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Post by dragon on Feb 2, 2019 15:08:59 GMT
I thought this thread was supposed to be about weapons that are at least somewhat practical. It was. Those extreme designs are OK, I suppose, but by this point I suspect we're far beyond the model's limitations. Especially considering they're all payload launchers, as I said I'm not quite sure if physics of those are accounted for properly. TBH, I'd really like to know if there are any huge kinetics on the other end of the scale. That is, "school bus launchers" with 1T+ payloads. That's something I've never been able to get to work. For sandblasters, increasing velocity is pretty much a matter of making your barrel longer. I'd like to see a gun that can throw 1T projectiles at combat-useful speeds and rates, while not blowing up from heat.
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Post by AtomHeartDragon on Feb 2, 2019 17:34:24 GMT
I thought this thread was supposed to be about weapons that are at least somewhat practical. It was. Those extreme designs are OK, I suppose, but by this point I suspect we're far beyond the model's limitations. Especially considering they're all payload launchers, as I said I'm not quite sure if physics of those are accounted for properly. TBH, I'd really like to know if there are any huge kinetics on the other end of the scale. That is, "school bus launchers" with 1T+ payloads. That's something I've never been able to get to work. For sandblasters, increasing velocity is pretty much a matter of making your barrel longer. I'd like to see a gun that can throw 1T projectiles at combat-useful speeds and rates, while not blowing up from heat. The main problem with k-slugs above several kg is that they really fall behind well constructed payloads of similar size in terms of destructive potential. Cannons slinging above a few hundred kg also get increasingly problematic.
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Post by dragon on Feb 2, 2019 22:04:27 GMT
I'm not saying those huge guns have to be firing slugs. What matters for a space gun (and what most hard SF writers miss) is the mass of the projectile, not where it comes from. It could shoot nukes, fragmentation rounds, whatever fits in the barrel, really. Indeed, one things I was trying to make was a gun that would shoot heavy rounds that would fragment into several large pieces a long distance from target, to maximize hit probability. A simple frag round didn't work, but I didn't try with blast launcher-based submuntions (that said, now I don't think it'd be particularly effective). Unfortunately, my only gun capable of shooting something like that turned out to only work because of a bug and had an abysmal rate of fire, anyway. So yeah, I know designs this big get problematic. I was wondering if anyone ever found a way to deal with that.
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Post by AtomHeartDragon on Feb 3, 2019 9:52:01 GMT
I'm not saying those huge guns have to be firing slugs. What matters for a space gun (and what most hard SF writers miss) is the mass of the projectile, not where it comes from. It could shoot nukes, fragmentation rounds, whatever fits in the barrel, really. Indeed, one things I was trying to make was a gun that would shoot heavy rounds that would fragment into several large pieces a long distance from target, to maximize hit probability. A simple frag round didn't work, but I didn't try with blast launcher-based submuntions (that said, now I don't think it'd be particularly effective). Unfortunately, my only gun capable of shooting something like that turned out to only work because of a bug and had an abysmal rate of fire, anyway. So yeah, I know designs this big get problematic. I was wondering if anyone ever found a way to deal with that. Launcher based submunitions can be very effective on an unpowered payloads (on powered ones you have the complications of payload thinking that it is a drone). I think jtyotjotjipaefvj 's is the master of this technique (check out screenshots thread for examples), although I have made some effective stuff as well. You can make some very effective (possibly unphysically so, but it only makes plane-sized holes in stock-like armour) continuous rod emulation using long, thin radiators too to go with that.
Of course, once you add nukes, it's no longer pure kinetics, and once you add engines it blurs the lines between a gun and launch system with a bit more kick.
In fact, you can use hi-powered blast launchers aligned with guide gun to hit targets with massive payloads.
You can also use more complex setups, like electrical launchers launching blast launchers (possibly with backblast countermass, and short burining motors to keep them alinged with launching ship), telescoping blast launchers and so on.
I currently have an MLRS that launches salvoes 30kg missiles at over 4.4km/s (that's muzzle velocity), accurately at target (when slaved to a nose mounted weapon);
similar kind of setup, except firing unpowered kinetic cluster artillery (horribly laggy and possibly ineffective against agile targets, but can wreck gunship unrecognizable at around 60km mark, despite lack of guidance); and slightly simpler (same setup, but single tube without telescoping or backblast countermass) launcher deploying torpedoes (single-use quasi-drones deploying aimed, but unpowered warheads up close) up to around 0.5t in mass.
An individual launch (school) bus for all of those is typically around 2t, although the mass travelling to the target is of course much lower. They are also not EM based as chemical propellants perform better at this point.
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Post by gyratron on Feb 3, 2019 13:31:07 GMT
The main problem I have found with large conventional cannons is that it doesn't seem to matter how much armor you have or where the magazines are hidden inside the ship, the ammunition always finds a way to explode and blow the entire ship to smithereens.
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Post by AtomHeartDragon on Feb 3, 2019 14:22:33 GMT
The main problem I have found with large conventional cannons is that it doesn't seem to matter how much armor you have or where the magazines are hidden inside the ship, the ammunition always finds a way to explode and blow the entire ship to smithereens. From my experience you either have to design the ship so that it can survive the explosion with maximum functionality intact, or you put the magazines somewhere they will only blow once the ship is dead anyway.
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Post by jtyotjotjipaefvj on Feb 3, 2019 21:05:29 GMT
TBH, I'd really like to know if there are any huge kinetics on the other end of the scale. That is, "school bus launchers" with 1T+ payloads. That's something I've never been able to get to work. For sandblasters, increasing velocity is pretty much a matter of making your barrel longer. I'd like to see a gun that can throw 1T projectiles at combat-useful speeds and rates, while not blowing up from heat. You can't blow up from heat if heat jump is negative! I suspect the gun might not be entirely physically feasible though. The same technique can be used to make smaller guns too, although it gets a bit tricky:
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Post by dragon on Feb 3, 2019 23:47:07 GMT
That's exactly the kind of weapon I specifically stated I didn't want to see here. Negative heat jump and efficiency over 100% is a dead giveaway of either a bug or an inadequate model that breaks down at values used.
I'm interested in weapons that would actually work and be useful. The first gun on the list is neither, as even if you look past the model bug, the reload time is 42.9s. I've actually tried using a similar weapon on a combat spacecraft (it fired frag payloads rather than slugs), and it failed to hit even once. The others, aside from the fact that they trigger the bug, seem unremarkable. Any attempts to increase ROF bring the weapon out of the bug area and into absolutely massive heat jump.
Coilguns in general seem to be extremely prone to heat issues at high energies, from what I've noticed. I'm not sure if it's the coilgun model being wrong in the other direction or a real physical effect. I've tried to improve on the stock Heavy Coilgun, for instance (trying to get the reload time down) and ended up with a weapon that would work great if not for the fact it overheated after a single shot. Active heat rejection would probably help matters, but at any rate I've had much better luck with railguns.
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Post by doctorsquared on Feb 4, 2019 1:53:56 GMT
After getting annoyed with having a fraction of my 1kg projectiles go flying by during high velocity intercepts I followed the Engineer from TF2's advice and used more gun. The end result is an unguided 'pod' for lack of a better word that fires from a ten-round mag of three gram depleted uranium rounds. Shots that miss can still take pot shots at subsystems as they fly by and shots that are on course can get some shots off before smacking into the target. It's fun simply for the fact that you're firing a gun out of another gun but if you want a better result a small nuclear warhead would be much more effective.
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Post by airc777 on Feb 4, 2019 18:21:40 GMT
I did some witchcraft, this turret is mighty.
If you optimise by pushing the projectile to the edge of exploding instead of trying to squeeze all of the efficiency you can out of the gun or put all of the stress on the barrel then you can make barrels really short. VCS armature and short barreled guns means you can make Mm/sec^2 guns in turrets that can actually turn without making the mass very high.
This is a 1Mm/s^2 gun that's accurate on 1m^2 targets @ 1Mm and it can turn 20 degrees/s AND it has a meter of turret armor and it's only 11kt.
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Post by airc777 on Feb 5, 2019 3:56:46 GMT
Switched to ferric stainless steel rails, was able to go way thinner with the barrel armor, shaved a few kilo tons. Feature complete turret is now 8.5kt.
EDIT: FSS appears to be a weird sweat spot at this scale. Tried again with tungsten and osmium and had no such luck. Osmium did make the turret much denser though if you just wanted a smaller cross section but at about 1/2 the mass efficiency.
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Post by cipherpunks on Feb 5, 2019 9:44:39 GMT
Can You downscale it to 10 GW? Less?
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Post by airc777 on Feb 5, 2019 13:12:22 GMT
Can You downscale it to 10 GW? Less? Well at these scales you kind of have to consider the powerplant as part of the weapon system when figuring how much they mass. When we start looking at weapons massing multiple kilotons it might make a less massive warship to just force feed a smaller turret with more reactors to get it to turn quickly. Turning doesn't really matter at these ranges if you just want to sit in front of the enemies guns, but if you want to turn and burn the whole time or if you want your weapons to do double duty as point defenses then you might want them to traverse faster.
Also firing rate is directly effected if you're using deliberately short barreled inefficient guns. You need to force feed the projectile as much energy as possible to maintain muzzle velocity, if you have less reactor filling your capacitors then it's going to be really noticeable how inefficient your guns are.
So more to your point how do you want to make the compromise? Would you rather they charge slower, or turn slower, or fire slower, or be less accurate, or require more power?
part 1 of 2:
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Post by airc777 on Feb 5, 2019 13:30:49 GMT
And I steal the lead for lightest Mm/s^2 gun with 1.86kt.
Part 2 of 2:
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Post by airc777 on Feb 5, 2019 15:45:13 GMT
Discovered silver might have some application as a high efficiency armature, but it doesn't appear to preform as well as Iron in the context of mass efficiency of the whole weapon system. Silver makes higher efficiency, but Iron can be used with narrower bore radius and it doesn't melt FSS rails. Continuing to investigate.
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