If the wind-mill fan is correctly engineered to be wind-driven it is unlikly
good as propeller.
A propeller have the convex side in the direction of flight, and the round
leading edge in direction of rotation, and the pitch ....

Jan Carlsson
www.jcpropellerdesign.com

"sebastian" skrev i meddelandet
om...
Hi I'm working on an aviation project...a motorized paraglider fan
specifically...and i had a question about using a wind turbine as the
propeller

The one on this page is the one im thinking of using:
http://www.hydrogenappliances.com/bladekits.html

Its some kind of plastic reinforced carbon fiber with ~60" diameter.
Six blades. Its supposed to be good up to several thousand rpm and
has a 70 year
outdoor weather rating...so im guessing its reasonably tough...not
bad for $89.

My main question is will it work as a propeller to generate enough
thrust...say 50-100lbs...im going to be able to supply it with
~15hp...(@2000-3000rpm) it seems to have a quite interesting blade
geometry...near the hub it has an eliptical cross section with a wide
base and a severe pitch... as the blade proceeds out to the tip it
goes COMPLETELY flat (no pitch) but in cross section it has a lovely
airfoil with a flat side (bottom of wing) and a curved airfoil on the
other side (top of wing)...for the wind turbine application use they
indicate to put the flat side of the airfoil facing the wind...which
way should I orient the flat side if I want to use it for thrust...how
would I make thrust calculations or even better measure thrust
directly?

Will the flexabilty of the prop be stabilized by centripital force
even when under load (pushing my 180lb body under a paraglider wing)
i.e. will the prop remain reasonably flat if spinning fast enough and
not bend and hack my legs/head off....it seems like it is really well
engineered from a aeronautics standpoint...i would probalbly make a
custom heavy duty hub so please focus replies on the
blades...thanks...more generally have any of you used 5/6 blade props
on an ultralight? id be interesting in hearing your impressions of
how well it worked for you compared to a 2/3/4 blade prop...