Rail Gun for Space weapon?

[mike wightman]

50,000 km. Which is the range of a bunch of the Turret weapons.

Which means to be useful your railgun must accelerate the projectile to 50,000km/s minimum - not even remotely possible even with the handwavium in game.

Mind you that I haven't been arguing for long ranged weapons, just a place at the table. As my focus is on Adventure scale class ships operating in a near world setting.

They only have a place at the table as a visual range weapon, or if you reduce the scale of starship combat.

 

[mike wightman]

Mongoose mandates that spinal mounts are maximum half of a hull.

Canon deckplans and illustrations show that that doesn't apply in the OTU.
edit - sorry I thought you meant hull length as per the context of the previous posts rather than total hull tonnage.

 

[AnotherDilbert]

50,000 km. Which is the range of a bunch of the Turret weapons.

Thanks, that is far longer than MgT2, they use 1250 km for bays, or 10000 km with spinals or tech upgrades.

 

[Condottiere]

Canon floorplans are optical illusions applying Tardisian physics.

As regards to inertial compensators and artificial gravity:

1. A table showing maximum inertial compensation and technological level available would be nice; it may be fifteen or twenty four by technological level thirteen, and then it stops.

2. A described shipboard defensive measure is a gravity trap, where intruders are constantly falling and slamming into the floor and ceiling, which leads you wondering, how much gravity can be created?

 

[AnotherDilbert]

Every Traveller ship since Kinunir was written up includes inertial/acceleration compensators in the fluff text which actually do negate inertia...

I don't believe Inertial Compensators actually negate inertia, merely compensate for the acceleration of the drive and gravity. It would be awkward it inertia was negated since any acceleration (such as swinging your arm) would instantly give you an extremely high speed, leaving you as a smear on the bulkhead.

Since, by MT, no special magic tech is described and artificial gravity and inertial compensators appears at the same TL and have roughly the same size and cost, I can guess that inertial compensators are just a strengthened internal artificial gravity field that accelerates you at the same rate as the ship.

Question is do these magic devices affect the structural integrity of the hull or do they only affect the interior?

If we could negate the inertia of the ship we could get to light-speed instantly with an ion drive, so I guess that is not happening.

M-Drives are clearly describes as producing more thrust, not less inertia, so I guess we cannot even reduce inertia.


Edit: I seem to have taken my guess straight from TNE:

Artificial gravity G compensators create an artificial gravity field in direct opposition to the axis of acceleration, thus negating the acceleration(up to the limit of the artificial gravity field).

FF&S, p77.

 

[AnotherDilbert]

1. A table showing maximum inertial compensation and technological level available would be nice; it may be fifteen or twenty four by technological level thirteen, and then it stops.

Explicitly TNE FF&S p77.
Implicitly it is the M-Drive tech level limit in CT & MT.
MgT doesn't worry about such details...

 

[AnotherDilbert]

Mongoose mandates that spinal mounts are maximum half of a hull.

Canon deckplans and illustrations show that that doesn't apply in the OTU.

I don't think we have any example of a craft with a spinal that takes up more than half the volume?

It's just an absolute maximum to prevent people from making silly craft.

 

[Condottiere]

You could create a negative gravity field in the direction of travel, but that doesn't help if you're jinxing about in a dogfight, especially at Mongoosian velocities, where you'd need a constantly shifting field three sixty back and front, which would imply inertial compensators.

For commercial ships, a negative gravity field in a predictable flight path would be the cheaper option, since I don't see the majority going faster than three gee.

 

[mike wightman]

I don't think we have any example of a craft with a spinal that takes up more than half the volume?

It's just an absolute maximum to prevent people from making silly craft.

My misunderstanding, I apologise.

The MgT limit is half hull displacement tonnage, not half the length of the ship which was, for some reason, how I read Condottiere's post.

 

[AnotherDilbert]

You could create a negative gravity field in the direction of travel, but that doesn't help if you're jinxing about in a dogfight, especially at Mongoosian velocities, where you'd need a constantly shifting field three sixty back and front, which would imply inertial compensators.

Thrust and hence acceleration comes from the drives. "Jinxing about" means turning the craft and applying thrust in the desired direction. The main acceleration, and hence compensation, is in the same direction.

By SSOM we can apply thrust in other directions, but much less than in the main direction. Since the G compensators are compensating reasonable small accelerations in random directions induced by external factors such as planetary gravity and presumably aerobraking, I don't think that is a problem.

 

[Condottiere]

If the upper limit of acceleration is six gees, that's probably viable.

But with Mongoose, it's been implied that it's twenty five, and once you go into dogfighting mode, turns are timed in six second intervals.

It would also depend on the internal layout of the ship: an Azhanti tail sitter that only accelerates at two gees could exert a negative gravity field from the ceiling, factor two to negate the acceleration, or if they're cheapskates, factor one, and the floor artificial gravity is switched off.

Otherwise, assuming the gravitational inducers are embedded in the floor, ceiling and/or walls, they would have to be angled, especially along corridors.

 

[AnotherDilbert]

If the upper limit of acceleration is six gees, that's probably viable.

I fail to see your point. What would the time scale or ship's orientation influence? Why would anything be angled?

 

[Condottiere]

If you're going to set up a negative artificial field, which is basically the same thing a gravitational motor would use to reject gravity and ascend, the most efficient place to it directly ahead.

If you've subdivided the layout into a high rise like the Azhanti, no problem, the field is projected from the ceiling.

The more common longitudal laid out ships will have problems along long stretches, so the field would have to be embedded in existing walls, top bottom and sides, but not really front and back.

If your dogfighting turn lasts six seconds, you can, and likely will, change direction, especially while evading and trying to achieve the high ground.

 

[AnotherDilbert]

If you're going to set up a negative artificial field, which is basically the same thing a gravitational motor would use to reject gravity and ascend, the most efficient place to it directly ahead.

In order to compensate acceleration in any direction we must have fields in three orthogonal axis: up-down, port-starboard, and fore-aft. What does the orientation of ship matter?

If your dogfighting turn lasts six seconds, you can, and likely will, change direction, especially while evading and trying to achieve the high ground.

And what does it matter if the time scale is six seconds or six minutes? However we turn the ass (drives, hence thrust) is always backwards?

 

[mike wightman]

There is no such thing as dogfighting in the space combat paradigm of Traveller.

Anything at visual range is dead.

MgT is desperate to include Star Wars fighter combat - it is total cinematic bull excrement at the ranges and energy levels of Traveller weapons.

 

[pendragonman]

Which means to be useful your railgun must accelerate the projectile to 50,000km/s minimum - not even remotely possible even with the handwavium in game.

Why? IIRC, a space combat round is 1,000 seconds (CT, book 2). So the target is still in the same relative position (relative to the firer) at all times in that 1,000 seconds. To hit at 50,000 km inside the same combat round all we need is 50 km/sec (50,000 m/sec).

Now today's Navy railgun gets ~2.5 km/sec (~2500 m/2). How much handwavium is necessary to get to 50km/sec? 100 km/sec?

Is it canon? Obviously not. Is it possible?

Now, what if we treat the rail gun as a ballisticly targeted multi turn weapon. As in, we fire it one turn based on projected target movement and they impact one or two turns later. Yes, once launched it is not redirectable but neither were WWI and WWII torpedoes and they were effective.

As the original poster, I return to the original question(s). How do you stat it? What is the range limit? (I think we have decided on 50,000 km here). Does it scale to a variety of weapon sizes (turret, bay, spinal)?

 

[kilemall]

There is no such thing as dogfighting in the space combat paradigm of Traveller.

Anything at visual range is dead.

MgT is desperate to include Star Wars fighter combat - it is total cinematic bull excrement at the ranges and energy levels of Traveller weapons.

The part I don't get is the DODGE roll- whatever maneuver you make to generate a miss/no-penetrate has to be underway before the shot is made.

ESPECIALLY at MgT ranges.

 

[AnotherDilbert]

Why? IIRC, a space combat round is 1,000 seconds (CT, book 2). So the target is still in the same relative position (relative to the firer) at all times in that 1,000 seconds. To hit at 50,000 km inside the same combat round all we need is 50 km/sec (50,000 m/sec).

In 1000 s even a 1 G ship can have moved 5000 km in any direction apart from the existing velocity vector. Where do you aim? 5000 km ahead of the ship? 5000 km above the ship?

As the original poster, I return to the original question(s). How do you stat it? What is the range limit? (I think we have decided on 50,000 km here). Does it scale to a variety of weapon sizes (turret, bay, spinal)?

MgT2 uses 1250 km range for railgun bays, I would prefer that.

Against a non-manoeuvring target the range is basically unlimited, hence it can be called ortillery if it fires larger projectiles.

For damage stats I would look at the specific books you are trying to model.

 

[aramis]

And how difficult is it to bend or twist a cable?


You can of course do whatever you like in your game, but if you use bays as 400 m spinals in 5000 Dt ships it is a house-rule.

Actually, it's not a house rule. You can, per CT, MT, TNE and MGT, install bays in sub-5K ships.

You're the one insisting on change of the rules.

The rules of most editions merely specify the tonnage, not the shape, of the bay. And canonical designs don't all show 1.4x1x1 bay layouts, either.

 

[aramis]

The part I don't get is the DODGE roll- whatever maneuver you make to generate a miss/no-penetrate has to be underway before the shot is made.

ESPECIALLY at MgT ranges.

Perhaps - FF&S (TNE/T4) provides a partial out.

FF&S postulates a beam-pointer - a rangefinding targeting laser with continuous output capability. Essentially a narrow-beam ladar.
FF&S also postulates non-constant attack lasers (and other weapons).

The FF&S-fluff-derive firing sequence:

1. Find target with area sensors (radar/ladar/mk1 eyball)
2. Target with beam pointer
3. Receive pingback from beam pointer and correct
4. Repeat 2&3 until suitable lock.
5. calculate solution for major weapon
6. fire major weapon

If the target detects the beam pointer, it can theoretically dodge. Again, Matthew ignored the physics involved when I pointed out that at the ranges given, no dodge could cause a miss.