GEVs/Grav

Allan wrote:

Chemical propellent is still pretty efficient. You launch a load into
the air
and let gravity drop it where you want it. I think you'll always be
able to
launch heavier warheads using chemical (or mass driver) propellent. In
fact,
mass driver artillery may be a better bet for grav vehicles,
particularly if
they are already using fusion power for the anti-grav units. Recoil
won't be a
problem.

** Pardon? Unless you eject a counterbalancing projectile, you'll
still have recoil. The only time that might change (and this changes
ALL the rules) is if tech is advanced far enough to make intertial
compensators for guns AND power cheap enough in mass and cost to make
this practical. Otherwise, and MDC gets no better than a CPR gun
(well, not much anyway) as a launcher. Newton still applies.

>3) Can we build a hovercraft that ways 80 tons, carries the kind of
>armour a Leopard II or Challenger or late model Abrams does, mounts a
>120-140mm CPR gun or another big main weapon? I have my doubts.

You also have to ask yourself "why".

** I could. This was just my skepticism about Oerjan's thought that
this could be done.

 What do you gain out of ground effect
tank. Ground effect tanks are actually not THAT useful, David Drake
not
withstanding. There is a very real limit to the slope a GEV could
scale,
regardless of the slope's potential traction. You raise the skirt too
much and
you lose lift. For that matter, you can't easily tilt the vehicle. I
think you
could probably kill a GEV with deep, wide trenches. True, that kills
tracked
AFVs too, but I'd imagine that narrower trenches would have a nasty
effect on
GEVs but allow tracked vehicles to pass. Likewise, anti-tank "dragon's
teeth"
wouldn't need to be as big. This is just off the top of my head, too.
I sure
wouldn't want to be infantry riding beside a GEV. You couldn't be that
close
(due to the ground effect) and imagine standing beside one when it
gets hit in
the side with an anti-tank weapon. Ever play table air hockey? Imagine
you're
an ant and the GEV is a puck! Nasty!

I think that tracked movement would still be more efficient. You don't
have to
lift and propel the tank, just propel it forward. I think a tracked
vehicle
would be able to move faster than a GEV given the same power plant. Of
course,
ground pressure would be more of a problem in a tank, as the weight is
spread
over a smaller area.

** Counter:
1) GEVs could have limited hop capability to pass over trenches and
some obstacles. They are less likely to set off mines (more
distributed weight, higher off the ground).

2) Speed - even with a set amount of max power for the vehicle, and a
GEV wasting a bunch for lift, it'd still potentially go faster for
several reasons. Low friction makes for efficient energy usage for
travel. So the power you do put in gives a much better return. Also,
with a tracked vehicle, you'll hit a limit of speed due to churning up
the ground. The speed limit for GEV, assuming the power is available,
is higher and a product of aerodynamics. With enough power, you can
probably scale almost the same range of terrain a track layer can. AND
cover lots of terrain it can't - rivers, lakes, areas of loose sand or
dirt or mud, landing zones, streams, defiles, trenches (with a hop, or
with some built up velocity), swamps. Many places conventional
tracklayers get stuck, it'd fly. It's fans are inside armour. Not so
some of the spindles and cogs on track layer systems.

3) GEV may well allow heavier armament. Why? Assume power is cheap and
plentiful (fusion/A-matter) - and fans can produce mucho lift by
advanced design - the limiter of tank weight then may become ground
pressure. You hit a point beyond which a tank will sink into the
earth. Because GEVs spread this weight, they can operate with a
greater total mass than a tracklayer unless the entire tank underbelly
is one big track - which probabaly has bad problem associated with it
in terms of complexity and manouvreability.

In the abscense of fusion power, the situation is different. And
unless the GEVs have fins and ducts, tracklayers will corner harder
and faster. But the GEVs should have the advantage in the long run
sheerly because a GEV tank can then double as a PBR and can operate in
more terrain types. They may never replace tracklayers, but then
again... they just might. You'd be foolish as a nation not to at least
have them in your force to use as raiders and assault units.

>4) GEVs can move through swamps and if packing non-recoil weapons
>could even fight there. I agree CPR arty would be problematic.

That's about the only type of terrain where it has an advantage. Okay,
mud and
snow would be advantageous.

** Mud. Mud = most places in spring or fall. Snow = most places in
winter. Both places track layers do badly.

But you still have that whole "slopes cause
spilling of air out of the curtain" problem.

** Sure. Powerful fans could push you up a slope even if you are
heavy. This whole argument of mine hinges on the presence of cheap
efficient fusion. But the GZGverse already presupposes that. So I'm
not just inventing the idea.

Thomas Barclay