RE: GEVs/Grav

Its not just the speed of the GEV/Grav tank. Unless you are aiming the
weapon EXACTLY perpendicular to the ground, there is also an angular
(downward) force on the vehicle. Take your example (and assuming your
math
is correct (as my mind is too fried to do the math right now).
  If the vehicle is not grounded, your GEV/Grav tank has 10,000kg of
force
that is torquing the vehicle (trying to make it rotate on axis), unless
its
gun is aimed through the center of gravity (doubtful unless it is a
fixed
weapon). Today's wheeled-tanks have a heavy suspension to counter act
this.
A GEV/Grav unit would have more problems, since the additional pressure
would be spread over a larger area (kinetic transfer by touch vs kinetic
transfer by pneumatic or gravitic means).
  If the vehicle grounds to fire, this negates much of the advantage of
GEV/Grav units (i.e. the ability to operate in mud, snow, water, and
other
soft terrain without getting stuck; and speed).
  While this cannot be overcome, it indicates the added complexity of
GEV/Grav units. Also, you would not want to be infantry behind one when
it
fires.

That having been said, I like GEV/Grav units. Given the cheap energy
that
seems apparent in the GZG universe, they make sense for certain
missions.
  For soft terrain such as snow, mud, marsh, coastal areas, cultivated
land
(not orchards), soft sand, etc. GEV/Grav make sense. Tread and wheeled
vehicles can get stuck easier. GEV/Grav would be especially useful in
amphibious assaults.
  For mountains and light woods (fruit orchards, edges of forests) tread
makes the most sense. It has the mass and power to push through light
trees
and up broken slopes. GEV's have trouble of air leakage around the skirt
if
the angle is too steep. GEV/Grav units would have trouble generating
enough
force to push through wooded areas. Also, tread has the advantage of
being
the cheapest ways to carry heavy loads (tread spreads the ground
pressure
over a larger area than wheeled and is much less expensive then
GEV/Grav).
  For urban wheeled makes the most sense. They are easier on the 
highways,
usually lighter than treaded units (so bridges and sinkholes are less of
a
problem), and often quicker on pavement than treaded units. Wheeled
units
are also the least expensive option.
  For hard flat ground, all units work fine.
  Grav units would seem to be a jack-of-all-trades. They can work in
most
terrains (even vacuum), they can do a pop-up attack (SG2), and they are
fast
(DS2). But the big disadvantage would be cost. Using the DS2
construction
rules Grav units cost BIG! I would also think that they would be
hard/expensive to maintain. If away from the supply depot and something
breaks, it would be hard to jury-rig a solution. Also, it may require a
full
maintaince bay to fix grav vehicles, where as other units may be able to
be
fixed in the field.

Just some thoughts.
-----
Brian Bell
bkb@beol.net
http://members.xoom.com/rlyehable/ds2/	     
-----

> -----Original Message-----
> From: Matthew Seidl [SMTP:seidl@vex.cs.colorado.edu]
> Sent: Tuesday, 1999.11.30 14:18
> To:	gzg-l@CSUA.Berkeley.EDU
> Subject:	Re: GEVs/Grav 
> 
[snip]

> Take a 1kg projectile, moving at 10000 km/hr (~9x the speed of sound).
> That would push the 80,000 kg tank backwards at 0.125 km/hr.	If the
> round was 10kg, and we fired 10 of them a minute, it would still only
> be 12.5 km/hr.  If the tanks internal engines can't counteract that
> much acceleration, they have a problem.
>