Naval Rail Gun

[Time]

http://beforeitsnews.com/story/306/067/Navys_Mach_7_gun_can_kill_from_100_miles_away.html

Most recent US Naval rail gun test shot.  33 MJ of muzzle energy on a 20 lb (~9.1 kg) projectile. 

[FreeThinker]

Sad

[Alex]

High energy projectile plus EM pulse as a bonus!

[scrat]

Does it work like a linear motor?

[Time]

Does it work like a linear motor?

Yes, a rail gun is a homopolar linear motor which is optimized for acceleration (Mach 8 in 100 feet or so in this case!).  They don't give details as to how it works but from the glimpses at the facility I am pretty sure its based around large marx generators similar to the one you might have seen that crushes rocks recently.  The fundamental concept is to charge a bunch of caps in parallel than discharge them in series to get large erected voltage pulses.  The force that is placed on a projectile is the induced lorentz force from the current going through one rail, through the projectile, and into the next rail.  EM guns have terrible efficiencies (<10%) for Muzzle Energy/Discharge Energy.  With 33 MJ muzzle energy it would be interesting to see the stored energy.  The capacitive bank takes 5 minutes to charge.

[XynxNet]

As a weapon, it seems kind of pointless to me. They don't face any longer russian battleships, but low-cost motorboats with explosives.
It would be better to invest the money in developing critical countries and in avoiding to piss of people.

[Hypernova]

As a weapon, it seems kind of pointless to me. They don't face any longer russian battleships, but low-cost motorboats with explosives.
It would be better to invest the money in developing critical countries and in avoiding to piss of people.

-Increased firing speed (once the heat, wear and power issues are sorted)
-Longer range
-More power for the same caliber
-More likely to hit the target as the rounds travel faster
-Safer as the rounds are inert, No need to armored magazines that take a lot of space and weight on ships.
-More ammo
-Dial-able power

[Time]

What he said!

[the_raptor]

As a weapon, it seems kind of pointless to me. They don't face any longer russian battleships, but low-cost motorboats with explosives.

This sort of R&D is for the future (When China and Brazil will be world naval powers) not for the bush wars we are having now.

Also one of the main drivers behind this is an economical gun boat to support infantry operations. With a rail gun you can do "dial-a-yield" in a way that isn't economical for conventional chemical propellant cannons. It will also probably be useful for long range missile interdiction.

[scrat]

Could also be a good fishing tool