"Neil" <paradoxer@lykose.com> wrote in message
news:10a2u0m3624pk93@corp.supernews.com...

"Gremlin" <Gr3mlin@hotmail.com> wrote in message
news:3c7ddd63.0405022134.1d5aa607@posting.google.com...

A gravity powered aircraft is being developed by former govornment and
millitary scientists.  It works in similar to a helium balloon, except
it is also able to contain large spaces of vacuum which is much
lighter than helium.  The ultralight aircraft becomes lighter than air
and rises high enough that it can then release some of its stored
vacuum and begin gliding back down to earth like a conventional
ultralight.  Once this technology is developed, which may not happen
in our life time, I am sure it will become more advanced and
vacuum-engineering will be able to take us to space.  You can move
through space in theory the same way because there are a small number
of particles still in the void, you just need to create better quality
vacuums.  This technology works similar to a submarine which changes

...

No, it isn't practical to use vacuum for lift, because of the need to

offset the

surrounding air pressure. The whole point of helium etc. is that it is

very

light (over 80% of the weight loss that would come from a total vacuum),

but it

does exert the compensating pressure from within that can allow the

enclosing

walls to be very thin. That's the only way for the lift to be enough to

work -

not much weight.

   Gary Shannon, 5/12 had a VERY interesting idea about a vacuum powered
sphere in the post "Nothing in Sphere but Sphere itself," posted by Carl G.,
5/2/04, at Rec. Puzzles.