burningtumbleweednologin
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Post by burningtumbleweednologin on Aug 29, 2018 7:33:43 GMT
With such light projectiles, high velocity is achieved, but wouldn't a projectile like this simply shatter against the first thing it touches, rather than achieve any penetration? I believe this is why modern KE weapons fire rods that are roughly eight hundred millimeters in length, as opposed to smaller rounds.
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Post by bigbombr on Aug 29, 2018 7:50:22 GMT
With such light projectiles, high velocity is achieved, but wouldn't a projectile like this simply shatter against the first thing it touches, rather than achieve any penetration? I believe this is why modern KE weapons fire rods that are roughly eight hundred millimeters in length, as opposed to smaller rounds. At high velocities (+3 km/s), projectiles act more as fluids than as solids. A long rod shape helps penetration. At higher velocities (10+ km/s), projectiles vaporize into plasma on impact. Rod shapes don't help penetration AFAIK under those circumstances. In space, with no atmosphere to slow you down, small rounds can have the same range as larger ones. Effective range is determined by muzzle velocity and shot dispersion. Lighter projectiles impose less stress on the barrel, leading to less dispersion. Lighter projectiles also mean that with the same energy, you can reach a higher muzzle velocity. Therefore, light projectiles with long effective ranges are desired over short ranged, heavier projectiles (even though heavier projectiles tend to penetrate better for the same kinetic energy). It doesn't matter if you have a weapon that can penetrate the enemy spacecraft in a single shot if you're out ranged by an order of magnitude. Even peashooters, especially with high rates of fire, will grind their way through most armor. |
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Post by AtomHeartDragon on Aug 29, 2018 8:21:17 GMT
Three reason reasons - two RL ones and one (sadly) grounded in game logic: - Because they need to be so fast to actually hit anything and accelerating more mass costs more energy
- Because in space they *can* be so fast without instantly burning up in the atmosphere
- Because module level damage modelling is nearly nonexistant (also because crews in COADE are dumb and don't suit up & depressurize before being shot at) and modules simply pop when successfully penetrated.
Do note that combat in deep gravwells actually shifts the balance to heavier, slower projectiles because relative velocities of the ships start to contribute major part of the impact velocities and guns start being relegated to the role of guidance system, merely putting the slugs/payloads where you want them.
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Post by fallingaggressively on Aug 30, 2018 1:17:06 GMT
I do wonder though, would the very light projectiles be ineffective against laser defense? Even despite their small cross-section, surely such a small amount of material would be burned away very quickly, necessitating the need for a balance of throw weight (including the rate of fire) and the size of the projectile versus the typical laser intensity in use. Also, wouldn't the ablative effect push the projectile off course (doubly so for pulse lasers I imagine)?
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Post by boersgard on Aug 30, 2018 2:36:59 GMT
For starters, I find it highly unlikely that 1g projectiles could be accelerated to 30km/s or higher by a railgun without annihilating the projectile. But even ignoring that, I've actually had more success with heavier projectiles, rather than lighter. There's probably a sweet spot in the game, and I'm absolutely certain it's not 1g projectiles.
Secondly, although the projectile mass and overall kinetic energy matters, so does the rate of fire - at least in gameplay terms. 20 guns firing peashooter rounds in the same place end up sandblasting through armor - especially whipple shield designs - extremely fast.
From what I've seen in the game my design philosophy for projectile weapons would be:
1. Maximize rate of fire
2. Maximize projectile mass
3. Maximize projectile velocity
I'd say that as long as your velocity is above 10km/s you're good. Higher dispersion/inaccuracy isn't even necessarily a bad thing if it only takes one hit to punch through. I think the present meta of 50km/s or faster sand grains is overexaggerating the benefit of velocity and sacrificing too much in other areas to achieve it. I've been using a railgun design with a 15g projectile and it has dramatically outperformed 1g projectiles at higher velocities.
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Post by The Astronomer on Aug 30, 2018 4:37:35 GMT
For starters, I find it highly unlikely that 1g projectiles could be accelerated to 30km/s or higher by a railgun without annihilating the projectile. But even ignoring that, I've actually had more success with heavier projectiles, rather than lighter. There's probably a sweet spot in the game, and I'm absolutely certain it's not 1g projectiles. Secondly, although the projectile mass and overall kinetic energy matters, so does the rate of fire - at least in gameplay terms. 20 guns firing peashooter rounds in the same place end up sandblasting through armor - especially whipple shield designs - extremely fast. From what I've seen in the game my design philosophy for projectile weapons would be: 1. Maximize rate of fire 2. Maximize projectile mass 3. Maximize projectile velocity I'd say that as long as your velocity is above 10km/s you're good. Higher dispersion/inaccuracy isn't even necessarily a bad thing if it only takes one hit to punch through. I think the present meta of 50km/s or faster sand grains is overexaggerating the benefit of velocity and sacrificing too much in other areas to achieve it. I've been using a railgun design with a 15g projectile and it has dramatically outperformed 1g projectiles at higher velocities. At what range do your railguns fight? My warships fight at several hundred kilometers away. Slow projectiles won't even hit. |
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Post by gedzilla on Aug 30, 2018 4:48:16 GMT
For starters, I find it highly unlikely that 1g projectiles could be accelerated to 30km/s or higher by a railgun without annihilating the projectile. But even ignoring that, I've actually had more success with heavier projectiles, rather than lighter. There's probably a sweet spot in the game, and I'm absolutely certain it's not 1g projectiles. Secondly, although the projectile mass and overall kinetic energy matters, so does the rate of fire - at least in gameplay terms. 20 guns firing peashooter rounds in the same place end up sandblasting through armor - especially whipple shield designs - extremely fast. From what I've seen in the game my design philosophy for projectile weapons would be: 1. Maximize rate of fire 2. Maximize projectile mass 3. Maximize projectile velocity I'd say that as long as your velocity is above 10km/s you're good. Higher dispersion/inaccuracy isn't even necessarily a bad thing if it only takes one hit to punch through. I think the present meta of 50km/s or faster sand grains is overexaggerating the benefit of velocity and sacrificing too much in other areas to achieve it. I've been using a railgun design with a 15g projectile and it has dramatically outperformed 1g projectiles at higher velocities. First off, the total end km/s of the projectile dont matter to it shattering in the barrel (1g or no). Only the RATE of acceleration matter to it shattering. Realistically, you could get the velocity up to 100km/s and be fine, or you can have a 5km/s that shatters in the barrel. The only thing that matters is the length of the barrel aka how much acceleration the projectile is being subject to. Obviously longer barrel for same speed equals lower rate of accel. Second, your (non PD) guns only have 10km/s ?!? What ranges are you engageing in ? Second, what standards are you judging your guns at ? Yes your gun may be better at killing stationary nose in ships, but can it take down a (anti-laser armored) run-and-gun ship that is constantly dodging ? |
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Post by apophys on Aug 30, 2018 5:01:47 GMT
From my fiddling with railguns, I get a rough relation that 2x projectile energy --> ~2.5x mass & cost of the gun (with much less traverse speed to boot). This is exponential; i.e. 4x projectile energy --> ~6.25x mass & cost, and so on.
Therefore, it is most mass-efficient and cost-efficient to use low energy bullets. High projectile velocity is the #1 concern, in order to have maximum range and actually hit things. The only other thing you can change to have low projectile energy is to reduce the mass as much as possible. Thus, sandblasters.
Cranking up their rate of fire as much as possible is just a matter of having sufficient power generation to hit the 30 shot/sec hardcap (or the 1 GW power input limit, whichever you reach first).
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Post by shiolle on Aug 30, 2018 5:57:35 GMT
First off, the total end km/s of the projectile dont matter to it shattering in the barrel (1g or no). Only the RATE of acceleration matter to it shattering. Realistically, you could get the velocity up to 100km/s and be fine, or you can have a 5km/s that shatters in the barrel. The only thing that matters is the length of the barrel aka how much acceleration the projectile is being subject to. Obviously longer barrel for same speed equals lower rate of accel. In railguns at least you are forcing hundreds of megawatts through a tiny needle at less than 50% efficiency without super-conductors. Where do you think the other half of that energy goes? Even much more massive projectiles, like in the navy railgun suffer a lot of heating. I don't think 1g projectiles are able to withstand that much current going through them, and sub-gram grains of sand even less so. An example from here: "If full power was to be applied to a static armature the rails and whatever was between them would instantaneously melt under the intense localized heat produced by Ohmic heating as 100thousand amperes tried to make it through the contact resistance. In order to prevent the Rail Gun from becoming a spot welder it is necessary that the armature be moving with some initial speed prior to electromagnetic acceleration. Most amateur designs fail because of lack of knowledge of this." They propose to inject the projectile with some initial velocity using pressurized gas, but I suspect there is a limit on how small you can make your projectile without it becoming plasma even using this method because as the inital speed increases the efficiency of your railgun should decrease. Besides there are no such systems in the game. The game checks projectile melting conditions, but I don't think it works correctly. |
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Post by gedzilla on Aug 30, 2018 6:22:26 GMT
First off, the total end km/s of the projectile dont matter to it shattering in the barrel (1g or no). Only the RATE of acceleration matter to it shattering. Realistically, you could get the velocity up to 100km/s and be fine, or you can have a 5km/s that shatters in the barrel. The only thing that matters is the length of the barrel aka how much acceleration the projectile is being subject to. Obviously longer barrel for same speed equals lower rate of accel. In railguns at least you are forcing hundreds of megawatts through a tiny needle at less than 50% efficiency without super-conductors. Where do you think the other half of that energy goes? Even much more massive projectiles, like in the navy railgun suffer a lot of heating. I don't think 1g projectiles are able to withstand that much current going through them, and sub-gram grains of sand even less so. An example from here: "If full power was to be applied to a static armature the rails and whatever was between them would instantaneously melt under the intense localized heat produced by Ohmic heating as 100thousand amperes tried to make it through the contact resistance. In order to prevent the Rail Gun from becoming a spot welder it is necessary that the armature be moving with some initial speed prior to electromagnetic acceleration. Most amateur designs fail because of lack of knowledge of this." They propose to inject the projectile with some initial velocity using pressurized gas, but I suspect there is a limit on how small you can make your projectile without it becoming plasma even using this method because as the inital speed increases the efficiency of your railgun should decrease. Besides there are no such systems in the game. The game checks projectile melting conditions, but I don't think it works correctly. You are saying that the round heats up due to the eletric currents running through it. Fair enough. Im just saying the shattering doesnt depend on the final km/s, only on the stresses (through accel or electric heating) on the round at any given time. |
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Post by AdmiralObvious on Aug 30, 2018 6:45:41 GMT
Aren't our loading mechanisms presumed to be linear induction motors anyways? When you're using grains of sand, it would be pretty easy to get the projectile moving, and then us the barrel.
The thing about light micro projectiles is that they can usually, fairly easily be stopped by a particularly well designed armor scheme, which coincidentally happens to be an extremely poor armor scheme for any other type of larger projectile.
Take our standard 1-4mm railgun defeating armor, then try shooting at it with the stock 60mm or 33mm autocannon. The autocannon will shred the armor and destroy the ship.
The key issue is at which ranges you can actually take advantage of these. Railguns and coilguns significantly outclass standard guns in terms of practical ranges. Conventional guns, however can deliver literal tons of kinetic energy, but at the cost of much less reliability in hitting the mark.
If you're using a slug thrower, you want the thing to actually HIT where you point it at. That's primarily velocity doing that. Fire rate needs more mass, and therefore more ammo cost. The actual mass of the projectile seems to be an afterthought, but that's due to the way armor, especially for turrets works in this game.
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Post by bigbombr on Aug 30, 2018 7:07:16 GMT
Aren't our loading mechanisms presumed to be linear induction motors anyways? When you're using grains of sand, it would be pretty easy to get the projectile moving, and then us the barrel. The thing about light micro projectiles is that they can usually, fairly easily be stopped by a particularly well designed armor scheme, which coincidentally happens to be an extremely poor armor scheme for any other type of larger projectile. Take our standard 1-4mm railgun defeating armor, then try shooting at it with the stock 60mm or 33mm autocannon. The autocannon will shred the armor and destroy the ship. The key issue is at which ranges you can actually take advantage of these. Railguns and coilguns significantly outclass standard guns in terms of practical ranges. Conventional guns, however can deliver literal tons of kinetic energy, but at the cost of much less reliability in hitting the mark. If you're using a slug thrower, you want the thing to actually HIT where you point it at. That's primarily velocity doing that. Fire rate needs more mass, and therefore more ammo cost. The actual mass of the projectile seems to be an afterthought, but that's due to the way armor, especially for turrets works in this game. Missiles are much lighter than conventional cannons though. A turreted cannon launching 10 kg slugs at 2 km/s with 1000 rounds of ammunition tends to be much heavier than a blast launcher launching 1000 kinetic missiles with an inert mass of 10 kg and over 2.3 km/s of delta-v. |
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Post by gedzilla on Aug 30, 2018 10:30:33 GMT
Aren't our loading mechanisms presumed to be linear induction motors anyways? When you're using grains of sand, it would be pretty easy to get the projectile moving, and then us the barrel. The thing about light micro projectiles is that they can usually, fairly easily be stopped by a particularly well designed armor scheme, which coincidentally happens to be an extremely poor armor scheme for any other type of larger projectile. Take our standard 1-4mm railgun defeating armor, then try shooting at it with the stock 60mm or 33mm autocannon. The autocannon will shred the armor and destroy the ship. The key issue is at which ranges you can actually take advantage of these. Railguns and coilguns significantly outclass standard guns in terms of practical ranges. Conventional guns, however can deliver literal tons of kinetic energy, but at the cost of much less reliability in hitting the mark. If you're using a slug thrower, you want the thing to actually HIT where you point it at. That's primarily velocity doing that. Fire rate needs more mass, and therefore more ammo cost. The actual mass of the projectile seems to be an afterthought, but that's due to the way armor, especially for turrets works in this game. Missiles are much lighter than conventional cannons though. A turreted cannon launching 10 kg slugs at 2 km/s with 1000 rounds of ammunition tends to be much heavier than a blast launcher launching 1000 kinetic missiles with an inert mass of 10 kg and over 2.3 km/s of delta-v. Tbh, i think cannons are only useful for small, super cqc drones ( which i love making lol) |
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Post by shiolle on Aug 30, 2018 12:14:20 GMT
You are saying that the round heats up due to the eletric currents running through it. Fair enough. Im just saying the shattering doesnt depend on the final km/s, only on the stresses (through accel or electric heating) on the round at any given time. I know, and the game seems to model the shattering. The quote was meant not to contradict your argument, but continue it to show that although shattering only becomes a problem at extreme accelerations, there are other reasons why the projectile may not survive till it reaches the end of the barrel. Aren't our loading mechanisms presumed to be linear induction motors anyways? When you're using grains of sand, it would be pretty easy to get the projectile moving, and then us the barrel. Yes, but it's not like you push it gently and in rolls into the barrel. In order to have good contact with the rails, the projectile must fit quite tightly, which means you have to keep shoving it in when you switch on the rails. Plus, this method, like any other, has its own limitations. With small enough projectile and strong enough current, the projectile will melt, moving or not. P.S. The article I linked contained another interesting point: to avoid fast rail degradation, the melting point of the rails should be significantly higher than the melting point of the projectile. |
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