T:TNE Space Combat Fix and more on missiles

Bertil Jonell [email removed] writes:
> The kinetic energy varies between 2.8e10 J and 2.5e13J which is the same
> as 0.006 to 6 kilotons. Redone into kg of TNT and via the demolition rules
> into penetration means 705 to 21,000 or 30 to 900 major hits worth. This is

 ... way too much.  Probably the kinetic energy of impact doesn't convert
readily into explosion damage, and so the demolition rules are producing
funny numbers.

>   Do we want this? And if we don't, how do we explain it away?

I don't think we want this, and it seems that you've managed to explain
it away pretty effectively below ...

> this is a best
> case penetration caculation) the maximum penetration is 318mm aka Pen 63.
> It won't penetrate an SDB!! (sorry, PDB:)

That's much better!  Lethal to unarmored ships, but a warship with
enough armor doesn't have to worry as much (and as you point out, it
leaves a place for the HEAP missile).

HEAP missiles can reasonably be restricted-purchase items (since the
only thing they are really good for is shooting at military-type ships).

> I think the question is if we want the missile boat to rule or
> not. If we do we mention the KEAPDU missile, otherwise we ignore it.

My feeling is that we keep very hush-hush about the KEAPDU missile;
after all, it may not even be practical (how much does that slug of
depleted uranium weigh, after all).

>   Evasion will make it smaller (to 12% or smaller, assuming skill 5 and stat 5
> of the firing character). And it is possible that having a MFD might increase
> it to up to 95%.

95% seems a little too high ... maybe we should work out some way that a
MFD has less (or no) effect on these new missiles.  Or maybe increase
the difficulty of impact and close-proximity so thatyou *have* to have a
MFD to have any reasonable chance of hitting with them.  What do you
think?

>   Why missiles? It would be cheaper to use the 'LGB preudomissile' model
> and fill the empty shell with guided bombs of different kinds. 7000kg of
> TL-13 'Rockeyes' will impress almost anyone.

Good point.  That's enough to ruin almost any TED's day.

> > Other possibilities: a cheap, light-weight missile with (say) about 7
> > G-turns of fuel and warhead, shorter endurance, etc.
>
>   Remember that a 6G ships has a 12 Gturns per turn capability. To reach it
> you need a missile that has more.

Ummm, I don't see that bit anywhere; but I do see on pp.313 "Each ship
may spend a number of G-turns limited by its G rating (maneuver
performance)" --- so I concluded that a 6 G ship has 6 Gturns of combat
maneuver capability.  Each Gturn of combat maneuver burns a half of a
G-Hour of maneuver fuel (because each turn is a half an hour).

I also see a potential problem with the space combat rules.  On pp.313
it says "each 2 Gturns of accelleration spent by a ship changes the
closing velocity for the current turn by one".  However, by referring to
good old Sir Isaac:

Accelleration = Constant             A = 10 m/s^2
Velocity = Acelleration * Time       V = 10 m/s^2 * 30 m
                                       = 10 m/2^2 * 1800 s = 18000 m/s
                                                           = 64800 km/hr
Distance = 0.5 * Accell * Time ^ 2   D = 0.5 * 10 m/s^2 * 1800^2 s^2
                                       = 5 m/2^2 * 3240000 s^2
                                       = 16200000 m = 16200 km

Putting this into T:TNE terms, a velocity of 1 is one range band per
combat turn (or 30000km per 30 mins; 60000 km/hr).  A distance of 1 is
one range band (or 30000km), and the unit of time is the turn (30
minutes; 1800 s).

SO, each Gturn of accelleration increases the ship's velocity *for next
turn* by slightly over 1 band/turn.  The distance travelled in the
*current turn* during this accelleration is slightly more than a half a
range band per Gturn of accelleration expended.


FIX: alter the "Speed Change" and "Compute New Range" paragraphs on
pp.313-314 to read as follows:
	SPEED CHANGE: Each ship may spend a number of Gturns limited by
its G rating (maneuver performance) in order to modify the closing
velocity.  Each Gturn of accelleration spent by a ship changes the closing
velocity *for the next turn* by one.  In addition, each 2 Gturns of
accelleration spent changes the closing velocity *for the current turn*
by one (drop fractions).  The closing velocity may be increased or
decreased.  As Gturns of accelleration are spent, players must
declare whether they are going to increase or decrease the closing
velocity.
	COMPUTE NEW RANGE: At the end of each turn, subtract the current
closing velocity (the velocity *for this turn* as computed above) from
the current range to get the new range for the next turn.  When the
closing velocity is a negative number, remember that subtracting a
negative number is the same as adding a positive number, thus actually
increasing the range.

ALTERNATE FIX: the above, while accurate, may seem too complicated for
some players.  Thus, the suggested simplified fix: alter the "Speed
Change" and "Compute New Range" paragraphs on pp.313-314 to read:
	SPEED CHANGE: Each ship may spend a number of Gturns limited by
its G rating (maneuver performance) in order th modify the closing
velocity.  Each Gturn of accelleration spent by a ship changes the
closing velocity *for the next turn* by one.  The closing velocity may
be increased or decreased.  As Gturns of accelleration are spent,
players must declare whether they are going to increase or decrease the
closing velocity.
	COMPUTE NEW RANGE: At the end of each turn, subtract the current
closing velocity (before the speed changes above) from the current range
to get the new range for the next turn.  When the closing velocity is a
negative number, remember that subtracting anegative number is the same
as adding a positive number, thus actually increasing the range.


EXAMPLES: To help clarify what's going on, the following examples
presime that a standard Scout/Courier (maneuver performance 2 G) is
closing in at velocity 4 on a patrol ship which is station-keeping 8
range bands away.  The scoutship wants to break to a stop as quickly as
possible.

NEWTON: A = 20 m/s^2.  240000 km/hr = 66667 m/s = 20 m/s^2 * T s.  Time
to decellerate to a stop is T = 3333 s = 55.6 min, or about 2 turns.
Distance travelled while stopping is D = 0.5 * A * T^2 = 111111 km, or
about 3.7 range bands.  The ship is stopped at the end of the second
turn, slightly more than 4 range bands from the patrol ship.

ORIGINAL: In the first turn, the scout/courier expends 2Gturns of
accelleration (at a cost of 1 Ghour of fuel).  Velocity changes by 1;
the new velocity is 3, and the new range is 5.  In the second turn, the
scout continues brakeing; new velocity 2, new range 3.  Turn 3: velocity
1, range 2.  Turn 4: the scout comes to a stop at a range of 2.

FIX: In the first turn, the scout expends 2 Gturns of accelleration (at
a cost of 1 Ghour of fuel).  Current velocity is decreases by 1 (to 3);
and the next turn's velocity decreases by 2 (to 2).  The new range is 5.
In the second turn, current velocity becomes 1, and the new velocity
decreases to 0 (the ship will stop at the end of the turn).  The new
range is 4.

ALTERNATE FIX: In the first turn, the scout expends 2 Gturns of
accelleration (at a cost of 1 Ghour of fuel).  Current velocity is
unchanged (still 4), and the next turn's velocity decreases by 2 (to 2).
The new range is 6.  In the second turn, the current velocity is 2, the
new velocity is 0, and the range is 4.


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