Monday, February 9, 2015

Railguns

As reported by Navy Times website, Adm. Jonathan Greenert, Chief of Naval Operations, listed his technology and developmental priorities while speaking at the Naval Future Force Science and Technology Expo (1).  Prominent among those priorities was,

“Getting off gun powder. Lasers and railguns will provide an incredibly deep magazine at remarkably low cost, he said.”

ComNavOps fully supports laser and railgun development efforts while, at the same time, recognizing the many technological challenges still to be overcome before those technologies can be applied on a practical basis.  Let’s set the technological challenges aside and look at some of the tactical and application issues that may not have been fully explored, yet.

Consider an arrow shot at a piece of paper.  The arrow will pass through the paper and leave a fairly large hole in the paper although the rest of the paper will be unaffected.  Fast forward on the technology scale and consider a bullet fired from a handgun at a piece of paper.  The bullet is much more advanced technology and much more powerful than an arrow so it should do much more damage, right?  Well, the bullet will pass through the paper and leave an even smaller hole than the arrow.  How can that be?!  The bullet is faster, more advanced, and more powerful.  The problem is that a bullet is an inappropriate weapon choice for a paper target. 

With that example in mind, let’s consider a railgun firing at a modern, small naval vessel.  You’ve probably seen the videos of test firings of railguns penetrating a foot of steel and the resulting destruction due to the kinetic effects.  However, as you know, modern small vessels such as corvettes and frigates are lightly built and thin skinned.  What will happen when a railgun projectile traveling at several times the speed of sound hits a modern vessel?  Well, the projectile is inert so there won’t be any fused explosion.  It has no unexpended fuel to disperse and ignite.  That leaves only kinetic effects but will the projectile encounter enough resistance to transfer its kinetic energy to the target, thereby causing damage or will the projectile pass through the thin skinned vessel without doing significant damage much like the bullet passing through the paper?  One could imagine a targeted vessel with a bunch of small, clean holes but otherwise largely undamaged after being engaged by a railgun.  I can’t answer this question and I may be completely off base but it’s at least a plausible scenario to ask about.

Now, let’s look at area effects.  One of the main uses for a naval gun has, historically, been to produce area explosive effects during land bombardment for area damage, suppressive fire, and similar uses.  Once again, consider how a railgun works.  The projectile is non-explosive and depends on the transfer of kinetic energy for its effect.  In short, it does not produce an area effect.  It is not really possible to provide area bombardment or suppressive fire from a railgun.  A railgun projectile hitting ground will kick up little dirt and bury itself. 

What about guidance?  Railguns are touted as shooting projectiles at such great speeds that they will strike before the target can move.  At close range, that may be true but railguns are being looked at as deep strike weapons hitting targets hundreds of miles away.  Do the math.  It still takes significant time to cover that distance.  Mobile targets, such as vehicles, will be well out of the path of a railgun projectile by the time it arrives.  Remember, with no explosive effect, a projectile must have a direct hit to be effective.  A miss of one foot is a total miss.  There is no area explosive effect to compensate for small misses.  Well, why don’t we add a guidance package to the railgun projectile?  Wouldn’t that solve the problem?  The answer is no, for two reasons.  First, we don’t have the technology to fit a guidance package into a projectile and have it survive the firing.  The stresses on the projectile are immense.  Second, if we start adding guidance packages (or ECM, or active radar, or whatever) we negate the main advantage of the railgun which is its cheap projectile cost.  Instead of shooting free rocks as projectiles, we’ll be right back to $50K+ projectiles like we have now.

Now let’s consider a railgun in an AAW/CIWS role.  Similar to a Phalanx CIWS, a railgun could be an effective AAW weapon especially given its very high speed and, thus, short travel time to the target.  Further, the low cost of projectiles makes it an economically viable counter to modern missiles.  The downside is that the great speed of the projectiles ensures a very long range which, if the projectile misses, makes it a potential friendly fire hazard for ships and aircraft much further downrange as opposed to the relatively very limited range of a Phalanx CIWS, for instance.

We see, then, that a railgun is akin to a sniper weapon.  It’s great for specific, fixed targets but suffers from significant limitations due to its non-explosive characteristic and inability to be guided.  A railgun could supplement and complement a conventional gun but it can’t totally replace it.


(1) Navy Times, "CNO wants more high-tech assets, delivered quickly", Lance M. Bacon, 4-Feb-2015,

35 comments:

  1. Is Navy Matters familiar with General Atomics Blitzer railgun? It doesn't look like the projectile is exclusively inert. Also many of these projectiles have command guidance, which at the projectile's speeds could be sufficient.
    https://www.youtube.com/watch?v=-xeHfxzjThQ

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    1. I am familiar with it although very little (no) information exists in the public domain outside of manufacturer's claims which are, invariably, wildly exagerated.

      As I mentioned in the post, the use of guided and/or fused projectiles invalidates the main advantage which is cost. Further, all accounts suggest that we do not yet possess the technology to protect the projectile's electronics during firing due to the extreme magnetic stress.

      I've read some suggestions that a rail gun could be "throttled back" to fire at a much reduced velocity so as to enable electronics-containing projectiles to survive but that simply takes us back to a coventional gun.

      Do you have links to any non-manf data for Blitzer? Thanks!

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    2. I fail to see how having guided or fused projectiles invalidates cost. The fusing required isn't much different than we already have in rounds costing in the low 10's of $ per round. And those rounds are already subject to as high if not higher shock forces than a railgun projectile.

      Its important to understand that a railgun actually has lower peak Gs than many already existing conventional weapons. A railgun generally relies on continuous G loading instead of instantaneous G loading. A traditional chemical based gun has an extremely high initial spike G loading when the chemical explosive fires initially followed by exponential decay in G loading as the resulting gases expand down the barrel. In contrast, the G loading in a rail gun is almost constant of the point of initiation to exit of barrel. Its this continuous constant G loading that allows railguns to achieve such high velocities but the peak G loading is in most cases significantly lower than the peak G loading on chemical guns.

      As far as magnetic field effect issues, those are likewise that that great depending where on the projectile that the actual electronics are located. Certainly, putting the electronics in the base of the projectile would present some significant difficulties, but it would be fairly stupid to put them there.

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  2. I largely agree with your assessment. Railguns firing inert projectiles seem to be of limited utility.

    However high velocity, inert rounds can have significant behind hull effects. Look up FAPDS or PELE rounds for autocannons.

    Certainly not the same as an HE round, but they can do better than a small hole.

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    1. FAPDS and similar projectiles are interesting. They were developed to penetrate tank or other heavily armored targets and depend, in part, on shattering (hence, frangible) as the penetrate the target. I'm very dubious that the projectile would function as intended against a very thin-skinned target (back to the bullet and the paper analogy).

      I hope that before we go off on an all-or-nothing rush to railguns, that someone has actually experimented with railguns and their projectiles against representative targets to see what, exactly, will happen. Knowing the Navy, I suspect this has not been done.

      The videos I've seen of railgun tests invariably show its performance against massive thicknesses of armor. I've only seen one example against a somewhat thinner target and in that one the projectile did exactly the bullet and paper thing. It went right through with very little damage to the object, though with an impressive shower of sparks!

      I'm not a railgun expert but this is a plausible point to bring up. Imagine a railgun projectile hitting a 1/4" aluminum skin of a modern vessel. I strongly suspect the projectile wouldn't even notice the skin and would pass through with little effect - just a small hole left behind.

      It warrants testing before we commit the fleet to railguns!

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    2. If you test in a realistic operational environment you will delay the flow of money tot he Contractors and they Admiral's Future Board of Directors position.

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    3. My guess is a FAPDS-style projectile passing through multiple bulkheads could be made break up somewhere along the way. I'm still not sure it makes much sense as a naval weapon, though.

      Long-ranged shots will still require guidance of some form.

      The quote, “Getting off gun powder. Lasers and railguns will provide an incredibly deep magazine at remarkably low cost".

      Just has me flummoxed. Is gunpowder really that expensive? Ships really carry that much? This is his #1 priority?

      An incredibly deep magazine of not terribly useful projectiles once we invest billions in R&D and production.

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    4. Generally something like 70-80% of a projectile stored volume is chemical explosives and casings. That's a significant increase in magazine capacity.

      CNO, I assume you are talking about the video with the projectile going though the truck cabin as the thinner target? That shot shows pyrophoric effects within the cab of the vehicle. Those are actually the exact same effects that a 120mm APFDS uses to kill a tank. An APFDS doesn't explode, it may even punch through the other side of the vehicle. What it does is cause extreme pyrophoric effects that effectively kills anyone inside and may as a side effect cause secondary explosions. Likewise, a railgun APFDS may punch clean through a ship, but on the way its likely going to ignite the actual aluminum and cause a shrapnel storm that nothing is going to live through.

      And for softer targets, the design goal is to utilize a minor bursting charge to distribute metal balls traveling at mach 5+.

      And also, it is important not to extrapolate too much the effects of projectile traveling at mach 1-2 with a projectile traveling at mach 5-10. In the mach 5+ range you actually start entering totally different projectile/target effects than you see at lower velocities. For one, even simple collisions result start to result in flash vaporization effects instead of fluid/elasticity effects.

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    5. ats, your descriptions are on the very extreme positive, optimistic end of the spectrum compared to any description or discussion of railguns that I've seen in the public domain. Do you have any documentation to support them?

      It's one thing to cause pyrophoric effects in a very small space like the inside of a tank which is packed with munitions and another to cause significant damage in the much larger compartments of a ship. Also, many anti-tank rounds depend on spalling of the tank's own armor for some or all of their effectiveness and I doubt whether the thin skin of a modern vessel would spall in these circumstances.

      Again, if you have any documentation of the effectiveness of rounds at railgun velocities, I'd love to see it. I'd also love to see documentation of the feasibility of firing electronic laden rounds from a railgun.

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    6. For electronics within the EM type fields experienced in railguns, look up ARL-MR-499. You can also reference, http://proceedings.ndia.org/5560/Wednesday/Session_III-A/Herr.pdf, which did some testing of simple electronic devices(aka cheap digital watches) in field upwards of 4x that would be experienced in a railgun. Also, we only have to wait two years to see if the HVP program pans out for the electronically guided projectile portion.

      As far as impact effects, APFDS don't rely on spalling for their effect. The only anti-tank rounds that depend primarily on spalling are HESH rounds. Pretty much everything else depends on overpressure and thermal effects. And those pyrophoric effects will do significant damage within a ship even with larger compartments. And in an actual ship case, the majority of the energy of a round should be dissipated as it goes through a ship. With the velocities and masses they are targeting you are looking at 15+ MJ of energy into the ship with is as much as a 155mm HE shell has. Lets put it this way, if you think the shapnel from an intercepted supersonic ASM is an issue for ships, you have to concede that a mach 5+ projectile impacting a ship is rather significant. Is one going to kill a ship? Probably not, then again, historically projectiles against ships have been rather ineffective. Also another thing to realize is that a mach 5+ HVP pretty much defeats the current trend in Naval warship design of thin skins with many compartments.

      The main issue with any railgun is the same as its ever been which is longevity and reliability of the armature. Pretty much everything else is well within the current state of art. The biggest concern I have is with longevity of barrel life. I certainly don't think we are anywhere close to the 3k round point. I don't even know for sure we are at the 1k round point. But the Armatures do have one significant advantage over chemical guns which is they weigh significantly less which allows things like replacement to be a lot easier. I could see deployment when they get a 32MJ system that can handle ~1k rounds at 6 per minute.

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    7. "Punching straight through":

      On a modern warship, how much "empty" space is there?

      If you hit any part of, say, a Burke with a solid slug and it went straight through, what are the chances of it NOT hitting something vital?

      If a round entered at near horizontal, going straight through, what is the probability of it damaging something significant? Vital mission systems? Weapons? Electronics? Hangar facilities? People?

      If a round entered at a more vertical angle, what about vital machinery (turbines, gearboxes / drives, generators)? Or weapons magazines? Fuel bunkers? Or opening up damn great holes in the bottom of the hull?

      And don't think of one round - think of 30/50/100. Now what are the chances of significant damage?

      Also, any pyrophoric effects of the materials used *could* be significant in starting fires, causing detonation of munitions and killing personnel.

      Even if you don't get destruction / fire / sinking like a barrage of 5" or a couple of Harpoons might inflict, a mission kill is still a kill.

      A ship limping off / towed away for several months of repair with non-functional radars, destroyed VLS, destroyed GTs, destroyed hangar facilities is a win.

      I'm by no means convinced about railguns, but I think that the paper target / pistol scenario MAY be too simplistic.

      Nobby Stiles.

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    8. "An APFDS doesn't explode, it may even punch through the other side of the vehicle. What it does is cause extreme pyrophoric effects that effectively kills anyone inside and may as a side effect cause secondary explosions."
      ================================================
      As CNO stated, this is an extreme case: there are many examples of this *not happening* particularly a well documented case of a penetration of an M1 tank that went through both sides of the crew compartment and caused zero casualties and the tank was still functional!

      Much of the pyrophoric effect depends upon the interaction of the projectile with the armor - a modern ship hull is nothing like tank armor.

      GAB

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    9. Nobby, you could be right. Or, maybe not. The point is that the Navy needs to prove out the actual effects in realistic tests before committing the fleet to this path. It's as simply as that. Think it's a good idea? Then let's demonstrate it in realistic testing to be sure.

      We've embarked on too many half-baked ideas like the LCS and JSF and whatnot without CONOPS and testing. Let's take a wiser approach before we announce that the entire fleet will be converted to railguns only to potentially find out later that they aren't as effective as we thought.

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    10. " And in an actual ship case, the majority of the energy of a round should be dissipated as it goes through a ship. With the velocities and masses they are targeting you are looking at 15+ MJ of energy into the ship ..."

      Take an extreme case ... Imagine a railgun round striking a sheet of 1/16" aluminum. What will happen? Absolutely nothing. The round will not encounter sufficient resistance (friction) to release any significant kinetic energy. There won't be any show of sparks or pyrophoric event on the other side. The round will pass through without ever having noticed the sheet of aluminum. Now, consider a series of 1/16" sheets in the path of the round (like a series of thin bulkheads). Would it make any difference? No. The round would pass through all of them with no appreciable disappation of energy because none of the sheets would offer enough resistance to transfer significant energy. This is the bullet through paper analogy.

      The question is whether the slightly thicker skin and bulkheads of a real ship offer enough resistance to trigger any effects. I suspect not. I suspect that little energy will be transfered to the ship, as you put it. I may be right, you may be right, or "right" may be something in between. My point is that the Navy needs to conduct realistic testing before committing to this path.

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  3. The challenge is the same as with lasers - you need to build up a lot of electrical charge. What will charge the gun, how many rounds will each charge be good for, and now long will it take to recharge once fired (time to recharge is time you are vulnerable). Unless we develop a capacitor breakthrough or much better batteries, rail guns are going nowhere

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  4. A few things. Railguns do have something of an advantage vs regular guns on the firing stress issue as the projectile is accelerated evenly as it travels down the barrel, while a regular guns acceleration peaks almost immediately, then drops off as the projectile moves down the barrel. Also you have no gas pressure problems. Unfortunately this is balanced out by the tendency of the massive magnetic fields to fry even hardened electronics. As for over penetration problems, the best solution would be a frangible projectile that breaks up on impact. Remember, projectile could be made of many materials, it only need a magnetic driving band for propulsion. A depleted uranium round would be very nasty. What most people don't know about DU is that it is pyrophoric, and usually ignites like magnesium on impact with a hard surface.

    Randall Rapp

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    1. Again, as pointed out in the post, the more complex the projectile and the more costly its maufacturing process, the more it negates the cost advantage of the railgun which is what the Navy is largely "selling" the gun on.

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    2. Wrong wrong wrong. The cost is supposed to be compared with missile, not other guns. Do you think its still 1945? Rail gun is to replace, or supplement, missile, not other guns.

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  5. If a mere anonymous may point something out, there is a touch of something that no one seems to be mentioning about the rail-gun that may put a stopper in the navy's fun.
    DU - what they have chosen to make the ammunition out of - traveling at Mach 7 - which is what they estimate the impact velocity as - is enough to create a (small) mushroom cloud when it hits virtually anything.

    That being said, in an all-out wartime scenario it would actually make an excellent ASuW weapon, but... even then, I don't think the friendly infantry would appreciate having something with the force of a tactical nuke dropped in just a few dozen yards from them.
    This goes along with what Anon (Randall Rapp) above me mentioned - even at slower speeds (Mach 3-5) it acts like a fairly decently sized fuel-air bomb, which is still something I wouldn't want dropped anywhere within a few hundred yards of myself...

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    1. I forgot something.
      W (Tungsten) has similar, but not as pronounced, effects.
      When speaking of Tungsten, most people seem to forget that it's radioactive and can and will 'react' when driven at extreme speeds.
      Oh, say, Mach 6.

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    2. There is nothing wrong with being anon. Your input is valued.

      Are you suggesting a nuclear explosion as a result of DU impacting at high Mach speeds? I am nowhere near a nuclear expert but that sounds highly unlikely. Nuclear explosions are very difficult to trigger. DU, as the name suggests, contains inadequate fissile material for a nuclear explosion. In fact, DU, as I understand it is used as radiation shielding and tamping.

      Now, you bring up a good point about the result of a DU impact. It might well create a dust cloud and DU dust is potentially toxic and pyrophoric.

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    3. Neither Tungsten nor DU is going to result in a nuclear reaction pretty much regardless of the velocity it is traveling at until you get into relativistic velocities (generally considers to be .1-2c or greater), and at those speeds even lead can have nuclear reaction effects! No railguns that are anywhere on the horizon are planning to get anywhere close to relativistic velocities (in comparison, to get to relativistic velocities today with extremely light weight particles(electrons, protons, et al), we require upwards of several miles of acceleration!)

      OTOH, most materials that would be used for a projectile will result in pyrophoric effects from a mach 5+ impact due to the instantaneous super-heating that occurs in impacts at such velocities.

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    4. It's me again, the Anon.

      Well, the way I worded all of that was more than slightly confusing, so let me take another shot at it.

      I as more-or-less referring to the pyrophoric effects - as ats and Randall pointed out – but in a scale where it causes a non-nuclear 'mushroom could'-like effect, similar to the M.O.A.B, and thus spreading the resulting toxic/hazardous dust over a much wider than usual area.
      A mile or more even, by some estimates.
      While what I'm getting at with DU is obvious (you already got that much), with W (Tungsten)... well, off the bat, I should point out that the jury is still out on the radioactivity of W, but the hazardous qualities of the material is pretty much like any other heavy metal dust... except compounded by the high relative density of the metal. Something about tearing holes in the human lungs merely by the force of the inhale... or, at least, it was something like that. I'll have to ask that you forgive me, it's been a long time since I sat through that class, so the details are eluding me at the moment.

      Now, don't get me wrong, I have no reservations about using such munitions against our enemies (in any full-fledged war scenario far worse things will probably be thrown around in cruise missiles on a daily basis), but for the stated purposes of the Electromagnetic Rail-Gun Project (local level fire support) it's a pretty harebrained scheme.

      Truly, from everything I can collect, the Electromagnetic Rail-Gun Project - as they are developing it - is almost exclusively a Strategic Level weapon (almost, because the ASuW capability).
      It's inaccurate at close ranges (it's pretty much point-and-shoot since the speed of the projectile doesn't give guidance systems enough time to react, and the mount [AGS] is not made for that type of shooting from what I can tell), it's Slow Firing (1 shot every 3 to 5 minutes - for the gun's size - and that's skewing things in the gun's favor), has a very-wide (for conventional artillery) destructive pattern (roughly equivalent to the crater made by the Iowa's 16s), and has a very low 'Barrel' (I suppose I should say 'Armature', but it's their term, not mine) FER of... 12, or - on a good day - maybe 20 (that is unless you want the 'barrel' alone to weigh 240 long tons, in which you could possibly get a respectable 70 something shots off). Not to mention that the accuracy is compromised after the first shot and further so by every subsequent shot due to heat warping the barrel, even the guided munitions may well have too much offset to fight in order to hit what they're aimed at.
      ...Okay, having typed all of that, the more I think about it the more this rail gun is looking like the Paris Gun on steroids.

      Good speaking with you,
      - Ray D.

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  6. I have a dumb question:

    As I understand it, rail guns seem to be a kinetic energy round. They get all their destructive power by having the A of the F=MA be really really high.

    So for something that's relatively close I can see a rail gun doing a ton of damage. But... at the 100 mile mark? If the rail gun's maximum range is 100 miles, doesn't that mean that by the end you just have a projectile moving at roughly terminal velocity?

    I mean, that's not good if its a 60 lb DU rock.. but its not like its got the hitting power of a 400lbs warhead on a cruise missile.

    Also, there were a couple people I think (Scott Brim maybe?) who pointed out some real issues with rail guns not being ready for prime time. IIRC one of those was the life expectency of the rails. Has that been fixed or are we looking at a weapon that we would put on a destroyer that can shoot 7 times and then has to have its rails replaced?

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  7. I have a dumb question:

    As I understand it, rail guns seem to be a kinetic energy round. They get all their destructive power by having the A of the F=MA be really really high.

    So for something that's relatively close I can see a rail gun doing a ton of damage. But... at the 100 mile mark? If the rail gun's maximum range is 100 miles, doesn't that mean that by the end you just have a projectile moving at roughly terminal velocity?

    I mean, that's not good if its a 60 lb DU rock.. but its not like its got the hitting power of a 400lbs warhead on a cruise missile.

    Also, there were a couple people I think (Scott Brim maybe?) who pointed out some real issues with rail guns not being ready for prime time. IIRC one of those was the life expectency of the rails. Has that been fixed or are we looking at a weapon that we would put on a destroyer that can shoot 7 times and then has to have its rails replaced?

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    1. "If the rail gun's maximum range is 100 miles, doesn't that mean that by the end you just have a projectile moving at roughly terminal velocity?"

      That's a very good question that I don't know enough about to answer. Maybe someone else can chime in.

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    2. For rail guns, there are two ranges worth talking about, you might know them, they are the same ranges that are used with most every other gun in existence: max effective range and max projectile range.

      Just like the bog standard M16, a railgun has a max projectile range significantly larger than the max effective range.

      Now a railgun projectile that has been properly shaped is going to reach 100 miles in roughly 1 minute. Its also going to have a significant amount of its velocity intact (still going mach 5+). That same railgun and projectile can sling a projectile upwards of 2-3knm but the effectiveness on a target at that point would be greatly reduced (basically you would be limited to terminal gravity velocity of the projectile via atmospheric re-entry!).

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  8. As any one seen how soon the barrels wear out on these things?

    From GlobalSecurity.org
    http://www.globalsecurity.org/military/systems/ship/systems/emrg.htm

    One important requirement for the implementation of a naval rail gun would be a firing rate or at least 6 rounds per minute with a barrel life of approximately 3000 rounds. At this point in time, this operation is not feasible because of rail erosion caused at the projectile rail interface. The conditions within the barrel for high-velocity launch of a multi-kilogram projectile are extreme. They can reach 10,000 atmospheres pressures, megampere currents, and tensof kilo gees acceleration. The barrel must withstand these conditions for up to several rounds per minutefor thousands of shots without failure or significant degradation. These parameters are well beyond the state of the art in materials science.

    So just like in silicon circuits, we can do neat things if we can just find a material with the right property.

    Unfortunately here goes the Navy chasing a Technology before it is fully cooked. Haven't we learned from DDG-1000, the Ford (EMALS), and LCS (Mission packages) to not chance technology? Oh sorry rhetorical question.

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    1. Well, the GS site is a little pessimistic. Also Barrel is also a little bit of incorrect terminology. railguns don't so really have barrels, they have Armatures. And yes, Armatures wear out, they are designed to wear out. Pretty much all railguns are designed to take this into account without much issue. Most of the issues however are not beyond current material science.

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  9. Anti Ship,
    I would imagine the explosives and the fuel is in the target you’re shooting at. The advantage of the rail gun is that YOUR magazine is no longer a disaster waiting to be hit. It’s a stack of inert projectiles and some massive capacitors.
    Probably projectile design will start to get into blended metals etc. etc.
    As in bullet design, designed to transfer energy to a target and not go straight through like your bullet paper argument.
    I doubt it’s relevant but the current projectile seems “flat headed”
    As I recall at about Mach 7 no chemical explosive you can possibly supply (per gram) more energy than 1g of inert mass. So we are pretty much near that tipping point.
    It will be a major shift backward in terms of ship to ship combat, back to the days of board sides, assorted cannon loads for effect, and shooting for the waterline.
    EXTREAMLY difficult to defend again though, small fast kinetic warhead, don’t think we have anything right now that would even knock it off course significantly !?!
    Long range land target? Different Game. Depends how fast its going and the trajectory I suppose ? can’t imagine that’s going to work without explosives ?

    Beno

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  10. Area effect and soft target I have seen animations of canister type rounds. At such speeds a canister even a simple timed one that just opened releasing hundreds/thousands (pending size/target) of small tungsten balls would have some devastating area effects. Literal steel rain and would go along way to help targeting against air targets. I don't see a solid round as much use except against stationary bunker type targets.

    Savings I didn't know anyone was selling rail guns for savings in comparison to standard cannon. Rail gun savings only come at range in comparison to what it would replace missiles. The elimination of the firing charges and all that comes with it to make such storage safe on a ship is no minor benefit for ship survival in a peer war were possibility of actually taking a hit must be considered.

    Bottom line I think ATS is right on the money with the challenge is making the rails have a reasonable life span.

    Rail guns will revolutionize naval power because the power requirements will require size and for mobile size, ships are option one. The range at which ships will be able to sit off coast X and target huge swaths with a weapon that has little to no defense is a big deal. If the rails can be made reliable then ships with rail guns could carry allot more than 150 shots by some multiples and resupply on station without some currently nonexistent complicated boom system reserved for port or calm sunny glass days. From a navy perspective its a tech that should be pushed hard.


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  11. Healthy skepticism is a virtue, and I must say Navy Matters does a great job of not getting caught up in the hype. I have read many, many articles and papers on railguns. In particular I find the articles by the Navy to be the most misleading. If you do a superficial reading of them you come away with the impression that we have railguns that can fire hundreds of full power shots on a singles set of rails. However, that impression would be wrong as there is nothing published that indicates that Navy railgun can fire hundreds of full-power shots on a single set of rails.

    You might also get the idea that we have working guidance packages for the railgun. Instead, what we have are claims with no specificity talking about command guidance However, there are zero details on this alleged command guidance capability. For example, can the command guidance package survive a full power shot?. Further, self-guided railgun projectiles, a critical capability, will be very difficult to achieve most likely it will be many years before we see such a package.

    Yet, despite not being anywhere near having a truly fieldable weapon, at least by naval gun standards, the Navy is talking about doing a sea trials.

    Another issues almost completely ignored is the Railgun's mid-range weakness,e.g. railguns do not look very impressive for mid-range engagement scenarios.

    A real good article in which the author interviewed the ONR is one of the few that points the railguns' mid-range issue is:

    "Railguns: The Next Big Pentagon Boondoggle?"

    http://www.nationalreview.com/article/394715/railguns-next-big-pentagon-boondoggle-mike-fredenburg

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  12. (To railgun proponents) please, read this first:

    http://warships1discussionboards.yuku.com/topic/18336/Ze-Scott-Brim-Gun-Gadgetry-Galore-Thread-ZSBGGG

    http://warships1discussionboards.yuku.com/topic/22118/Navy-wants-railguns-for-missile-defense

    before making some statements, like this:

    > "chemical explosives and casings... That's a significant increase in magazine capacity."
    (but you forgot about the need to store electrical energy in capacitors or batteries - which energy density is currently 10-20 times less than the explosives ;)

    > "Also you have no gas pressure problems..."
    (but you forgot about the magnetic pressure ;)

    > "DU ... traveling at Mach 7 is enough to create a (small) mushroom cloud"
    (are you talking about nuclear fission in _depleted_U ?! or just the "kinetic energy" effect? Remember, fission of 1 kg of _non-depleted_U gives 80 million(!) MJ, and 1 kg of TNT - just 4.6 MJ)

    >"...destructive power by having the A of the F=MA"
    (No, it's because of a kinetic energy: Ekin=(1/2)MV^2, where V is the projectile speed at target, not at the muzzle ;)

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  13. What are the technologies at now? How many rounds can they fire before they have to replace the rails? And do you think it could be placed on aircraft? Pardon my lack of knowledge, I am only 14, but I understood most of what you guys said up there although the numbers seem to change drastically through out, and I want some solid answers for my railgun research.

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    1. For 14 years, you've taken on a fairly complex topic. Well done! Unfortunately, there are no definitive answers for you. The technology is under development and data is sparse and sketchy. The Navy and manufacturer's claims are, inevitably, exaggerated. That leaves us to speculate.

      The best answer is to read through some of the references that were cited in the comments and draw your own conclusions. I'll offer this thought: if the various problems (rail longevity, power, cooling, etc.) were solved we'd have a functional rail gun and we don't. That should tell you something about the practicality of the technology at the current time.

      Good luck!

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