, which carries the current.
Rail guns are of particular interest to the military, as an alternative to current large artillery. Rail gun ammunition, in the form of small tungsten missiles, would be relatively light, easy to transport and easy to handle. And because of their high velocities, rail gun missiles would be less susceptible to bullet drop and wind shift than current artillery shells. Course correction would be important, but all missiles fired from rail gun artillery would be guided by satellite.
It would be more difficult to engineer small arm rail guns, mainly because of recoil. Recoil, the backward action of a firearm upon discharge, is determined by the momentum of the escaping projectile. Multiplying a projectile’s mass by its velocity yields its momentum, which for high-velocity rail gun projectiles would be considerable. A portable rail gun that fires very small bullets may be the solution. A small bullet would limit recoil but still carry enough kinetic energy to inflict serious damage.
Rail guns have also been proposed as important components of the Strategic Defense Initiative, popularly known as Star Wars. Star Wars is a U.S. government program responsible for the research and development of a space-based system to defend the nation from attack by strategic ballistic missiles. Rail guns could fire projectiles to intercept the incoming missiles. Some scientists argue that rail guns could also protect Earth from rogue asteroids, by firing high-velocity projectiles from orbit. Upon impact, the projectiles would either destroy the incoming asteroid or change its trajectory.
Rail guns have some interesting non-military applications as well. For one thing, they could potentially launch satellites or space shuttles into the upper atmosphere, where auxiliary rockets would kick in. On bodies without an atmosphere, such as the moon, rail guns could deliver projectiles to space without chemical propellant, which requires air to function.
Rail guns have also been proposed as important components of the Strategic Defense Initiative, popularly known as Star Wars. Star Wars is a U.S. government program responsible for the research and development of a space-based system to defend the nation from attack by strategic ballistic missiles. Rail guns could fire projectiles to intercept the incoming missiles. Some scientists argue that rail guns could also protect Earth from rogue asteroids, by firing high-velocity projectiles from orbit. Upon impact, the projectiles would either destroy the incoming asteroid or change its trajectory.
Rail guns have some interesting non-military applications as well. For one thing, they could potentially launch satellites or space shuttles into the upper atmosphere, where auxiliary rockets would kick in. On bodies without an atmosphere, such as the moon, rail guns could deliver projectiles to space without chemical propellant, which requires air to function.
Rail guns could also be used to initiate fusion reactions. Fusion occurs when two small atomic nuclei combine together to form a larger nucleus, a process that releases large amounts of energy. Atomic nuclei must be traveling at enormous velocities for this to happen. On the earth, some scientists propose using rail guns to fire pellets of fusible material at each other. The impact of the high-velocity pellets would create immense temperatures and pressures, enabling fusion to occur.
Many of these applications remain in the realm of theory, experimentation and development. Current rail guns do not generate sufficient energies to enable nuclear fusion to occur, for example. And it will likely be 2015 before an all-electric battleship uses a rail gun to launch projectiles at an enemy.
Still, the technology is promising. In 2003, the British Ministry of Defense hosted a one-eighth-scale test of an electromagnetic rail gun that achieved a muzzle velocity of Mach 6, or approximately 2,040 meters per second.
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