Confused about railguns

[JetBlack (OP)]

It's a long while ago since I had my last Aurora session, and I never really got into the military aspect of the game so far.  Now I finally started a new game again, because I remembered the good times. . .

At the moment, though, I'm somewhat confused about railguns.  Search didn't turn up anything useful, most people just seem to go with lasers.  I found some railgun-centered designs, but looking at them didn't answer many questions.  From how I understand things currently, railguns can't seem to hold a candle to lasers, but it's very much possible that I just didn't understand things correctly.  It would be kind of a pitty too, because my empire seems to be terribly devoid of energy weapon experts. . .

I researched Railgun velocity 2 and the 12cm railgun.  I designed the best railgun I could (i. e.  all the best options) and tried to build it into a ship.  The design view tells me that it's going to have a maximum range of zero. . .  This could be due to the lack of fire control (still researching hardening 1, don't want the stuff to blow up in my face immediately).  Weapons still gave their ranges even without fire control in the older versions, but maybe that's changed with 6. 43? Just tell me if this is normal.

But then, there were other gripes.  The game picked visible light lasers and 12cm lasers for me as starting tech, so currently I am still able to build lasers of comparable sophistication (until my kinetics expert runs away with his research because there's noone that could keep up with laser weapons).  But after designing a 12cm VL-laser, things look a bit worrysome for my railguns.

True, they have a better damage potential due to firing 4 shots at once.  Spreading the damage out over several shots also increases possibility to do at least some damage as opposed to none when the laser beam misses, so that's fine.  But the overall fire-rate is 50% higher (15 vs.  10 seconds), which takes the edge off somewhat.
But then I realised that railguns can't be mounted on turrets. . .  or at least I couldn't find out how to do it.  Meaning the tracking speed is mostly dependant on the speed of your ship, meaning that a railgun carrying vessel must be extremely maneuverable to actually use the damage advantage. . .  Otherwise the four shots per salvo might just about make up for the poor precision of the thing, getting a shot in every now and then, while the slower ROF clearly puts it at a huge disadvantage compared to the laser.

To add insult to injury, it's got only half the range, too.

So either I'm doing several things completely wrong, or railguns are just no match for lasers, except maybe as a fighter weapon, where the tracking penalty is much lower.  Please tell me if I'm right or if I'm just stupid. . .

Ah yes, do railguns need a magazine and consume ammo, or is that strictly for missiles?

[Barkhorn]

Railguns are decent anti-missile and anti-fighter weapons until Gauss cannons get rate of fire 5, since they automatically fire 4 shots.  Even once Gauss cannons get rate of fire 5 railguns might still out-perform gauss cannons at anti-fighter or FAC work due to better damage output, gauss cannons never do more than one damage per hit after all, while a railgun will often do more.

Oh, and railguns dont need magazines or ammo.  Only missiles need magazines.

[Iranon]

10cm railguns are a staple for point defence on all my fast ships. Gauss weapons are bulky and require a much higher tech investment... turret tracking, rate of fire, sophisticated fire control.

I don't really bother with larger sizes, because you don't actually get the benefit of a large weapon (shock damage, long range, decent damage at moderate range).
While a large railgun is more compact than 4 small lasers with the same damage per shot, putting it into a single big weapon probably means we're throttled by capacitor tech and get a much lower rate of fire.

No beam weapon needs ammunition, but all except Gauss weapons need a power plant.

[Theodidactus]

this is probably as good a time as any to ask if the massive advantage of lasers was deliberate.

I see a lot of tactical discussion where the conclusion is that every other weapon has this tiny niche application, but really it seems like lasers are almost always better than everything except, obviously, missiles.

[JetBlack (OP)]

Railguns are decent anti-missile and anti-fighter weapons until Gauss cannons get rate of fire 5, since they automatically fire 4 shots.

Ok, that is somewhat counterintuitive, what with their low tracking speed. . .  What's the exact ToHit calculation?

Thanks for all the replies, by the way.

[Bremen]

Railguns should have the same rate of fire as an equal sized laser, unless things have changed. I have no idea why yours were different unless you used different capacitor tech.

Railgun advantages vs lasers:
33% more damage for the same size and power consumption
4x as many shots means they can shoot down multiple missiles when used as PD
Don't use Corundium, which is often short as it's used for mines

Railgun disadvantages vs lasers:
Can't be turreted
Less range
Less armor penetration due to multiple shots (IE, sandpapering)
Can't be spinal mounted (yet)


This, in my mind, makes small railguns an awesome fighter weapon. Fighters don't use turrets, don't need long range, and seldom penetrate enemy armor without sanding it down anyways. And a bunch of high speed fighters firing four shots each can shoot down an amazing number of missiles, while having higher dps and lower cost than a laser based fighter.

Very large railguns also negate the range advantage of lasers; for particularly large weapons range will be limited by your fire control rather than the weapon range itself, and that's the same regardless of whether you're using

Also, compared to gauss weapons, a 10cm railgun is 3 HS while a 100% accurate gauss weapon is size 6, so even accounting for a power plant gauss weapons don't eclipse rails until fire rate 6. Railguns are also cheaper. If railguns could be mounted on turrets, they would be by far the best anti-missile weapons in the game, as is they're still really good PD when mounted on fast ships.

[JetBlack (OP)]

Railguns should have the same rate of fire as an equal sized laser, unless things have changed.   

That seems to be the case, but higher-level lasers seem to be generally smaller than higher-level railguns (well, I can't really tell, since I'm only at size two and strength 2 for both, but the comparisons at this level don't seem very favourable for the railgun).   

Here's a 10cm VL-laser compared to a 10cm Vel2 railgun:

Code: [Select]

Damage Output 3     Rate of Fire: 10 seconds     Range Modifier: 2
Max Range 60 000 km     Laser Size: 3 HS    Laser HTK: 1
Power Requirement: 3    Power Recharge per 5 Secs: 2
Cost: 6    Crew: 9
Materials Required: 1.2x Duranium  1.2x Boronide  3.6x Corundium

Code: [Select]

Damage Per Shot (4): 1     Rate of Fire: 10 seconds     Range Modifier: 2
Max Range 20 000 km     Railgun Size: 3 HS    Railgun HTK: 1
Power Requirement: 3    Power Recharge per 5 Secs: 2
Cost: 6    Crew: 9
Materials Required: 1.2x Duranium  1.2x Boronide  3.6x Neutronium


The railgun has a higher damage potential by 33% for the same size at the same RoF, but only 33% the range.     So, superior in close quarters.     The question remains how exactly the low tracking speed will affect precision.     It does indeed seem predestined for a fighter weapon as suggested, where the ships' maneuverability will improve the tracking, and where a laser would suffer the same disadvantage due to no turret.     So far so good.   

Here's a comparison of a 12cm VL-laser and a 12cm Vel-2 railgun:

Code: [Select]

Damage Output 4     Rate of Fire: 10 seconds     Range Modifier: 2
Max Range 80 000 km     Laser Size: 4 HS    Laser HTK: 2
Power Requirement: 4    Power Recharge per 5 Secs: 2
Cost: 8    Crew: 12
Materials Required: 1.6x Duranium  1.6x Boronide  4.8x Corundium


Code: [Select]

Damage Per Shot (4): 2     Rate of Fire: 15 seconds     Range Modifier: 2
Max Range 40 000 km     Railgun Size: 5 HS    Railgun HTK: 2
Power Requirement: 6    Power Recharge per 5 Secs: 2
Cost: 9    Crew: 15
Materials Required: 1.8x Duranium  1.8x Boronide  5.4x Neutronium

The railguns damage potential is now a whopping 100% higher than the laser's, while the range is only halfed.     That looks like a great development for the railgun at first glance.     However, this is a bit mitigated b the railgun being 25% larger and having its RoF increased by 50%.     That means the effective damage potential per minute is exactly 33% higher.    .    .     In effect, we get a better range comparison for a larger size at same relative damage potential.     Still, it's an improvement over the 10cm comparison.   

But now starts the tracking problem, since this gets a bit too big to put into a fighter, though it could still go well with an FAC.     While (depending on turret technology) the laser will be larger, it does retain the range advantage, but will be much more precise, possibly mitigating the higher damage potential of the railgun.    .    .     I say possibly, because that's really the question now.     The comments here that railguns are great PD weapons give the impression that the tracking penalty isn't actually that big of a deal (otherwise they'd never hit any missiles).     Just how big of a deal it is would be really interesting to know before spending more research on railgun size.   
If it's not that big of a deal, from what I see currently the railguns will retain their advantage of damage potential while mitigating the inferior range more and more up the tech-tree, which could make high-level railguns extremely deadly weapons.     
Otherwise, they might make a good weapon for some kind of cap-ship killer type vessel that is more maneuverable than the big boys and can bring the full damage advantage to bear against them while not suffering too much of a range disadvantage.     But I'm not sure yet if such a specialised class would justify the research cost of higher-level railguns along with high-level lasers, which would still be needed for the really heavy hitters.   

Might be considered a question of fleet paradigm, I guess.   


EDIT:

Ah well, through trial comes expierience.  .  .   With a higher recharge rate the 12cm railgun can be brought to the same RoF as the laser.   We're talking a full 100% more damage potential then.   If this trend increases on higher levels, then railguns should be able to hold their own against lasers.   The only problem would be armor penetration, the precision should be made up by the salvo fire.  Hmmm.  .  . 

[Bremen]

Tracking speed is linear. So if a missile is traveling at 30,000 m/s and you have a 7,500 m/s tracking speed, then your accuracy due to tracking is 25%.

The advantage of railgun point defense is that it's tiny and hurls massive numbers of projectiles. A turreted laser could easily be 4-5 HS per barrel, and a turreted gauss weapon could easily be 8 (or 4 at 50% accuracy). A railgun will only ever be 3 HS. You also save space with the fire control since it doesn't need as high a tracking speed. So a railgun is roughly as effective at point defense as a turreted laser with quadruple its tracking speed while being smaller, or less effective than a turreted gauss cannon but much smaller.

Awhile back I wrote up a post of fleet designs that included a railgun point defense frigate. It was a small, stripped down, and extremely fast vessel that could fire clouds of railgun shots (40 every 5 seconds) to intercept missiles, or could charge enemy vessels and engage at point blank range. It's the same principles as fighters, really, just scaled up.

Large railguns lose their effectiveness against missiles because you have fewer, but become more comparable to lasers in terms of range, as you've noted. Generally I don't turret anti-ship weapons anyways, so that isn't really a problem. The bigger loss with anti-ship railguns is less armor penetration and shock damage, as well as the inability to develop spinal mounted weapons.

Edit: The capacitor upgrade is kind of illusory, though, or at least temporary. If you bump capacitor rate up to 4 then the 12cm laser will have a ROF of 5, and the damage between the weapons the same. Then when you get to capacitor 6 the railgun will be ROF 5 and have double the damage again. Sometimes your capacitor tech determines what size weapon you use more than any other tech.

[JetBlack (OP)]

Tracking speed is linear.  So if a missile is traveling at 30,000 m/s and you have a 7,500 m/s tracking speed, then your accuracy due to tracking is 25%.

Aha.  So in other words, if I have a railgun that fires 4 shots at once, but the tracking speed is only a fourth as the targets' velocity, I basically have the same chance to hit it as with a turreted laser that matches the targets velocity.  Only at much lower cost and complexity.  Yes, I can definitely see how that will pay of.  Also, I just noticed this minute that there's a tech area that allows you to reduce tracking penalties against missiles, making it pretty clear why railguns rock at PD 

The capacitor upgrade is kind of illusory, though, or at least temporary.

Yes, I can see that.  It was more of a potential assesment than a capability assesment.  The railgun does have the potential to deal double the damage. . .  although I guess the armor penetration still makes lasers the better heavy hitters.

[Brian Neumann]

Aha.  So in other words, if I have a railgun that fires 4 shots at once, but the tracking speed is only a fourth as the targets' velocity, I basically have the same chance to hit it as with a turreted laser that matches the targets velocity.  Only at much lower cost and complexity.  Yes, I can definitely see how that will pay of.  Also, I just noticed this minute that there's a tech area that allows you to reduce tracking penalties against missiles, making it pretty clear why railguns rock at PD 

There are two other aspects that can help the railgun.  The first is crew quality.  The bonus is applied to each shot so even having a 5% better to hit adds up when you figure in 4 shots instead of 1.  The second is the way tracking speed is calculated.  On non turreted weapons it is the slower of the fire control or the ships speed.  If your base fire control speed is 4000 km/s, and your ship is 6,000 km/s then having a little bigger fire control gives a big increase in base to hit.  A railgun with a 1.5 size multiplier on the fire control will have a tracking speed of 6000 km/s, and will get 4 shots.  The best a turreted weapon will have is a tracking speed of 16,000 km/s and will only get 1 shot.  Comparing a 10cm laser with a 10cm railgun gives an idea of how much this matters.  Fire control for this railgun would be .7 hull spaces, for the laser 2 hull spaces.  The railgun needs 3 hull spaces each, while the laser needs 4.2 hull spaces or 16.32 for a quad laser turret.  They will need the same size capacitor.  Total compared size for 4 railguns, 1 fire control or 1 quad turret plus fire control is 12.7hs in railguns vs. 20.32 in lasers.  This means that I can fit in about 50% more (not exact as depends on your capacitor tech as well) railguns for the same hull space, and if my ship speed is greater than the base fire control tracking speed, I will have a better chance to shoot missiles down as well.

Hope this helps to illustrate why some people like small railguns.  All of this is based on version 6.43.  Earlier versions had the fire control be twice as large.

Brian

[SteelChicken]

Railguns work great for missile defense and in large numbers can shred very powerful ships.   Because of their smaller size, need for smaller firecontrols and 4 shots per barrage, you can put a lot of metal in the air real quickly.

I've not used them much, but in a recent game an NPR with 3 large mass driver ships put a hurting on one of my fleets.  Each one of these ships were able to destroy one of my mid-tech 20,000ish ton cruisers in a single volley.   I couldn't touch them with missiles and when I got close enough to hit them with lasers I was shredded.   The only thing that saved me was my ships were a bit faster and I was able to retreat.   

[Iranon]

Don't compare equal-sized weapons.

A 15cm Railgun isn't doing the job of a 15cm Laser, it's doing the job of multiple 10cm Lasers.
4 times as many shots looks good for twice the weight and three times the power consumption. Still ahead if the capacitors limit us to half the rate of fire - same volume of fire for the same weapon weight, but we can get by with a smaller power plant and the whole thing will be cheaper to build as well.

Problem: Do I really want to pursue another tech line for slightly more efficient medium artillery that has to be installed in multiples of 4 and can't be turreted?

[Bremen]

Generally I pick either Railguns or Lasers as a primary weapon, not both.

Of course, if you're using small railguns as point defense you don't really need high tech; just 10cm railgun and maybe a few ranks of railgun launch velocity.