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Post by ash19256 on Nov 23, 2016 23:13:57 GMT
As far as I can tell, using amorphous carbon at a radiator thickness of 4 mm with an armor thickness of 3 mm maximum is the best you can get for balancing efficiency with thermal output and durability. Not sure if diamond is bugged or something, but having diamond as a surface finish doesn't register in the weight and cost pie-charts, and as far as I can tell it doesn't increase efficiency at all, so I don't really think it's worth it unless someone can prove that it does make the radiators more likely to deflect railgun/coilgun shots.
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Post by ash19256 on Nov 23, 2016 5:24:35 GMT
Could you show us the design for the launcher coilgun? I have been having trouble with making coilgun that's cost effective AND effective enough to launch payload. The only successful result I have is with conventional cannon launcher and they are...heavy so to speak. Sure, I can do that for you. Though, I don't think it'll help you much since all I'm doing is launching a 1500g inert lump of metal and not a 1500kg guided missile. I feel that there really are better people on the forums than me when it comes to coilguns and launching payloads. Would it be possible for you to share the design of the flare and the penetrator as a whole? My attempt didn't go so well.
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Post by ash19256 on Nov 22, 2016 22:45:58 GMT
Question. Does it need the flare?
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Post by ash19256 on Nov 21, 2016 20:39:54 GMT
My running theory on how the EM Drive works is that it smacks the aft end of the resonant chamber with so many microwave frequency photons that it starts losing electrons, which are launched away from the engine at high speed, with the truncated cone shape causing this to preferentially happen towards the wider end of the cone. This means that while it does produce thrust, it isn't technically reaction-less, as it uses the copper end plate of the cone as reaction mass. Granted, my understanding of physics comes from browsing through this forum, Spacebattles, Sufficient Velocity, along with watching Scott Manley videos and reading Atomic Rockets, so if some smart person (paging illectro , paging illectro) could tell me if I'm being an idiot, that would be much appreciated. I think you got your wish www.youtube.com/watch?v=JGcvxg7jJTsActually, that was the video I created my theory after watching, mostly doing my best to take into accounts complaints leveled in the video against other theories as to how the EM Drive works.
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Post by ash19256 on Nov 21, 2016 3:27:21 GMT
One limiting factor on the EM Drive, as far as I understand NASA's paper, is the efficiency of the drive itself. There is no way that this drive magically converts 100% of its power input into thrust with no thermal inefficiency. I foresee practical upper limits on the amount of power which can be pumped into these things without melting them, even with a high-tech radiator system. We even have 1.3 gigawatt nuclear reactors already (http://www.power-technology.com/features/feature-largest-nuclear-power-plants-world/). But we haven't put one into space yet, and it seems impossible in the current political climate to do something like orbit a gigawatt nuclear power plant. We already know how mass-inhibiting the radiator system for a 1-gigawatt nuclear reactor is in this game's universe. That doesn't really help with the physics problem, though. If P-In produces T-Out without needing to haul propellant, conservation of energy is dead, because of that damned squared term in kinetic energy. The faster relative to a thing the object is going, the more energy it 'gains' from every additional m/s, so if power in produces m/s, sooner or later you'll get a net positive. My running theory on how the EM Drive works is that it smacks the aft end of the resonant chamber with so many microwave frequency photons that it starts losing electrons, which are launched away from the engine at high speed, with the truncated cone shape causing this to preferentially happen towards the wider end of the cone. This means that while it does produce thrust, it isn't technically reaction-less, as it uses the copper end plate of the cone as reaction mass. Granted, my understanding of physics comes from browsing through this forum, Spacebattles, Sufficient Velocity, along with watching Scott Manley videos and reading Atomic Rockets, so if some smart person (paging illectro , paging illectro) could tell me if I'm being an idiot, that would be much appreciated.
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Post by ash19256 on Nov 20, 2016 13:48:35 GMT
This is definitely news to me. Interesting... maybe low-energy nuclear reactions like the E-Cat are next in line for weird things for NASA to verify. So I guess the EM drive can be equated to a thruster with an exhaust velocity of c? If so, it might actually be seriously competitive with MPDs. Power may not scale linearly for a single module, but it should be linear if you use a bunch of modules. Assuming they don't interfere with each others' function. 20GW of power, and radiators, can be done in less than 400 tons, if ingame designs can be exported to the real world. It's not that bad. True enough, but I imagine it would only be practical for applications where the power generation and propellant for ion engines would mass more than what that 20 GW of power generation plus radiators does.
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Post by ash19256 on Nov 19, 2016 21:11:49 GMT
Here is the missile I mentioned earlier. I'll need to retract my statement about it's effectiveness against 1GW lasers; I ran a quick test before posting and it seems that the 1GW is able to burn through around the spacer and pop the tank even with a graphite thermal plate being added. It is still effective against 6x150MW lasers though. The missile itself costs 16 kc, but I've managed to get it to engage across the 1Mm range in about 120 seconds. The design is scalable without affecting the hull or armor profile; between 1 and 4 3kt nukes can be mounted along with a standard osmium NEFP slug. Whether the slug is effective or not I can't confirm for certain. I know there is another thread dedicated to solving the NEFP problem. What do know is that these missiles tend to engage the enemy front-on when they flyby, so and I have seen occasional NEFP-looking holes in a few gunships. *Edit* To clarify, the thermal plate I mentioned is not included in the picture. The Rear Warhead Cap is a thin osmium plate designed to help protect the warhead and control unit within a miniature "citadel" style armor, styled after real life ICBM reentry vehicles. If it can survive reentry it can survive a laser right? Could we get stats for the unique modules in use with this missile? I kind of want to try it for myself.
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Post by ash19256 on Nov 19, 2016 19:55:33 GMT
www.iflscience.com/space/the-peer-reviewed-emdrive-paper-is-officially-out/So apparently...it works. It produces 1.2 mN per kW. In gameplay terms for us: (1.2 (millinewtons per kilowatt)) * 1 Gigawatt = 1200 newtons Twenty of them strapped to the back of a ship would be 24 kilonewtons of thrust.. with no propellant. If this thing is really, actually real...we're in for some cool stuff in the next few decades. True, but that 24 kN of thrust would also require 20 GW of power, which isn't going to be easy to produce. You're much more likely to see at an absolute maximum 1 GW EM Drive thrusters as main engines, possibly with smaller EM Drive thrusters as reaction control thrusters. Granted, this does make missions to mars much more feasible, because now all you need to do is push the payload (be it crew or rover or whatever) and power generation, allowing you to accelerate almost constantly along the first half of the trip, possibly flipping around to decelerate for the second half.
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Post by ash19256 on Nov 19, 2016 5:09:59 GMT
What kind of temperatures would we be talking about? Would it be something that would need dedicated cooling to keep it from melting concrete and such? Or would it be practical for use in large scale power grids without any sort of dedicated cooling, ie. replacing the cables on top of the long-distance power poles you see along the highways occasionally?
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Post by ash19256 on Nov 18, 2016 17:18:42 GMT
Well its power use is 440 kW and output 275 MW. 624.000 % broken. [bnr] Well damn. I'll have to reoptimise my secondary batteries. Just reduce their rate of fire and you should be fine. Granted, you'll have to reduce it by a lot, but that also means that long-range engagements aren't going to kill your computer from the sheer number of slugs being launched.
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Post by ash19256 on Nov 18, 2016 13:32:10 GMT
4) Things made out of extremely thin foils. When I see an engine bell with a thickness of 1/10th of a millimeter the first thing I can think of is "how come it doesn't crumple"? In general, it appears to me that a lot of miniaturized designs rely on components that would make them impossible to handle (like the aforementioned engine bell). I wonder if it is reasonable for some sliders to go as low as they do. My understanding of it is that because these engines aren't designed for use outside of an atmosphere, they only have to deal with the mechanical stresses of operating as engines, which can be lowered to the point where foils are a legitimate option. Granted, it does appear that mechanical stresses from gimballing aren't modeled in the game, so these foil engines are able to gimbal at extreme rates without problems, which is somewhat unrealistic.
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Post by ash19256 on Nov 17, 2016 20:16:59 GMT
On the subject of superconductors, I've actually heard of a kind of interesting idea for superconducting cables over on Spacebattles, and figured this forum might be a good place to look for a reality check on it. I'm not really all that hopeful about it standing up to scientific scrutiny, but it at least sounds plausible to someone who doesn't know much about how superconductors work. Basically, the idea was that you would contain a substance that becomes a superconductor when cooled (the original poster of the idea specified hydrogen sulfide) inside of a graphene matrix that was specially created to serves an electrically driven cooling system (ie. when electricity is flowing through it, it uses some of it to cool the interior of the cable), which rapidly cools down the substance within until it becomes a superconductor (temperature specified by the original poster of the idea was 203 Kelvin, although I think they may have forgotten a minus symbol), at which point power switches from flowing purely through the graphene matrix to flowing through both the graphene matrix and the substance inside of it. It technically isn't a superconductor, but it becomes one when power is run through it.
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Post by ash19256 on Nov 16, 2016 15:33:43 GMT
I haven't bothered to exactly calculate the power draw, but here's picture of it: i.imgur.com/uC8FEAe.png Figure an average of ~28V @ ~375 amps for 14ms. Obviously the time is going to get longer as you add more coils, and shorter as you increase the power (projectile moves faster). For rapid fire sound without the impacts I could write some code to dryfire the coils in a fixed sequence based on data from a real shot. But I imagine it'd sound like the single click/thump from the single coil but multiplied by however many coils there (intervals getting smaller as projectile speed increases), then repeated for each shot. I don't really have any solid numbers for fire rate either except that it's going to be limited by the power supply. The issue isn't necessarily the overall power consumption (e.g. my gun can do hundreds (thousands?) of shots on a single charge with just 4800mah of battery), but the fact that the consumption is very bursty. Nuclear reactors are great at providing a constant current, but not so great at dumping gigawatts of power into something for just a few milliseconds at a time. You need a cap bank for that, at which point it becomes a question of how fast can you charge and discharge your caps without damaging them and how much weight/space are you willing to sacrifice. e.g. say you can't cycle your caps more than once every few seconds. You can add in more cap banks and rotate through them (actually, this may be ideal because it would help smooth the load on the reactor) to shoot faster, but these things aren't small or light. Here's an article with a picture of the kind of thing powering the railgun the navy plays with: www.naval-technology.com/news/newsraytheon-delivers-pulse-power-containers-for-us-navys-railgun-programme-4904013 Then if you watch the youtube videos of it fireing, there are often multiple containers like that visible in the background. So imagine tens of these things per coil/rail gun on the ship, and having to add more the faster you want the fire rate to be (though come to think of it, this may be kind of covered by whatever the "loading mechanism" is in the module designer.) .. So you're basically saying it would be most realistic for our ships to only have either a small number of rapid firing coilguns or railguns, or a larger number of slower firing weapons. Interesting.
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Post by ash19256 on Nov 16, 2016 15:25:13 GMT
Target a hiveship's cannons with a 1GW laser at 1000km. The first magazine will detonate in seconds, usually chain-detonating the others and splitting the ship in two. I think this happens every time. A wider range of outcomes for magazine cookoffs would maybe make this less of a liability though. Huh. I never really bothered with lasers above 320 MW, mostly because that was good enough for point defense work and I'm a sucker for high-power kinetic weapons. Although, the magazine detonations could still just be the high explosive that propels the shells and compresses the fissile material cooking off, which shreds the magazine itself and sets off the magazines around it, which turns the magazines and their armor into shrapnel to shred the structural material around the guns.
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Post by ash19256 on Nov 15, 2016 18:20:37 GMT
Ya. For a good example of how not to arrange your ammo bins- the stock Hiveship has 4 nuke mags placed very precisely around the ship's wasp waist... Well, in all fairness, the nukes, as far as I can tell, would only really be a problem in that the propellant might get lit off by sustained laser fire, which isn't likely to set off the nuclear warheads as anything other than a fizzle. Granted, that would still fuck the ship up something fierce, because you've got several kilos of high explosive going boom surrounded by lots of shrapnel behind all of your armor, but that's better than having your nukes light-off in full on detonations. Although, really, I question the use of conventional guns to propel ordinance in the first place. Honestly, all of the Nippon Prime designs seen in the game that we can be relatively certain are purely Nippon Prime designs seem rather extraordinarily terrible. The Cutter and Corsair both have utterly fracking pointless water resistojet RCS, along with using water as the fuel for their NTRs, which is a terrible choice because water produces terrible exhaust velocity compared to even decane, and is actually almost as bad if not worse than LH2/LOX chemical rocket motors, which leaves me wondering why Nippon Prime even bothered. The Hiveships are also horrible designs, because they have to close to suicide range to employ their most dangerous weaponry, which makes them functionally useless in any fight with someone packing coilguns or railguns. Sure, they have railguns of their own, but a tiny number of them, which are practically guaranteed to get sniped by anyone with lasers followed by the Hiveship being ignored until every other enemy ship is dead.
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