What are some of the key differences in how they function and what that means in practical applications?
In: Technology
A coilgun have a coil wrapped around the barrel creating an electromagnet. When you pull the trigger you activate this electromagnet which attracts the projectile to it. When the projectile is moving past the electromagnet you turn it off so that you do not pull it back again. A railgun on the other hand only have two rails going along the barrel. The projectile creates a short circuit between these rails. If you apply a current through the projectile you are essentially creating a coil with only one turn which acts as an electromagnet. But as you activate an electromagnet there are forces pushing it outwards. This is often the source of the buzzing sound you hear in transformers. But since nothing is holding the projectile in place it will just accelerate forward until it loses contact with the rails.
Coilguns are very attractive at first compared to railguns. All the wires are insulated so there is no risk of shock or short circuits. There are much less friction and currents are lower so less heating of the components. You also do not have to worry so much about the projectile losing contact with the rails as it travels down them. However a coilgun requires a lot of precise components to open and close the circuit at the exact right time. For something small like a BB gun this is a nice little challenge. However for much larger projects there just is not components that are both large and precise enough. On the other hand the issues with railguns does not grow as the size of the gun is increased. In fact if you get enough energy some of the problems resolve themselves, such as heating the projectile enough that it contacts the rails much better. And there is no active electronics involved, just capacitors, two rails and a switch. This is why we are actively researching railguns to possibly be used in future warfare while coilguns are more of a novelty concept for small devices.
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