Spinal Mount Railguns?

[EDG]

Or you have a slug that breaks up into smaller shells en route to target (which may be what you mean by a shotgun approach?).

I generally have trouble visualising space combats anyway, especially when lightspeed delay is involved. I think it's like hurricane prediction - all you can do is say where the target was when you sensed it, and then there's a big spread of volume ahead of it where it might be as of the moment you fire your weapon, and you may or may not hit it depending on whether your probability spread is correct.

Really, it seems to me that pinpoint weapons like lasers and meson guns and particle beams are about the worst you can use in space combat, because the chance of hitting a target is much lower. On the other hand, projectile weapons that can explode (or that can fire lots of rapid shots), or huge spreads of missiles that cover large areas and that can easily fill up that probability space, are much more effective.

Hell, realistically the deadliest weapon in the game is probably the sandcaster. Throw up a cloud of debris in the path of a rapidly moving ship, and you'll rip the hull to shreds in no time.

 

[Infojunky]

Assuming a mach 10 slug(10*1220 km/hr), it takes about 1/10 hour to transit out to the limit of short range - or whole turn.

Ah that is what missed from earlier.... The stated speed....

If you eliminate it, and assume equivalent performance from all magnetic weapons then Railguns look much better.

 

[captainjack23]

Assuming a mach 10 slug(10*1220 km/hr), it takes about 1/10 hour to transit out to the limit of short range - or whole turn.

Ah that is what missed from earlier.... The stated speed....

If you eliminate it, and assume equivalent performance from all magnetic weapons then Railguns look much better.

Well, do tell. I think I got the mach 10 from an earlier post. So what is a likely speed for railgun projectiles ?

 

[captainjack23]

Or you have a slug that breaks up into smaller shells en route to target (which may be what you mean by a shotgun approach?).

yeah, or one could have final tracking guidance and boost systems for the last milliseconds, I suppose.

Or just use the fire hose approach and spew out a vast cloud of slugs.

Either would improve its accuracy, but the time to target would still be an issue unless the slugs are moving at near relativistic speeds - I'm hoping we can get some input on that...Infojunky ?

I should note that a relativistic mass driver already exists -particle beams. IIRC they are stripped atomic nuclii fired at near c - they pack a BIG punch for their size (that old devil V^2 in kinetic energy really adds up)

I generally have trouble visualising space combats anyway, especially when lightspeed delay is involved. I think it's like hurricane prediction - all you can do is say where the target was when you sensed it, and then there's a big spread of volume ahead of it where it might be as of the moment you fire your weapon, and you may or may not hit it depending on whether your probability spread is correct.

Distant range is about 1/6 lsec. Laser optimum range is from 1250 to 10,000 - 1/30 lsec. You're either still thinking CT ranges, or confusing detection range with engagement range. MGT dialed the latter back significantly. Plus, a six minute round presupposes lots of beam shots fired in probability maximizing patterns. Kind of a firehose effect, again.

besides. Lasers and death rays are just plain cool. right ?

Gotta have beam weapons.8)

Plus, lasers have better ammo storage requirements than missiles or even mass drivers. Lots o' room for photons.

Hell, realistically the deadliest weapon in the game is probably the sandcaster. Throw up a cloud of debris in the path of a rapidly moving ship, and you'll rip the hull to shreds in no time.

Check out the new pebble rounds for sandcasters...nasty.

 

[EDG]

Well, do tell. I think I got the mach 10 from an earlier post. So what is a likely speed for railgun projectiles ?

http://en.wikipedia.org/wiki/Railgun

I got the Mach 10 number from there. Though technically I think for SF purposes we're really talking about Coilguns ( http://en.wikipedia.org/wiki/Coilgun ).

 

[captainjack23]

Well, do tell. I think I got the mach 10 from an earlier post. So what is a likely speed for railgun projectiles ?

http://en.wikipedia.org/wiki/Railgun

I got the Mach 10 number from there. Though technically I think for SF purposes we're really talking about Coilguns ( http://en.wikipedia.org/wiki/Coilgun ).

Cool link (thanks !) which leads to another good 'un. Some snippets from http://www.coilgun.info/theorymath/electroguns.htm

By using a non-conducting lexan projectile and confining the arc behind it they were able to achieve a performance level of 16 gram accelerated at 250,000 g along a 5 m barrel to a final velocity of 5.9 km/s.
.............
Westinghouse[18], with support from DARPA, will construct a practical railgun system including the first pulse-rated homopolar generator designed with attention to overall weight. The objective is to demonstrate feasibility of accelerating a 0.33 kg (.73 pound) projectile to a velocity of 3 km/s (9.8 ft/s), corresponding to a muzzle energy of 1.5 MJ.


........
Some preliminary calculations based on a four inch caliber mass driver using aluminum bucket coils and copper drive coils suggest an acceleration limit between 100,000 and 250,000 g. This is comparable to railgun performance.
.......
Railguns can operate in two distinct modes. In the metallic conduction mode, current flows through the sliding projectile itself, and this mode has been demonstrated to a performance level of about 1 kg mass and 2,000 g (20,000 m/s2) acceleration by the switching gun used in the Canberra installation to feed the main gun. Marshall and Barber tound that if the railgun is driven very hard, a plasma arc tends to bypass the projectile, leaving it behind. By using a non-conducting lexan projectile and confining the arc behind it they were able to achieve a performance level of 16 gram accelerated at 250,000 g along a 5 m barrel to a final velocity of 5.9 km/s.
.........
For reference, modern armor penetrating chemical rounds are about 1.5 km/sec (IIRC)

 

[Mithras]

Build your warship around this:

Still think there are BIG issues with the painfully slow speed of the projectile compared to a meson or laser.

 

[alex_greene]

Basically, what you're describing amounts to a mile - long ruddy great spinal mount shotgun ...

 

[tneva82]

Railguns are going to be long range... whether they're actually still effective at long range is another matter, but that slug's just going to keep on going - and not slow down - until it hits something.

Sure but we are talking about game, not simulation. At long range those rocks aren't going to be effective weapon so can simply be ignored since there's no need to determine that in next n+1 years it will by freak random chance hit the poor ship that had 0.0000...lots of 0's...1% chance of getting it's way.

I mean...What does that add to your RPG campaign?

 

[Gee4orce]

Railguns are going to be long range... whether they're actually still effective at long range is another matter, but that slug's just going to keep on going - and not slow down - until it hits something.

Maybe that's the reason the don't exist - they are banned under conventions of war because they are too dangerous ! All that high velocity mass shooting round a star system (probably in highly elliptical orbits) could leave a legacy that remains a danger for thousands of years.

I imagine that the projectiles are heavily stealthed too, to prevent target ships detecting them with ladar or radar and shooting them down or manoeuvring out of the way. That would make them very dangerous objects to have shooting round your system at high velocity. Maybe this is a potential reason for red zoning a system ?

 

[Stainless]

Loose and lost railgun slugs flying through a system as the aftermath signature of a space combat would be a geat adventure seed.

Could have been the cause of this...

"This is the Free Trader Beowulf, calling anyone ...
Mayday, Mayday ...
we are under attack ...
main drive is gone ...
turret number one not responding ...
Mayday ...
losing cabin pressure fast ...
calling anyone ...
please help ...
This is Free Trader Beowulf ...
Mayday ... "

 

[Mithras]

Starship equivalent of land-mines... banned by interstellar agreement

I imagine that the projectiles are heavily stealthed too, to prevent target ships detecting them with ladar or radar and shooting them down or manoeuvring out of the way. That would make them very dangerous objects to have shooting round your system at high velocity. Maybe this is a potential reason for red zoning a system ?

 

[Colin]

Starship equivalent of land-mines... banned by interstellar agreement

Which works so well in the real world, I'm afraid.

I think you would see spinal mount railguns as "stand-off" bombardment weapons for use against habitats, space stations, "fixed" orbital assets and planetary targets.

 

[The Chef]

like the sci fi equivilent of a seige mortor, pounding stationary platforms to dust.

 

[Skaran]

Though from a different version of Traveller this may help; TNE sets a maximum velocity for Mass Drivers based on TL, from 3000m/s at TL8 to a maximum of 6000m/s at TL11+. What this means is that in a 6 minute (360 second) round a TL8 slug can travel 1,080 km, TL9 1,440km, TL10 1800km and the TL11+ one 2,160 km. So if you are using 1,250 km range bands TL8-10 can traverse about 1 hex/round and the TL11+ 2 hexes if you don't mind rounding to the nearest whole number.
Range is effectively unlimited but the vectors are fixed at the time of launching. In my TU I have them detonating after a couple of rounds to blast themselves into small enough fragments or plasma perhaps, which the explosion vectors all over the place so that if a vessel is hit after this its micrometeorite protection should cope. Of course this does not always work!

 

[F33D]

If you look at the range table for this weapon they would have to be traveling at a significant fraction of c in order to be able to have a chance of hitting a maneuvering ship at the longer ranges. At least ~.2 c. That would mean that one of the projectiles would traverse the entire diameter of our solar system in ~65 hours.

Not a long term problem...

 

[DickTurpin]

I hate to derail this thread about why there are no spinal mount railguns but I thought I should mention that Trillion Credit Squadron has Spinal Mount Railguns as the first item under New Equipment on page 22.

 

[barnest2]

I hate to derail this thread about why there are no spinal mount railguns but I thought I should mention that Trillion Credit Squadron has Spinal Mount Railguns as the first item under New Equipment on page 22.

Why yes. Yes it does. *coughs*. I think they're rather nice...

 

[phavoc]

Simplified combat rules don't account for this, but if you think about it, ships closing with one another would have increased damage due to the addition of the velocity of the target being added to the velocity of the round, while ships being pursued should have less damage.

I like the ideas of railguns, and them doing massive amounts of damage. But since we are talking space combat they are going to be limited in range, and smaller ships with high agility ratings would only really be hit through bad luck.

 

[Galadrion]

Well, small ships and/or high-agility ships are only going to be hit by any spinal mount if they're unlucky. Going after small, agile ships with a spinal mount is the equivalent of going after houseflies with a sledgehammer: very, very unlikely to hit, but massive overkill if you do. Pretty much any sub-kiloton ship hit by any spinal mount is going to be destroyed, barring a miracle, but it's hitting the target that's the trick...