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Post by airc777 on Feb 5, 2019 21:40:52 GMT
I feel like I've completely hijacked this thread, I think this is as far as I'm going to explore this topic for a bit.
This ship's MPDT's have a 98y burn time and make 4.81µg wet acceleration. It has 8.9km/s of delta V via NTR's for maneuvering.
The 'spinal' gun makes 8.5Mm/s, has a 9.12 Mm range estimation (1m^2), throws 43.4Gj projectiles, has a 10 sec reload, and is turreted with a 45* arch.
The point defense guns are the 1Mm/s, 66.4ms reload, 20.7*/s traverse turrets I posted earlier.
It has a crew of 87, and it uses 1.68Kt of 97% u-233 dioxide in total. The armor is completely untested.
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Kalaron (Can't find my detail)
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Post by Kalaron (Can't find my detail) on Feb 8, 2019 5:08:12 GMT
Dunno if this is still open. Take my fuck-off coilgun.
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Post by bigbombr on Feb 8, 2019 8:27:37 GMT
Dunno if this is still open. Take my fuck-off coilgun. How does beryllium copper compare to zirconium copper?
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Post by AtomHeartDragon on Feb 8, 2019 14:55:45 GMT
Dunno if this is still open. Take my fuck-off coilgun. I find your gun's mass and heat jump conspicuously absent from your screenshot (but the acceleration curve alone indicates pretty well that it is a b0rkgun).
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Post by dragon on Feb 9, 2019 1:52:08 GMT
100% efficiency is a good cue, as well. Doesn't matter, I suppose, since even if it worked the >1min reload time would render it completely useless in combat.
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Post by airc777 on Feb 9, 2019 4:34:33 GMT
Doesn't matter, I suppose, since even if it worked the >1min reload time would render it completely useless in combat. Not necessarily, just don't miss. Effect on target should be plenty nasty.
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Post by dragon on Feb 9, 2019 9:23:15 GMT
I've tried guns with that kind of reload times before. "Don't miss" is a tall order on a target that's not staying put. COADE's poor dodge prediction makes it worse, but at 10km/s it's not a fast round.
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Post by AtomHeartDragon on Feb 9, 2019 17:16:25 GMT
Doesn't matter, I suppose, since even if it worked the >1min reload time would render it completely useless in combat. Not necessarily, just don't miss. Effect on target should be plenty nasty. Even if you can expect hole the size of an airliner + a whole lot of spallation damage in the surrounding area (which I expect to be the result), you are still not guaranteed a 1hk against a large, well designed ship. Even if you were, it's easily defeated by simply sending in more than one ship - might even be of a tincan+popgun variety. You won't be firing this baby twice.
Anyway,
and now for something completely different: This is the whole ship because the kinetic weapon it uses requires quite specific setup.
It's a small (if a bit expensive) ship, just below 750t (qualifying it for 750t wonders thread) It is a low-powered design, not even bothering with a power reactor, instead relying on 8 >101kW RTGs (just shy of 9kg each) for power, due to personnel considerations. It is armed with battery of small, low-powered, low-velocity railguns on the nose, and an assortment of similarly performing, very small coilgun and conventional gun turrets, neither of which is its main weapon. It's main weapon is this: and it is a pre-aimed, free-floating recoilless artillery pack. Those packs are launched from three side-mounted electrical launchers, pre-oriented to aim at whatever the launching ship has locked its nose-mounted railguns on. At launch, the artillery pack activates its short burning UDMH DNTO motors that push it clear of the launching ship even as it manoeuvres, then rapidly fires off 6 launch containers and corresponding 6 frangible countermasses to balance the recoil, then self-destructs. Each launch container then serves as the kick-stage for an unguided ballistic trajectory shell: and, together with the rest of the launch system, endows it with relative velocity of around 4.5km/s.
A single salvo from all three launchers consists of 18 such shells, each massing 35kg the majority of which is comprised of variety of kinetic submunitions: - blast launched 2km/s penetrators hopefully killing some vital subsystems
- a ring of 6 unfolding 10m transverse continuous osmium rods inflicting severe structural damage to the hull and internals beneath, possibly breaking the target up
- cloud of micro-flak bomblets and a single large-ish follow up flak bomb damaging whipple shielding and stripping off radiators
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Post by AtomHeartDragon on Feb 9, 2019 18:19:07 GMT
Now,
- It's not an accurate weapon. There is some inaccuracy inherent to the contrived launch process (it uses notoriously inaccurate spinal guns as its aiming mechanism!), it fires unguided munitions and there is also a delay making it unsuitable against targets moving with large angular velocity.
- It's not an efficient weapon (with single-shot 1.72t "cartridge" being spent to launch a mere 210kg of kinetics).
- It's not a cheap weapon with all the aramid and UHMWPE fibers used for mass-efficient telescoping blast tubes.
- It's not the most useful application of the whole concept (assisted missile launch, for example, would be better, and the whole idea started as a way to fine-tune the assisted missile launch).
- It's not going to be effective against highly manoeuvrable (high-acceleration, low turnabout) targets or ones with more effective PD
- It's, despite my best efforts, still laggy
- It's not entirely safe weapon - in some (very rare) cases it can kill the launching ship
But, it does allow a fun-sized ship (750t) with fun-sized powerplant (804kW, with launchers themselves only taking 150kW while being terribly unoptimized - in fact I deliberately underclocked them to conserve ammo and framerate alike and to minimize launch velocity) sling 630kg salvoes of kinetic impactors per pop at 4.5km/s, with a bit of luck hitting stock-like targets from around 60km and usually shredding them:
Plus, the frangible countermass technique I use produces kickass-looking backblast:
The launcher pack itself is named "Ironblast" in tribute to certain very fun weapon from certain very fun z-doom mod.
I have also nicknamed it "scattergun". Not for its accuracy, mind you - it's because it tends to scatter a gunship if it hits it.
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Post by dragon on Feb 13, 2019 2:09:20 GMT
So, here's some findings from a recent experiment. It did not result in any usable weapon, but at least I know why: 1. The biggest issue hampering high-mass railguns is the heat jump. An actively cooled railgun could be a solution to those problems. 2. The second is barrel stress, which is to be expected on a gun that big, but it reduces accuracy a lot, especially if you're trying to deal with thermal expansion at the same time. Carbon slugs help. 3. If heat issues were solved, slow rates of fire could be mitigated by pumping more power into the capacitor.
It seems like a 10GW railgun, firing 1T slugs at about 8km/s, should be within realm of possibility, but not without active cooling. Which makes sense, if you're putting multiple GJ through a weapon in a time measure in ms, there's gonna be a lot of heat building up very quickly, which needs to be removed quickly if the gun is to have a decent rate of fire. An interesting idea would be a coolant dump system where each round is packaged with a mass of water that gets pumped through the gun and ejected from the ship in the opposite direction through a nozzle, combining a cooling system with a recoil damper. Dunno what kind of mass we'd be talking about, though (might be large, though this doesn't have to be the only cooling system for the weapon).
I haven't tried replacing the slug with a payload, but I suspect it would do little to help the fundamental problem with thermal stresses.
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Post by airc777 on Feb 13, 2019 5:00:30 GMT
So, here's some findings from a recent experiment. It did not result in any usable weapon, but at least I know why: 1. The biggest issue hampering high-mass railguns is the heat jump. An actively cooled railgun could be a solution to those problems. 2. The second is barrel stress, which is to be expected on a gun that big, but it reduces accuracy a lot, especially if you're trying to deal with thermal expansion at the same time. Carbon slugs help. 3. If heat issues were solved, slow rates of fire could be mitigated by pumping more power into the capacitor. It seems like a 10GW railgun, firing 1T slugs at about 8km/s, should be within realm of possibility, but not without active cooling. Which makes sense, if you're putting multiple GJ through a weapon in a time measure in ms, there's gonna be a lot of heat building up very quickly, which needs to be removed quickly if the gun is to have a decent rate of fire. An interesting idea would be a coolant dump system where each round is packaged with a mass of water that gets pumped through the gun and ejected from the ship in the opposite direction through a nozzle, combining a cooling system with a recoil damper. Dunno what kind of mass we'd be talking about, though (might be large, though this doesn't have to be the only cooling system for the weapon). I haven't tried replacing the slug with a payload, but I suspect it would do little to help the fundamental problem with thermal stresses. Gave it a try with a payload, I only managed 200Km/s.
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Post by dragon on Feb 13, 2019 20:58:21 GMT
Can you make one that isn't bigger than the battleship I wanted to mount it on? And/or one that would get a decent ROF? High speeds are nice, but you still need to hit, and with that kind of spread your chances of landing a 1Mm shot are slim, anyway, so speed could probably be lower. One way of dealing with heat jump is making the gun absurdly big and letting it cool off between shots, but I observed that a practical space-to-space weapon pretty much requires a sub-second reload time.
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Post by AtomHeartDragon on Feb 13, 2019 21:48:44 GMT
Can you make one that isn't bigger than the battleship I wanted to mount it on? Or entire fleet. Or several hundreds of such fleets. My artillery pack launcher actually only fires once per 5s to conserve ammo and framerate (and I have recently reduced power draw to 1.5kW), but that's because it's an AoE weapon with high lethality and each shot is actually a burst.
So, yeah, I definitely agree.
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Post by airc777 on Feb 13, 2019 23:10:01 GMT
Can you make one that isn't bigger than the battleship I wanted to mount it on? Or entire fleet. Or several hundreds of such fleets. My artillery pack launcher actually only fires once per 5s to conserve ammo and framerate (and I have recently reduced power draw to 1.5kW), but that's because it's an AoE weapon with high lethality and each shot is actually a burst.
So, yeah, I definitely agree.
Will down scale the weapon in a bit. FSS rails / VCS armature / payload / high voltage Hafnia capacitors is so far the most mass efficient launcher I've found with stock materials. I haven't played with modded materials yet.
On ROF, well in the context of this gun specifically the reactors and radiator area would be such a small fraction of the weapon systems mass that you could easily go up another order of magnitude or two in reactor power to increase the ROF without actually making the weapon system as a whole that much more massive.
On ROF as a whole that mostly depends on the engagement range. The longer the engagement range, the longer the engagement time (assuming same closing velocity), the more shots you can fire before the enemy can close range. Tens of seconds is fine if your enemy can't reach you, plus if your enemy has a weapons system capable of responding at such extreme ranges then they themselves are probably also a large target. Everything's relative. I'd imagine at some point you could just leave a big enough gun in the Jovian system firing continuously in the general direction of earth for months on end and it would eventually ruin someones day.
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Post by airc777 on Feb 14, 2019 0:18:20 GMT
Can you make one that isn't bigger than the battleship I wanted to mount it on? I have chosen to follow your request to the letter, and not to the intent. Meaning I've constructed the densest possible weapon system of 10GW power draw and 8km/s muzzle velocity and 1ton payload.
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