Re: [DSII] Sinking hover tanks

Roger Books wrote:

> >Some time ago we had a discussion about heavy hover tanks over water.
The
> >conclusion was that if the tank massed enough that the pressure/area 
> (PSI in US terms) >was too great the tank would sink while furiously 
> blowing bubbles from under its' skirt. >Basicly a Hammer's Slammer 
> hover-tank would probably sink.

Not just "probably"...

> >The thing we didn't discuss was how movement would affect this. If
the tank
> >were moving at 100KPH would this affectively give it a greater area 
> under the skirts?

Don't think so, no. If it is really lucky it might plane on the water 
surface much like a fast-moving snow-mobile can do - but that requires
that 
it comes into actual physical contact with the water (as opposed to
being 
separated from the water by its air cushion), so it'd run a major risk
of 
damaging at least the rear wall of its plenum chamber.

Roger B-W wrote:

>Depends on the design, but generally the skirts are designed to keep
>outside air away from the cushion as much as possible. I very much
doubt
>that compression under the leading edge will be significant compared
>with compression from the main lift fan.
>
>On the other hand, a vehicle could be _designed_ for this mode of
>motion; googling for "ekranoplan" will show a lot of vehicles that were
>quite specifically intended to operate over water.

But such a vehicle would not be a hovercraft. Ekranoplans - aka WIGEs or

GEVs (the proper use of the term "GEV", as opposed to the incorrect SF
use 
of the term to mean "hovercraft") - have no plenum chamber; they are 
essentially aircraft with wings too stubby to allow them to fly very
high, 
instead relying on the lift-increasing Wing-In-Ground-Effect (or just 
"Ground Effect" for short) to keep them flying.

Regards,

Oerjan
oerjan.ariander@telia.com

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