Post by millesmissiles on Nov 20, 2016 19:27:42 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.
There are serious flaws in relying on a heavy missile doctrine. It can easily be countered with a non-symmetric capital ship mounting a powerful laser on one side and hiding the radiators behind its mass on the other side. Add in a decoy launcher and the missiles will never touch the ship. 350MW to 1GW lasers can engage at 150 Km+ and will start sniping your missile launchers and radiators well outside your missiles' full-powered envelope.
Regardless, the missile homing algorithms in the game right now are pretty bad. Counter missiles don't really work unless you're trying to blast swarms with multi-megaton nukes. Swarms of more than 40 missiles slow the game to a crawl even with a good processor. So it's hard to say what missile heavy space warfare would really be like.
What kind of flares do you have that are light and cheap enough to hide a gigawatt laserboat against 25 salvos of missiles ? Like I said in my post above yours, I don't think it's actually possible to make flares which can hide a high-power laser ship from a large number of salvos. For that matter, nuclear warheads will fry you real nice after a few closely-missed salvos.
But I agree: COADE is pretty limited in how it can handle missile combat. I suspect that the biggest barrier to the "Missile Meta" is the game's optimization and algorithms, rather than physics or game mechanics.
Post by millesmissiles on Oct 18, 2016 22:55:46 GMT
As to drunk-walking:
It's already been mentioned that ships accelerate primarily on 1 axis using gimbals to turn. A 6-axis ship would require large engines placed all around the ship, which is inefficient (only use 1 for main burns, haul around a bunch of useless engines) and creates a radiation hazard. I don't think a 6-axis ship is a viable solution at all, considering the massive penalties incurred.
For that matter, drunk-walking is most often discussed in the context of laser fights from thousands to millions of kilometers away. At 100km, which is a pretty long distance already in COADE's combat system, drunk walking is much less effective.
Consider: our main weapons are 10 kps railguns. This means they cross the void to our target at 10 seconds.
How much the enemy capital ship can "drunk walk" depends on a few factors, primarily acceleration. Many capital ships have accelerations under 500 milligees, and given 10 seconds to dodge this means that they can displace themselves AT MOST by 250 meters. Other directions are limited by the strength of the ship's attitude thrusters and its angular momentum.
I want to say that this is an area where "broadside" ships are more effective (squat design gives less angular momentum and higher turn speeds), but I'm not so sure. Others have already pointed out that the RPM-ratings on our railguns mean drunk-walking is a lot less effective. For that matter, broadside ships present a much larger target cross-section, which means more hits when the hits inevitable start coming in.
In the end, I prefer needle designs with a nice big plate of steel + spall shield up at the front. Not only is a 10m diameter circle a tough size to hit with a gun, but even if you do connect a hit it's probably not going to penetrate the citadel unless it's a nuke or something physics-defying.
Missiles used to be about equivalent until armouring with silica aerogel (or basalt fibre). With those armours, the missiles cannot be stopped by a laser and have to be intercepted by another missile. As you said, guns are ineffective at stopping even small missile constellations, even if they had independent targeting.
However, I do not agree that flares are not useful. Minimize your heat output on your launching ships (extremely easy, launcher require tiny amounts of power and heat rejection) and maximize the burn time on flares. You can get flares that burn for 10 minutes at heat levels that are sufficient to conceal your ships. A single flare per missile volley is fairly cheap (cost and mass). Sending small constellations of missiles can more easily be intercepted by defensive missiles (they tend to target the same missiles, so a wave of 20 will only have 8-10 knocked out with equivalent missiles).
If flares ever become less effective, something better be done about the various missile armours or weapon variety will die and missiles will reign supreme.
As to this, I might mention drones as another cheap remote weapon system which negate the idea of passive defense for capital ships.
Drones aren't distracted by flares, and a laser-toting drone-killer will necessarily have a high heat output which means that its flares must be hotter and correspondingly shorter-burning or hideously expensive. At this point you might use laser drones to kill incoming drones, but those can be targeted by missiles- not to mention confirming my original point that remote weapon systems and active defense dominates.
Post by millesmissiles on Oct 18, 2016 21:23:51 GMT
Ironically enough for the guy who started this crazy thread, I've been turned off from the idea of armor recently. This is based on experimentation over the past few weeks, and I've come to a few conclusions:
1. The Missile Will Always Get Through: if you take a look at the micro missiles thread, you'll be amazed by how small and cheap missiles are getting. It's trivial to build a missile weighing a few hundred kilograms for less than 500c with a dV approaching 5-10 kps. At this point, you don't even need warheads: sheer velocity means these missiles punch through ships like they're butter. Armoring against a 10 kps missile impact is impossible with anything like a reasonable budget- and budgeting is a whole other issue unto itself.
2. Missiles Spam Rules: the best (and arguably only) defense against missiles is more missiles. Interceptor missiles are a fascinating thing unto themselves, and I suspect there's a great deal of development to be had of the missile meta in general. Flares are limited (and surprisingly expensive), and an enemy throwing small salvos at you will deplete your flare supply quickly. Gun interception of missiles is mediocre at best (especially because we can't do independent targeting) and seems flawed in principle, considering the cost in crew, credits, and kilograms of a ship sporting enough guns to shoot down upwards of 100 incoming missiles. "Using dV for armor" is also a flawed concept: a ship firing missiles in salvos possesses, in practice, the dV of its missiles times however many salvos it can fire plus the ship's own dV. There is no means of defeating missile swarms as cost-, mass-, and crew- effective as another missile swarm.
3. Missiles Are the Most Lethal Weapon Systems: I guarantee you that even those fancy new stuffed whipple shield designs won't stop a 10 kps missile, especially considering how cheap and easy it is to throw 50-100 missiles per salvo at your enemy. For that matter, designing a 1-ton KKV missile is trivial- and I haven't met a block of armor yet that doesn't get holes punched in it by one of these things. Missiles also possess the most tactical diversity: I have ships with batteries of flak, nuke, and kinetic impactor missiles to use at will. It'd be pretty ludicrous to make a railgun which could throw a 1-ton projectile at 10 kps with any decent rate of fire, but it's cheap as dirt to shoot 100 missiles which do the same thing.
4. Guns Are Obsolete: gun systems built to physics-respecting, economical, and mass-saving standards will not approach the lethality of a missile system which does the same. Consider: my Fleet Standard Missile I masses 75 kg with a dV of 7.8 kps for only 171 credits. It carries a 2kg octogen flak bomb, which I like to think creates shrapnel that bounces around the inside of a ship even after the missile overpenetrates. A launcher system which carries 50 of these costs 12 Kc, masses 4 tons, and uses only 200 Kw to fire them at a rate of 180 rpm.
A 2 MW railgun firing 1g rounds at 9.6 kps does so at a rate of (physics-breakingly) 16,500 rpm. It masses 3 tons and costs 64 Kc. Even using my (now apparently obsolete) Boron-Boron-Boron armor setup, ships of mine can take a solid 1-3 minutes of fire from these 'lil guys if I angle. Meanwhile, I can carry 250 missiles for the same cost as that one railgun (they're heavier but fuel is cheap). With each launcher pumping out 3 missiles a second, these missiles accelerate to 7.8 kps in 45 seconds for a fully powered (non-ballistic) engagement range of 60km. I think there's a clear winner here.
I've still been armoring my ships with my usual Boron-Boron-Boron hull/ Steel-Boron citadel setup, but much less thick. My main worry is drones that might slip past my interceptor missiles and laser escorts, but for this rare case angling and relatively thin armor works just fine. One of my missile cruisers sports 120 FSM II's (60 with nukes, 60 with flak) and 300 FSM I's (150 with nukes, 150 with flak) with a total mass of 3 kt for little more than 30 Mc. I've talked about comparing ships in terms of Mc per kt, and for this ship the ratio is 11.8 Mc per kt. For comparison, the ship with the stuffed whipple shield stuffed earlier is 15.8 Mc per kt.
I'm often struck by how this game accurately parallels the development of tactics in human history. In the modern age, we've learned a key lesson: missiles are king, and active defense trumps passive defense every time.
Then again, they don't call me "Millesmissiles" for nothing. Missiles have their flaws, and it takes patience to painstakingly manually arrange 5 different salvos (especially when the enemy DODGES SLIGHTLY EVERY FREAKING MINUTE of a two-hour flight). Guns and drones are certainly more convenient weapons systems, and perhaps I'm overconfident in my long-range sword-arm. What do you think? Do you believe in the Missile Meta, or are you a gun nut through and through?
Alright, I've found a setup I'm happy with for smaller, more "economy" ships. Described here: imgur.com/a/mXCsT
Main rundown is that I'm using 5mm titanium as a whipple shield, a 70cm gap, 2cm of boron backed by 5mm of zirconium copper (to act as a heat spreader), a small gap, a 5mm osmium (!) citadel -- heavy as hell, but seems to work better than 2.5cm of van-chrome -- and a base layer of 3.0cm of amorphous carbon (because RCC is for fancy rich navies).
I switched from methane to decane to make the ship cross-section smaller, which helps reduce cost and mass for a given thickness of armor and makes my ships a smaller target. I currently have 6x 260t decane tanks armored with 1.5cm of boron (the high density fuel lets me armor my tanks heavily and still have a better mass ratio than some methane tanks), but I'm considering shrinking them down to 12x 130t tanks, because right now if a couple tanks go in quick succession, the resulting spin kills my crew through g-forces.
I'm going to start testing against stock ships now, instead of putting the thing up against itself. However, I am happy to report that against itself, most kills are due to losing all four 10cm thick radiators, or due to crew death caused by propellant venting induced spins.
I love it, and can't wait to shoot it. Got a userdesigns? Would love to pit 4 of those against my ship costing the equivalent thereof and see what happens. Us damn fancy rich navies and our 20 Mc/ kt Spaceboats . Mad respect for 10 Mc/ kt.
Boron seems to be pretty good at heat transfer, I'd wonder if you even need that copper. Have you tested that much?
Also: does 0.5 cm of Osmium really do a decent job as armor? That sounds a whole lot better than an inch or more of steel, even if it is folded 10,000 times...
Post by millesmissiles on Oct 4, 2016 20:05:12 GMT
Boron really is some amazing stuff, though I can't wonder if it's not perhaps a *bit* too cheap in-game. The speed of sound through boron is something like 16 kps, and coupled with the thermal diffusivity means it doesn't fracture under hypervelocity impact, doesn't take much heat from slugs hitting it, spreads that heat out well, and absorbs laser fire like a champ. I've developed a new Boron-Boron-Boron-Maraging Steel-RCC armor schema that I've been calling the "boron moron." I wanted to use aluminum for a whipple shield but boron is stronger by mass and withstands nukes much better than aluminum.
Also: reading around, I've found nothing about elemental boron being used as armor. The closest thing to it is usage as Boron Fiber, which is fine tungsten mesh coated with boron fibers. Other uses are as reinforcement for fiberglass composite structures and as Boron Carbide, a well-known tank armor. I wonder if the values for Boron and Boron Carbide aren't mixed up in-game, or if the values for Boron reflect its use as Boron Fiber? Paging qswitched
The outermost layer of my whipple shield is 1 cm of boron, spaced about 1.5 m from the inside of the hull. Spacing doesn't seem to change much so long as its more than a few cm, but I've been liberal with it just in case. Also: dat mass fraction.
The next stage in my whipple shield is 1.5 cm of boron. The two-stage makeup works well against high-velocity/ low mass and low-velocity/ high mass slugs. At least, that's what I tell myself at night.
My actual armor layer is 2.5 cm of boron. At this point, slugs that have gone through the two-stage whipple shield are usually messed-up enough to just impact against this.
That's it for the hull armor. At this point it's citadel shielding and a place to mount those railguns, which must have some INSANE recoil on them. 3.5 cm of Maraging Steel doesn't appreciate your bullets, and frowns on any attempt to be penetrated. The speed of sound in the steel armor is lower than the velocities of my slugs but the steel seems to cope just fine with that. The biggest threat to my ships has consistently been spalling from citadel strikes- I'd consider using something other than steel if it weren't so cheap and strong. I'm debating whether to call this armor "Soviet steel stronk like Stalin" or "Glorious Nippon steel folded ten thousand times."
With that, we come to the fifth and final layer: the spall shield! 10 cm of RCC does a good job of supporting the steel citadel outer armor, as well as catches any spalling (the first and biggest issue with steel citadels) and insulates the crew module against heat transmitted through the steel (the second issue with my steel citadels). If anything were to penetrate the steel, it'd have a fun time contending with 10 cm of RCC .
Switching to a triple Boron-Boron-Boron setup for the hull armor shaved off nearly 40 Mc from my ship. I still can't tell if I want to replace the RCC spall liner with something else... maybe boron ? I would use a radshield for the purpose but spalling happens all over the metal citadel, not just the bow. Ah well. I'm thinking I'll switch this thing over to methane perhaps, as its pretty expensive (20 Mc per kt of wet mass) to operate because of its size.
I'd love to know your cost metrics, in terms of Mc per kt of wet mass. I think that'd be a neat way of standardizing ship costs for the sake of comparison. In the meantime, though, enjoy these pictures of my Laser Frigate with the Boron Moron schema taking fire from two laser frigates at once:
Starting to take fire. That whipple shield is holding well, and the inner boron armor is untroubled.
Getting closer. I lost my guns fairly quick (definitely should armor them more... or at all...) but the real kicker is the radiators. Anyone got good radiator armoring designs?
Bearing down. Look at all those bounces! The inner Boron hull armor bounces shots at decent angles, and the citadel is impenetrable from the stock 11mm guns.
Point-blank and broadside-on. I think the inner Boron armor would be penetrated if I sat here long enough, especially if the whipple shield was depleted. They killed my radiators, though, and I didn't get a chance to test this.
Bonus image: the citadel armor glowing after the Boron-Boron-Boron hull at the bow was stripped off. Even taken on the flat nose nothing penetrates the citadel.
I've been using Hydrogen Deuteride because of the slightly higher exhaust velocity (and because it sounds remarkably close to Hydrogen Dude-eride) but the cost probably outweighs the benefits, especially with a shiny hydrogen NTR like yours- thanks. My hydrogen ships are already running at payload fractions of 50-65% and getting great dV despite that- methane ships literally suck farts.
Especially using an all-or-nothing schema, I definitely agree that the armor mass and volume penalty is offset by the gains of using hydrogen. My citadels are in the bow where I don't have fuel tanks anyways. My cross-section doesn't increase all that much either because I try to build long and thin.
I like the idea of tenders but am more excited for drop tanks. I think they'll still be useful if we do get drop tanks though, as some kind of general support/ fuel/ ammo storeship will always be helpful.
At first I was reinforcing the armor around important modules like crew compartments and ammo stores with an extra 1 or 2 cm of heavy armor for just the small segment containing the modules. But I then realized that I was wasting a lot of the armor on just empty space around the module, specially with smaller ammo containers. So I decided to drop that extra 1 or 2 cm of armor and instead increase the armor of the modules themselves to 5 or more cm while still reducing a considerable amount of weight on my ship.
As for the aerogel, you can basically consider it a paintjob for your ship. It isn't going to do anything for kinetics, but since it weighs so little, it's still worth it. I wonder how useful it is as a whipple shield. I doubt it even does anything but I still place it a small amount away from my main armor.
I could see module armoring being a solid tactic. It'd be interesting to use your hull armor as a lightweight whipple shield alone and rely on module armoring to withstand constant penetrations of the hull. Part of the big appeal of hull armor is its ability to bounce projectiles entirely even when they might have penetrated instead thanks to angling, but the internal structure of most of my ships would mean that any shot that bounces off a module would ricochet into a wider module behind it. Spall shielding also becomes tough for modules because you can't use complex multiple layer arrangements like for hull armor.
I think I'll play with building a module-armored version of my laser cruiser and just use the hull for whipple shielding. I'll report back when I figure that one out.
Have been playing with that 1 GW laser station and definitely see a need for some aerogel bukkake all over my ship.
This thing was still fighting right up until the radiators got too shot up to work:
Those crew modules haven't been armored yet, so the fact that one survived is pretty impressive. Citadel armor is 2.5cm vanadium-chrome steel. The main hull armor is 1.5 cm of titanium diboride, with a 60cm gap before a composite whipple shield of 0.5mm copper with 1.0mm silicon carbide backing. (The idea there is that the silicon carbide has a high specific heat capacity, so would cool the copper plasma down before it hits the hull armor.
I'm not impressed with titanium diboride as armor, honestly. I'm going to switch to an equivalent mass of silicon nitride: it has twice the yield strength, is less dense, and is cheaper.
Primary weapon used in these trials is a 2 MW railgun with 3mm, 9km/s, 1.0 g rounds. Rails are only powered at 1 MW for the sake of accuracy at range -- engagement range on these is over 50km against capital ships. Not really a massive shipkiller, but seemed like a good starting point.
I would test that ship against a railgun firing a much heavier slug at those same velocities. Spalling is the biggest downfall of metal armor: you really need some kind of backing, in my case a cm or two of RCC, to prevent deadly spalling when dealing with heavy rounds.
Let me know how the whipple shields work out, I'm interested to know.
I'm personally a fan of the idea of engagement ranges starting at a set range- 250 km or something of that sort. After all, our spaceships are approaching them this whole time- we're only handed the controls at what is essentially point blank. This would make ammo much more relevant. You're *technically* able to start firing your railgun batteries at 200 km, but those 10,000 rounds will go quick...
A change like this might make lasers stupidly powerful, though. Then again, this is supposed to be realistic space combat: combat can technically start at any range. Weapons in space don't really have "ranges" per se, but beyond a certain point accuracy and travel time make you seriously unlikely to hit anything.
You can make radiation shields out of anything. 100cm of Amorphous Carbon can stop a fairly significant amount of things. Even better when you make another radiation shield in front of it as a whipple shield.
Also, a high speed of sound is important for armour intending to stop hypervelocity impacts (4km/s and up). If the muzzle velocity of the round exceeds the material's speed of sound, it creates shock waves on the surface of the material that can crack it.
I hadn't considered using the radiation shields as internal armor to that extent. With that said, however, part of the appeal of RCC-Boron-Steel-RCC is its relative cheapness.
Also, I had no idea about that speed of sound issue. Not sure what the value is for Maraging Steel in particular but Google gives me a value of 5-6 kps for typical steel alloys. I wonder if there would be a better armor for this kind of thing. I assumed the Soviet mentality of "steel stronk like Stalin" when armoring my citadel.
Wouldn't one just....directly armor the crew module, in the module editor?
Not necessarily- and that's not just because I haven't played with crew modules in particular . I would say that for the same reasons as not relying on internal "radshields" to serve as armor: having a layer of external armor is great because it protects the bow of the ship from penetration in the first place, which also stops rounds from penetrating elsewhere. I can use the bow of my ship to bounce rounds from hitting the rest of my ship because of its tough armor. I'd also wonder whether you could make a radiation shield wide enough to protect the entire core of your ship without ballooning its cross-section and mass, as armor conforms to the shape of the hull.
Note that in many circumstances, heavy Whipple shields actually make things *worse*, because more mass gets thrown at the belt armor. I suspect this was the problem with your 5cm aluminum/5cm RCC setup. The optimal Whipple shield is, I understand, proportional to projectile mass and inversely proportional to shell velocity (as higher velocity shells take less motivation to disintegrate). This also drives the usefulness of aerogel in a capship: the thin Whipple shields that are optimal against projectiles are susceptible to lasers, and a layer of aerogel can dramatically improve survivability while only minimally increasing shield mass.
I built a lot of short, tubby ships for better volumetric efficiency, but am coming over strongly to the side of long, skinny ships. Not only do thinner ships make a smaller target (even if total area is greater, area within the circle of fire of an enemy gun is smaller), but they are less susceptible to radiator loss (since radiators will be, on average, further from the aim point).
I also second observations that RCC is weak against optimized laser designs. I recently killed a laser frigate by cutting through its 5cm RCC armor to kill the reactors with a score of 2.5MW laser drones. If you want to leverage high conductivity and re-radiation, use diamond; if you want high heat capacity, use amorphous carbon; if you want low thermal conductivity, use aerogel (or basalt). That said, a smart opponent will be using lasers to snipe modules, not etch the Whipple shield.
Care to share UserDesigns so that we can test against this cruiser?
I hadn't known that about whipple shielding. I wonder if multiple 0.75 cm layers of RCC would serve better than a single 2.5 cm block, especially for my railguns.
As for the aerogel, I'd be concerned about it being utterly destroyed by the kinetic pounding that the citadels of my ships routinely take before laser fire could even be an issue. How does it stand up to kinetic barrage?
I'm including my Designs as .txt download. The craft referenced here in particular is the "TF Laser Cruiser I". Please note that the railguns and radiators could DEFINITELY use some armoring, and I haven't yet mustered the courage to design a better laser in the module designer. I used an earlier version of this ship in conjunction with the "TF Missile Cruiser II" to beat Vesta Overkill, which was a time and a half.
Well...so far my armor has looked like a couple layers of lithium as a whipple shield, then a couple centimeters of sapphire. I then back that with a lot of hopes and dreams, with my citadel armor being "avoid contact with the enemy" and "kill them with missiles and drones."
However, after reading your post, I think I'm going to revisit that particular arrangement. Have you looked into radiation shields for the fore and aft of your citadel, as a last-ditch layer?
Haven't really looked into using radiation shields as armor, though I can imagine that the game engine might regard them as such. I have them mounted behind my crew modules of course, but not in front as bow armor. Generally, if something is going to penetrate through 2.5 cm RCC, 2.5 cm Boron, 3.5 cm Maraging Steel, and more 5 cm RCC then I wouldn't imagine that a lithium plate would do a whole lot to stop it.
I was wondering as I can't really test well via sandbox...is boron better than boron carbide? In regards to hyper velocity rounds at least.
Edit because I forgot: Some of my line warships use citadel armor, along the midsection where the AI fires at when not targeting modules. Usually ~5cm in thickness, over 5cm or so thick base armor. Under silica aerogel anti-laser armor.
I've been doing my testing using some careful enabling/ disabling of modules. Basically, I'll pit two of my ships against each other and disable my own ship's guns/ retract radiators so I can see how it withstands attack. Boron Carbide sounds better than Boron from what I've read on Wikipedia, but Boron seems to perform better in-game. It's also cheaper and lighter than its Carbide form if I remember correctly.
I've never really bothered with aerogels. RCC does a fantastic job of insulating against laser fire- the 1 GW laser won't even cut through my whipple shield- and Boron serves well enough if the whipple shield is depleted. Midsection armor is neat but I wish you could build internal "bulkheads" as ships with strong midsection armor can still be "cored" by a tough hit on the bow. My crew modules are all at the bow anyways so my midsection is mainly fuel tanks- although I can understand the need for midsection armor if you're carrying a few hundred tons of highly explosive missiles...