Navy Railgun Tests Leading to Ship Superweapon by 2020

jonesy · Mar 5, 2012

Dannyalcatraz said:
Besides, even if the odds are vanishingly small, how'd you like to be the lucky officer who won the "I just shot an expensive satellite with my backblast" lottery?

Or even "I just accidentally destroyed a colony on Mars".

Umbran · Mar 5, 2012

Kzach said:
Could you propel a form of energy using a rail-gun?

A rail gun operates by running a large electric current up one rail, through the projectile, and down the other rail. The currents create magnetic fields that interact, and the result is a force on the projectile parallelto the rails.

So, no. Not unless your "energy" is a solid conductor of electricity.

Joker · Mar 5, 2012

jonesy said:
Or even "I just accidentally destroyed a colony on Mars".

Or even "I just started a war with the Klingons".

Dannyalcatraz · Mar 5, 2012

"Dammit- Earth shot first!"

Kzach · Mar 5, 2012

Umbran said:
So, no. Not unless your "energy" is a solid conductor of electricity.

You couldn't push a gas, like say a plasma?

Mustrum_Ridcully · Mar 5, 2012

Kzach said:
You couldn't push a gas, like say a plasma?

I am not sure, but at least plasma is ionized gas, e.g. that means it will react to electrical currents.

But while sci-fi loves plasma weapons, they aren't really practical weapons. At least not in the idea "Let's shoot tiny bolts of plasma". Plasma is gas.
You're basically trying to shoot (hot) air. That's also ionized, which means that it will even have a stronger inherent effect to expand (more so than just hot air). It's already bad in a pressurized enviroment, but it gets worse in vacuum.

Maybe you could put that plasma into a bullet, so it doesn't expand. But then the question is - can you really create a form of plasma that significantly adds to the bullet's impact - and also be better than filling the bullet with an explosive?

Kzach · Mar 5, 2012

Ah, well, the density of the plasma would matter but at the same time, the idea would be to shoot it along an ionised path, like say a laser-beam? It'd then be a sort-of ray-l-gun

Umbran · Mar 5, 2012

Kzach said:
You couldn't push a gas, like say a plasma?

Well, let's note that you started with "form of energy". Gas and plasma (which is just ionized gas) are not "forms of energy" any more than your body, or any physical matter, is a "form of energy".

But no, you can't accelerate a gas or plasma with a rail system like you can a solid projectile. If you jump a current through a gas or plasma, you get a lightning bolt, which heats the gas and disperses it, rather than moves it in one direction cohesively, and the next instant the current passes through *different* atoms of gas, rather than the same gas. The projectile being able to slide, but solid, is required for the rail system to work.

There are ways to accelerate charged particles. Every CRT TV and monitor does this. So do the ion drives for spacecraft currently under development. They just do it differently than rail systems do.

TanisFrey · Mar 6, 2012

El Mahdi said:
You're forgetting that the projectile also has a magnetic field. It's the opposing magnetic fields between the projectile and the rails that propel the projectile. The magnetic field generated by the rails is essentially "fixed" to the barrel. The force generated by the two fields both push the projectile out (at an extreme velocity) and also push the weapon back (recoil).

Recoil is very much a consideration. The larger the projectile (such as a larger guided projectile vs. a simple slug) the more recoil there is.

There is a difference by stating a rail-gun would minimizing recoil rather than eliminate it. I did state that a rail-gun will minimize recoil.

The projectile does not need to have its own magnetic field, alto it helps. All you need is ferrous metal, that is metal that reacts to a magnetic field.

Nagol · Mar 6, 2012

TanisFrey said:
There is a difference by stating a rail-gun would minimizing recoil rather than eliminate it. I did state that a rail-gun will minimize recoil.

The projectile does not need to have its own magnetic field, alto it helps. All you need is ferrous metal, that is metal that reacts to a magnetic field.

Recoil is only dependent on the momentum gain of the projectile and other particles -- like escaping gases. How that projectile gets its momentum boost is immaterial.

About the only way to reduce recoil is to provide an equivalent negative momentum -- like gases in a a recoilless rifle or small plastic pellets in an armbrust.