World's Most Powerful Rail Gun Delivered to Navy

[Kodiak]

The problem with railguns isn't that the coils get damaged, it's that the rails the projectiles ride along get severely eroded away. Also, these rails are fairly large pieces of metal. Swapping them isn't going to be easy while the ship is underway.

That's not to mention the torque that the rails (or coils) feel due to the magnetic forces. I saw a science-fair "rail launcher" rip itself off of concrete bases when a sufficient amount of current was run through it. I believe that some significant metallurgical advances will be needed before railguns become feasible for battlefield deployment

[Darth Wong]

What's the point of a battlefield railgun anyway? Given its support requirements, it seems totally impractical when conventional weapons are much easier to use and support. Conventional weapons can also do plenty of things that railguns can't, like striking over the horizon or without line of sight. Even if someone were to somehow develop a railgun that could be fired a hundred times or more before rail replacement became necessary, would it be worth the bother?

[Darth Smiley]

Conventional weapons can also do plenty of things that railguns can't, like striking over the horizon or without line of sight.

What? I thought railguns had the same basic function as conventional guns, just much higher muzzle velocity (and, of course, the wear/power issues). If they aren't, then what is the difference?

[Davey]

The way I see it, until a railgun can fight against itself and win every time, withstand the test of time, and remain in widespread use for generations with no immediately foreseeable replacements, I'll put my faith in conventional guns, cannons, missiles, bombs and rockets, thank you very much.

Just because it's exotic and 'kewel!' doesn't mean we can depend on it to win us a war when conventional weapons already can, and we know for certain they will.

[Darth Wong]

Conventional weapons can also do plenty of things that railguns can't, like striking over the horizon or without line of sight.

What? I thought railguns had the same basic function as conventional guns, just much higher muzzle velocity (and, of course, the wear/power issues). If they aren't, then what is the difference?

Well, at least based on all the railguns I've seen, it's a pretty big deal to elevate it to a high angle. Much more difficult than elevating a conventional gun.

[Darth Smiley]

Ah. From what I've read (admittedly not much), the whole point was greater range. I guess they haven't gotten there yet. Still, a "big deal" is not impossible, so maybe in another decade or so they have working prototype rail artillery.

I think the big thing with railguns is that it IS possible to get absurd muzzle velocities, where as conventional guns cannot. Given time, an advanced railgun could potentially out range and overpower conventional artillery by a significant amount - which is why so much money is being spent on it.

Of course, as nice as shiny new uber-artillery would be, I can't actually see it being useful in the kind of fights the modern military gets itself into. What's the point of having absurd range and damage if you opponent isn't ever out in the open?

[Beowulf]

What's the point of a battlefield railgun anyway? Given its support requirements, it seems totally impractical when conventional weapons are much easier to use and support. Conventional weapons can also do plenty of things that railguns can't, like striking over the horizon or without line of sight. Even if someone were to somehow develop a railgun that could be fired a hundred times or more before rail replacement became necessary, would it be worth the bother?

One of the more useful ideas for a battlefield railgun is for tanks. Instead of having several hundred pounds of rather explosive ammunition, you instead have a rather smaller amount of inert metal, plus capacitors. Lack of a high angle capability doesn't hurt. Most tanks can't do that anyway.

High angle capability shouldn't actually be a big deal. Test railguns haven't been capable because it's unnecessary work when the gun isn't going to actually be weaponized. Once the railguns are at a point where they can actually be weapons, then they'll add the extra required mounting hardware to do so.

[CmdrWilkens]

Conventional weapons can also do plenty of things that railguns can't, like striking over the horizon or without line of sight.

What? I thought railguns had the same basic function as conventional guns, just much higher muzzle velocity (and, of course, the wear/power issues). If they aren't, then what is the difference?

Well, at least based on all the railguns I've seen, it's a pretty big deal to elevate it to a high angle. Much more difficult than elevating a conventional gun.

Given that the weapons version is suppossed to have a range of 220mi I rather think that exceeds pretty much anything in terms of ordnance which isn't either rocket or aircraft delivered. Given the refire rate and the speed of travel it would make an awesome deep strike artillery weapon for marines operating beyond the range of conventional naval weaponry.

[Sea Skimmer]

Yes, because the projectile needs to conduct current.

No it does not; current concepts use a separate armature which pushes the projectile.

Is there a way to create a swappable magnetic coil system sort of like replacing the barrel of a burned out machine gun in WW2.

With a barrel weighing 15 something tons on a ship underway, no, that will never be possible. You need a port, a crane and probably about two days to do that kind of job.

What's the point of a battlefield railgun anyway?

The biggest single issue is you have no propellant requirement, propellant being inherently much more dangerous and prone to induced explosions then the explosive fillings found in projectiles. You also have the possibility of much greater ranges then are practical with current technology, and shells which can effective without explosive payloads, making them much more compact and safe to use close to friendly forces. If the technology ever works, a railgun of the same caliber as a conventional gun is expected to have triple the ammo capacity for the same overall magazine weight and volume, and that’s accounting for the space taken up by the electrical power feed system. What’s more, since the explosive hazard has been removed, the magazine can be allowed to protrude above the ships waterline, making designing the whole ship easier.

Given its support requirements, it seems totally impractical when conventional weapons are much easier to use and support.

If you build a conventional gun with a 2,500m/s muzzle velocity its going to have a barrel life of about ten rounds and would need every shell to be a different size like the Paris gun. That’s hardly more practical or easier to use. Meanwhile the railgun needs no explosive ammo, and is powered by the ships own fuel supply so it’s logistically very easy to support.

Conventional weapons can also do plenty of things that railguns can't, like striking over the horizon or without line of sight.

What the hell gave you the idea that an EM weapon is going to be line of sight only? With 2,500m/s muzzle velocity a 150mm railgun is expected to have a maximum range of over 400km, and the projectile will still impact with enough remaining velocity to destroy any tank or fighting position type bunker. Shrapnel shells would be used against area targets; creating the same effect as a cluster bomb but with zero dud risk. That alone would be immensely useful. It will have trouble hitting reverse slopes, but it may well be that a combat ready railgun will have variable velocity to let it act as a howitzer when needed.

In comparison the immensely large and heavy, but still conventional 155mm Advanced Gun System can reach only 180km, and only then using a rocket assisted shell that glides most of the way, making it more gun launched missile then shell. Range with ballistic projectiles is more like 50km.

Even if someone were to somehow develop a railgun that could be fired a hundred times or more before rail replacement became necessary, would it be worth the bother?

A mere 100 round life would not be worthwhile, but a barrel life of several thousand rounds would be great. Such a weapon will never be adapted if the barrel life isn’t at least equal to one magazine fill of ammo plus some margin for training. Assuming no more ammo was carried per barrel then is the case with AGS that would mean a lifetime of about 400-500 rounds as a minimal. Course this would mean you gain no increase in ammo capacity, you just have a more compact magazine.

[Darth Wong]

Given its support requirements, it seems totally impractical when conventional weapons are much easier to use and support.

If you build a conventional gun with a 2,500m/s muzzle velocity its going to have a barrel life of about ten rounds and would need every shell to be a different size like the Paris gun. That’s hardly more practical or easier to use. Meanwhile the railgun needs no explosive ammo, and is powered by the ships own fuel supply so it’s logistically very easy to support.

Who said the conventional weapons had to be guns? I was thinking of missiles.

Conventional weapons can also do plenty of things that railguns can't, like striking over the horizon or without line of sight.

What the hell gave you the idea that an EM weapon is going to be line of sight only?

I figure it would be rather difficult to make it elevate to a reasonably high angle because of the size of the structure which would undoubtedly surround the length of the firing race, although if we're simply assuming that all of the existing technical problems can be solved, I suppose that one goes with it.

With 2,500m/s muzzle velocity a 150mm railgun is expected to have a maximum range of over 400km, and the projectile will still impact with enough remaining velocity to destroy any tank or fighting position type bunker.

How accurate could such a weapon be over such long ranges? Wouldn't a missile make more sense?

[JointStrikeFighter]

With 2,500m/s muzzle velocity a 150mm railgun is expected to have a maximum range of over 400km, and the projectile will still impact with enough remaining velocity to destroy any tank or fighting position type bunker.

How accurate could such a weapon be over such long ranges? Wouldn't a missile make more sense?

Missiles are much more expensive per shot.

[Darth Wong]

With 2,500m/s muzzle velocity a 150mm railgun is expected to have a maximum range of over 400km, and the projectile will still impact with enough remaining velocity to destroy any tank or fighting position type bunker.

How accurate could such a weapon be over such long ranges? Wouldn't a missile make more sense?

Missiles are much more expensive per shot.

You're assuming that this railgun will be cheap to operate and maintain.

[Pu-239]

How accurate could such a weapon be over such long ranges? Wouldn't a missile make more sense?

Missiles are much more expensive per shot.

You're assuming that this railgun will be cheap to operate and maintain.

I don't think the cost argument is really good, since at such ranges, there must be a guidance system of some kind, only saving you the cost of a rocket motor- granted, that part probably costs a fair bit compared to guidance (I don't really know)- barrel replacement may or may not offset the cost savings.

It's been mentioned that rate of fire as well as more capacity are the benefits of railguns (although I do believe modern VLS systems can fire missiles pretty quickly).

I believe the biggest benefit of railguns is that the time for projectile to travel to target would be decreased too, which is rather important- 5600mph is substantially faster than most cruise missiles, useful for fire support that needs to arrive ASAP before the target moves or friendly positions wiped out, etc.

[Sea Skimmer]

Who said the conventional weapons had to be guns? I was thinking of missiles.

Missiles and tube artillery do not have interchangeable missions, why else do you think warships and land armies still use gun?. Tube artillery provides all weather sustained fire support which can respond rapidly and close to friendly troops, even when aimed at area targets. Long range missiles are good for destroying point targets that don’t move and are worth spending a lot of money to destroy. A warship has a limited capacity for missiles and they cost too much and don’t have the flexibility to do the job a gun does.

I figure it would be rather difficult to make it elevate to a reasonably high angle because of the size of the structure which would undoubtedly surround the length of the firing race, although if we're simply assuming that all of the existing technical problems can be solved, I suppose that one goes with it.

I’m not seeing elevation as being a serious issue at all. The 180 ton gun barrels on battleship Yamato could elevate to 45 degrees in only about fifteen seconds, and this more then sixty five years ago. Battleship guns fired with the same level of accuracy we’d now expect from a very high end modern sniper rifle too, that elevating system had to be very good at holding the barrel in alignment with the mounting and the rest of the fire control setup.

Even if the railgun barrel weighed four times as much as a conventional barrel of 150mm caliber, that would still only be 25 tons. That’s not small, but actually by naval standards it’s only a medium weapon, not that much heavier then a typical 8in weapon from WW2.

How accurate could such a weapon be over such long ranges? Wouldn't a missile make more sense?

All long range projectiles are expected to be guided by GPS, work is already underway for a separate program for GPS shell guidance kits costing as little as 3,000 dollars. This is the advantage of a gun; everything expensive about the system is reusable.

Against some targets, sure, missiles would be better, but plenty of targets move too much or are too dispersed or just aren’t worth firing off a super expensive weapon. Even then, if the missile can hit the target, it still only explodes once. If you need covering fire, nothing can replace the value of many impacts spread over time. Anyway, you wont find many missiles with 400km range that aren’t slow flying cruise missiles, totally unsuited to directly supporting troops in the field. The US Army does have ATACMS, a ballistic missile that has variants with as much as 300km range, but only with a reduced warhead, and a three quarters of a million dollar pricetag. A naval version was proposed at one point, but was killed off by lack of funding and limited interest (at the time) in shore bombardment weapons.

[Ariphaos]

I find it hard to believe that timing could be a long term obstacle to developing a coilgun. Even back in WW2 the Germans were able to build cannon which had multiple firing chambers spread along the length of its barrel. Each chamber fired in succession precisely as the shell passed to build up to an unprecedented 1,500m/s velocity. The timing system worked, but the barrel had a tendency to burst because propellant gas would leak past the shell and prematurely ignite firing chambers. This concept was standardized for Hitles V-3 super cannon farm.

It's not, at least in the sense of a freshly designed gun, or if you can accept certain levels of inefficiency.

The problem is that replacement coils may have varying strengths, especially when they are prone to shock in a combat situation and timing needs to be redone when it gets installed. It just increases the order of complexity by an order of magnitude - this isn't insurmountable by any means, but it's a dozen more things that can go wrong.

Barrel erosion has no real solution, and the jobs we want railguns for mostly involve high volumes of fire. It’s too bad we don’t have battleships to shoot them at, then a barrel life of as little as 100 rounds would become acceptable.

Rail life may be 100 shots, the barrel can easily be far more durable. Replacement rails are just long, meticulously straight rods. One way to extend it might be to use a conductive fluid or plasma that gets reapplied every shot.

[fusion]

Oh another point on the rail gun issue is that the projectile will be about 3.2Kg and is designed to replace the armaments of the battleship and the Tomahawk.
More info at: more info ^_^

[Darth Wong]

Missiles and tube artillery do not have interchangeable missions, why else do you think warships and land armies still use gun? Tube artillery provides all weather sustained fire support which can respond rapidly and close to friendly troops, even when aimed at area targets. Long range missiles are good for destroying point targets that don’t move and are worth spending a lot of money to destroy. A warship has a limited capacity for missiles and they cost too much and don’t have the flexibility to do the job a gun does.

That's great, provided the railgun actually becomes so similar in use to a conventional gun that it can be treated the same way.

I’m not seeing elevation as being a serious issue at all. The 180 ton gun barrels on battleship Yamato could elevate to 45 degrees in only about fifteen seconds, and this more then sixty five years ago. Battleship guns fired with the same level of accuracy we’d now expect from a very high end modern sniper rifle too, that elevating system had to be very good at holding the barrel in alignment with the mounting and the rest of the fire control setup.

Even if the railgun barrel weighed four times as much as a conventional barrel of 150mm caliber, that would still only be 25 tons. That’s not small, but actually by naval standards it’s only a medium weapon, not that much heavier then a typical 8in weapon from WW2.

A conventional gun barrel is a fairly simple tube, however. Stresses are distributed evenly around its cross-section, and tolerances don't have to be that tight. A railgun barrel is considerably more complicated and would be less forgiving, but as I said earlier, I suppose if one is simply waving a wand and assuming that all technical problems can be solved, then this one would presumably go with the others. Especially if, as you say, the projectile is guided anyway, so you don't really need that much positioning accuracy.

How accurate could such a weapon be over such long ranges? Wouldn't a missile make more sense?

All long range projectiles are expected to be guided by GPS, work is already underway for a separate program for GPS shell guidance kits costing as little as 3,000 dollars. This is the advantage of a gun; everything expensive about the system is reusable.

Against some targets, sure, missiles would be better, but plenty of targets move too much or are too dispersed or just aren’t worth firing off a super expensive weapon. Even then, if the missile can hit the target, it still only explodes once. If you need covering fire, nothing can replace the value of many impacts spread over time. Anyway, you wont find many missiles with 400km range that aren’t slow flying cruise missiles, totally unsuited to directly supporting troops in the field. The US Army does have ATACMS, a ballistic missile that has variants with as much as 300km range, but only with a reduced warhead, and a three quarters of a million dollar pricetag. A naval version was proposed at one point, but was killed off by lack of funding and limited interest (at the time) in shore bombardment weapons.

Ah. Interesting.