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.

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"?) is clearly implying that such an hypothetical craft could
remain airborne without downwash.

How else can it be read?

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