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Post by omnipotentvoid on Feb 11, 2017 16:59:31 GMT
So I recently started playing and a few questions came to mind pretty quickly. Specifically on the subject of targeting. Targeting and guidance are two of the most important fields in modern military technologies. Targeting, for instance, being one of the defining factors of modern tank generations. The same goes for missiles and bombs, though advances guidance and target acquisition are more emphasized by them. In the game, targeting seems to be a bit of a black box, as far as I can tell, with ships simply knowing each others position, orientation and structure. Missile target acquisition is slightly more transparent, obviously being heat seeking since flares work. . In both cases no actual systems are used to acquire, track or target specific points on the targets. Despite apparently being magic, a lot of this tech seems to act like it's at or below todays standards as far as I can tell. Heat seeking specifically seems rudimentary, considering how easy it is to fool. Personally I would have expected target acquisition via heat and then target verification and tracking via laser and/or cameras (thus rendering flares obsolete). Additionally accuracy of the guns, at least of the explosively propelled weapons, seems a bit off. This might be due to my inexperience with the game or some lack of understanding of the underlying physics, but I have been unable to produce a 120mm cannon with the characteristics of a modern 120mm tank gun (the best I have gotten is a cannon that produces the similar muzzle velocities as the regular cannon with the same caliber, length and shell weight, however the barrel wall is as at least as thick as the caliber and the accuracy is just above 4Km for a 10m² target. This is underwhelming, seeing as modern cannons have an effective range of about 4Km with significantly thinner barrels).
All in all, I would have expected more advanced systems in these areas (specifically accuracy, targeting and guidance) after 200 years. Especially accuracy and the way the aim of turrets wanders seems odd.
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Post by newageofpower on Feb 11, 2017 17:13:03 GMT
The problem is that the game assumes that gun barrels are monolithic; while in reality they are composite. Irl tank cannon barrels are actually differentially heat treated, allowing barrel thickness to be dropped dramatically.
Also, what are you making the barrels out of? Vanadium Chromium shouldn't require a high thickness.
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Post by omnipotentvoid on Feb 11, 2017 17:34:24 GMT
The problem is that the game assumes that gun barrels are monolithic; while in reality they are composite. Irl tank cannon barrels are actually differentially heat treated, allowing barrel thickness to be dropped dramatically. Also, what are you making the barrels out of? Vanadium Chromium shouldn't require a high thickness. I was using maraging steel, so my barrels are probably unduly thick (I stopped playing around with HEP weapons pretty quickly). However such a thick barrel should yield pretty good accuracy despite the material. Achieving only the accuracy of a modern tank gun with an extremely thick barrel and without the interference of gravity/Coriolis forces 200 years in the future is pretty underwhelming, which is the point I tried to make.
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Post by bigbombr on Feb 11, 2017 18:08:48 GMT
Aren't vanadium chromium steel and boron the two best barrel materials ingame?
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Post by newageofpower on Feb 11, 2017 18:21:19 GMT
In CoADE though, range is assuming your target is capable of 1G (I assume). Your accuracy would be higher vs earth-speed targets.
UHMWPE (Spectra) is pretty good as a barrel material, though it builds up heat quite rapidly. Not an issue for most microdrones issued with small magazines; they'll run out of ammo before the barrel melts.
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Post by lieste on Feb 11, 2017 21:14:59 GMT
Point accuracy of high v KE weapons can be extremely good in COADE - I've got weapons that have better than 0.0075 millirad spread patterns, but this accuracy is only meaningful against small non-manoeuvring targets (and to a lesser extent to the extreme range anti-component sniping against capitals).
Accuracy consistent with modern chemical guns is definitely possible (tank guns get SD of 0.2-0.3 millirad, which only requires a quite modest gun to match. A heavy gun with a V0 of 1.65km/s has twice the required accuracy at it's best performance, and can be lightened somewhat to still meet the requirement.
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Post by omnipotentvoid on Feb 11, 2017 22:35:40 GMT
In CoADE though, range is assuming your target is capable of 1G (I assume). Your accuracy would be higher vs earth-speed targets. UHMWPE (Spectra) is pretty good as a barrel material, though it builds up heat quite rapidly. Not an issue for most microdrones issued with small magazines; they'll run out of ammo before the barrel melts. Thats another thing I find rather odd. Engines in CoaDE are generally rear mounted. This means, assuming that you can tell which way the target is pointed, you can predict the general direction the ship will accelerate. This is especially true if you observe the exhaust plumes. In reality a good targeting system should be able to predict the movement of a ship with only rear facing engines easily. The only propulsion setup thats truly unpredictable is side mounted omni directional thrusters (like RCS ports, but with big engines). To really have a chance against a good targeting system you need the ability to accelerate in at least perpendicular directions, otherwise a range of possible positions is easily predictable and relatively easy to saturate with fire.
As a side note, speed is not the deciding factor, but acceleration. Looking at terrestrial targets, most are engaged (even at extreme combat ranges) with dumb fire munitions (cannons) often beyond the horizon. The only targets that accelerate fast enough that homing munitions or rapid fire guns are thought necessary are jet planes which can achieve acceleration in excess of 10Gs. As far as I can tell, only drones and missiles achieve that level of acceleration. To that extent, I find the rapid fire nature of large weapons somewhat silly. Area saturation/fire density are only relevant against targets with very high and/or unpredictable acceleration, which, as stated only really applies to missiles and drones. This means super high rate of fire guns or lasers are still the most effective point defense weapons, but super high energy / velocity weapons would probably be more effective against capital ships. Especially projectile weapons should be more effective. Enemies shouldn't automatically be able to tell if you fire your guns. Accelerating under the assumption the enemy is firing is a bad idea, because fuel is limited and you simply have to hold fire until they've run out of deltaV. The only option they have is to accelerate once they spot the projectile. This isn't ordinarily a problem, since, in railguns for example, the projectile is very hot upon exciting the barrel and thus easy to spot. However, most of my ship use reactors with outlet temperatures in excess of 2500K. Far above the melting point of my projectile. At maximum, I'd say you'd be able to spot up to 30Kg slugs at a range of several Km. Considering the velocity of these slugs is at least 1 or 2 Km/s this gives you only a few seconds to accelerate. Small targets up to about 10-20m long accelerating at >1G have a good chance of dodging. A ship over 100m long accelerating at a few hundred mG does not. This means that barrel alignment with the target and barrel deformation become the main limiting factors (as they are today) of accuracy. With a combination of gyros, geared turret rings and piezoelectric stepper motors, barrel alignment should be amazing 200 years in the future. Barrel deformation should also be significantly reduced, considering the advanced materials and production capabilities available. Add to this that the main reason for inaccuracy on earth is atmospheric interference (and thus irrelevant), guns in CoaDE should probably be accurate in the thousands to tens of thousands (if not hundreds of thousands) of kilometers for capital targets.
To emphasize this, I'd like to point out that I've made a railgun that fires 1g projectiles at 82km/s. Spotting those projectiles before they hit should be extremely difficult, never mind dodging them.
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Post by newageofpower on Feb 12, 2017 0:28:31 GMT
Suppose I am travelling at 5km/s perpendicular to your firing arc and at 1000 km. Your shells take over 12 seconds to arrive. An acceleration of even half a gravity can vastly change my predicted flight path vs your projctiles. This is an known issue even with a 212km/s railgun (check the first link in my signature, second page); even an sub 0.1g sideways acceleration from giballed nozzles massively increases dodging (ask apophys for more information on his Gladiator design) to the point where you need saturation to get hits. As for target gunnery prediction, Rocket Witch created an extremely detailed infographic on which models of gunlaying were mathematically superior in which situation. Also, as for heavy rounds vs sandstorms, the Sandstorm guns are not inhibited by atmospheric drag; thus they are actually ballistically more efficient than heavy munitions. No armor is effective against 200km/s + projectiles, and even the best composite designed so far is only moderately effective against 50km/s projectiles. Thus, there is no real benefits to heavy weapons when sandcasters are superior.
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Post by Rocket Witch on Feb 12, 2017 0:41:38 GMT
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Post by Enderminion on Feb 12, 2017 0:44:44 GMT
There is a thread somewhere about gunlaying in particular
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Post by newageofpower on Feb 12, 2017 1:00:23 GMT
Not this post - there was one on NPN vs saturation fire. Probably not you then.
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Post by omnipotentvoid on Feb 12, 2017 8:09:43 GMT
I think you were referring to this thread when it comes to gun laying? I was unable to find anything else. Suppose I am travelling at 5km/s perpendicular to your firing arc and at 1000 km. Your shells take over 12 seconds to arrive. An acceleration of even half a gravity can vastly change my predicted flight path vs your projctiles. Thats kind of what I'm saying: ships shouldn't be able to do. If I fire my guns at long ranges, ships instantly start dodging and they shouldn't be. Even with tracers, the projectiles are much dimmer than most radiators for reactors, making it difficult, even impossible at long ranges, to tell when an enemy is firing. Then, the only way to know your being fired at is spotting the projectiles or getting hit. The range at which you can spot the slugs should still be pretty short, even with advanced technology (especially if you're not using tracers). This should mean that you have a couple of seconds, at most, to dodge and realistically (in combat situation with possible debris in the area) the time should be in the region of a few to a few hundred milliseconds depending on projectile size, speed and your own detection capabilities. The only time the ships distance to the enemy should really matter, is if the ships can tell if the other is firing its weapons. The fact that dodging is instant is what makes for relatively short ranges for KE weapons. Like I said, with the construction techniques, materials and technologies available, dispersion on guns should be insanely small. In fact, I think that KE weapons with low fire rate (even with reloads upwards of 10s) and kinetic energies in the hundreds of megajule or even several gigajules would be viable, if ships didn't magically know round were coming in their direction.
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Post by Enderminion on Feb 12, 2017 15:42:51 GMT
I think you were referring to this thread when it comes to gun laying? I was unable to find anything else. Suppose I am travelling at 5km/s perpendicular to your firing arc and at 1000 km. Your shells take over 12 seconds to arrive. An acceleration of even half a gravity can vastly change my predicted flight path vs your projctiles. Thats kind of what I'm saying: ships shouldn't be able to do. If I fire my guns at long ranges, ships instantly start dodging and they shouldn't be. Even with tracers, the projectiles are much dimmer than most radiators for reactors, making it difficult, even impossible at long ranges, to tell when an enemy is firing. Then, the only way to know your being fired at is spotting the projectiles or getting hit. The range at which you can spot the slugs should still be pretty short, even with advanced technology (especially if you're not using tracers). This should mean that you have a couple of seconds, at most, to dodge and realistically (in combat situation with possible debris in the area) the time should be in the region of a few to a few hundred milliseconds depending on projectile size, speed and your own detection capabilities. The only time the ships distance to the enemy should really matter, is if the ships can tell if the other is firing its weapons. The fact that dodging is instant is what makes for relatively short ranges for KE weapons. Like I said, with the construction techniques, materials and technologies available, dispersion on guns should be insanely small. In fact, I think that KE weapons with low fire rate (even with reloads upwards of 10s) and kinetic energies in the hundreds of megajule or even several gigajules would be viable, if ships didn't magically know round were coming in their direction. Why do we even use chemical tracers, stick a bit of UV paint on the back and have the computer fill it in from there
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Post by apophys on Feb 12, 2017 20:22:53 GMT
Thats kind of what I'm saying: ships shouldn't be able to do. If I fire my guns at long ranges, ships instantly start dodging and they shouldn't be. Even with tracers, the projectiles are much dimmer than most radiators for reactors, making it difficult, even impossible at long ranges, to tell when an enemy is firing. Then, the only way to know your being fired at is spotting the projectiles or getting hit. Ingame, a ship with side-mounted thrusters is constantly dodging while in combat, whether the enemy fires or not, whether the enemy is in range to fire or not, or whether the enemy even has any guns to fire or not (and even whether dodging maneuvers are enabled or not...). Spotting projectiles is thus unnecessary. Sideways acceleration that approaches 1 g 0, off of gimballed thrusters, can be quite unpredictable, and very annoying to try to hit with dumb projectiles. Thus we need saturation algorithms, since our guns can actually be very accurately fired (as you see if you ignore range against an unmoving target).
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Post by omnipotentvoid on Feb 12, 2017 20:57:04 GMT
Thats kind of what I'm saying: ships shouldn't be able to do. If I fire my guns at long ranges, ships instantly start dodging and they shouldn't be. Even with tracers, the projectiles are much dimmer than most radiators for reactors, making it difficult, even impossible at long ranges, to tell when an enemy is firing. Then, the only way to know your being fired at is spotting the projectiles or getting hit. Ingame, a ship with side-mounted thrusters is constantly dodging while in combat, whether the enemy fires or not, whether the enemy is in range to fire or not, or whether the enemy even has any guns to fire or not (and even whether dodging maneuvers are enabled or not...). Spotting projectiles is thus unnecessary. Sideways acceleration that approaches 1 g 0, off of gimballed thrusters, can be quite unpredictable, and very annoying to try to hit with dumb projectiles. Thus we need saturation algorithms, since our guns can actually be very accurately fired (as you see if you ignore range against an unmoving target). So why don't we just hold fire until the enemy has expended all deltaV? Thrusting under the assumption the enemy is firing is like a modern destroyer noticing theres an enemy ship in the area that could fire missiles and then firing its point defense weapons under the assumption that missiles are incoming. Thrusting without confirmation may be theoretical solution to the problem of avoiding guns that cannot adequately saturate an area. However, since acceleration is a limited resource for a spaceship during combat, it's tactical suicide.
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