Highguard 2.0 - Railgun Barbette

[Solomani666]

While converting some of my 1.0 ship designs to 2.0 I notices the conspicuously absent Railgun Barbette so I decided to add one of my own design.

Please chime in and give me your input as this is a work in progress.

Railgun Barbette: 
Though the rounds a railgun uses are low technology 
armor penetrators, the weapon itself uses electromagnetic
forces to accelerate them to sizeable fractions of the 
speed of light, delivering a high dose of kinetic energy 
to the target. Railgun barbettes contain enough ammunition 
for 5 attacks each. 

Weapon             TL  Range  Power Damage  Cost    Traits 
Railgun Barbette   9   Short  7     2D      MCr 4   Auto 2
Railgun Barbette   12  Short  6     3D      MCr 4   Auto 2

Mass Driver Ammunition:
Tons Per Attack 0.10
Cost Per Attack Cr3000

 

[EldritchFire]

Instead of a fractional tons/attack you should use a whole-number attacks/ton. In this case, it's 5 attacks/ton, at a cost of CR15,000.

Per this older thread on batbette railguns, my suggestion is:

Barbette Railgun: TL10, short range, 3 power, 2D, Auto 3, MCr3.

12 attacks/ton of ammo, but I hadn't figured out cost for the ammo.

 

[Condottiere]

It looks like the designers pulled the numbers out of a hat, so extrapolation requires more data.

 

[Solomani666]

Instead of a fractional tons/attack you should use a whole-number attacks/ton. In this case, it's 5 attacks/ton, at a cost of CR15,000.

I wrote it that way so that it would be consistent with the existing railgun ammo chart.

 

[Solomani666]

Railgun Barbette: 
Though the rounds a railgun uses are low technology 
armor penetrators, the weapon itself uses electromagnetic
forces to accelerate them to sizeable fractions of the 
speed of light, delivering a high dose of kinetic energy 
to the target. Railgun barbettes contain enough ammunition 
for 5 attacks each. 

Weapon             TL  Range  Power Damage  Cost    Traits 
Railgun Turret     9   Short  5     1D      MCr 2   Auto 3
Railgun Barbette   9   Short  6     2D      MCr 4   Auto 3

Mass Driver Ammunition:
Tons Per Attack 0.20
Cost Per Attack Cr3000

Railguns are definitely operational by TL 9.
This is consistent with 1.0, Orbital, and current technological trends.

 

[AnotherDilbert]

What we call Railgun today is what High Guard calls Mass Driver or Ortillery. It is way to slow to hit any manoeuvring spacecraft.

A High Guard TL12 Railgun is something very different; it fires a tiny slug at immense speed, in the region of 1000 times faster than a lower tech railgun.

Based on the bays, I would suggest something like:

Railgun (aka ortillery, aka mass driver) [a railgun as we know it, big slow slug]
Barbette: TL8, 5D, Short range, 8 Power, MCr 15. Ammo: 5 attacks/ton.
Turret: TL8, 3D, Short range, 4 Power, MCr 8. Ammo: 15 attacks/ton

Frac-c auto railgun (aka railgun) [pure magic tech, tiny very fast slugs]
Barbette: TL12, 2D, Auto 3, Short range, 6 Power, MCr 12. Ammo: Negligible? 10 attacks/ton?
Turret: TL12, 1D, Auto 3, Short range, 3 Power, MCr 6. Ammo: Negligible? 30 attacks/ton?

 

[Solomani666]

What we call Railgun today is what High Guard calls Mass Driver or Ortillery. It is way to slow to hit any manoeuvring spacecraft.

A High Guard TL12 Railgun is something very different; it fires a tiny slug at immense speed, in the region of 1000 times faster than a lower tech railgun.

Based on the bays, I would suggest something like:

Railgun (aka ortillery, aka mass driver) [a railgun as we know it, big slow slug]
Barbette: TL8, 5D, Short range, 8 Power, MCr 15. Ammo: 5 attacks/ton.
Turret: TL8, 3D, Short range, 4 Power, MCr 8. Ammo: 15 attacks/ton

Frac-c auto railgun (aka railgun) [pure magic tech, tiny very fast slugs]
Barbette: TL12, 2D, Auto 3, Short range, 6 Power, MCr 12. Ammo: Negligible? 10 attacks/ton?
Turret: TL12, 1D, Auto 3, Short range, 3 Power, MCr 6. Ammo: Negligible? 30 attacks/ton?

The US Navy has railguns mounted on ships now (Can't say more), so TL9 is appropriate.

 

[Solomani666]

Railgun Barbette: 
Though the rounds a railgun uses are low technology 
armor penetrators, the weapon itself uses electromagnetic
forces to accelerate them to sizeable fractions of the 
speed of light, delivering a high dose of kinetic energy 
to the target. Railgun turrets contain enough ammunition 
for 5 attacks each. Railgun barbettes contain enough
ammunition for 10 attacks each. 

Weapon             TL  Range  Power Damage  Cost    Traits 
Railgun Turret     9   Short  5     1D      MCr 2   Auto 3
Railgun Barbette   9   Short  6     2D      MCr 4   Auto 3

Mass Driver Ammunition:
Tons Per Attack 0.10
Cost Per Attack Cr2000

Note: 
Railgun Turrets and Barbettes use the same ammunition type.
The difference in damage is due to the velocity of the projectiles.

 

[AnotherDilbert]

The US Navy has railguns mounted on ships now (Can't say more), so TL9 is appropriate.

Yes, experimental versions of this exists:

Mass Driver Bay: Also known as an ortillery railgun, this weapon fires large, solid projectiles at speeds optimised for smashing planetary targets.

I would be very surprised if experimental versions of this exists, even as a rough idea:

Railgun Bay: Though the rounds a railgun uses are low technology armour penetrators, the weapon itself uses electromagnetic forces to accelerate them to sizeable fractions of the speed of light, delivering a high dose of kinetic energy to the target.

Current railguns fires projectiles at a speed of a few km/s. Place them in vacuum and the speed would be higher, perhaps 5 - 10 km/s? They are not even remotely approaching the rate of fire of a machinegun, so they do not have an Auto trait.

Frac-c railguns would require speeds in the 30 000 km/s range, far beyond what is possible today, even on a theoretical stage. This is magic tech.

 

[phavoc]

The big question(s) are going to be - the size/mass of the projectile, how much energy do you have to power your accelerators, and how big your accelerators they are.

Larger projectiles require more power, but do more damage.

More energy allows larger projectiles and more velocity.

Larger accelerators (length wise mostly) requires more power, but imparts more velocity on your projectiles.

There are a number of inter-related questions here. Plus, depending on how you engineer things, you could conceivably give mass drivers/rail guns the auto trait by having batteries to allow for rapid or even continuous fire. Much depends on the energy requirement of the weapon and the size of the projectile.

Something else to be considered would be what about making a mass driver use rounds similar to Pournelle's powerguns? In that each individual round is essentially it's own power source, thus they are able to have rapid-fire energy weapons. Maybe each round is similar to caseless ammo, but instead of using gunpowder they are using graphene that holds an electrical charge. The graphene acts as a capacitor and is "discharged" when the stored power is discharged into the mass driver and the round is accelerated out the tube. Or maybe instead of graphene cabon nanotubes are used. In either case it's super-science not available to us today, but theory says it's possible, so since it's a game and everyone has handwavium capabilities...

 

[Solomani666]

Frac-c railguns would require speeds in the 30 000 km/s range, far beyond what is possible today, even on a theoretical stage. This is magic tech.

Agreed.
IMTU railgun projectiles are not frag-c but still go really really fast.

 

[AnotherDilbert]

The big question(s) are going to be - the size/mass of the projectile, how much energy do you have to power your accelerators, and how big your accelerators they are.

For the bays we know size and power consumption. The power sets rather firm limits on muzzle energy. That gives us the most important characteristics of the system.

 

[phavoc]

The big question(s) are going to be - the size/mass of the projectile, how much energy do you have to power your accelerators, and how big your accelerators they are.

For the bays we know size and power consumption. The power sets rather firm limits on muzzle energy. That gives us the most important characteristics of the system.

Right, so if you could augment power you should be able to increase the ROF, or the damage.

 

[AnotherDilbert]

Right, so if you could augment power you should be able to increase the ROF, or the damage.

Yes, but that might require heavier equipment to handle. If we assume that the given bays are a reasonable engineering compromise, greater muzzle energy or RoF would require a heavier weapon system.

 

[phavoc]

Right, so if you could augment power you should be able to increase the ROF, or the damage.

Yes, but that might require heavier equipment to handle. If we assume that the given bays are a reasonable engineering compromise, greater muzzle energy or RoF would require a heavier weapon system.

Maybe, but also maybe not. Electrical circuits can often hold more power without major increases in scale, or at least very minor ones. For 100% power increase you may only need a 1% increase in wiring. It could easily go either way (though I do totally agree it's always a design balance and trade-off. But in this instance we've got nothing to go by)

 

[Condottiere]

Mass drivers are supersonic, railguns are sublight

It's pretty easy to isolate the components of a torpedo or missile bay, and then retrospectively apply them to a barbette, if that was you starting point, since it would be one launcher , with a rate of fire of one per round.

Mass drivers probably RoF at one projectile per round as well, but all we know is the weight of fire per round for railguns, otherwise you'd could isolate one gun from that battery, and embed that in a barbette.

 

[FallingPhoenix]

Frac-c railguns would require speeds in the 30 000 km/s range, far beyond what is possible today, even on a theoretical stage. This is magic tech.

Agreed.
IMTU railgun projectiles are not frag-c but still go really really fast.

Now I totally want a weapon that I can call "Frag-C". It sounds awesome.

 

[wbnc]

It occurs to me that maybe the answer to long range accuracy isn't in making a faster bullet. But allowing the bullet to track its target. by adding a relatively small set of grav plates and a compact capacitor to the ammo, you could allow it to make lateral adjustments to its flight path. put a relatively simple tracking head on the tip. it's not ass accurate as a fully guided smart missile, but it has the advantage of being able to fire hundreds of projectiles in a wide cone to sort of compensate.

 

[-Daniel-]

It occurs to me that maybe the answer to long range accuracy isn't in making a faster bullet. But allowing the bullet to track its target. by adding a relatively small set of grav plates and a compact capacitor to the ammo, you could allow it to make lateral adjustments to its flight path. put a relatively simple tracking head on the tip. it's not ass accurate as a fully guided smart missile, but it has the advantage of being able to fire hundreds of projectiles in a wide cone to sort of compensate.

But once you add all of that to the ammo are you getting the best bang for your buck? Or would it just be better to go with a missile?

 

[wbnc]

It occurs to me that maybe the answer to long range accuracy isn't in making a faster bullet. But allowing the bullet to track its target. by adding a relatively small set of grav plates and a compact capacitor to the ammo, you could allow it to make lateral adjustments to its flight path. put a relatively simple tracking head on the tip. it's not ass accurate as a fully guided smart missile, but it has the advantage of being able to fire hundreds of projectiles in a wide cone to sort of compensate.

But once you add all of that to the ammo are you getting the best bang for your buck? Or would it just be better to go with a missile?

depends on your priorities.

The components would not have to be of the same quality or capability as a missile system so they are much cheaper. the volume of the package could be about the size of a beer can so that's not a major issue. In this case, you could get hundreds of seeker rounds off in a few seconds with things like sand, point defense, and anything short of a Black Globe being pointless. if you are firing something like depleted Uranium or tungsten carbide it also has a pretty good armor penetrating capability.

if you are using Lare diameter rounds the volume and mass of the seeker, controls vs impacter are even lower

if you want t hit at extreme ranges the way to go is a missile of course. more predictable and a much longer effective range. but at say short and close range the pure brute force of a rail gun has the edge over defenses.