grav everywhere

I've been following the thread on grav vehicles with some interest (DSII
being my game of choice in GZG-land).

My overly literal mind keeps coming back to the same thing.  "If it
works
like that, yes; otherwise....."

What it all boils down to is "How do grav drives work?"  In the one
sci-fi
universe that I'm familiar with where this is addressed (Renegade
Legion)
Grav drives are not "anti-gravity" per se.  The grav drives warp the
planetary gravity  "field" around the tank so that the tank effectively
"falls" in the direction of travel.  IIRC the crew has artificial
gravity
inside so that they don't notice the difference.  The tank grav drives
require more power the weaker the gravity field they're warping, so that
the farther away from the surface the more power it takes to move.  This
effectively limits them to modern helicopter performance envelopes (at
least for altitude).  The game also had other mechanisms to keep your
tank
on the ground (the weak bottom armor and no ballistic protection on the
record sheet).

This is obviously just one set of PSB that is made to justify the way
that
game works.  Anyone can make up a PSB to make things work like they
want.

The more I think about levitation type propulsion systems the less
suitable
I find them (from a technical standpoint) for combat missions.	With
anything that hovers over the ground you're going to be subject to
"unintended movement".	This could be as simple as wind, or as complex
as
collisions or projectile impacts.  You also have terrain limitations (ie
GEV's aren't good at hill climbing).  With tracks or wheels "station
keeping" is as simple as stopping where you want.  Obviously for grav
this
depends on how your grav drive works.  If it works like the ones in RL
then
it's simply a matter of having the computer adjust the warping so that
the
tank stays where you put it and compensate for impacts.  If it's true
anti-gravity (as in the tank is not affected by gravity) then you have
the
the biggest air-hocky puck ever made.  Mag-lev without the rails.

Gravity being the least understood of the cosmic forces the
possibilities
are truly mind boggling.  One sci-fi story written about someone who
creates anti-gravity  postulates that in an area where gravity was not
in
effect then neither would Eistein's relativity be in effect and
therefore
objects could attain a velocity of C instantly.  It would effectively
mean
that true anti-gravity would give limitless energy.

This is all JMO, and I'm sure that given sufficient incentive some
brainiac
will come up with a way to make a floating vehicle stay where it's put,
but
there are much easier and more reliable alternatives.