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Post by koganusan on Jan 22, 2018 8:59:21 GMT
I was wasting time online and, through some odd chain of events, ended up speculating on just how bullshit battletech is, which lead to trying to find hard numbers on something to see how close I can get to duplicating it. The armor is of course known to be aphysical space magic of some sort and extracting real numbers on it are hard, so I figured weapons are probably the place to start. To that end, after a bit of research involving digging up second and third hand numbers and fluff, I figured out the following: A battletech Gauss rifle: - Appears to be a conventional coil gun.
- Has a rate of fire of approximately one shot every ten seconds.
- Achieves a muzzle velocity on the order of 2km/s.
- Masses around 12 to 15 tons without ammo.
- Uses capacitors.
- Can be effectively aimed at targets in the 10m2 range that are two thirds of a km away, in an atmosphere, aimed by a very fallible human, under combat conditions. This places a limit on just how inaccurate it can be.
- Is small enough to fit on the arm of a big, stompy robot.
- Can fit 8 shells and an unknown amount of structure and ammunition handling equipment in a ton of ammo storage, suggesting to me that the shells are at least in the mid tens of kilograms.
Leaving aside the desirability of such a gun, the question becomes whether physics and reasonable engineering can permit it. My best attempt to build such a thing achieves about half the expected muzzle velocity, fires a projectile on the extreme low end of the reasonable mass range and needs questionable materials to keep the mass low enough, but I have admittedly never really figured out how to make coil-guns that I am happy with. Does anyone think they can do better? |
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Post by Enderminion on Jan 22, 2018 11:24:34 GMT
no, coilguns suck
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Post by jtyotjotjipaefvj on Jan 22, 2018 12:20:05 GMT
It might be doable with a railgun though. Not sure why it would have to be a coil gun, I don't think the guns are that closely described.
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Post by dragonkid11 on Jan 22, 2018 15:20:48 GMT
Battletech gauss rifle is fucking magic as far as what we can do with CoaDE coilgun system.
2 kmps? Make that at least 60. In space range, the guass rifle can reach to 360 kilometer at its max range in space.
Yeah a space turn takes a whole minute, but I think at this point we know how inaccurate a unguided projectile can be after just travelling for several seconds.
A 15 ton weapon capable of propelling a 125 kilogram slug at almost 60 kmps in space, BT guass rifle is fucking bullshit.
EDIT:
Honestly, considering the sheer range difference in ground, air and space, it's probably that aside from the magical ECM that BTverse is saturated in, large scale weapon works different when dealing with atmospheric pressure.
The ground range is still honestly stupid short though.
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Post by Kerr on Jan 22, 2018 15:34:17 GMT
I was wasting time online and, through some odd chain of events, ended up speculating on just how bullshit battletech is, which lead to trying to find hard numbers on something to see how close I can get to duplicating it. The armor is of course known to be aphysical space magic of some sort and extracting real numbers on it are hard, so I figured weapons are probably the place to start. To that end, after a bit of research involving digging up second and third hand numbers and fluff, I figured out the following: A battletech Gauss rifle: - Appears to be a conventional coil gun.
- Has a rate of fire of approximately one shot every ten seconds.
- Achieves a muzzle velocity on the order of 2km/s.
- Masses around 12 to 15 tons without ammo.
- Uses capacitors.
- Can be effectively aimed at targets in the 10m2 range that are two thirds of a km away, in an atmosphere, aimed by a very fallible human, under combat conditions. This places a limit on just how inaccurate it can be.
- Is small enough to fit on the arm of a big, stompy robot.
- Can fit 8 shells and an unknown amount of structure and ammunition handling equipment in a ton of ammo storage, suggesting to me that the shells are at least in the mid tens of kilograms.
Leaving aside the desirability of such a gun, the question becomes whether physics and reasonable engineering can permit it. My best attempt to build such a thing achieves about half the expected muzzle velocity, fires a projectile on the extreme low end of the reasonable mass range and needs questionable materials to keep the mass low enough, but I have admittedly never really figured out how to make coil-guns that I am happy with. Does anyone think they can do better? Including current capacitor tech the Navy Railgun can fire 20kg slugs with muzzle energies of 64MJ for a mass of 67 tons. 16-24MJ might be possible for a advanced electromagnetic launching system. The other stats aren't unheard of either. I would even say it is rather low-tech. |
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Post by Rocket Witch on Jan 22, 2018 18:43:59 GMT
Not sure why it would have to be a coil gun, I don't think the guns are that closely described. Far as I know it's consistent across nearly all squishy sci-fi for a 'gauss gun/rifle' to be a coilgun. |
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Post by thorneel on Jan 22, 2018 23:41:30 GMT
Well, I can somehow make a coilgun throwing a 120 magnetic metal glass projectile at about 2km/s, with 10s of reload, but it is a 200+ m monstrosity consuming 1 GW of continuous power as I haven't even tried to put a capacitor on this thing.
And for the railgun, the best I could get was about 1km/s for a 200 m gun.
It is however possible to make a 2 km/s chemgun throwing 120 kg projectiles under 10 m long (precision is high enough to not matter), or with a 120 kg total projectile + propellant (about 1/3 - 2/3). The damn thing still mass on the order of 100 t, though, so it may still be too much to lug around on a mecha's arm.
Then again, CDE is very conservative with its railgun and coilgun possibilities, so there may be a way to make better electroguns with plausible future techs.
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Post by Rocket Witch on Jan 23, 2018 17:55:06 GMT
koganusan here is your gauss rifle. The mass and size of the gun itself is not an issue, only 1.28t and 1.6m long, but the capacitor is relatively huge. I gave it a typical real world calibre but one could play with the dimensions to buff efficiency a little, which could make the cap smaller, but it's not getting down to below 20t. Image Design CoilgunModule 31.0 MW 120mm Capacitor Coilgun
UsesCustomName false
PowerConsumption_W 3.1e+07
Capacitor
DielectricComposition Hafnia
Dimensions_m 1.15 2
Separation_m 1e-07
Coil
Composition Maraging Steel
WireRadius_m 0.025
NumberOfTurns 32
NumberOfLayers 1
NumberOfStages 1
BarrelArmor
Composition Graphite
Thickness_m 0.053
Armature
Composition Magnetic Metal Glass
BoreRadius_m 0.06
Mass_kg 50
Tracer Strontium Nitrate
Payload null
Loader
PowerConsumption_W 10000
ExternalMount true
InternalMount false
AttachedAmmoBay
Capacity 300
Stacks 1
TargetsShips true
TargetsShots true
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Post by Kerr on Jan 23, 2018 18:32:54 GMT
koganusan here is your gauss rifle. The mass and size of the gun itself is not an issue, only 1.28t and 1.6m long, but the capacitor is relatively huge. I gave it a typical real world calibre but one could play with the dimensions to buff efficiency a little, which could make the cap smaller, but it's not getting down to below 20t. Image Design CoilgunModule 31.0 MW 120mm Capacitor Coilgun
UsesCustomName false
PowerConsumption_W 3.1e+07
Capacitor
DielectricComposition Hafnia
Dimensions_m 1.15 2
Separation_m 1e-07
Coil
Composition Maraging Steel
WireRadius_m 0.025
NumberOfTurns 32
NumberOfLayers 1
NumberOfStages 1
BarrelArmor
Composition Graphite
Thickness_m 0.053
Armature
Composition Magnetic Metal Glass
BoreRadius_m 0.06
Mass_kg 50
Tracer Strontium Nitrate
Payload null
Loader
PowerConsumption_W 10000
ExternalMount true
InternalMount false
AttachedAmmoBay
Capacity 300
Stacks 1
TargetsShips true
TargetsShots true
I doubt that the battletech gauss rifle shots 50kg slugs with 100MJ of KE. |
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Post by Rocket Witch on Jan 23, 2018 19:35:03 GMT
I doubt that the battletech gauss rifle shots 50kg slugs with 100MJ of KE. Haha, well, that's what OP gave as a low end estimate! |
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Post by thorneel on Jan 24, 2018 0:35:44 GMT
koganusan here is your gauss rifle. The mass and size of the gun itself is not an issue, only 1.28t and 1.6m long, but the capacitor is relatively huge. I gave it a typical real world calibre but one could play with the dimensions to buff efficiency a little, which could make the cap smaller, but it's not getting down to below 20t. I doubt that the battletech gauss rifle shots 50kg slugs with 100MJ of KE. Using this design as a starting point and, mostly, switching coils to Osnium, I could get a ~6.4 m long, 185 t coilgun throwing 100 kg projectiles for 51 MW. Though without the ammo bay and the capacitor, that can be put elsewhere, it is about 3 m long for 32 t. Yes, it needs 150 t of Hafnia for the capacitor. Assuming they have those fancy superconductor solenoids for pulse energy storage, this becomes almost believable. Also, 100 kg of MMG, or slightly cheaper Nickel Iron Molybdenum (for a slightly bulkier coilgun) are ridiculously expensive. But then I guess if they have excess resources to sink into 100+ t mecha knee joints, cost is not an issue anyway. (screenshot pending) |
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Post by koganusan on Jan 25, 2018 0:37:54 GMT
koganusan here is your gauss rifle. The mass and size of the gun itself is not an issue, only 1.28t and 1.6m long, but the capacitor is relatively huge. I gave it a typical real world calibre but one could play with the dimensions to buff efficiency a little, which could make the cap smaller, but it's not getting down to below 20t. Oh shit. You actually did it. I am deeply impressed. As has been stated, if we make a few assumptions that are still bullshit but less bullshit than/implicit in the bullshit of the rest of the setting, this is actually looking somewhat reasonable. Now if only I could find numbers for their lasers... |
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Post by koganusan on Jan 25, 2018 7:21:36 GMT
I doubt that the battletech gauss rifle shots 50kg slugs with 100MJ of KE. The 50kg thing comes from not being able to imagine enough mass going into ammo handling and structure and such to justify only 8 per ton for anything much smaller than that. The 2km/s comes from a piece of fluff saying it launches shells at mach 6, which is just a hair over 2km/s. The rest is physics. If you think that's high, remember that it is after all a very bullshit soft-scifi/space-fantasy setting with poorly thought out technology and inconsistent lore. If you think that's low, you're probably right in-universe given the ammo storage mass issue and the speeds needed to account for its supposed space performance, but I wanted the lower end of plausible so that there was even a chance. |
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Post by dragonkid11 on Jan 25, 2018 9:30:45 GMT
I doubt that the battletech gauss rifle shots 50kg slugs with 100MJ of KE. The 50kg thing comes from not being able to imagine enough mass going into ammo handling and structure and such to justify only 8 per ton for anything much smaller than that. The 2km/s comes from a piece of fluff saying it launches shells at mach 6, which is just a hair over 2km/s. The rest is physics. If you think that's high, remember that it is after all a very bullshit soft-scifi/space-fantasy setting with poorly thought out technology and inconsistent lore. If you think that's low, you're probably right in-universe given the ammo storage mass issue and the speeds needed to account for its supposed space performance, but I wanted the lower end of plausible so that there was even a chance. This is from the same universe where the structural frame of most land based warmachines and space or air fighters weighs only 10% of the total weight of the warmachines. Which in real life, accounts for nearly half the weight of modern battle tank. The battlemech internal structure also accounted weight for the actuators, sensors, and other miscellaneous things that isn't tied to the fusion reactor, so it's even more ridiculously light. And all weapon systems in game weighed that heavily (Autocannon-2 which can goes from 20mm to 50mm weighed 6 tons) because they also included ammo feed, aiming system and such. So the ammo feed issue problem isn't in the ammo bin weight, which could have been made from ultra light titanium alloy that all structural frames for all warmachines are made out of so they can fit as much ammo in as possible. |
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Post by Kerr on Jan 25, 2018 9:31:12 GMT
I doubt that the battletech gauss rifle shots 50kg slugs with 100MJ of KE. The 50kg thing comes from not being able to imagine enough mass going into ammo handling and structure and such to justify only 8 per ton for anything much smaller than that. The 2km/s comes from a piece of fluff saying it launches shells at mach 6, which is just a hair over 2km/s. The rest is physics. If you think that's high, remember that it is after all a very bullshit soft-scifi/space-fantasy setting with poorly thought out technology and inconsistent lore. If you think that's low, you're probably right in-universe given the ammo storage mass issue and the speeds needed to account for its supposed space performance, but I wanted the lower end of plausible so that there was even a chance. You should model projectile mass after it's performance, take a APFDS for example or the Navy railgun. |
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