Navy Railgun Tests Leading to Ship Superweapon by 2020

Umbran · Mar 7, 2012

TanisFrey said:
My bad, I did not mean ferrous (indicates the presents of iron) but relatively reactive to magnetism. Most materials that are conductive will be reactive to magnetism.

I think you may be getting your terminology confused. There are a small number of materials (like iron, nickel, and cobalt) that are called "ferromagnetic" - which traditionally means that they can show spontaneous magnetization, or have a magnetic moment without an externally applied magnetic field.

The phrase "reactive to magnetism" doesn't mean anything to me. The rails and projectile need to be good electrical conductors, but that's about it.

3) The Explosive force is in all directions including direction not directly in line with the path of the projectile. These do get redirected into the expanding gasses.

This last is not exactly true. The round is fired in a chamber specifically so the expansion is restricted, and more of the energy of expanding gas will be transferred to the bullet.

Kzach said:
Sigh, such a buzz-kill

An engineer friend of mine looked at fiction (with it's aliens, super-powered heroes, and such) and realized that there is a lot of cool stuff we can conceive happening, that doesn't. He reasoned that there must be a maximum amount of Coolness in the Universe, and anything that exceeded this Universal allotment was not allowed to happen. He dubbed this the "Too Cool Rule."

I'm not sure he was correct. If he was, then when we suffered the losses of Johnny Cash and Warren Zevon (who were among those who are "Cooler than You" for almost all values of You), we should have seen a sudden increase in incidence of adamantium claws and aliens coming down to play Super Mario Bothers with terminally ill children. But the idea may still have merit.

Suffice it to say, I'm dreadfully sorry the laws of the Universe don't yield your desires. I don't make 'em, I just report the results. If you wish, you may take a number to file a complaint with The Management.

Dannyalcatraz · Mar 7, 2012

I'm not sure he was correct. If he was, then when we suffered the losses of Johnny Cash and Warren Zevon (who were among those who are "Cooler than You" for almost all values of You), we should have seen a sudden increase in incidence of adamantium claws and aliens coming down to play Super Mario Bothers with terminally ill children.

*snikt*

Who says it hasn't happened?

*snikt*

(BTW, the myth is false- black guys' adamantium claws are no bigger on average than white guys'.)

Olgar Shiverstone · Mar 8, 2012

Thunderfoot said:
As for the power - how long it would take to ramp back up using a conventional power plant, assuming a smaller shell than the Navy test? And if the drain is that much what wouldn't that be a problem on the small diesel electric engines of naval gunships? Only the cruisers would have the kind of power it would take to run those and the rest of their ships systems. (My cousin was a scope dope on a destroyer - he said when they did evasive actions they had to pull power from other systems, usually lighting and environmental systems (ie, lower priority).
Considering the 5" is the standard ship mounted weapon the rail would actually reverse the downsizing of the main gun, and even if it is a guided package, most vessels would only have one or two of these on board. Power would still be a problem for these little ships if it takes the power plant you're describing. That would mean that no current application is possible. Wonder if the testing is trying to downsize the power plant?

Those size generators and capacitors were for a 120mm APFSDS round --much smaller/lighter than a 155mm HE projectile, or a 5" HE projectile. So no smaller scale application soon, probably not for 5-10 years.

Nagol · Mar 8, 2012

TanisFrey said:
My bad, I did not mean ferrous (indicates the presents of iron) but relatively reactive to magnetism. Most materials that are conductive will be reactive to magnetism.

When I speak of minimizing recoil I do not mean that it is eliminated but reduced to the minimum expected by the monument being generated in the projectile.

A standard gun has more recoil than what can be expect to be generated by the monument of the bullet. Due to the following:
1) The need to over come friction of the bullet with the barrel.
2) The expanding gasses that propel the bullet. (Automatics and semi-automatics use this to reload the weapon.)
3) The Explosive force is in all directions including direction not directly in line with the path of the projectile. These do get redirected into the expanding gasses.

These 3 items are eliminated be the rail gun, leaving only Newton's Laws of Motion.

I think you're thinking of a mass driver and not a railgun. They are similar concepts with different details.

Railguns use the Lorentz force, in effect a magnet will accelerate charged particles. Anything conductive placed across the rails completes the circuit and carries a charge between the rails. This creates a powerful electromagnet. The magnet accelerates the projectile by pushing on the electrons flowing through it. The projectile could be made from conductive plastic if it wouldn't melt.

Recoil is all about momentum transfer, nothing else. Think of it this way. If the gun was fired and the barrel was sealed and the gases contained in a large chamber so that nothing escaped, there would be no recoil. If the explosive were detonated with no constraints of how the force was applied (i.e. with no walls around it) the expansion would be in all directions and there would be no recoil. Recoil happens when the expansion is directed and momentum is transferred.

Fricition in the barrel reduces recoil in that it converts kinetic energy into heat and reduces forward momentum of the bullet.

Expanding gases affect recoil, but with proper design can be made to reduce it -- see the recoillless rifle. Railguns lose the gases and hence lose a property that could be used to reduce recoil.

The explosive force in a gun just a high pressure burst of gas. That gas is directed by the walls of the chamber into expanding in a specific direction. The bullet is in the way and pushed by the gas absorbing some of its momentum. So the recoil of a gun is pretty much the same if a bullet is present or if the explosive charge is bare when detonated. The momentum of the gases alone is about the same as the momentum of the gases and bullet.

El Mahdi · Mar 8, 2012

jonesy said:
I think there might be quite a line in the complaints department.

I think you have to fill out an application in quadrillioncate before even getting approval to stand in line.

Dannyalcatraz · Mar 9, 2012

All this discussion has made me want to make a new Warforged PC: I don't know its class yet, but it will be some kind of blaster or ranged attacker, and its name will be Ferrous Beuller.