RE: [GZG] Re: Jon's question on rotate/thrust/rotate

Taking a slightly different tack on the rotation/thrust question.

What are we actually asking - pretty much it boils down to how much
rotation can you impart in a ship in a certain amount of time.

Basically the question is how many degrees of rotation in a FT turn.  

So how do you produce rotation?

In a physical sense it would be force applied to an axis not along the
direction of travel, the most obvious method being maneuver thrusters
that operate perpendicular to the axis of travel.  Less efficient would
be re-directing thrust from the main engine to produce off-set thrust.
Other PSB would be large gyros, gravitic or warp generators etc.

So the next question becomes - where does thrust for rotation come from?

If the rotational thrust is generated by maneuver thrusters, then the
rating is simply the force generated by the thrusters vs. the mass they
are moving.

If rotational thrust is generated by the main engines, the vector of
force that is deflected off the main axis by the main engines and would
be dependent on how much and how far off the main axis of thrust you can
deflect. This has the problem that to rotate, in most designs you will
still have a degree of forward thrust while trying to turn. (Exception
would be designs where the main engines are on the ends of "wings")

Once you know the relative rotational force to mass ratio, then you will
know which ships will turn faster than others.

The next question - how to model this for FT?
There are several questions to answer - 
How is rotational thrust generated?
How much mass needs to be moved?
How much does it cost? 

One quirk with the current FT system is that rotation is discrete,
meaning that to turn two points, you start rotation, turn two points,
then stop rotation, when in reality, once you start rotation you can
continue to rotate without any additional cost, but to stop rotation you
need to apply thrust in the opposite direction. So effectively a two
point turn requires 4 points of rotational thrust - 2 to start and 2 to
stop.

Currently there is no separate ship system for rotational thrust.
Either a system needs to be added, or rotational thrust needs to be
abstracted in such a way that tactical differences can be generated.

Proposal 1 - Abstracting rotational Thrust
This is basically a continuation of the traditional FT model that simply
abstracts rotational thrust as a sub-set of main engine thrust, and that
some combination of side thrusters and deflection of main thrusters is
used to produce the rotation effect for the game.  This has the
advantage of simplicity, and the disadvantage of lack of detail.  It
would be like lumping all the weapons into a single category and basing
the anti-fighter rolls as a sub-set of your overall weapon strength.  By
abstracting thrust to such a level, you really can't get much
differentiation in rotational effect and the proposals that were
mentioned in previous posts will be suitable solutions.

Proposal 2 - Split Rotational thrust and Main thrust
This basically breaks apart the two concepts and would add a new ship
system - Rotational Thrusters or Maneuver Thrusters.  They would be
priced, massed and added as a separate system. (Perhaps using the
current Engine rules).	

Proposal A - Continuous rotation
This basically is a variation of the vector movement idea in that
momentum is carried from turn to turn and once a ship starts rotating,
it continues to rotate at the same rate until thrust is applied. For
example, if a ship applies 2 points of rotational thrust (RT) to
starboard on turn 1, it turns two points at the end of turn 1.	If it
applies no additional RT, it turns two points at the end of turn 2.  If
it wanted, on turn 3 it could apply 2 more points of RT to starboard and
accelerate to 4 turning points/turn and would turn 4 points at the end
of turn 3.  Ships could split their thrust so a ship with 4 points of RT
could apply 2 points starboard, turn two points and apply 2 points RT
port to stop rotating.	This system would require an additional spot on
the record sheet to record rotational direction and speed.

Proposal 2 allows for a lot more differentiation of ship designs since
you can then vary rotational thrust from main thrust, and for different
races or technologies give them different costs and masses.

--Binhan



_______________________________________________
Gzg-l mailing list
Gzg-l@lists.csua.berkeley.edu
http://lists.csua.berkeley.edu/mailman/listinfo/gzg-l