I caught the orange man talking on the radio, as I am not american I knew it was going to be something stupid but this? I thought it was a joke, an onion like thing, but nooooo. What sealed it is when in the very speech about the new 100x battleships, trump stated that he did not know why the us stopped using battleships…

  • M0oP0o@mander.xyzOP
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    8 days ago

    “Relatively” flat sorry, but yes the range was a major issue as if you fling a thing slow enough for a over the horizon shot you lose the whole point of the super high velocity railgun. So in the end you have a stupid expensive, very experimental, with a high amount of needed maintenance gun that can ether work like a normal naval gun (that has long been subplanted as the main offensive system on ships) or like a hypervelocity gun that can only shoot real close or real far away.

    • theunknownmuncher@lemmy.world
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      8 days ago

      if you fling a thing slow enough for a over the horizon shot

      That doesn’t make any sense and is not how physics works.

      can only shoot real close or real far away.

      No!

      • M0oP0o@mander.xyzOP
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        8 days ago

        The world is, and I know this might be a shocker, round.

        Railguns when tested have an odd issue in that they shoot things real fast, and therefor a much flatter ballistic trajectory. Now this is good! if the curve of the earth did not put a fuck load of water between the railgun and the target. In fact due to physics (you know that thing that we are both clearly experts in) you end up with a big old dead spot in your range tables (more so with high sea states) where the railgun’s dart will hit the waves on route to the target and although moving wicked fast the uncaring ocean will still stop or really change the darts course. This changes when you range out far enough that the ballistic trajectory curves enough but at those ranges accurate guidance is another issue (this was found out in 2019).

        So yeah according to physics shooting a thing at over 8000 km/h out of a tube means a flatter then needed trajectory for mid range (in ship to ship context) and when you get out to the full range you are talking 180 km or so, and at that point even the super fast darts are avoidable/hard to get on target.

        • theunknownmuncher@lemmy.world
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          8 days ago

          This is nonsense, and the source you linked does not support or even mention anything about what you’ve claimed about trajectories. Did you just hope no one would actually read it? It does, however, talk about the sustainability problems with maintaining the railgun as well as the benefit of simply using the projetile developed for the railgun in conventional guns. From your source:

          As the Navy was developing EMRG, it realized that the guided projectile being developed for EMRG, which weighs about 23 pounds, could also be fired from 5-inch and 155mm powder guns. When fired from EMRG, the projectile reaches hypervelocity (i.e., Mach 5+) speeds, and thus came to be known as the hypervelocity projectile (HVP). When fired from a power gun, the projectile flies quickly, but not as quickly as it does when fired from EMRG.

          “We thought rail guns were something we were really going to go after, but it turns out that powder guns firing the same hypervelocity projectiles gets you almost as much as you would get out of the electromagnetic rail gun, but it’s something we can do much faster,” [then-Deputy Secretary of Defense Robert] Work said.

          The trajectory of any projectile, including the shot of a railgun, follows an elliptic ballistic curve.

          There’s no such thing as a dead spot in the range. You just aim up.

          • M0oP0o@mander.xyzOP
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            8 days ago

            Yes, for longer range shots. For the middle of your range, you can’t “aim up” that would not hit the target at the speeds needed. Lobbing rounds with a railgun is mostly worthless and can be done, as you have said, with a normal naval gun. So take your diagram (that has the labels wrong) and compare to an old one, from when battleships where still in use. See you are assuming that all ballistic curves are the same but the old 16 inch guns (for example) shot at 762 m/s vs the railgun that shoots at 2,220 m/s so the railgun will be more “flat” then the naval gun. Still a curve yes, but one that is now awkward when at sea. From what I was seeing this issue can be mitigated by moving the gun higher on the ship (its not by much the dart clips the waves) but that introduces new issues. The distance before something is “lost” over the horizon at sea is between 5 and 10 km (based on the height of the ship), at this range the railgun is still mostly going “straight” (its not but the drop is not enough yet). So if you want to hit something say 12 km away (in range of normal naval guns fyi) you would need to shoot so high that you would be putting the dart into a sub orbital trajectory and without guidance be lucky to hit anything (and good luck making a system that can withstand air at sea level when traveling at mach 6).

      • ulterno@programming.dev
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        8 days ago

        It can actually (theoretically) shoot real far away.
        As in, when the target area is far enough that the projectile would have slowed down due to drag, long ago and start dropping more than it is going forward.
        The problem here, would lie in the stabilisation of the bullet and making sure it actually hits the target instead of a few km away, because faster bullets apparently have a greater difficulty staying on track.

          • M0oP0o@mander.xyzOP
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            8 days ago

            Yeah, did you look into what “GPS guided” means here? Its not what you think.

            • ulterno@programming.dev
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              8 days ago

              I think they are trying to crack a joke.

              Considering that the escape velocity on Earth’s surface is ~11200m/s and railgun speeds tend to be around 5000m/s[1] (i.e. less than half) and also that the escape velocity would be considering a normal direction whereas railgun usage tends to be more tangential (from the surface of the Earth), I wouldn’t be expecting any casual leave-the-atmosphere scenarios.

              As far as guided systems go, last I checked there wasn’t enough leeway to add any electronic or mechanical elements in the projectiles.


              1. at least in Wikipedia, all stated values are < 5km/s ↩︎

    • justOnePersistentKbinPlease@fedia.io
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      8 days ago
      1. You don’t shoot it slowly. You fire it at the same speed, but tilt the gun up. The resulting parabolic trajectory is considerably greater than anything a standard gun can get.

      However:
      2. As mentioned in the video, they are very power hungry. Like they need their own nuclear reactor in a ship to power it. 3. The barrels only last less than a dozen shots. This means you either need tons of extra barrels and the crane to replace them, or you need a logistics ship to do that every few hours in a battle.

      In short: railguns are neat but we don’t have the tech to power or build them.