On Mon, 04 Aug 2003 02:36:31 GMT, Terry Spragg
wrote:

If I claim to be a little perlexed, at least you must respect my
honesty. In autorotation flight, part of the rotor disk must be
in - air aoa, yes or no?

G'day Terry,

I am going to read your post in full again offline, but let me answer
this bit quickly.

There is no need for any part of the aerofoil to be in -ve AoA. It is
not blown around like a toy fan. Have a look at this page
http://www.copters.com/aero/autorotation.html

See in figure 2-89 that because of the upward inflow the lift vector is
tilted forward? The portion of lift in the forward direction acts to
pull the blade forward (or around).

Hope this helps. I'll reread your post and send some more later, if
required.

Cheers,


Phil
--
Pfft...english! Who needs that? I'm never going to England.
Homer J. Simpson