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Post by Rocket Witch on Jan 3, 2017 21:44:05 GMT
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Post by kitten on Jan 3, 2017 21:48:27 GMT
That seems like something's wrong in the simulation though. Whipple shields are sacrificial but sufficiently hard to cause breakup or vapourisation of incoming projectiles; a simple aluminium alloy shield is capable of turning inbound aluminium hypervelocity (~10 to 20km/s) projectiles into plasma with a shield thickness of about 60% of the projectile's diametre; but that is for civilian applications stopping random micrometeorites. Experimentally, ceramics like alumina, silicon carbide and boron carbide as well as certain alloys offer much superior performance. Also note NASA experiment put a premium on weight due to the high cost of moving materials off Earth currently; if we accept slightly heavier materials we can improve peak performance.
Also note, if you are testing high density, refractory Whipple shields like tungsten, osmium, etc then spall from the bumper may be a bigger threat than the projectile. A monolithic bumper has to be low density but composite bumpers such as tungsten nanospheres in a matrix of rubber would perform well in theory (we don't have that ingame though).
As a very very general rule, the way to beat spaced armour/Whipple shielding with KE impactors is to go heavy and "slow", not light and superfast, IRL.
PS. NASA have released numbers from their tests so we could try fact-checking CoDE whipple armours.
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Post by newageofpower on Jan 3, 2017 22:30:53 GMT
That seems like something's wrong in the simulation though. Whipple shields are sacrificial but sufficiently hard to cause breakup or vapourisation of incoming projectiles; a simple aluminium alloy shield is capable of turning inbound aluminium hypervelocity (~10 to 20km/s) projectiles into plasma with a shield thickness of about 60% of the projectile's diametre; but that is for civilian applications stopping random micrometeorites. Experimentally, ceramics like alumina, silicon carbide and boron carbide as well as certain alloys offer much superior performance. Also note NASA experiment put a premium on weight due to the high cost of moving materials off Earth currently; if we accept slightly heavier materials we can improve peak performance. Also note, if you are testing high density, refractory Whipple shields like tungsten, osmium, etc then spall from the bumper may be a bigger threat than the projectile. A monolithic bumper has to be low density but composite bumpers such as tungsten nanospheres in a matrix of rubber would perform well in theory (we don't have that ingame though). As a very very general rule, the way to beat spaced armour/Whipple shielding with KE impactors is to go heavy and "slow", not light and superfast, IRL. PS. NASA have released numbers from their tests so we could try fact-checking CoDE whipple armours. No. If you fire a sandstorm, the whipple shield is good against the first dozen hits - just as designed.
Which at our current borked rate of fire would be perhaps a fraction of a second. If rate of fires are brought in line with sub 100% or even DTIC's 64% railguns (although, it would be strange if we couldn't increase EM weapon efficiency) Whipple shields might add multiple seconds to the lifespan of a craft. Then, you have no more whipple shield, and the rest of the rounds connect with the 'Main Belt' of armor. My issue with Whipple Shields is that in-game accuracy is calculated vs cross section. Large whipple shields = big cross section = get hit from much further away = get hit a lot more.
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Post by amimai on Jan 3, 2017 22:44:56 GMT
Wipple shields are only rated to withstand ~40km/s impacts max and even then they will only work on the lightest of projectiles... at a certain point the mass or velocity involved will either cause the whole wipple plate to buckle/shatter or just keep going as if the wipple plate was not there at all.
Deflecting a heavy or high velocity impact is far more reliable then relying on wipple protection when said impact is outside the little box a (thin) wipple works at.
Course a multilayer 2cm boron carbide wipple, it will stop near anything, but it will also weigh far too much to be workable. That's why I like my diamond/AMcarbon slope armour, it's a good balance for 90%+ bounce, laser resistance, and reasonable sandblasting protection.
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Post by kitten on Jan 4, 2017 0:10:34 GMT
Wipple shields are only rated to withstand ~40km/s impacts max and even then they will only work on the lightest of projectiles... at a certain point the mass or velocity involved will either cause the whole wipple plate to buckle/shatter or just keep going as if the wipple plate was not there at all. Deflecting a heavy or high velocity impact is far more reliable then relying on wipple protection when said impact is outside the little box a (thin) wipple works at. Course a multilayer 2cm boron carbide wipple, it will stop near anything, but it will also weigh far too much to be workable. That's why I like my diamond/AMcarbon slope armour, it's a good balance for 90%+ bounce, laser resistance, and reasonable sandblasting protection. But going faster doesn't lessen the violence of the impact for the projectile. In fact, if you go too fast, a mixture of nitrogen, oxygen, carbon dioxyde and other gases becomes a viable armour Higher mass and higher density projectiles work well because they are more likely to survive the impact, or at least a bigger part of them/deadlier fragments will. But increasing the velocity should not help you beat the Whipple shield, increasing the total KE though may help with penetrating the rear wall. I mean, Whipple shields wouldn't be of any use against a 1-ton osmium rod (even at lowish speeds) but they're not designed for that. However, a hypervelocity projectile weighing a few grams is what they excel against IRL. I've recreated some of NASA's published tests in the simulations (5mm spherical aluminium pellets launched at 10.1km/s versus a 2.6mm aluminium Whipple shield with a 10.2cm standoff over 6mm of aluminium) and seen full penetration of the armour where it isn't sloped, from a single hit. IRL that doesn't happen, and if it did, the ISS and many other satellites would take catastrophic damage from space dust. So as far as I'm concerned, that's enough to say that Whipple shields are underperforming ingame. P.S. some reading about protecting RL spacecraft against micrometeorites. Obviously the RL Whipple shields aren't meant to stop tungsten at 40 km/s but they should stop projectiles equivalent to random micrometeorites, at least until they suffer multiple impacts to the same tile.
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Post by caiaphas on Jan 4, 2017 0:14:59 GMT
Actually I now use 10g+ coilguns or 70km+ railguns so wipple armour is a horrible idea, the rounds I shoot cut through soft wipples like paper... hard surface layers are useful since they can bounce off most kinetic rounds Agreed. My favorite weapon right now is a heavy coilgun throwing one-kilo rounds at 20 km/s, cuts through even a 10 cm layer of osmium (no backing) with decent enough efficiency.
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Post by David367th on Jan 4, 2017 0:28:17 GMT
Actually I now use 10g+ coilguns or 70km+ railguns so wipple armour is a horrible idea, the rounds I shoot cut through soft wipples like paper... hard surface layers are useful since they can bounce off most kinetic rounds Agreed. My favorite weapon right now is a heavy coilgun throwing one-kilo rounds at 20 km/s, cuts through even a 10 cm layer of osmium (no backing) with decent enough efficiency. To be honest I don't think 10cm of anything can stop a kilo going 20km/s
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Post by kitten on Jan 4, 2017 0:42:40 GMT
10cm of Osmium is actually not that impressive. An RL anti-tank would pierce several times that thickness (at any range in space). I don't think a single layer, monolithic armour is a good idea at all.
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Post by caiaphas on Jan 4, 2017 0:42:45 GMT
Agreed. My favorite weapon right now is a heavy coilgun throwing one-kilo rounds at 20 km/s, cuts through even a 10 cm layer of osmium (no backing) with decent enough efficiency. To be honest I don't think 10cm of anything can stop a kilo going 20km/s By the way, has anyone done any more testing on stopping middleweight rounds like that? I've only done testing on stock ships (mostly gunships) for a quick and dirty effectiveness test and on a hard armor target surrounded in multiple layers of 10 m-thick osmium (and for that you still only need something on the order of a few thousand heavy 10 km/s KKVs to punch through that, those are seriously nasty weapons).
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Post by David367th on Jan 4, 2017 0:53:46 GMT
10cm of Osmium is actually not that impressive. An RL anti-tank would pierce several times that thickness (at any range in space). I don't think a single layer, monolithic armour is a good idea at all. Especially Osmium seeing that it's extremely brittle. The amount of times I have to point out that Osmium is actually a fairly bad armor, especially as an innermost layer, is pretty funny. To be honest I don't think 10cm of anything can stop a kilo going 20km/s By the way, has anyone done any more testing on stopping middleweight rounds like that? I've only done testing on stock ships (mostly gunships) for a quick and dirty effectiveness test and on a hard armor target surrounded in multiple layers of 10 m-thick osmium (and for that you still only need something on the order of a few thousand heavy 10 km/s KKVs to punch through that, those are seriously nasty weapons). Honestly I don't see much less than a meter or so more of a boron/steel composite stopping a kilo going tens of km/s.
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Post by caiaphas on Jan 4, 2017 1:06:00 GMT
10cm of Osmium is actually not that impressive. An RL anti-tank would pierce several times that thickness (at any range in space). I don't think a single layer, monolithic armour is a good idea at all. ...well, bugger. Time to go peruse the armor threads for ideas for a better testbed, then.
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Post by newageofpower on Jan 4, 2017 1:06:33 GMT
My standard PD coilgun fires rounds at 48 km/s. 1 gram of plasma hitting your hull at 50km/s is almost as bad as 1 gram of solid maglass hitting it at 50km/s. Whipple shields work against micrometeorites. Broken sandguns will chew through them in under a second. Fixed sandguns will do it in a few dozen.
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Post by caiaphas on Jan 4, 2017 1:08:42 GMT
My standard PD coilgun fires rounds at 48 km/s. 1 gram of plasma hitting your hull at 50km/s is almost as bad as 1 gram of solid maglass hitting it at 50km/s. ... 48 kilometers per second. The hell.
Obviously I have some optimizing to do on my coilguns, then.
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Post by newageofpower on Jan 4, 2017 1:14:52 GMT
Obviously I have some optimizing to do on my coilguns, then. It's the only way for kinetics to retain any degree of usefulness with the standardization of fairly efficient giant death lasers. Keep in mind, these are Point Defense coils; my main battery needleguns all exceed 150km/s.
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Post by David367th on Jan 4, 2017 1:33:56 GMT
Obviously I have some optimizing to do on my coilguns, then. It's the only way for kinetics to retain any degree of usefulness with the standardization of fairly efficient giant death lasers. Keep in mind, these are Point Defense coils; my main battery needleguns all exceed 150km/s. Those are your sub-gram designs though aren't they? A whipple shield worth it's weight would gobble them like nothing.
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