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  • Navy tests Rail-Gun

    Story....

    Firing (x-ray flash image)


    Incoming to laminated target @ hypersonic speed


    Big hole for a 3.2kg projectile with no warhead


    A missile punch at bullet prices

    Dahlgren demonstrates electromagnetic rail gun


    Normally, new weaponry tends to make defense more expensive. But the Navy likes to say its new railgun delivers the punch of a missile at bullet prices.

    A demonstration of the futuristic and comparatively inexpensive weapon yesterday at the Naval Surface Warfare Center at Dahlgren had Navy brass smiling.

    The weapon, which was successfully tested in October at the King George County base, fires nonexplosive projectiles at incredible speeds, using electricity rather than gun powder.

    The technology could increase the striking range of U.S. Navy ships more than tenfold by the year 2020.

    "It's pretty amazing capability, and it went off without a hitch," said Capt. Joseph McGettigan, commander of NSWC Dahlgren Division.

    "The biggest thing is it's real--not just something on the drawing board," he said.

    The railgun works by sending electric current along parallel rails, creating an electromagnetic force so powerful it can fire a projectile at tremendous speed.

    Because the gun uses electricity and not gunpowder to fire projectiles, it's safer, eliminating the possibility of explosions on ships and vehicles equipped with it.

    Instead, a powerful pulse generator is used.

    The prototype fired at Dahlgren is only an 8-megajoule electromagnetic device, but the one to be used on Navy ships will generate a massive 64 megajoules. Current Navy guns generate about 9 megajoules of muzzle energy.

    The railgun's 200 to 250 nautical-mile range will allow Navy ships to strike deep in enemy territory while staying out of reach of hostile forces.

    Rear Adm. William E. "Bill" Landay, chief of Naval Research, said Navy railgun progress from the drawing board to reality has been rapid.

    "A year ago, this was [just] a good idea we all wanted to pursue," he said.

    Elizabeth D'Andrea of the Office of Naval Research said a 32-megajoule lab gun will be delivered to Dahlgren in June.

    Charles Garnett, project director, called the projectile fired by the railgun "a supersonic bullet," and the weapon itself is "a very simple device."

    He compared the process to charging up a battery on the flash of a digital camera, then pushing the button and "dumping that charge," producing a magnetic field that drives the metal-cased ordnance instead of gun powder.

    The projectile fired yesterday weighed only 3.2 kilograms and had no warhead. Future railgun ordnance won't be large and heavy, either, but will deliver the punch of a Tomahawk cruise missile because of the immense speed of the projectile at impact.

    Garnett compared that force to hitting a target with a Ford Taurus at 380 mph. "It will take out a building," he said. Warheads aren't needed because of the massive force of impact.

    The range for 5-inch guns now on Navy ships is less than 15 nautical miles, Garnett said.

    He said the railgun will extend that range to more than 200 nautical miles and strike a target that far away in six minutes. A Tomahawk missile covers that same distance in eight minutes.

    The Navy isn't estimating a price tag at this point, with actual use still about 13 years away. But it does know it will be a comparatively cheap weapon to use.

    "A Tomahawk is about a million dollars a shot," McGettigan said. "One of these things is pretty inexpensive compared to that."

    He said estimates today are that railgun projectiles will cost less than $1,000 each, "but it's going to depend on the electronics."

    Projectiles will probably eventually have fins for GPS control and navigation.

    To achieve that kind of control and minimize collateral damage, railgun ordnance will require electronic innards that can survive tremendous stress coming out of the muzzle.

    "When this thing leaves, it's [under] hundreds of thousands of g 's, and the electronics of today won't survive that," he said. "We need to develop something that will survive that many g 's."

    At the peak of its ballistic trajectory, the projectile will reach an altitude of 500,000 feet, or about 95 miles, actually exiting the Earth's atmosphere.

    The railgun will save precious minutes in providing support for U.S. Army and Marine Corps forces on the ground under fire from the enemy.

    "The big difference is that with a Tomahawk, planning a mission takes a certain period of time," McGettigan said. "With this, you get GPS coordinates, put that into the system and the response to target is much quicker from call to fire to actual impact."

    General Atomics, a San Diego defense contractor, was awarded a $10 million contract for the project last spring.

    The concept was born in the 1970s then promoted when President Ronald Reagan proposed the anti-missile "Star Wars" Strategic Defense Initiative. The SDI railgun was originally intended to use super high-velocity projectiles to shoot down incoming ballistic missiles.
    Last edited by Dr Mordrid; 19 January 2007, 21:47.
    Dr. Mordrid
    ----------------------------
    An elephant is a mouse built to government specifications.

    I carry a gun because I can't throw a rock 1,250 fps

  • #2
    I read somewhere (still searching for the link) that unless the ship is nuclear powered, current generators onboard will only allow 7 - 10 shots of a 5 inch gun per DAY... (at 64 megajoules). (and thats with replaseing the available space from the armours with energy storage systems)

    Each sabot has only a fraction of the explosive power (overall energy is the same, I believe, due to the sabots kinetic energy) of a tomahawk (indeed see the picture above). The problem (insome cases an advantage too!)with that being kinetic only (rather than being a combination, as per the Criuse), is that because the energy is focused in a single point, its damage radius is very, very limited. It would be good at ship to ship engagements, or taking our a selected building, for example, but it would be poor against massed toops or armour.

    Think it will be a while before it is practical yet. it is not a question of warheads not being NEEDED (which is a little bitmisleading in the article) - its a question of warhead sabots not being possible, with current technology, due to the crazy accelerations involved.

    further there is no possible guidance systems - so that it would be OK against a ship or a building, but (becasue of the kinetic issue) - useles against a mobile target (ships are not mobile over the space of 6 minutes - you can estimate where they will be) - again becasue the energy is in one point - traditional 15 inch guns fired a barage, they didnt aim to hit a particular target - the explosive shells dont have to score a direct hit to work.(on bombard, modern ship to ship would be different)

    Intresting stuff, however, for very specific purposes.

    Might be more intresting as a field gun for AT purposes (short range, less travel time), or on board a 747 - perhaps rather than the laser solution proposed before?
    Last edited by RedRed; 20 January 2007, 04:49.
    Dont just swallow the blue pill.

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    • #3
      It's geared to replace conventional ships guns in most applications on our upcoming next-gen cruisers, destroyers and carriers. In fact the plane catapults on the new carriers will be a sort of speed-limited rail gun instead of the current steam units.

      Ever see what happens when an anti-tank shell enters the turret? The copper sabot impacts, vaporizes, penetrates and the temperature inside goes up to 8,000 C instantly causing an expansion which is what explodes the tank. Scale that up by 50-100 times and you're getting close to the rail gun.

      FYI: there is now a self-contained 5 megawatt superconducting gas turbine power generator under test by NASA and the military that is only 4x2x2 meters in size & 2,700kg. Developed by a small company (Long Electromagnetics Inc.) full of maniac engineers.

      Last edited by Dr Mordrid; 20 January 2007, 14:38.
      Dr. Mordrid
      ----------------------------
      An elephant is a mouse built to government specifications.

      I carry a gun because I can't throw a rock 1,250 fps

      Comment


      • #4
        The world’s greatest Navy recruitment ad
        P.S. You've been Spanked!

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        • #5
          what exactly can be seen on the first picture?

          I'm surprised about the flight path they describe: 6 minutes/200 miles & leaving the atmosphere? what kind of precision do they expect with unguided bullets (aka current tech), until they get their g-safe electronics?

          mfg
          wulfman
          "Perhaps they communicate by changing colour? Like those sea creatures .."
          "Lobsters?"
          "Really? I didn't know they did that."
          "Oh yes, red means help!"

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          • #6
            The leaves of the sabot sheath peeling away at about 70,000 G's. A short bit later the projectile clears the sheath and the aerodynamics set in.

            Don't let those G loads vs. electronics statements fool you; the US is already fielding a 155mm GPS guided artillery shell that can withstand 12,000 G's at firing and it's not pushing the electronics capabilities. It works so well you can fire it 45 degrees off axis and it'll still hit the target with a CEP of 5 meters. Some of the test shells hit within 2 feet of zero.

            The G target is very achievable.
            Last edited by Dr Mordrid; 20 January 2007, 18:18.
            Dr. Mordrid
            ----------------------------
            An elephant is a mouse built to government specifications.

            I carry a gun because I can't throw a rock 1,250 fps

            Comment


            • #7
              Testing, shmesting. We all know that they've already rolled these puppies out - here's the photographic proof!

              Smaller pictures are clickable!
              The Internet - where men are men, women are men, and teenage girls are FBI agents!

              I'm the least you could do
              If only life were as easy as you
              I'm the least you could do, oh yeah
              If only life were as easy as you
              I would still get screwed

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              • #8
                Ever see what happens when an anti-tank shell enters the turret? The copper sabot impacts, vaporizes, penetrates and the temperature inside goes up to 8,000 C instantly causing an expansion which is what explodes the tank. Scale that up by 50-100 times and you're getting close to the rail gun.
                which makes it useless for soft targets, and pretty ineffective for buildings......
                no overpressure.

                if a sabot hits earth (even concrete), generally it vapourises and thats the end of it.

                Artillery needs different payloads for different applications.... (and accelerating a conventional shell to 70K G is not going to be healthy for any explosive material - too much energy added will explode the shell during exceleration.

                also there is a LOT of difference between 12K G's and 70K G's....... Electronics will still take a while to be makeable....


                as for power.... Are my sums wrong, or would it take a 5 megawat generator would allow 1 shot per 13 seconds? If thats the case - impressive!
                Dont just swallow the blue pill.

                Comment


                • #9
                  That generator tech is scalable, so imagine banks of larger ones. Besides, our carriers are nuclear.

                  The next-gen ships are getting updated electric systems for rail guns, EM launch catapults and directed energy weapons: microwave, plasma, laser and others. These include the CVN-21 Ford Class carriers & the DDG-1000 Zumwalt Class stealth destroyers, both of which get their keels laid down this year.

                  As for kinetic warheads not working on buildings etc., I expect there will be shaped charge options.
                  Last edited by Dr Mordrid; 21 January 2007, 14:50.
                  Dr. Mordrid
                  ----------------------------
                  An elephant is a mouse built to government specifications.

                  I carry a gun because I can't throw a rock 1,250 fps

                  Comment


                  • #10
                    Originally posted by RedRed View Post
                    which makes it useless for soft targets, and pretty ineffective for buildings......
                    no overpressure.

                    if a sabot hits earth (even concrete), generally it vapourises and thats the end of it.
                    uhm, a solid steel warhead that vaporises exposivly inside a building would be verry bad to anyones health in that building
                    If there's artificial intelligence, there's bound to be some artificial stupidity.

                    Jeremy Clarkson "806 brake horsepower..and that on that limp wrist faerie liquid the Americans call petrol, if you run it on the more explosive jungle juice we have in Europe you'd be getting 850 brake horsepower..."

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                    • #11
                      I looked up that generator - Larry Longs - and yes it would fit on a flatbed truck (16m^3), howver, it does go on to mention that to generate its power, it needs a 15,000 RPM powersource. Thats going to be a Rolls Royce jet engine - 3 times or more the size. Then the fuel for each. Then power storage and cooling systems (an power for them too).

                      ANyone have any idea how you store 64 megajoules of elecrical energy? This needs to deplete in nanoseconds, I guess.


                      Perhaps on the megaships (the aircraft carriers). I think its unlikely to have more than 2 on a destroyer class.
                      Last edited by RedRed; 21 January 2007, 15:22.
                      Dont just swallow the blue pill.

                      Comment


                      • #12
                        Originally posted by Technoid View Post
                        uhm, a solid steel warhead that vaporises exposivly inside a building would be verry bad to anyones health in that building
                        just imagine the shockwave of anything closing in on anything at that speed. probably enough for most "soft" buildings.

                        mfg
                        wulfman
                        "Perhaps they communicate by changing colour? Like those sea creatures .."
                        "Lobsters?"
                        "Really? I didn't know they did that."
                        "Oh yes, red means help!"

                        Comment


                        • #13
                          surpringly little, Wulf....

                          The reason sabots are so destructive to tanks is that tanks are basically a sealed box.

                          the vapourising metal from the warhead burns a tiny hole in the side of the tank, and injects this vapour into it. This causes massive overpressure inside the tank, causing it to explode.

                          When such a sabot hits a 'soft' target (ie anything that isnt armoured), it either passess straight through (in the case of a truck, car or the like), or in the case of concrete (as in a building wall or roof) it injects its stuff, but the windows blow out before enough overpressure causes significant damage to the building.

                          If it his soil, dirt, or other 'fluid' it passess into it, decelerating before it vapourises.....

                          there is a form of munition that, as doc says, may be fireable - its called a shaped charge. This is an older armour peircing round with some explosive potential. Not much though.

                          I just noticed something with the xray at the top. It seems to be a somewhat unstable round. The front half of the sabot appears to be vibrating. Note how there appear to be 3 or 4 shadows of the head of the round, and the round before the sabot part is dislocated slightly.This could be a problem for accuracy and for energy loss. It is not possible (as far as I know) to add spin to a sabot from a rail - unless it has a rifeled barrel?
                          Dont just swallow the blue pill.

                          Comment


                          • #14
                            There isn't a rifled barrel in a rail gun. That's why the GPS guidance. I also think you're way underestimating the effect of a MACH 7-8 projectile weighing several kilograms on normal structures.
                            Last edited by Dr Mordrid; 21 January 2007, 19:15.
                            Dr. Mordrid
                            ----------------------------
                            An elephant is a mouse built to government specifications.

                            I carry a gun because I can't throw a rock 1,250 fps

                            Comment


                            • #15
                              Well, we all know what dammage soft objekts can do to a building when thrown by wind at moderate speeds
                              If there's artificial intelligence, there's bound to be some artificial stupidity.

                              Jeremy Clarkson "806 brake horsepower..and that on that limp wrist faerie liquid the Americans call petrol, if you run it on the more explosive jungle juice we have in Europe you'd be getting 850 brake horsepower..."

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