In article ,
Beryl wrote:

Alan Baker wrote:
In article ,
Beryl wrote:

Alan Baker wrote:
In article ,
Jim Logajan wrote:

Alan Baker wrote:
If there is no downwash, it will not fly. No.
You are arguing a point not under contention (at least with respect to
heavier-than-air aircraft.)

See everyone: this is why understanding of the actual facts is
required.
The ground isn't required. Air has inertia, and it's just as much a part
of the earth as dirt and rocks are. So why are you fixated on the
earth's solid surface? It compresses too, you know. You could argue that
the downforce travels through the whole planet and back into the
atmosphere in China.

You simply haven't really read anyone else's posts to understand what
they
are stating.
The previous poster just said:

"Let's talk about helicopters. We can replace that rotor with a squirrel
cage fan. Air is drawn down into the fan as before, and most of the
pressure differential is due to lowering pressure above the fan. As
before... except that now the air is exhausted out the periphery of the
centrifugal-flow squirrel cage fan, not down as it was with the old
axial-flow rotor. Will it fly? Where's the downwash?"

She ("Beryl"?)
A mineral

is clearly implying that such an hypothetical craft could remain airborne
without downwash.
No, I only asked.

How else can it be read?
Read it as a question.

So what is your answer? Can the postulated craft fly if there is no
downdraft?

The inflow strikes the underside of the conventional rotor disk, but
strikes the topside of the centrifugal fan disk. That's all!

I'm betting you'll find a way to avoid answering...

I did.


No surprise there.

So where are we? Your downward accelerated air might continue traveling
until it's stopped by the earth's surface, which is the only thing that
can stop it. But it isn't simply thrown down. Much of the finite energy
put into to the air is "wasted" in spinning it. Kinetic energy becomes heat.

And now you're just ducking.

--
Alan Baker
Vancouver, British Columbia
http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg