Re: GEVs

On  3-Dec-99 at 12:00, Bell, Brian K (Brian_Bell@dscc.dla.mil) wrote:
> An interesting question.
> A GEV must displace an amount of air equal to or exceeding its mass in
> order to hover. 
> 

Not quite, it must put enough pressure in the plenum that there is
as much pressure on the ground as the mass of the GEV.

> Perhaps I misunderstood the question, but it seems like you are asking
what
> if you took a battleship that you know will float in Lake Erie and put
it
> in a pond. It would sink because there is not enough water to support
it.
> But then a battleship is not designed to work on both land and water
like a
> GEV. 

Let's get extreme so I can make my point.

I have an 80 ton block of iron sitting on a 1 cm x 1 cm skirt.	This
skirt
has air in it equal to 80 tons/cm^2.  I put it over the a 300 foot deep
lake.  It's pretty obvious it will bubble wonderfully as it sinks to the
bottom.  We have to pay attention to wether our tanks will do this also.
If the pressure required to lift them is greater than what the water
will
support they will sink.

If our Slammer Tank sinks in water that means it is going to sink in
swamp.	As a matter of fact, much as I would like it to be, I can't
see a situation where a GEV that sinks would be more useful than a
tracked tank.  I guess with proper equipment it could jump short
puddles, but it won't do an amphibious assault.  So, anyone have any
idea what the max is we could use on the cushion?  Sounds like 
a little empiricle testing with an air compressor, a tub of water and
some bricks is necessary.

Roger (who currently has no compressor)