How big a deal is this? :shrug:

Navy Tests High-Powered Electromagnetic Railgun

DAHLGREN, Va. — A futuristic weapon getting a trial run by the Navy demonstrated its destructive power at the Naval Surface Warfare Center in Dahlgren.

In the demonstration Thursday, engineers fired the electromagnetic railgun at what they said was a record power level: 10 megajoules.

The previous railgun power-use record was about 9 megajoules of muzzle energy.

Railguns use electromagnetic energy to launch projectiles long distances — more than 200 nautical miles....

http://www.onr.navy.mil/newimage/railgunSM.wmv

I think if they already had one that launched projectiles at 9 MJ, 10 MJ is probably not a big deal. They probably just found a slightly more efficient way to charge the projectile.

How big a deal is this? :shrug:

Navy Tests High-Powered Electromagnetic Railgun

DAHLGREN, Va. — A futuristic weapon getting a trial run by the Navy demonstrated its destructive power at the Naval Surface Warfare Center in Dahlgren.

In the demonstration Thursday, engineers fired the electromagnetic railgun at what they said was a record power level: 10 megajoules.

The previous railgun power-use record was about 9 megajoules of muzzle energy.

Railguns use electromagnetic energy to launch projectiles long distances — more than 200 nautical miles....

http://www.onr.navy.mil/newimage/railgunSM.wmv


So if any enemy submarine was only 1 mile away this "gun" couldn't be of any use whatsoever. Also if a cruise missile is coming at the ship at 3 times the speed of sound and it's traveling just above the water which no radar can detect until its to late, would it be of much use?

So if any enemy submarine was only 1 mile away this "gun" couldn't be of any use whatsoever. Also if a cruise missile is coming at the ship at 3 times the speed of sound and it's traveling just above the water which no radar can detect until its to late, would it be of much use?

I think these things are used more for naval bombardments.

And if the sub was a mile away, you could just shoot straight up.

I think these things are used more for naval bombardments.

And if the sub was a mile away, you could just shoot straight up.

Navel bombardments of what, land bases? If you shoot straight up it would only come straight down and could hit your own vessel!:eek:

So if any enemy submarine was only 1 mile away this "gun" couldn't be of any use whatsoever. Also if a cruise missile is coming at the ship at 3 times the speed of sound and it's traveling just above the water which no radar can detect until its to late, would it be of much use?
Do you understand what a railgun is? Simply put, it is just a gun that launches its projectiles by electromagnetic energy instead of gunpowder. The railgun is capable of much higher muzzle velocities and correspondingly longer range because of the increased muzzle velocities. The target can be much closer than the maximum range the gun is capable of, just like with any gun. The longer range allows the ship with the railgun to engage an enemy ship or land-based target while it is still out of the range of the target's guns. Their purpose is not as a defensive weapon to shoot down missiles, but as an offensive weapon to engage the same types of targets as the normal big guns on a destroyer. Besides increased range, some other advantages are the elimination of storing large amounts of volitile gunpowder and increased accuracy due to the more consistent muzzle velocities of the launched shell. The navy already has awarded contracts for a 32 megajule launcher and is planning a 64 MJ version.

Besides increased range, some other advantages are .....


....they can be given to the Israelis and sold to the Saudis. :bugeye:

Couldn't an electromagnet just be set up to "catch" the projectiles?

So if any enemy submarine was only 1 mile away this "gun" couldn't be of any use whatsoever. Also if a cruise missile is coming at the ship at 3 times the speed of sound and it's traveling just above the water which no radar can detect until its to late, would it be of much use?

Why not? Ever heard of supercavitation?

If you put it on a ship, would the ship flip over when it went off?

Why not? Ever heard of supercavitation?

No. what's that? :confused:

It's the technology of enclosing an underwater projectile in a bubble of air formed by a specially shaped nosecone. It allows a missile to break the sound barrier. Underwater.

seriously?! You have a video clip of that? Wouldn't that hurt animals in the ocean?

I'm not sure if there's a video of it. I suppose if it hit something underwater, it would hurt. Bad.

but what about the concussion when it breaks the sound barrier?

I don't know, probably the water absorbs it. I'm not sure if one has gone that fast yet, but they have achieved around 300mph, which is damn fast for an underwater object.

It's the technology of enclosing an underwater projectile in a bubble of air formed by a specially shaped nosecone. It allows a missile to break the sound barrier. Underwater.
Never read of a missile that could break the sound barrier underwater. The Russians were supposed to have demonstrated a rocket-powered torpedo (the Shkval) that used supercavitation to reach speeds of about 230 mph. Cavitation doesn't enclose the projectile in a single 'bubble of air', it is a method to introduce many small bubbles into the water to make the water less dense. Whatever device or nosecone is used to 'make the bubbles' still must move through normal, dense water though. Supercavitation doesn't eliminate the friction from water, but reduces it.

According to the wikipedia article, that is incorrect. It does form one large bubble of air around the object.
http://en.wikipedia.org/wiki/Supercavitation

German press reports of an underwater anti-torpedo missile named Barracuda that allegedly reaches 800 km/h.

According to the wikipedia article, that is incorrect. It does form one large bubble of air around the object.
http://en.wikipedia.org/wiki/Supercavitation

German press reports of an underwater anti-torpedo missile named Barracuda that allegedly reaches 800 km/h.
I hadn't seen that site on wiki. I found a source of the article I read a while back (from the Federation of American Scientists) which explained supercavitation around the Shkval differently (link below). I suppose a better understanding of the phenomenon has been achieved. I still don't think an underwater missile can break the sound barrier, as the speed of sound in water is over 3200 mph. :)
Apparently fired from standard 533mm torpedo tubes, Shkval has a range of about 7,500 yards. The weapon clears the tube at fifty knots, upon which its rocket fires, propelling the missile through the water at 360 kph [about 100 m/sec / 230 mph / 200-knots], three or four times as fast as conventional torpedoes. The solid-rocket propelled "torpedo" achieves high speeds by producing a high-pressure stream of bubbles from its nose and skin, which coats the torpedo in a thin layer of gas and forms a local "envelope" of supercavitating bubbles.
http://www.fas.org/man/dod-101/sys/missile/row/shkval.htm

Railguns are the way forward for line-of-sight weaponary (compared to guided torpedoes etc) - as the energy needed for firing the thing can be generated from the same engines that run the boat, rather than have massive amounts of explosives onboard.

10MJ might not sound that big an advancement - but 10% or so increase in energy means longer range or more kinetic energy imparted to target.

And prototypes for 32MJ are already around, with 64MJ on the horizon.

They may not do that much more damage at present than conventional weaponary - but are a fraction of the cost, easier to handle, and the projectiles do not generally explode when hit by enemy fire - so are far safer to carry on board.

10MJ might not sound that big an advancement - but 10% or so increase in energy means longer range or more kinetic energy imparted to target.

And prototypes for 32MJ are already around, with 64MJ on the horizon.

This seems a bit large... I mean, coservation of momentum is a bitch---if you mounted one of these rail guns on something that weighs 10^6 kg, you'd end up with a backwards velocity of 30 m/s, which is like 80 miles per hour.

I'd imagine that they can damp the kick somehow. Anyone know how they deal with this?

I guess a better question would be, how much does a battleship weigh?

how is a railgun different than another gun? I just kept thinking it was on railroad tracks on a ship so they could move it around easier. no?

how is a railgun different than another gun? I just kept thinking it was on railroad tracks on a ship so they could move it around easier. no?

Rail guns use electromagnetic fields to launch projectiles at high velocities, they dont use gun powder to propell the projectiles.


http://static.howstuffworks.com/gif/railgun-8.gif

<doh> got nothing to do with a railroad then, huh. lol
The rails are inside and a charge build up between then then right?

<doh> got nothing to do with a railroad then, huh. lol
The rails are inside and a charge build up between then then right?

Yes, then they use the magnetic charge to propell the projectile out of the gun. The problem is that almost all rail guns suffer damage everytime they fire, so the technology is expensive and not reliable enough to really justify any widespread military use ...at least for now.

I guess a better question would be, how much does a battleship weigh?
Battleships are active no longer. A DDG displaces ~8500 tons, a CG ~9500.

The Navy has been playing with railguns for quite some time. Surface warfare is about the only application where one might be feasible in the foreseeable future, in part because a shipboard weapon will always be in close proximity to a high flux power source. They're still in the research stage at this time however.

http://www.defensetech.org/archives/003978.html

So what happens to a target that gets hit with one of these rails anyway? If you say it travels 20 miles then what's its impact at the target?

This seems a bit large... I mean, coservation of momentum is a bitch---if you mounted one of these rail guns on something that weighs 10^6 kg, you'd end up with a backwards velocity of 30 m/s, which is like 80 miles per hour.

I'd imagine that they can damp the kick somehow. Anyone know how they deal with this?I'm not sure of the exact mechanisms used - but I think it's basically done by storing the recoil energy in something like a spring, which can release the energy in a controlled fashion.

But I'm guessing the recoil is why most conceptual designs (esp. in sci-fi) for their usage revolve aroung the railguns being along the central axis of the craft, to minimise effect of the recoil.

So what happens to a target that gets hit with one of these rails anyway? If you say it travels 20 miles then what's its impact at the target?It depends on the mass of the projectile and the muzzle velocity (and any drag effects from muzzle to target).
9 MJ is apparently sufficient to propel a 2kg mass at 3000 m/s.

A rifle typically fires a c.0.15kg bullet at under 1000 m/s.

The energy in just a 9MJ railgun is thus 120 times more than that of a rifle.
One shot would most likely penetrate a modern tank.

A 32MJ weapon is likely to be as damaging as a typical surface missile.
They're not necessarily more destructive (at present) but will ultimately be far cheaper per round and far safer to use (no explosives).

Do you understand what a railgun is? Simply put, it is just a gun that launches its projectiles by electromagnetic energy instead of gunpowder. The railgun is capable of much higher muzzle velocities and correspondingly longer range because of the increased muzzle velocities. The target can be much closer than the maximum range the gun is capable of, just like with any gun. The longer range allows the ship with the railgun to engage an enemy ship or land-based target while it is still out of the range of the target's guns. Their purpose is not as a defensive weapon to shoot down missiles, but as an offensive weapon to engage the same types of targets as the normal big guns on a destroyer. Besides increased range, some other advantages are the elimination of storing large amounts of volitile gunpowder and increased accuracy due to the more consistent muzzle velocities of the launched shell. The navy already has awarded contracts for a 32 megajule launcher and is planning a 64 MJ version.


In addition to the above, handling explosives on ship is dangerous. If a ship takes an enemy missle to its munitions storage area, you have a big explosion and fire. Getting rid of or lessening the explosives carried on ships (especially fast frigates) dramatically improves the odds that a ship can withstand an enemy assualt.

It depends on the mass of the projectile and the muzzle velocity (and any drag effects from muzzle to target).
9 MJ is apparently sufficient to propel a 2kg mass at 3000 m/s.

A rifle typically fires a c.0.15kg bullet at under 1000 m/s.

The energy in just a 9MJ railgun is thus 120 times more than that of a rifle.
One shot would most likely penetrate a modern tank.

A 32MJ weapon is likely to be as damaging as a typical surface missile.
They're not necessarily more destructive (at present) but will ultimately be far cheaper per round and far safer to use (no explosives).



From 20 miles away? These are being deployed on ships so just what impact happens at the 20 mile limit of their range? Also if the rail gun does hit something wouldn't it only damage that one thing unlike a bomb which can destroy a very wide area with just one hit?

From 20 miles away? These are being deployed on ships so just what impact happens at the 20 mile limit of their range? Also if the rail gun does hit something wouldn't it only damage that one thing unlike a bomb which can destroy a very wide area with just one hit?
You are still a little confused as to what is being developed. The 10 megajule railgun that was just tested is not for use as a weapon, it is only a testing phase. The actual railgun that will be mounted in ships will be a 64 megajule advanced version capable of launching large projectiles over 200 nautical miles. The projectiles will have a guidance system in them, somewhat like rocket propelled missiles. The projectiles will strike their target at extremely high velocities, causing the projectile to 'explode' without the use of explosives inside the projectile itself. Here are a couple of links to the Navy's site, plus one about the recent test gun. BAE is one of the contractors being used in the development phase before the final design of the 64 mj weapon version is arrived at and built.
http://www.onr.navy.mil/emrg/faqs-electromagnetic-railgun.asp
http://www.spacedaily.com/reports/BAE_Systems_Wins_Contracts_For_Electro_Magnetic_Ra il_Gun_Programs_999.html

You are still a little confused as to what is being developed. The 10 megajule railgun that was just tested is not for use as a weapon, it is only a testing phase. The actual railgun that will be mounted in ships will be a 64 megajule advanced version capable of launching large projectiles over 200 nautical miles. The projectiles will have a guidance system in them, somewhat like rocket propelled missiles. The projectiles will strike their target at extremely high velocities, causing the projectile to 'explode' without the use of explosives inside the projectile itself. Here are a couple of links to the Navy's site, plus one about the recent test gun. BAE is one of the contractors being used in the development phase before the final design of the 64 mj weapon version is arrived at and built.
http://www.onr.navy.mil/emrg/faqs-electromagnetic-railgun.asp
http://www.spacedaily.com/reports/BAE_Systems_Wins_Contracts_For_Electro_Magnetic_Ra il_Gun_Programs_999.html



Thank you for that information BUT neither of those links provides us with any real time images of this railgun in action. Why don't they show it working and what happens when it hits something 200 miles away?From what I gathered it was "shooting" a projectile which was NOT a bomb or was it? That's what confuses me, wether or not the projectile is a bomb or a piece of metal traveling at high speeds. :shrug:

cosmictraveler,
Thank you for that information BUT neither of those links provides us with any real time images of this railgun in action.
A link of the test is listed on their website, below. I haven't watched it because it requires Windows Media Player, which I don't use.
http://www.onr.navy.mil/emrg/electromagnetic-railgun.asp

Why don't they show it working and what happens when it hits something 200 miles away?
What they tested was not the 64 mj weapon that has yet to be built, but a simple, lower-powered, preliminary testing of the EM power concept. It is just a phase leading to the development of the final weapon version.

From what I gathered it was "shooting" a projectile which was NOT a bomb or was it? That's what confuses me, wether or not the projectile is a bomb or a piece of metal traveling at high speeds.
No, it is not being developed to shoot a 'bomb'. I imagine the test just conducted only launched some type of metal 'bullet' (projectile), but the future weapon-grade version will lauch larger metal 'shells'(also called projectiles). When a solid object traveling at very high speed strikes another solid object, the effects are much the same as a bomb exploding even though no explosives are used. Have you seen the photos of meteor craters that are much, much larger than the actual meteorite that struck? Or what happens to a watermellon when was struck by a high velocity rifle bullet? Same principle.

cosmictraveler,

A link of the test is listed on their website, below. I haven't watched it because it requires Windows Media Player, which I don't use.
http://www.onr.navy.mil/emrg/electromagnetic-railgun.asp


What they tested was not the 64 mj weapon that has yet to be built, but a simple, lower-powered, preliminary testing of the EM power concept. It is just a phase leading to the development of the final weapon version.


No, it is not being developed to shoot a 'bomb'. I imagine the test just conducted only launched some type of metal 'bullet' (projectile), but the future weapon-grade version will lauch larger metal 'shells'(also called projectiles). When a solid object traveling at very high speed strikes another solid object, the effects are much the same as a bomb exploding even though no explosives are used. Have you seen the photos of meteor craters that are much, much larger than the actual meteorite that struck? Or what happens to a watermellon when was struck by a high velocity rifle bullet? Same principle.


Thanks again! I guess my problem is that I understand it when a bomb is shot because a highly explosive shell is launched into the air at a angle that will allow it to go up then down into its intended target. Does this do the same thing whenever it "projects" its projectiles? Say a tank was going down a street inside a town would the projectile go over the towns buildings then land or hit the tank missing everything else in its path?

cosmic---

I think that this type of technology would not be used to target tanks and things that are moving. If you're shooting something from 200 miles away, you can't be quite as accurate as a tank, I would imagine. I think that this could be used to target stationary things like buildings and strategic targets.

Plus, I'd imagine that one of these projectiles does similar damage as a bomb (remember...conservation of energy) for much less cost, and at much less danger to the crew on the ship.

cosmic---

I think that this type of technology would not be used to target tanks and things that are moving. If you're shooting something from 200 miles away, you can't be quite as accurate as a tank, I would imagine. I think that this could be used to target stationary things like buildings and strategic targets.

Plus, I'd imagine that one of these projectiles does similar damage as a bomb (remember...conservation of energy) for much less cost, and at much less danger to the crew on the ship.

Thanks for the info. :)

Thanks for the info. :)

Don't take my word for it, though. I'm just speculating :)

Sounds like the supercavitation bubbles work to form a lower friction envelope around the missile.

At first I though they were using a massive cavitation bubble itself to destroy the torpedo by collapsing it on it, and only needed the hypervelocity missile to create the bubble. Sort of like a transfer of energy from a kinetic energy weapon.

Thanks again! I guess my problem is that I understand it when a bomb is shot because a highly explosive shell is launched into the air at a angle that will allow it to go up then down into its intended target. Does this do the same thing whenever it "projects" its projectiles? Say a tank was going down a street inside a town would the projectile go over the towns buildings then land or hit the tank missing everything else in its path?A railgun will shoot in a straight line, like a rifle. What you're describing is a mortar round. Again, there's no bomb involved with railguns. Just pieces of metal moving really fast. The "explosion' is caused by the sudden release of kinetic energy as the object moving at very high speed hits its target (remember energy=mass x velocity squared, so the amount of energy imparted increases exponetially as the speed increases).

This seems a bit large... I mean, coservation of momentum is a bitch---if you mounted one of these rail guns on something that weighs 10^6 kg, you'd end up with a backwards velocity of 30 m/s, which is like 80 miles per hour.

I'd imagine that they can damp the kick somehow. Anyone know how they deal with this?

I'm sure the 64 MJ figure is the amount of electrical energy that they dump into the gun upon firing, not the kinetic energy of the projectile.

Why so sure? A bit of reading indicates that rail-gun ratings seem to usually be muzzle energies.
For example, regarding the 10 MJ test, the Navy says (http://www.onr.navy.mil/emrg/electromagnetic-railgun.asp):
On January 31, the Office of Naval Research made history with the muzzle velocity of its electromagnetic railgun at the Naval Surface Warfare Center Dahlgren Division. Fired at 2,520 meters per second, the shot generated 10.64mj of muzzle energy.

Never mind, it looks like you're correct Pete.