Re: GEVs/Grav/Arty

Thomas Barclay wrote:

> ** D'oh! My bad. Sorry. But my point about any heavy vehicle eating
> lots of diesel still applies.

Sure. I made the same point in the original post <shrug>

> It'd definitely have severe problems with dust/spray
> clouds and noise, too.
> 
> ** Depending on skirt design, dust spray could be minimized. Noise
> might also be minimized - I've encountered quiet high volume fans.
> Nothing like a GEV would use, but who knows? I'm not vizier enough to
> suggest the technology couldn't be adapted.

The highest-pressure hovercraft I found - the US MCAC/LCAC - was also
the most modern, and the noisiest and most dust-throwing.

The problem isn't with the skirt design. It's with the basic gas
dynamics - no matter how your skirts are designed they won't have an
airtight seal against the ground (not if you want to move at any kind
of speed, anyway!), so you'll get air leaking out from the cushion.
These gas jets cause most or all of the dust whirl-up... and the higher
the cushion pressure is the faster these jets will be, and the worse
the dust or spray whirl-up will be. 

> The most serious problem isn't the energy supply, though -
> it is finding space for the lifting and maneuvering fans and air
> intakes, preferrably somewhere where they won't be wrecked by the
> first burst of small-arms fire directed at the vehicle <g>
> 
> ** Admittedly. But we might use some form of air-ram and vectored
> thrust. 

Sure; that was what I was thinking of. Still difficult to find good
places to put them, and tricky to design them so they won't be damaged
by small arms fire.

> We might develop a lot more fan efficiency. 

Quite likely. Won't help much for the vulnerability problems, though.

> We might heat the exhaust gas to give us more lift.

Gives you very little extra lift unless you get scaldingly hot gasses
(the cushion volume is way too small for any measurable hot-air balloon
effect), but even a small increase in gas temperature would cause you
massive IR signature problems.

> > 4) GEVs can move through swamps and if packing non-recoil 
> > weapons could even fight there. I agree CPR arty would be 
> > problematic.
> 
> There are no non-recoil weapons.
> 
> ** Laser? Gyrojet? Harsh words?

Lasers, true <g> Well, not exactly true, but at least an extremely low
recoil.

Gyrojets have recoil from gas friction against the launch tubes, just
like all other rocket-ish weapons; not nearly as much as guns of
course, but still quite measurable (and on a hover vehicle with no
ground friction, it'd impart a certain amount of velocity too). 

Harsh words tend to be rather inefficient as combat weapons - "Sticks
and stones...", etc <g>

>  and I'd want
> to be *very* certain of my platform's stability (and ability not to
> drift into various nearby objects) before I fired any large weapons
> from it while hovering over a swamp :-/
> 
> ** Assuming your computer couldn't compensate with vectored thrust.

Could be done, yes.

I've been a resident of the world of too many things to do for the past
fifteen years. You merely added another load onto the too-big burden
<g>

Regards,

Oerjan Ohlson
oerjan.ohlson@telia.com

"Life is like a sewer.
  What you get out of it, depends on what you put into it."
- Hen3ry