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Post by airc777 on Jun 22, 2019 19:36:11 GMT
Again, wrong shape, correct numbers.
Big part of the problem is CDE doesn't have tapered or fluted barrels, they're the same thickness for the entire length. Typical rifles and cannon aren't. Work around for this is just make really thin barrels, causes the problem of not handling high chamber pressures, work around for this is large grain radius and large bore diameter to lower the chamber pressure.
Typical guns don't fire osmium projectiles with octogen charges either, but CDE is the future and we're going to ignore that because CDE also has kiloton homogeneous diamond manufacturing.
Firing coin shaped projectiles isn't the most realistic thing, but if the projectile was rigid enough to sustain the acceleration forces without deforming it's actually not that big of a problem. There's no air in space, the bullet doesn't have to be bullet shaped. If the coin tumbles there's no air resistance to cause it to deviate from it's course.
If the coins have the correct mass and the correct velocity but they still aren't having the correct effect on target then make a needle payload sabot.
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Post by walterscientist on Jun 23, 2019 0:56:01 GMT
Well, I did some test engagements... One drone with 7 40mm guns vs stock corvette - this goes about 50/50 depending on which side gets lucky. Two drones vs one corvette win always.
So I did a bit more elaborate test... Drones start with drop tanks from my fleet, maneuver to intercept enemy fleet of one corvette, jettison tanks and intercept enemy corvette, blow it up, turn around and fly back to rejoin their fleet. In about half the tests both drones survive and return successfully. In other half of the tests one drone is either destroyed or unable to rejoin the fleet under its own power.
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Post by AtomHeartDragon on Jun 23, 2019 8:51:11 GMT
Firing coin shaped projectiles isn't the most realistic thing, but if the projectile was rigid enough to sustain the acceleration forces without deforming it's actually not that big of a problem. Except we know that they would deform. And slapping target with a pancake is likely to be less effective than poking it with a rod, especially way short of hypervelocity regime (for disgustingly high velocities it might actually work as it makes all your projectile contact the target on impact instead of only small portion that will then turn into plasma and explode disrupting or deflecting the rest, but for anything that can be reasonably handled using Newton's approximation rods are way better). If the coins have the correct mass and the correct velocity but they still aren't having the correct effect on target then make a needle payload sabot. The problem with needle sabots is that I really have my doubts regarding the way CDE handles ship-to-ship collisions and that's what all your payload impacts ultimately are. For anything that isn't a pocket size drone with power problems (or a really low-power subcap), you can try and make small, low velocity coilgun. CGs tend to have better aspect ratio for projectiles and can be made very light and compact. Of course they are not going to help you model the gun part and may impose restrictions on the bullet material.
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Post by airc777 on Jun 23, 2019 11:57:42 GMT
Entirely fair, the simulation isn't perfect.
It's possible we could develop some fancy metal sponge structure that's mechanically competent at larger bore radius's, So you would have the same low mass and a much larger projectile volume making it more cylinder shaped without sacrificing too much strength. A metal sponge might also make a decent armature for a sabot, or a non discarding two piece projectile with a penetrator core.
It's also maybe possible, though perhaps less reasonable, that we could develop chemical guns with charges that have precisely engineered enough blast fronts to accelerate the projectile evenly instead of deform it. I mean we build fission implosion devices.
But coin firing pencil barreled cannon is how we best get the simulation to mostly behave at higher mass efficiencies.
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Post by dragon on Jun 23, 2019 12:10:23 GMT
Electrostatic blooming would like to have a talk with you. Besides, IMO, XFEL's are less interesting than far UV FEL's. Being able to easily reflect, steer and focus a beam is important for a laser weapon. I don't think blooming would be much of an issue given the relativistic speeds FEL liniacs operate at. Of course, this would limit the range of the weapon. UV FELs might have an advantage in that area, but I haven't ran the numbers on the particle cannon, so I'm not sure. Not to mention any effective FEL will be quite a big piece of hardware. No matter how you slice it, you're using a particle accelerator. Also, XFELs are quite viable as weapons, if you can stuff the undulator into the turret. You don't need to fiddle around with X-ray optics if you can just point the electron beam at the target. It's difficult to maintain packet coherence with bending magnets, but it can be done. Current high-performance lasers are efficient, but they work in laboratory conditions. In particular, their interior doesn't get up to 1500K. Also, IIRC the beam quality in COADE is limited by the fact the lasers use a steerable mirror. There was a post about that somewhere. Heat pumps are, unfortunately, quite inefficient. They will consume power and generate a lot of waste heat of their own. I don't think they're viable for, say, stepping a laser up from 500K to 1500K. There's a limit of about 8 meters for those, IIRC. If you limit your laser aperture to that, you'll generally find range to be lacking. For gaps in the mirror, actively cooled carbon will not work. Nothing will, in fact, due to sheer amount of energy you're outputting. A non-mirror will be absorbing about 100 times as much energy as the mirror, maybe more (depending on mirror efficiency). Carbon, isn't that much better than silver at withstanding extreme heat. If you have "hours", they are. Engagements generally do not last for hours. At any rate, the "more dakka" approach does not apply to lasers, because their physics are different. A beam does less damage with increasing distance, but hit probability is 100% until the turret pointing error comes into play (usually far beyond the point at which you can get a useful energy density). Meanwhile, a kinetic slug will be as damaging 10 light years away as at point blank range, but hit probability depends heavily on range.
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Post by bigbombr on Jun 27, 2019 17:48:36 GMT
I don't think blooming would be much of an issue given the relativistic speeds FEL liniacs operate at. Of course, this would limit the range of the weapon. UV FELs might have an advantage in that area, but I haven't ran the numbers on the particle cannon, so I'm not sure. Not to mention any effective FEL will be quite a big piece of hardware. No matter how you slice it, you're using a particle accelerator. Also, XFELs are quite viable as weapons, if you can stuff the undulator into the turret. You don't need to fiddle around with X-ray optics if you can just point the electron beam at the target. It's difficult to maintain packet coherence with bending magnets, but it can be done. True, but they're pretty much dedicated spinal mounts. Not a huge downside, but still. Particle beams are also great at frying electronics, but they're incapable of hitting ground based targets.Current high-performance lasers are efficient, but they work in laboratory conditions. In particular, their interior doesn't get up to 1500K. Also, IIRC the beam quality in COADE is limited by the fact the lasers use a steerable mirror. There was a post about that somewhere. Heat pumps are, unfortunately, quite inefficient. They will consume power and generate a lot of waste heat of their own. I don't think they're viable for, say, stepping a laser up from 500K to 1500K. Heat pumps are only limited by materials, and jet turbines seem to indicate we can do some impressive high temperature fluïdum manipulation. But yes, for pumping temperature 'up' a temperature gradient, they consume power, as dictated by the Carnot cycle. Considering radiated power scales with the fourth power of temperature, this might be worthwhile to an extend if you have a lot of waste heat to dissipate.
There's a limit of about 8 meters for those, IIRC. If you limit your laser aperture to that, you'll generally find range to be lacking. If your mirror is made in free-fall, it could be much bigger. Single piece mirrors tend to be not bigger because they have trouble supporting their own weight (and a massive single piece mirror is also a massive production challenge). Also, you could have multi-piece mirrors with a secondary layer overlapping the gaps the first layer has. And pulsed lasers tend to also have a slightly larger range. On top of that, lasers can blind and even burn out sensors at much greater ranges than they can burn through dedicated anti-laser armor. A blind opponent is a target.For gaps in the mirror, actively cooled carbon will not work. Nothing will, in fact, due to sheer amount of energy you're outputting. A non-mirror will be absorbing about 100 times as much energy as the mirror, maybe more (depending on mirror efficiency). Carbon, isn't that much better than silver at withstanding extreme heat. If you have "hours", they are. Engagements generally do not last for hours. This is in part an artefact of how CoaDE handles battles, as you can't have multiple intercepts simultaneously, and sensors aren't modeled. And in fights lasting only dozens of seconds, I'd put my money on missiles rather than guns. At any rate, the "more dakka" approach does not apply to lasers, because their physics are different. A beam does less damage with increasing distance, but hit probability is 100% until the turret pointing error comes into play (usually far beyond the point at which you can get a useful energy density). Meanwhile, a kinetic slug will be as damaging 10 light years away as at point blank range, but hit probability depends heavily on range. More laser dakka means more intensity on target at the same range, or a greater range at the same intensity. Adding more lasers has it's use. Also, a kinetic slug that missed it's target will slow down a little traveling through the interplanetary/interstellar medium, but probably not by much over sane timescales (though after 10 light years, it might have slowed down a lot assuming no gravitational slingshots occurred), but that's more of a technicality than a practical consideration. Them going of on a hard to predict ballistic trajectory sounds like a navigation hazard. Also, decreased odds of hitting your target means less targets destroyed. The same same goes for less intensity on target.I personally think that space combat in the near term will mostly be about missiles being deployed against satellites, with those satellites potentially deploying some countermeasures. In the mid term, we might see countries/corporations/... try to lay claim to valuable resources in the solar system, probably mostly consisting of a dispersed network of drones and missile batteries, probably directed by a human crew on a separate platform (a compromise between mitigating crew expenses, the risk to crews and the need for crews for lightlag-free tactical decision making and maintenance). Think A2D2 doctrine. In the long term, we might see the development and use of means to deploy such swarms in a way that allows them to seize a target or quickly guard it without a long buildup time during which the system is vulnerable to hostile intent. Think a mix of A2D2 and carrier doctrine. So if I had to design a combat spacecraft in the long term, it would likely be outfitted with a large VLS section for deploying whatever munitions are most suited to the mission (recon drones, laser drones, mirror drones, space to surface missiles, perhaps space to space missiles, ...), a laser system (preferably with continuous/pulsed capability) for point defense and general utility (debris field clearing, long distance data transmission, powering laser thermal parasite craft, ...) and possible a spinal mounted relativistic e-beam to discourage anyone from closing in. I'd still put the emphasis on the VLS and laser system though.
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Post by airc777 on Jun 27, 2019 22:46:41 GMT
Kind of hoping we just don't space war in the very near term. More debris in low earth orbit doesn't really help anybody in the long run regardless of the short term tactical or political gains on the ground. In the longer term yeah sure why not. If Elon's Mars colony wants to grab their laser muskets and dump the space tea into the space harbor I'd be fine with that. Let's hope we just get to the point of being a multi planetary species first.
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Post by Rocket Witch on Jun 30, 2019 13:44:20 GMT
Hmm, just... 1 millimeter thick barrel? That can't be right :-S So the key to hyper-velocity is to shoot hockey pucks? I have to say, I am kinda confused how such gun could work at all. The game is simply missing something like a 'tumble' check for short & wide projectiles. A hockey puck shape is probably about the shortest you could get away with, but a lot of optimal designs go further and are like Compact Discs. The very large bores used in such guns reduce the stress on the barrel to the width of millimeters, which looks like an exploit of another missing check. Armature geometry isn't considered either when using payloads; they're simply placed behind payloads when they should be annular and surround them. A gram wafer armature can fill a 150mm barrel and somehow not crumple up around the payload in front of it like a vacuum-formed yoghurt pot when fired.
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Post by airc777 on Jun 30, 2019 14:55:36 GMT
On the topic of railguns and why high projectile mass probably isn't realistic let's talk about the scales depicted in contemporary sci-fi.
The Expanse is almost reasonable, so I'm going to pick on Halo for a bit.
Halo's marines use just normal guns and that makes the series feel grounded, 14.5x114mm anti material rifles are things that have been around sense the world wars, and that makes it easy to forget how completely insane Halo's navy is.
I'm going to cite this source for information on the Halcyon class cruiser. He pulled his info from one of the novels that I also read years ago but I don't remember which one it was and I don't feel like digging through my collection.
Timestamp 12:35 to 12:60.
The main railgun fire 300 Ton projectiles at 12 megameters per second velocity. Makes 21.6 yottajoules muzzle energy. Same yield as 5.162 petatons of tnt. (Yes, that's Peta with a 'P'.) The nukes that are also on the ship with yields in tens of megatons would do basically nothing compared to the maingun, and it fires three of these things in rapid succession, AND the reactor can charge the capacitors in minutes.
That two meters of alpha titanium armor the Halcyons have would do absolutely nothing to stop it's own main gun. You remember that scene in Halo Reach where a frigate fires it's main gun as close air support against a surface target? Turns out the UNSC destroyed Reach, the Covenant did nothing wrong.
The Halcyons aren't even the biggest ships with the biggest guns in the lore, the Marathons and the Infinity are way bigger and Earths orbital defense platform make the Deathstar look like a toy. The writers didn't realize they accidentally made the UNSC have a massive energy advantage over the Covenant, either that or the UNSC losing the war was just an unreliable narrator and ONI propaganda to fuel recruiting.
Hell even the Gauss Hog, the 3.5 ton reconnaissance vehicle, fires a 25x130mm projectile of unspecified mass at 13.7km/s. Assuming the projectile is of a density not too dissimilar to iron and of a shape not too dissimilar too a cylinder it's throwing enough mass fast enough that it's probably about as energetic as some of the larger guns on the forum.
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Post by AtomHeartDragon on Jun 30, 2019 16:35:03 GMT
Timestamp 12:35 to 12:60. The main railgun fire 300 Ton projectiles at 12 megameters per second velocity. Makes 21.6 yottajoules muzzle energy. Same yield as 5.162 petatons of tnt. (Yes, that's Peta with a 'P'.) The nukes that are also on the ship with yields in tens of megatons would do basically nothing compared to the maingun, and it fires three of these things in rapid succession, AND the reactor can charge the capacitors in minutes.
That two meters of alpha titanium armor the Halcyons have would do absolutely nothing to stop it's own main gun. You remember that scene in Halo Reach where a frigate fires it's main gun as close air support against a surface target? Turns out the UNSC destroyed Reach, the Covenant did nothing wrong. That's around 43 Chicxulub impactors per pop. If you hooked it up to a Dyson sphere (a magical one, that doesn't have to worry about <100% thermodynamic efficiency) you wouldn't quite manage to reach COADE's rate of fire cap, although 17.5 shots per second isn't half bad either.
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Post by walterscientist on Jun 30, 2019 20:41:26 GMT
The problem with Halo books is that there was very little attention paid to the numbers that the writers thrown around. There was a bit of lack of oversight in general, but some specified stats for tech were obviously wrong. It is some years since I read the books, but in some places the authors even mixed up fractional caliber numbers for millimeters resulting in 30mm machine guns and similar nonsense. Getting even ballpark numbers for a railgun sized for a kilometer long ship would require fairly lengthy research, so the authors probably just put in an arbitrary number with very little consideration.
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Post by airc777 on Jun 30, 2019 21:06:40 GMT
That's around 43 Chicxulub impactors per pop. Or about 322.6 GigaHiroshima's.
Or a few hours of clicking around the CDE forums, yay for hindsight and more modern internet resources.
They also do dumb things like list the MA5B's effective firing range at 150 yards when it's specifically a 7.62x51 and modern 7.62x51 nato in a combat rifle has practical accuracy out to about 500 or 600 yards and in a spare no expense precision rifle is accurate out to 1,100 yards where it transitions to subsonic. They could have figured that one out with a Wikipedia search, or sense Halo is an American thing a trip to Walmart.
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Post by AtomHeartDragon on Jul 1, 2019 6:18:19 GMT
Getting even ballpark numbers for a railgun sized for a kilometer long ship would require fairly lengthy research, so the authors probably just put in an arbitrary number with very little consideration. Plugging numbers into kinetic energy formula, followed by a quick trip to en.wikipedia.org/wiki/Orders_of_magnitude_%28energy%29 to see if what they came up with is not particularly retarded is not lengthy research.
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Post by walterscientist on Jul 1, 2019 21:38:34 GMT
Yeah, it is not hard to check for absurd numbers. But I stand by the opinion that getting reasonably numbers is not so trivial. Just for fun I tried to derive what could be a reasonable figure... 100 cm bore - bore of Project Babylon gun 15,000 kg projectile - 16" gun projectile x 2.5^3 1,000 m barrel length - AFAIK Halo ships have their MAC cannons going through the whole ship 15,000 g acceleration - artillery shells have electronics rated for this --- 17,400 m/s muzzle velocity 2,271 GJ muzzle energy = 0.5 kiloton --- I'd say that seems reasonable enough. The power requirements would be quite high, but if the ship's reactors had power output similar to a nuclear power plant the gun could fire every few seconds. (I hope I didn't mess up the calculation, it's late)
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Post by AtomHeartDragon on Jul 1, 2019 23:18:19 GMT
Yeah, it is not hard to check for absurd numbers. But I stand by the opinion that getting reasonably numbers is not so trivial. Just for fun I tried to derive what could be a reasonable figure... 100 cm bore - bore of Project Babylon gun 15,000 kg projectile - 16" gun projectile x 2.5^3 1,000 m barrel length - AFAIK Halo ships have their MAC cannons going through the whole ship 15,000 g acceleration - artillery shells have electronics rated for this --- 17,400 m/s muzzle velocity 2,271 GJ muzzle energy = 0.5 kiloton --- I'd say that seems reasonable enough. The power requirements would be quite high, but if the ship's reactors had power output similar to a nuclear power plant the gun could fire every few seconds. (I hope I didn't mess up the calculation, it's late) That's a much more reasonable ballpark for a hideously unreasonable EM gun.
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