[Spaceships] External Weapons (Missiles, etc)

[scc]

OK, I'm sure I remember reading something along these lines before but I can't seem to find it.

OK, in real life fighter planes have missiles hanging from their wings, if I want something similar for Spaceships. I figure the Handheld rules from Spaceships 4 are a starting point, but how much stuff can you put on the outside of a fighter? And do wings help? And I'm sure there's stuff I haven't thought of

[vierasmarius]

I see two approaches here. The simplest is to treat the hardpoints as simple missile launchers - in this case their external nature is just fluff with no impact on the stats.

Alternately, build them as Small External Clamps (SS8:5). One module could represent several individual hardpoints, together carrying ordinance equivalent to 3% of the ship's mass. For example, a SM+6 fighter could carry three 32cm or fifteen 20cm missiles. This is probably light enough that you can round it off without affecting the ship's performance, though strictly speaking you should recalculate delta-V and acceleration for the increased mass. Note however that this can allow ships to carry more or larger missiles than a Weapon Battery, at a lower cost, so should include some counterbalance. Reduced Acc would make sense, since the system may lack appropriate targeting equipment.

[SCAR]

Originally Posted by vierasmarius

The simplest is to treat the hardpoints as simple missile launchers - in this case their external nature is just fluff with no impact on the stats.

This is by far the simplest, and avoids any need to recalculate Acceleration and deltaV.

You can also easily mix and match different weapon sizes (although not strictly RAW) the Small Systems Rules extend quite handily.

1 Major Weapon Mount = 3 Medium Mounts = 10 Secondary Mounts = 30 Tertiary Mounts; and since each 'Size' is just a step down on the Beam Output/Calibre table, it's easy to mix and match.

e.g. One SM+10 Weapon Battery; 1x 1GJ Particle Beam; 3x 16cm Missile Launchers; 10x VRF Improved 1MJ Lasers (for Point Defence);

[scc]

OK, so how many hard-points does a fighter get?

[SCAR]

Originally Posted by scc

OK, so how many hard-points does a fighter get?

Whatever you want really, or can fit. The fighters in Spaceships 4 have 2 or 3 Systems as Weapon Batteries, of varying sizes depending on design and purpose.

[Ulzgoroth]

There's no compelling reason for Spaceships missiles to need a launch tube. The missiles are fully self propelled and their 'aiming' is done by the missile's maneuvering, not by pointing the launcher. The launcher could provide telemetry features, but if it does they've got to be very small to fit into the available space in a 16mm mount.

Really I'd say externally clamping about as many missiles as you want to is reasonable, particularly if you have a tactical sensor array. If you've got too many it should probably make your ship count as unstreamlined for aerodynamic purposes, but so long as you're in space no problem except the extra mass.

There is a bit of a drawback though. Missiles are established to be easy to break (no minimum damage for PD) and to explode spectacularly when things go wrong (volatile systems, p62). Having a bunch of them strapped to your hull, outside your armor, means two things. First, they can probably be detonated by even a very weak laser hit. And second, we need to figure out what happens when a missile explodes on the exterior of the ship.

Since an exploding ship does 6dxHP to things docked with it, I'd probably do the same for a missile. How many HP in a missile? By mass I'd say about 2 dHP for a 16cm. And of course one missile going off will chain-fire any others that aren't somehow screened off from the explosion.

[Kale]

Originally Posted by vierasmarius

Alternately, build them as Small External Clamps (SS8:5). One module could represent several individual hardpoints, together carrying ordinance equivalent to 3% of the ship's mass. For example, a SM+6 fighter could carry three 32cm or fifteen 20cm missiles. This is probably light enough that you can round it off without affecting the ship's performance, though strictly speaking you should recalculate delta-V and acceleration for the increased mass. Note however that this can allow ships to carry more or larger missiles than a Weapon Battery, at a lower cost, so should include some counterbalance. Reduced Acc would make sense, since the system may lack appropriate targeting equipment.

I've used this concept for several designs and it works well. I house ruled it that the mass of missiles carried cannot exceed the mass of the small external clamp without causing problems under full acceleration: The attachment point needs to be sturdy enough to hang onto the missiles when maneuvering hard.

Originally Posted by Ulzgoroth

There is a bit of a drawback though. Missiles are established to be easy to break (no minimum damage for PD) and to explode spectacularly when things go wrong (volatile systems, p62). Having a bunch of them strapped to your hull, outside your armor, means two things. First, they can probably be detonated by even a very weak laser hit. And second, we need to figure out what happens when a missile explodes on the exterior of the ship.
Since an exploding ship does 6dxHP to things docked with it, I'd probably do the same for a missile. How many HP in a missile? By mass I'd say about 2 dHP for a 16cm. And of course one missile going off will chain-fire any others that aren't somehow screened off from the explosion.

Since missiles are usually kinetic kill, the energy in their propellant isn't great at exploding compared to an actual explosive warhead. I probably wouldn't use your exploding-ship-based damage rule, but I would rule that any hit to a section with externally clamped missiles wrecks all the missiles automatically, unless you could make the argument that a hit to the top of a fighter is unlikely to damage missiles on the underside, but that would be a GM's call or maybe a 50/50 random chance roll to see which way you were turned when the attack hit.

[Ulzgoroth]

Originally Posted by Kale

Since missiles are usually kinetic kill, the energy in their propellant isn't great at exploding compared to an actual explosive warhead. I probably wouldn't use your exploding-ship-based damage rule, but I would rule that any hit to a section with externally clamped missiles wrecks all the missiles automatically, unless you could make the argument that a hit to the top of a fighter is unlikely to damage missiles on the underside, but that would be a GM's call or maybe a 50/50 random chance roll to see which way you were turned when the attack hit.

Rocket propellant going up can be pretty catastrophic. And in Spaceships terms any system containing missiles counts as volatile and is likely to annihilate the entire vessel if destroyed (p62).

Explosive warheads would actually be much safer than rocket fuel. Modern military explosives are hard to set off except by use of the proper detonator and that's a quality people will still want in the future. (Of course, antimatter warheads are intrinsically not safe at all.)


I definitely wouldn't rule that any hit to a section with external missiles automatically wrecks the missles. A ship can carry missiles without being completely covered in them! Certainly a hit to the external clamp mounting the missiles should wreck those missiles and any others nearby, though.

[SCAR]

Originally Posted by Kale

I've used this concept for several designs and it works well. I house ruled it that the mass of missiles carried cannot exceed the mass of the small external clamp without causing problems under full acceleration: The attachment point needs to be sturdy enough to hang onto the missiles when maneuvering hard.

I really don't see the point of doing this - why not simply replace your Small External Clamp with a Small Weapons Battery - especially if you're limiting the Clamped Weapons to the mass of the Clamp anyway - just get rid of the clamp, put the weapons in the Spaceship as a standard Small System and be done with it - much simpler - and the unfired missiles are protected by the armour.
Yes you get slightly fewer missiles (by mass) when they are part of a Weapons Battery, but is that really such a big issue?

[vicky_molokh]

Originally Posted by Kale

I've used this concept for several designs and it works well. I house ruled it that the mass of missiles carried cannot exceed the mass of the small external clamp without causing problems under full acceleration: The attachment point needs to be sturdy enough to hang onto the missiles when maneuvering hard.

Under what acceleration? A SSTO HEDM-powered craft and a FPD-powered DSV have wildly differing top accelerations.