|
|
Post by dman1791 on Mar 3, 2017 22:09:40 GMT
(Almost) Every time I try to build a railgun in the new update, I meet rather stiff walls... The most nefarious of which being the "Barrel will shatter from thermal expansion" warning message... Raiguns firing at much higher velocities and that were similar otherwise in the previous update did not have this problem. I get that they now conserve energy, but why did the heating math change? Or am I just lost? I am sometimes just lost and don't know it  |
|
|
|
Post by AdmiralObvious on Mar 3, 2017 22:41:20 GMT
Are you using capacitors? If so, you've got to watch the voltage and be mindful of how big said capacitor actually is, else the electronic shock often will detonate the barrels in the real world.
If you aren't, they work largely the same as before. Except that adding armor to the barrels help with thermals and accuracy.
|
|
|
|
Post by dman1791 on Mar 3, 2017 22:49:05 GMT
I am using capacitors, yes.
Most of my capacitors are relatively tiny, I think. I don't do for 100km/s sandblasters, I go for 4-5km/s. My only (useful) working railgun atm has a capacitor that's only a fraction of the entire weapon.
How do I change the voltage without my velocity going out the window?
|
|
|
|
Post by David367th on Mar 3, 2017 23:00:58 GMT
I am using capacitors, yes. Most of my capacitors are relatively tiny, I think. I don't do for 100km/s sandblasters, I go for 4-5km/s. My only (useful) working railgun atm has a capacitor that's only a fraction of the entire weapon. How do I change the voltage without my velocity going out the window? If you're building normal sized railguns you should be hitting your material strengths before you're velocity gets more than 20km/s or so. I've found that we can keep our old designs if we just give them a good size hafnia cap and tweak the barrel dimensions. |
|
|
|
Post by tukuro on Mar 3, 2017 23:24:57 GMT
 
4 MW:RailgunModule 4 MW 4mm Turreted Capacitor Railgun
UsesCustomName true
PowerConsumption_W 3.8e+006
Capacitor
Count 1
DielectricComposition Hafnia
Dimensions_m 0.153 0.1
Separation_m 1e-007
Rails
Composition Aluminum Copper Lithium
Thickness_m 0.087
Length_m 2
BarrelArmorThickness_m 0.15
Armature
Composition Vanadium Chromium Steel
BoreRadius_m 0.002
Mass_kg 0.001
Tracer Samarium
Payload null
Loader
PowerConsumption_W 2e+005
Turret
InnerRadius_m 0.45
Extruded true
ArmorComposition Boron
ArmorThickness_m 0.0001
MomentumWheels
Composition Boron
RotationalSpeed_RPM 3118
AttachedAmmoBay
Capacity 40000
Stacks 1
TargetsShips true
TargetsShots true
33MW:RailgunModule 33 MW 4mm Turreted Capacitor Railgun
UsesCustomName true
PowerConsumption_W 3.3e+007
Capacitor
Count 1
DielectricComposition Hafnia
Dimensions_m 0.3 0.1
Separation_m 1e-007
Rails
Composition Aluminum Copper Lithium
Thickness_m 0.087
Length_m 7.7
BarrelArmorThickness_m 0.43
Armature
Composition Vanadium Chromium Steel
BoreRadius_m 0.002
Mass_kg 0.001
Tracer Lithium
Payload null
Loader
PowerConsumption_W 2e+005
Turret
InnerRadius_m 1.2
Extruded true
ArmorComposition Boron
ArmorThickness_m 0.01
MomentumWheels
Composition Boron
RotationalSpeed_RPM 1622
AttachedAmmoBay
Capacity 40000
Stacks 1
TargetsShips true
TargetsShots true
These might be good starting points. Note that without separate bracing materials it's not really cost-effective to use large railguns. AlCuLi is the main alloy used these days because it combines most of the desired properties ( relatively low density, high conductivity, low resistivity, high enthalpy of fusion, high thermal diffusivity, high yield strength and high moduli). For micro railguns however you can try magnesium or calcium. |
|
|
|
Post by David367th on Mar 3, 2017 23:26:27 GMT
4 MW:RailgunModule 4 MW 4mm Turreted Capacitor Railgun
UsesCustomName true
PowerConsumption_W 3.8e+006
Capacitor
Count 1
DielectricComposition Hafnia
Dimensions_m 0.153 0.1
Separation_m 1e-007
Rails
Composition Aluminum Copper Lithium
Thickness_m 0.087
Length_m 2
BarrelArmorThickness_m 0.15
Armature
Composition Vanadium Chromium Steel
BoreRadius_m 0.002
Mass_kg 0.001
Tracer Samarium
Payload null
Loader
PowerConsumption_W 2e+005
Turret
InnerRadius_m 0.45
Extruded true
ArmorComposition Boron
ArmorThickness_m 0.0001
MomentumWheels
Composition Boron
RotationalSpeed_RPM 3118
AttachedAmmoBay
Capacity 40000
Stacks 1
TargetsShips true
TargetsShots true
33MW:RailgunModule 33 MW 4mm Turreted Capacitor Railgun
UsesCustomName true
PowerConsumption_W 3.3e+007
Capacitor
Count 1
DielectricComposition Hafnia
Dimensions_m 0.3 0.1
Separation_m 1e-007
Rails
Composition Aluminum Copper Lithium
Thickness_m 0.087
Length_m 7.7
BarrelArmorThickness_m 0.43
Armature
Composition Vanadium Chromium Steel
BoreRadius_m 0.002
Mass_kg 0.001
Tracer Lithium
Payload null
Loader
PowerConsumption_W 2e+005
Turret
InnerRadius_m 1.2
Extruded true
ArmorComposition Boron
ArmorThickness_m 0.01
MomentumWheels
Composition Boron
RotationalSpeed_RPM 1622
AttachedAmmoBay
Capacity 40000
Stacks 1
TargetsShips true
TargetsShots true
These might be good starting points. Note that without separate bracing materials it's not really cost-effective to use large railguns. AlCuLi is the main alloy used these days because it combines most of the desired properties ( relatively low density, high conductivity, low resistivity, high enthalpy of fusion, high thermal diffusivity, high yield strength and high moduli). For micro railguns however you can try magnesium or calcium. Quick question, what does enthalpy of fusion have to do with railguns? |
|
|
|
Post by tukuro on Mar 3, 2017 23:46:13 GMT
Quick question, what does enthalpy of fusion have to do with railguns? I guess I could've better put that as "Energy required to melt the railgun."  |
|
|
|
Post by diamondback on Mar 3, 2017 23:46:33 GMT
Enthalpy of fusion is science for how much energy is required melt the substance once its warm enough.
|
|
|
|
Post by David367th on Mar 3, 2017 23:50:24 GMT
...is that not melting temperature?
|
|
|
|
Post by tukuro on Mar 3, 2017 23:54:11 GMT
...is that not melting temperature? The energy required to increase a material's temperature by 1 kelvin is not universal. High melting temperature doesn't always correlate with high specific heat. Which together determine how much energy is required to melt the material.  Using "Heat of Fusion" technically isn't correct though, because it refers to the amount of energy required for a phase change from solid to liquid, without a corresponding change in temperature. |
|
|
|
Post by David367th on Mar 3, 2017 23:57:40 GMT
...is that not melting temperature? The energy required to increase a material's temperature by 1 kelvin is not universal. High melting temperature doesn't always correlate with high specific heat. Which together determine how much energy is required to melt the material. Using "Heat of Fusion" technically isn't correct though, because it refers to the amount of energy required for a phase change from solid to liquid, without a corresponding change in temperature. Oh I got you thanks  |
|
|
|
Post by n2maniac on Mar 4, 2017 21:40:51 GMT
AlCuLi is the main alloy used these days because it combines most of the desired properties ( relatively low density, high conductivity, low resistivity, high enthalpy of fusion, high thermal diffusivity, high yield strength and high moduli). I find the unrealistically stiff AlZnMg substantially better at longer ranges. Yea, it is 10x more resistive, but that isn't an issue with 1g projectiles going 30km/s (material volume * strength scales with projectile energy, I*t scales with projectile momentum). Or maybe I found another bug to use. Also, holy crap hafnia is broken (10^7 J/kg or about 3000Wh/kg, energy density similar to uncombusted hydrogen + oxygen?  ?? Someone check my math?). For comparison IRL values this is an order of magnitude better than the best lithium batteries (plot is probably slightly out of date, but not badly so):  |
|
?? Someone check my math?). For comparison IRL values this is an order of magnitude better than the best lithium batteries (plot is probably slightly out of date, but not badly so):