9 ms·

Navy Sets World Record With Rail Gun

91 points by gibsonf1 16y ago

hugh3 16y ago
Pretty awesome. There's an unfortunate focus in the admiral's comments on ship-to-ship warfare, which really isn't something we get a lot of nowadays. What's deliberately not mentioned is how useful this might be for shooting down a missile at launch. It is, as they say, hard to hit a bullet with a bullet. But hitting a bullet with a much faster bullet...
- iuhjyftgrd 16y ago
  That's their main use With a missile coming toward you at Mach 2-3 you don't want to be shooting subsonic cannon shells at it. The rail gun ammunition is much smaller so you can carry much more of it and make a much more mobile gun turret because it doesn't need to store tonnes of shells or have a feed back to a magazine.
  - Estragon 16y ago
    But if you look at the video, it's clear they're a long way from making any kind of agile turret out of this. It's HUGE.
    - scdlbx 16y ago
      It is not that big compared to the guns on a destroyer or a battleship. It is still large and bulky, but not that far off. Current destroyer's gun: http://en.wikipedia.org/wiki/5%22/54_caliber_Mark_45_gun http://en.wikipedia.org/wiki/5%22/54_caliber_Mark_45_gun Iowa Class gun: http://en.wikipedia.org/wiki/16%22/50_caliber_Mark_7_gun http://en.wikipedia.org/wiki/16%22/50_caliber_Mark_7_gun
      - tsotha 16y ago
        Yeah. The part of the turret you can see when you look at the ship is only the tip of the iceberg.
  - tsotha 16y ago
    They'll be able to hit incoming missiles, but the primary strength of the system is as long-range artillery for land attack. It won't have the rate of fire you'd need to defend yourself against multiple incoming missiles.
- steve19 16y ago
  Thier main use will be hitting targets far in land. The article says "Indeed, a railgun could be used to inflict just such harm on another vessel.", which is true, it could be used for this purpose, but they would not be sinking money into this just for that.
gvb 16y ago
"We're also eliminating explosives from the ship, which brings significant safety benefits and logistical benefits," Ellis said. In other words, there is less danger of an unintended explosion onboard, particularly should such a vessel come under attack. The first half (logistics benefits) is a good statement. The rephrasing the the second half is bogus. Joules are joules the world over. If the enemy fire hits the caps full of joules, it ain't gonna be good for the good guys even if there are no conventional explosives involved.
- 1053r 16y ago
  Joules are joules, but what you are failing to account for is the form the joules might take. If the enemy hits the caps and they explode, an amount of energy equal to one projectile launch is liberated. If, on the other hand, you take out a magazine, you liberate an amount of energy equal to all the shots the ship is capable of taking ALL AT ONCE. The energy necessary to fire all those shots is probably still on board, but it is likely in the form of a nuclear pile in the reactor, which is shielded up the wazoo. Even if the ship is running a conventional generator, diesel fuel doesn't have a tendency to explode in quite the same way as gunpowder.
  - bigiain 16y ago
    That's true, but 33megajoules is almost exactly the amount of energy in 1L or 1/4Gal of gasoline. I don't know how much explosive a typical ship mounted canon requires for propellant and payload, but even given all the inefficiencies turning gasoline into electricity Id be quite surprised if there's quite a bit less energy on board to supply the rail gun.
    - zitterbewegung 16y ago
      200 pound of tnt is 30.2 mJ in the M107 round you have 14.6 lbs of tnt in that shell. So basically 14 shells would equal about that many mJ. I'm sure that the ship has more than 14 shells.
- InclinedPlane 16y ago
zoomzoom 16y ago
What is the possibility of using these for space launches? edit: obviously would have to be slower then these for the sake of any fragile cargo (including people)...
- dasil003 16y ago
  Hard to imagine anything useful withstanding that acceleration. You could make a longer launch tower, but how tall would it have to be?
  - cperciva 16y ago
    For humans who can survive an acceleration of about 3 g, you'd need a 1000 km long railgun in order to deliver enough energy. For cargo a railgun a few miles long would probably be enough, but designing a missile which can survive surface air densities while travelling at orbital velocities would be very difficult.
    - stcredzero 16y ago
      Launching bulk cargo would still be a very worthwhile thing to do. Solar power satellites, anyone? The main obstacle is the launch cost. If we could reduce the shipment of bulk items to orbit to freight rates, then solar power satellites would become a reality. The US military already has specs for electronic components that can withstand 100,000 gravities. (Yes, the number of zeroes is correct!) I bet we could develop lightweight thin-film solar panels that could be rolled up and packaged to survive 1000.
  - SerpentJoe 16y ago
    Why not aim for the horizon? That way your track can be on the ground, and even better your impulse is spent approaching orbital speed rather than struggling against gravity drag. Even traditional space rockets turn east as quickly as possible, and a (semi) ballistic launch can do it from the start. That said for human payloads you'd need a really long track, tens or hundreds of kilometers. I wouldn't want to live near the launch end. (edit: to get a useful amount of speed; still assuming rockets to get us the rest of the way)
pingswept 16y ago
"[A] railgun offers 2 to 3 times the velocity of a conventional big gun, so that it can hit its target within 6 minutes." I'd expect that most projectiles decay exponentially toward a terminal velocity, so the impact of shooting a bullet faster is negligible when it's going to be in flight for 6 minutes. Anyone know whether that's true for long range projectile weapons these days?
- cperciva 16y ago
  Railgun ammunition is designed to lose as little kinetic energy as possible. After all, there's no point hitting someone with a non-explosive projectile unless it's moving fast.
  - pingswept 16y ago
    This suggests that the terminal velocity of a rail gun projectile is around Mach 5: http://www.globalsecurity.org/military/systems/ship/systems/emrg.htm http://www.globalsecurity.org/military/systems/ship/systems/... I guess I can spend my time worrying about other things!
joeycfan 16y ago
Never happen. Yanks will go broke before 2025 - never happen in AMERICA, CHINA is another story....
vl 16y ago
Lets get bunch of rails into the low polar orbit. Once a 1000 or so is deployed, there will be an almost-instant (20 minutes) strike capability for any location on the earth. The good part is that kinetic energy of re-entering rail will be unmatched by any railgun. On the serious note, they didn't specify the weight of the projectile, and this is quite important factor. Comparison of the energy delivered at the target range to the energy delivered by the conventional winged missile would be useful as well. Blog of the guy who build portable supersonic railgun at home (in Russian): http://railgun.org.ua/ http://railgun.org.ua/ Check out his video page: http://railgun.org.ua/video/ http://railgun.org.ua/video/
- bigiain 16y ago
  If you take the numbers from the article as accurate, 33 megejoules at Mach 7 means the weight is ~15kg (assuming I got all my conversions and orders of magnitude right, feel free to do your own e=1/2mv^2 calculation...)
  - aidenn0 16y ago
    I got ~10kg from the 2500m/s number, and under 12kg from the Mach 7 number. Google agrees: http://www.google.com/search?q=2*33megajoules/(2500+m/s)^2+in+kg http://www.google.com/search?q=2*33megajoules/(2500+m/s)^2+i... http://www.google.com/search?q=2*33megajoules/(7+*+speed+of+sound)^2+in+kg http://www.google.com/search?q=2*33megajoules/(7+*+speed+of+...
  - borism 16y ago
    Projectile speed will be much less after it has travelled 100km.
- pak 16y ago
  I don't think other world powers would be totally cool with us putting superweapons into low polar orbit right over their heads... you should totally expect those satellites to be shot down as soon as you put them up there.
  - 16y ago
ahi 16y ago
A big rail gun is nothing new. The hard part, the part they still haven't figured out, is firing the thing without blowing it up at the same time.
essayist 16y ago
This is great! When the Soviets come roaring through the Fulda Gap, or the Japanese descend on Pearl Harbor, we got 'em! Oh, wait. We're preparing for the last war or even the one before that, all over again. How does this help in the world of asymmetric warfare, failed states, nukes in container ships, and Stuxnet? (I'll bet the Maginot Line was pretty cool technology in its day as well.)
- nickpinkston 16y ago
  Well, you may be surprised by the increasing relevance of naval forces in our modern world. Even though big ships fighting Bismarck style is rare, big ships are still very useful in securing seaways for shipping. This is why China, India, S. Korea are all building up their navy. Sure, SpecOps / "terrorists" grab the headlines, but remember that countries have many other threats and don't openly promote them without cause.
  - stcredzero 16y ago
    Yes, spending $569,000 on a cruise missile to take out a merchant vessel of comparable cost wouldn't be good economic warfare doctrine. If the navy can develop weapons that can sink merchant vessels from 200 miles away with dirt-cheap munitions (like a dozen $1000 ceramic slugs) then this makes for a more credible threat.
    - nickpinkston 16y ago
      They probably wouldn't be blowing up merchant vessels like U-Boats, but they certainly would still spend whatever money it takes though: Mark 48 torpedos are a cool $1M to $3.5M. http://en.wikipedia.org/wiki/Mark_48_torpedo http://en.wikipedia.org/wiki/Mark_48_torpedo I think the main advantage for rail guns are that they allow a much higher volume of fire and faster time to engage more targets. It just happens to use cheaper ammo - I'm sure the gun will be much more expensive to make than a standard machined barrel.
      - stcredzero 16y ago
MichaelApproved 16y ago
So it leaves the gun traveling at Mach 7 and can go 100 miles but how fast is it going when it reaches the target 100 miles away? By the time it reaches the target most of it's energy is lost. The main power of this weapon is the kinetic energy it delivers to the target but that information is nowhere to be found in the article.
- tsotha 16y ago
  >So it leaves the gun traveling at Mach 7 and can go 100 miles but how fast is it going when it reaches the target 100 miles away? The one they plan to deploy is supposed to go something like mach 20 and have a ballistic trajectory. Not something you could destroy a city with, but it'll make a bigger bang than an 8-inch shell.
  - stcredzero 16y ago
    Navies still get an awful lot of leverage out of the ability to destroy merchant vessels.
CallMeV 16y ago
When they started putting big guns on battleships, they came up with a new term: "gunboat diplomacy." When the Easter Uprising began in Ireland, the Royal Navy just sat their gunships in the bay and started shelling them from a safe distance. So I guess they're hoping that they can bring back gunboat diplomacy in a form more suited to the 21st century. And if they're aiming for ranges of two to three hundred miles, I guess that theoretically means that no part of the UK would be entirely safe except maybe Birmingham, and that's mostly because nobody wants to go there even to blow it up.
kahawe 16y ago
I am sorry, I have to say this... my Quake bits won't let me rest otherwise. "Now they just have to figure out the Quad Damage and it's going to be insta-gibs on any target!"
Murkin 16y ago
Wonder if a startup could get those Tomahawks down to 60,000$ a pop.
lispm 16y ago
The last thing we need is new weapons.
dstorrs 16y ago
Ok, granted, this is cool. And I see a lot of utility for space launch and other applications, so I support the research. My question: does it actually have practical utility as a weapon of war for the modern US Navy? This seems like fighting the last war -- this is about building a weapon that goes on giant ships, when the new war is all about information and special forces strikes.
- essayist 16y ago
  Yup. See the "Maginot line" discussion above.

91 points by gibsonf1 16y ago

hugh3 16y ago

Pretty awesome. There's an unfortunate focus in the admiral's comments on ship-to-ship warfare, which really isn't something we get a lot of nowadays. What's deliberately not mentioned is how useful this might be for shooting down a missile at launch. It is, as they say, hard to hit a bullet with a bullet. But hitting a bullet with a much faster bullet...

iuhjyftgrd 16y ago
That's their main use With a missile coming toward you at Mach 2-3 you don't want to be shooting subsonic cannon shells at it. The rail gun ammunition is much smaller so you can carry much more of it and make a much more mobile gun turret because it doesn't need to store tonnes of shells or have a feed back to a magazine.
- Estragon 16y ago
  But if you look at the video, it's clear they're a long way from making any kind of agile turret out of this. It's HUGE.
  - scdlbx 16y ago
    It is not that big compared to the guns on a destroyer or a battleship. It is still large and bulky, but not that far off. Current destroyer's gun: http://en.wikipedia.org/wiki/5%22/54_caliber_Mark_45_gun http://en.wikipedia.org/wiki/5%22/54_caliber_Mark_45_gun Iowa Class gun: http://en.wikipedia.org/wiki/16%22/50_caliber_Mark_7_gun http://en.wikipedia.org/wiki/16%22/50_caliber_Mark_7_gun
    - tsotha 16y ago
      Yeah. The part of the turret you can see when you look at the ship is only the tip of the iceberg.
- tsotha 16y ago
  They'll be able to hit incoming missiles, but the primary strength of the system is as long-range artillery for land attack. It won't have the rate of fire you'd need to defend yourself against multiple incoming missiles.
steve19 16y ago
Thier main use will be hitting targets far in land. The article says "Indeed, a railgun could be used to inflict just such harm on another vessel.", which is true, it could be used for this purpose, but they would not be sinking money into this just for that.

gvb 16y ago

"We're also eliminating explosives from the ship, which brings significant safety benefits and logistical benefits," Ellis said. In other words, there is less danger of an unintended explosion onboard, particularly should such a vessel come under attack. The first half (logistics benefits) is a good statement. The rephrasing the the second half is bogus. Joules are joules the world over. If the enemy fire hits the caps full of joules, it ain't gonna be good for the good guys even if there are no conventional explosives involved.

1053r 16y ago
Joules are joules, but what you are failing to account for is the form the joules might take. If the enemy hits the caps and they explode, an amount of energy equal to one projectile launch is liberated. If, on the other hand, you take out a magazine, you liberate an amount of energy equal to all the shots the ship is capable of taking ALL AT ONCE. The energy necessary to fire all those shots is probably still on board, but it is likely in the form of a nuclear pile in the reactor, which is shielded up the wazoo. Even if the ship is running a conventional generator, diesel fuel doesn't have a tendency to explode in quite the same way as gunpowder.
- bigiain 16y ago
  That's true, but 33megajoules is almost exactly the amount of energy in 1L or 1/4Gal of gasoline. I don't know how much explosive a typical ship mounted canon requires for propellant and payload, but even given all the inefficiencies turning gasoline into electricity Id be quite surprised if there's quite a bit less energy on board to supply the rail gun.
  - zitterbewegung 16y ago
    200 pound of tnt is 30.2 mJ in the M107 round you have 14.6 lbs of tnt in that shell. So basically 14 shells would equal about that many mJ. I'm sure that the ship has more than 14 shells.
InclinedPlane 16y ago

zoomzoom 16y ago

What is the possibility of using these for space launches? edit: obviously would have to be slower then these for the sake of any fragile cargo (including people)...

dasil003 16y ago
Hard to imagine anything useful withstanding that acceleration. You could make a longer launch tower, but how tall would it have to be?
- cperciva 16y ago
  For humans who can survive an acceleration of about 3 g, you'd need a 1000 km long railgun in order to deliver enough energy. For cargo a railgun a few miles long would probably be enough, but designing a missile which can survive surface air densities while travelling at orbital velocities would be very difficult.
  - stcredzero 16y ago
    Launching bulk cargo would still be a very worthwhile thing to do. Solar power satellites, anyone? The main obstacle is the launch cost. If we could reduce the shipment of bulk items to orbit to freight rates, then solar power satellites would become a reality. The US military already has specs for electronic components that can withstand 100,000 gravities. (Yes, the number of zeroes is correct!) I bet we could develop lightweight thin-film solar panels that could be rolled up and packaged to survive 1000.
- SerpentJoe 16y ago
  Why not aim for the horizon? That way your track can be on the ground, and even better your impulse is spent approaching orbital speed rather than struggling against gravity drag. Even traditional space rockets turn east as quickly as possible, and a (semi) ballistic launch can do it from the start. That said for human payloads you'd need a really long track, tens or hundreds of kilometers. I wouldn't want to live near the launch end. (edit: to get a useful amount of speed; still assuming rockets to get us the rest of the way)

pingswept 16y ago

"[A] railgun offers 2 to 3 times the velocity of a conventional big gun, so that it can hit its target within 6 minutes." I'd expect that most projectiles decay exponentially toward a terminal velocity, so the impact of shooting a bullet faster is negligible when it's going to be in flight for 6 minutes. Anyone know whether that's true for long range projectile weapons these days?

cperciva 16y ago
Railgun ammunition is designed to lose as little kinetic energy as possible. After all, there's no point hitting someone with a non-explosive projectile unless it's moving fast.
- pingswept 16y ago
  This suggests that the terminal velocity of a rail gun projectile is around Mach 5: http://www.globalsecurity.org/military/systems/ship/systems/emrg.htm http://www.globalsecurity.org/military/systems/ship/systems/... I guess I can spend my time worrying about other things!

joeycfan 16y ago

Never happen. Yanks will go broke before 2025 - never happen in AMERICA, CHINA is another story....

vl 16y ago

Lets get bunch of rails into the low polar orbit. Once a 1000 or so is deployed, there will be an almost-instant (20 minutes) strike capability for any location on the earth. The good part is that kinetic energy of re-entering rail will be unmatched by any railgun. On the serious note, they didn't specify the weight of the projectile, and this is quite important factor. Comparison of the energy delivered at the target range to the energy delivered by the conventional winged missile would be useful as well. Blog of the guy who build portable supersonic railgun at home (in Russian): http://railgun.org.ua/ http://railgun.org.ua/ Check out his video page: http://railgun.org.ua/video/ http://railgun.org.ua/video/

bigiain 16y ago
If you take the numbers from the article as accurate, 33 megejoules at Mach 7 means the weight is ~15kg (assuming I got all my conversions and orders of magnitude right, feel free to do your own e=1/2mv^2 calculation...)
- aidenn0 16y ago
  I got ~10kg from the 2500m/s number, and under 12kg from the Mach 7 number. Google agrees: http://www.google.com/search?q=2*33megajoules/(2500+m/s)^2+in+kg http://www.google.com/search?q=2*33megajoules/(2500+m/s)^2+i... http://www.google.com/search?q=2*33megajoules/(7+*+speed+of+sound)^2+in+kg http://www.google.com/search?q=2*33megajoules/(7+*+speed+of+...
- borism 16y ago
  Projectile speed will be much less after it has travelled 100km.
pak 16y ago
I don't think other world powers would be totally cool with us putting superweapons into low polar orbit right over their heads... you should totally expect those satellites to be shot down as soon as you put them up there.
- 16y ago

ahi 16y ago

A big rail gun is nothing new. The hard part, the part they still haven't figured out, is firing the thing without blowing it up at the same time.

essayist 16y ago

This is great! When the Soviets come roaring through the Fulda Gap, or the Japanese descend on Pearl Harbor, we got 'em! Oh, wait. We're preparing for the last war or even the one before that, all over again. How does this help in the world of asymmetric warfare, failed states, nukes in container ships, and Stuxnet? (I'll bet the Maginot Line was pretty cool technology in its day as well.)

nickpinkston 16y ago
Well, you may be surprised by the increasing relevance of naval forces in our modern world. Even though big ships fighting Bismarck style is rare, big ships are still very useful in securing seaways for shipping. This is why China, India, S. Korea are all building up their navy. Sure, SpecOps / "terrorists" grab the headlines, but remember that countries have many other threats and don't openly promote them without cause.
- stcredzero 16y ago
  Yes, spending $569,000 on a cruise missile to take out a merchant vessel of comparable cost wouldn't be good economic warfare doctrine. If the navy can develop weapons that can sink merchant vessels from 200 miles away with dirt-cheap munitions (like a dozen $1000 ceramic slugs) then this makes for a more credible threat.
  - nickpinkston 16y ago
    They probably wouldn't be blowing up merchant vessels like U-Boats, but they certainly would still spend whatever money it takes though: Mark 48 torpedos are a cool $1M to $3.5M. http://en.wikipedia.org/wiki/Mark_48_torpedo http://en.wikipedia.org/wiki/Mark_48_torpedo I think the main advantage for rail guns are that they allow a much higher volume of fire and faster time to engage more targets. It just happens to use cheaper ammo - I'm sure the gun will be much more expensive to make than a standard machined barrel.
    - stcredzero 16y ago

MichaelApproved 16y ago

So it leaves the gun traveling at Mach 7 and can go 100 miles but how fast is it going when it reaches the target 100 miles away? By the time it reaches the target most of it's energy is lost. The main power of this weapon is the kinetic energy it delivers to the target but that information is nowhere to be found in the article.

tsotha 16y ago
>So it leaves the gun traveling at Mach 7 and can go 100 miles but how fast is it going when it reaches the target 100 miles away? The one they plan to deploy is supposed to go something like mach 20 and have a ballistic trajectory. Not something you could destroy a city with, but it'll make a bigger bang than an 8-inch shell.
- stcredzero 16y ago
  Navies still get an awful lot of leverage out of the ability to destroy merchant vessels.

CallMeV 16y ago

When they started putting big guns on battleships, they came up with a new term: "gunboat diplomacy." When the Easter Uprising began in Ireland, the Royal Navy just sat their gunships in the bay and started shelling them from a safe distance. So I guess they're hoping that they can bring back gunboat diplomacy in a form more suited to the 21st century. And if they're aiming for ranges of two to three hundred miles, I guess that theoretically means that no part of the UK would be entirely safe except maybe Birmingham, and that's mostly because nobody wants to go there even to blow it up.

kahawe 16y ago

I am sorry, I have to say this... my Quake bits won't let me rest otherwise. "Now they just have to figure out the Quad Damage and it's going to be insta-gibs on any target!"

Murkin 16y ago

Wonder if a startup could get those Tomahawks down to 60,000$ a pop.

lispm 16y ago

The last thing we need is new weapons.

dstorrs 16y ago

Ok, granted, this is cool. And I see a lot of utility for space launch and other applications, so I support the research. My question: does it actually have practical utility as a weapon of war for the modern US Navy? This seems like fighting the last war -- this is about building a weapon that goes on giant ships, when the new war is all about information and special forces strikes.

essayist 16y ago
Yup. See the "Maginot line" discussion above.