Hello There,
Well, all this talk about permanent armour has gotten me thinking...
All this is a bit rule-of-thumb, so take with pinch of NaCl :-)
most of the quoted MASS values seem a little low (IMHO) like 1-3% per
level of armour, compared with screens, that take up 5% per level, and protect
against less.
So, ok, first we define how armour works, keeping it simple, lets use the
screen mechanic:
So, armour works vs beams, stingers, pulsars, and plasma bolts as the
equivalent level in screens.
If protects against Pulse Torpedoes, Missiles, Lance Pods and Torpedo
fighter attacks in the same way that screens protect against plasma -
Level 1 Armour negates damage rolls of 6, Level 2 negates damage rolls of 5 &
6 (see FB2 p36).
Note that only the _damage_ roll for pulse torps is affected.
Submunitions Packs and Scatterguns are affected in the same way as beam
battery attacks. All fighter attacks, including KV fighters (except Torpedo
fighters) are also affected in the same way as beams.
Kinetic Guns are affected as follows: Firstly, any rolls of 6 (if against
Level 1 Armour) or 5 and 6 (if against Level 2 Armour) on the
damage doubling dice roll is negated. Secondly, the K-Gun rolls to
double damage as if it were one class less.
Thus a K-3 normally does 6 damage on a roll of 1-3, and 3 damage on a
roll of 4-6. Against Level 1 Armour it would do 6 damage on a roll of
1-2, 3 damage on a roll of 3-5, and no damage on a roll of 6.
Multiple Kinetic Penetrator packs simply have the damage per hit reduced by
the Armour Level. The 'beam' dice rolled to see how many hit is unaffected.
Leech Pods do only 1 damage point on the first turn vs. Level 1 armour, and 1
damage point on the first 2 turns vs. Level 2 armour, they then do 2 points
per turn as normal.
Needle Beams are unaffected by armour - they fire through the chinks.
PDS in anti-ship mode is unaffected - the damage is too piddling anyway!
The armour system is represented by symbols on the SSD, 1 per level, my
recommendation is a simple 'heraldic shield' symbol. Armour takes
threshold checks as for any other system (PSB - failing a threshold
means
that significant armour has been blown away) - I am open to suggestions
as to if it can be repaired...
Cost, well, beam-class weapons are common, but there are quite a few
weapon out there that are not affected by screens, at a wild guess, I'd say
that there are 3 times as many weapons that would be blocked by armour as
there would be blocked by screens.
So, with this in mind, Level 1 armour uses 20% of the ships total MASS, Level
2 uses 40%, the COST is 2x the MASS used (like ablative armour).
Ok, this is a bit steep (but then this stuff will potentially block a small
nuke!), how to make it cheaper?
1) Say it cannot be repaired - should be worth, oh, say a 5% reduction
(to 15% per level).
2) Put the symbols adjacent to the 1st (and 2nd if Level 2) damage
tracks - like power generator systems for SV - when 1st threshold is
reached, loose 1 level of armour, when 2nd threshold is reached, lose
2nd level. Again, cannot be repaired - I think this could cut the cost
to 5% or 10% per level.
3) Reduce what it protects against - an idea I like is to say that it
doesn't work against beams, stingers, and pulsars (for whatever reason
you want - say radiation effects), so it becomes complementary with
screens.
4) Increase the COST/MASS ratio.
If you want armour on specific arcs (and I don't), try this: Armour on 1 arc
uses half the mass value given above.
Armour for each additional arc adds 1/4 times the cost of 1 arc.
If you want different levels on different arcs, buy the level 2 arcs first,
then buy the Level 1 arcs at the cost of additional arcs of level 1. (use
whatever PSB for the mass differential you like)
As a thought, dis-allow any armour on the aft arc (again, insert PSB you
like).
Sorry it a bit long winded, Oerjan, over to you :-)
From: Charles Stanley Taylor <charles.taylor@cableol.co.uk>
> most of the quoted MASS values seem a little low (IMHO) like 1-3% per
armor has all been Per Facing, IIRC
> So, with this in mind, Level 1 armour uses 20% of the ships total
I agree it should be relatively massive--IMHO we'd want to set it up to
be possibly cost effective for large ships, but definitely not for small
ships.
> 3) Reduce what it protects against - an idea I like is to say that it
Interesting.
In message <000d01c0394e$dc13eea0$1e0aa8c0@hqmknt04enu>
> "Chris DeBoe" <LASERLIGHT@QUIXNET.NET> wrote:
> From: Charles Stanley Taylor <charles.taylor@cableol.co.uk>
Hmm... could use the same trick they use for screens - set a minimum
MASS - much harder to justify though!
> >
> Charles Stanley Taylor wrote:
> I agree it should be relatively massive--IMHO we'd want to set it up
Not very. Assuming a roughly similar shape for all ships regardless of size,
the Mass of the armour will realistically be proportional to
(ship's volume)^(2/3). Plot that function out vs the ship's volume, and
then figure out how to best approximate that with a straight line... and check
where that straight line intersects the armour mass axis. It
won't be in origo unless your approximation is way off :-)
Replacing the volume with TMF isn't entirely accurate since not all components
have the same density, but it's the best we can do without
introducing a new variable in the design system :-/
> At 2000-10-21 +0100 10:45, you wrote:
Oerjan,
Where did you get the (ship's volume)^(2/3) figure?
I assume that it is a surface area to volume figure, but for what shape? A
sphere has the least surface area per volume of any shape. It appears as if
you were using a cube as a modle for your volume to surface area formula (a
cube with edges of length 10 would make a cube with 1000 cubic units and a
surface area of 600 square units. This gives a
ratio of 1-2/3 volume to area). A simple cube is still
too simple for any of the ship designs in FTFB. I would suggest that the
surface area of the average
ship if FTFB has 2-3 times the surface area of a
cube made with the same volume. So a formula of
(ship volume)^(4/3) or (ship volume)^2 would be more
accurate.
---
> Brian Bell wrote:
> Hmm... could use the same trick they use for screens - set a
You seem to have interpreted my post as saying that the surface area is
EQUIVALENT to volume^(2/3). If you read a little more carefully you'll
find that I said that it is PROPORTIONAL to volume^(2/3). The
difference is that when things are only proportional to a function instead of
equivalent, there's an undetermined but constant factor in front of the
function; when you have equivalence that constant factor has also been
determined.
Assumption: "roughly similar shape for all ship classes" = the ratios between
the ship's length, width and height remain more or less the same for all ship
classes.
This means that you can use any of the three (W, D or L) as a generic
"size measurement" - it doesn't matter much which you use, since
converting from one to the other simply involves multiplying with a fixed
factor. Below I use L as the "size measurement".
With the assumption above, the ship's volume scales as L^3 - or,
conversely, L scales as volume(1/3).
It's surface area scales as L^2, but L was proportional to volume^(1/3)
which means that the surface area is proportional to volume^(2/3).
The Mass of the armour is directly proportional to the area it covers, so for
any given thickness of armour the Mass of the armour is also
proportional to volume^(2/3), which is what I wrote above.
> A sphere has the least surface area per volume of any shape.
The relation between the sphere's surface area A and volume V is
A = 4*Pi*(3/4Pi)^(2/3) * V^(2/3) (roughly 4.84 * V^(2/3) ), ie. A is
*proportional* to V^(2/3). It isn't *equivalent* to V^(2/3).
For a cube, the relation is A = 6 * V^(2/3), ie A is *proportional* but
not *equivalent* to V^(2/3).
For a box with L = 2X, W = H = X the relation is
A = 10 * (1/2)^(2/3) * V^(2/3) (roughly 6.3 * V^2/3), ie. again A is
*proportional* but not *equivalent* to V^(2/3).
For a needle with L = 100X, W = H = X the relation is
A = 402 * (1/100)^(2/3) * V^(2/3) (~18.7 * V^(2/3) ). *Still*
proportional but not equivalent to V^(2/3), provided you keep the same
L:W:H ratios for all values of the "generic size measurement" X.
No matter what basic shape you use, if you just scale the size up and down
while keeping the general shape intact you will *always* get an
area:volume relationship of A = [constant] * V^(2/3). The actual
constant will depend on the specific shape (ie., the L:W:H ratios), but it
doesn't depend on the *size* of the body.
The value of your constant should be determined WRT game balance and not WRT
the actual shape of the ships. Remember that since you're interested in the
armour *mass*, not its *area*, the constant also includes a rather arbitrary
armour density and thickness.
> I would suggest that the surface area of the average ship if FTFB has
Brian, I don't know how much maths you've read and I do hope that this is
redundant info for you, but squaring a number is only the same as multiplying
it by 2 or 3 is a couple of very specific cases (2 and 3
respectively, to be exact) - the further away you get from those
numbers, the more wildly inaccurate the formula becomes.
So, if you say that 2 times the surface area of a cube gives the
formula area = volume^(4/3), you're effectively stating the exact
volume of the ship. That formula is correct for exactly 1 Mass rating for each
basic hull shape (OK, mathematically there are 2, but the
other mass rating is less than 0 :-/ ).
Regards,