Futuristic Navy railgun with 220-mile range closer to reality

CNET News ^ | 1/30/12 | Daniel Terdiman

[Nachum]

Imagine a Naval gun so powerful it can shoot a 5-inch projectile up to 220 miles, yet requires no explosives to fire. That's the Navy's futuristic electromagnetic railgun, a project that could be deployed on the service's ships by 2025, and which is now a little bit closer to reality with the signing of a deal with Raytheon for the development of what's known as the pulse-forming network. (Snip) At the same time, because the power for the railgun will come from ships' standard battery banks, the Navy shouldn't have to maintain large amounts of space on board for storage

[DBrow]

“Note that little phrase “pulse forming network” in the article.”

Note the same phrase in my post!

If you have a 10MJ projectile, your PFNs have to handle much more than that. The caps in your PFN must have a very high energy density to squirt the projectile, or the sheer size will be awkward.

So you might be storing 20 megajoules in those PFNs, at what energy density do they pose a threat? I’ve seen a Maxwell FXR capacitor blow up.

Nuclear can supply the electricity, sure, to charge the caps. Not every ship is nuclear, though. Burning fuel means that you must burn perhaps 40 MJ of fuel to get 20 MJ to the caps and 10 MJ to the projectile.

[Noumenon]

Sir Isaac Newton is...

[Timber Rattler]

Good! Now make a big one with gradual acceleration to send capsules with men and cargo orbital. Do it! Now!!

It's what Jerry Bull wanted to do before going to work for Saddam and then getting assassinated by the Mossad.

[mamelukesabre]

That one got me scratching my head too. It sounds like the writer thinks a cable carrying high amps and a cable carrying high voltage must not be too close to each other. But what I think the buffoon is referring to is the old saying that high current is not dangerous and high voltage is not dangerous, but put the two together and you have the danger for electrocution.

[bert]

This is a waste and should be canceled
It is a boondogle that should die

[LeonardFMason]

During D-DAY, as the landing at Omaha Beach faltered, Destroyers armed with 5” guns ran up so close to the beach they grounded themselves. The 5” projectiles they used did devastating damage to the vaunted Atlantic Wall and its offensive capacity.

A 5” shell might not be a threat to a battleship, but battleships are a relic of the past. The future Navy will be comprised of smaller, faster ships. A 5” shell might be plenty enough to do big damage.

A modern 5”/54 caliber Mark 45 gun can fire up to 20 5” shells per minute. A railgun would be an UPGRADE on this.

I am a fan of the 5” gun because my father was when he was on a Destroyer in 1946.

[LeonardFMason]

During D-DAY, as the landing at Omaha Beach faltered, Destroyers armed with 5” guns ran up so close to the beach they grounded themselves. The 5” projectiles they used did devastating damage to the vaunted Atlantic Wall and its offensive capacity.

A 5” shell might not be a threat to a battleship, but battleships are a relic of the past. The future Navy will be comprised of smaller, faster ships. A 5” shell might be plenty enough to do big damage.

A modern 5”/54 caliber Mark 45 gun can fire up to 20 5” shells per minute. A railgun would be an UPGRADE on this.

I am a fan of the 5” gun because my father was when he was on a Destroyer in 1946.

[AnTiw1]

I’m ignorant on physics but I think that’s really important. Master getting payloads into orbit on the cheap and we’ve got it all.

[Steely Tom]

That one got me scratching my head too. It sounds like the writer thinks a cable carrying high amps and a cable carrying high voltage must not be too close to each other. But what I think the buffoon is referring to is the old saying that high current is not dangerous and high voltage is not dangerous, but put the two together and you have the danger for electrocution.

I'm not sure that the word "electrocution" is the right order of magnitude in this case.

Here, the consequences of a direct electrocution incident would include fatal blast effects to everyone within a large volume of space filled by the rapidly-expanding cloud of what was left of the molecules that previously comprised the body of the electrocuted individual.

[RinaseaofDs]

“Why does fire trail behind the projectile when no explosives are used to fire the gun?”

I can tell you where some of it comes from - friction. This 5 inch bullet is still something that only gets a force on it in the first few milliseconds, and then from there, gravity takes over.

Not sure what the speed is, but its gotta to be moving at many times the speed of sound. (This will account for any ‘boom’).

At the speed of sound, the air around the object is going to get hot, so hot that it will make a trail of vapor behind it. The projectile will rub the air, and the water in the air, causing it to heat up and form ‘clouds’ behind it.

What may ALSO happen, though I’m not sure about this bit, is that a rail gun works on electromagnets. It wouldn’t surprise me if there was some plasma forming behind and around the projectile in the first second of flight. Ships are made of metal, but you are creating a magnetic field in order to launch the bullet. Move metal through any magnetic field and you get static (Direct Current type) electricity. Static electricity and lightning are literally the same thing.

Consider that the Earth has a magnetic field around it, and consider that the core of the earth is made of iron and nickel. As the Earth turns inside the magnetosphere, the atmosphere builds up electrical charge. Get enough charged clouds in one place and you end up with lightning.

[GonzoGOP]

Here, the consequences of a direct electrocution incident would include fatal blast effects to everyone within a large volume of space filled by the rapidly-expanding cloud of what was left of the molecules that previously comprised the body of the electrocuted individual.

Way better than lethal injection. When it comes to getting rid of they guys in Gitmo we have a solution.

[wildbill]

What can a 200 mile naval gun do that a cruise missile can’t do better with already proven technology?

We’re spending sparse resources on this technology????? No wonder the defense budget is out of control

Are the Admirals still thinking in terms of battleships and ‘crossing the T” on sea battles?.

Naval gunnery has largely been mothballed along with the battleships. Great for its day, but those days are gone.

[colorado tanker]

Thanks!

[mamelukesabre]

true that, homey!

and this is safer than gunpowder right? heh

[Tex-Con-Man]

dooooood!!!!

A traveling Hispanic Carnivale. Make it a ride.
Booom....next stop...Chihuahua!

[RinaseaofDs]

FR is a good place to ask questions like that. I can’t tell you how many times others have stepped up to help me in the past.

[DesertRhino]

“and a 5” round isn’t much of a threat to a naval target.”

You might want to check with the US Marines on Wake Island about that. And any crew members of the IJN destroyer Hayate,,, (if you can find any) They learned the hard way about what a 5 inch can do.

5 inch was always very deadly to anything except the armor of a battleship. Countless ships have fallen to 5 inch.

[Jeff Head]

Yep...that was just looney. He is determined to remake our armed forces into something other than what they were made for...defending the United States and taking the fight to our enemies.

[Bender2]

Re: What can a 200 mile naval gun do that a cruise missile... can’t do better with already proven technology? We’re spending sparse resources on this technology????? No wonder the defense budget is out of control-- Are the Admirals still thinking in terms of battleships and ‘crossing the T” on sea battles?. Naval gunnery has largely been mothballed along with the battleships. Great for its day, but those days are gone.

Gadzooks, bill, you are just pissed 'cause Jack McCall... crossed your 'T' to put a slug in the back of your head and was played on "Deadwood" by Garret Dillahunt--

The same actor... that is such a tool in "Raising Hope."

Yeah, I damn well deserved to be killed by a much better actor... like Spencer Tracy or Olivier!

Now, calm down... and have a Bloody Mary or twelve with me-- The ones they make here hit you with the force of a 5 inch shell!

[DesertRhino]

A 200 mile 5 inch is an incredible tool for cheap and devastating fire support of marines ashore.
It lets you do fun thing like cover close to 80% of Somalia with cheap pinpoint fire support just the size a grunt needs.

It realistically lets you cover almost every inch of land from Mexico City south through Guatemala, Nicaragua, Panama, etc all the way south to Columbia.

Every inch of the Philippines, Korea, Japan, Taiwan, England
It lets you cover all the apace in Egypt where people live. It lets you pound Damascus all day long. Or Paris, Berlin, and if you live in Spain, you better not stray far from Madrid.

In Vietnam, everywhere we had troops would have been covered. Ask any nam vet who got naval gunfire support how much they loved it.

It’s a cheap effective tool that the Navy badly needs.