How Lasers work in Fire, Fusion, and Steel

[robject]

The formula I see for output energy is based on "Damage Value", which as far as I can tell corresponds to target armor values. Right?

So for instance, if you want to design a grav-focused laser that can hit unarmored starships, that's a DV 20 laser, where, disregarding range for the moment:

DV = 2.5 x sqrt( input energy / 5 )

If DV = 20, then:

20/2.5 = sqrt( input energy / 5 )

8 = ...

64 = input energy / 5

320 = input energy, in Megajoules.

FFS says a ROF of 10 is typical for starship lasers, so input energy is

3,200 Mj distributed over 30 minutes,

or 100Mj per minute,
or 1.78Mj per second.

What am I missing? Is this correct?

 

[Zparkz]

Unlike most other weapons in TNE lasers do penetrating damage. Damage values are usually listed as 1/x-y. Where x is an abritrary armor value and y is the damage value.

This reads as damage value is dropped by 1 for each x in armor of the target.

The best way to calculate this is to multiply the y with x, subtract armor of target, then divide the result with y.

For instance a laser doing 1/9-36 (The values are just taken out of the air in this example). The target got an armor value of 20.

9 times 36 is 324. 324 - 20 is 304, which agaun is divided by 9 is 33.777 or a total of 33 damage point that penetrate the armor.

In TNE everything got armor in one way or the other. Civilian starships got usually 10 to 30 armor points.

 

[deniable]

Assuming the 5 is the 20% (in)efficiency of grav focusing, all of your numbers look good.

You now have a 20 DV laser using 64 MJ output energy. Step 7c gives an IPR of 6.4 giving fractional penetration rating of 1/6. This means that you penetrate with a penetration value of 20*6 or 120 +2d6 giving 4 or 5 major hits against AV 20.

This weapon will penetrate the Patrol Cruiser or TNE Gazelle. It can even scratch an SDB.

It's been a while so I might have the PV = DV / PR around the wrong way, but I hope this helps.

 

[robject]

Thank you, that does help a lot.

 

[Anthony]

TNE had a general problem with lasers being able to shoot through mountains if properly designed (this may be a carryover from Striker). Your original description is approximately correct for FF&S2 lasers, however (though in FF&S2, you generally don't build grav focus lasers, you build X-ray lasers).

 

[TheDS]

You now have a 20 DV laser using 64 MJ output energy. Step 7c gives an IPR of 6.4 giving fractional penetration rating of 1/6. This means that you penetrate with a penetration value of 20*6 or 120 +2d6 giving 4 or 5 major hits against AV 20.

You're good right to the end. You wouldn't get 4 or 5 major hits, because you have to divide the remaining damage back down. Zparkz got it right.

The other way you could say it is that the target's ARMOR is divided by 6 - this'll keep the numbers smaller and easier to manage. So in the above example of a 1/6 - 20 weapon vs AV20, divide the AV20 by 6 to get 4 (3.333 rounded up). Subtract 4 from the DV20, leaving 16 damage points, which IIRC is a minor hit or two.

 

[deniable]

You're good right to the end. You wouldn't get 4 or 5 major hits, because you have to divide the remaining damage back down. Zparkz got it right.

The other way you could say it is that the target's ARMOR is divided by 6 - this'll keep the numbers smaller and easier to manage. So in the above example of a 1/6 - 20 weapon vs AV20, divide the AV20 by 6 to get 4 (3.333 rounded up). Subtract 4 from the DV20, leaving 16 damage points, which IIRC is a minor hit or two.

You're correct. I forgot that space combat is completely different from vehicle combat.
I was hazy on the damage done so I looked it up and found a table that had FPV [1] > 100 giving five major hits to starships. I had another look at the table and it clearly states DPV not FPV so it's my mistake.

[1]Final Penetration Value = Weapon Penetration - Armor Value