On 17 Mar 2004 13:03:08 -0800, (sebastian) wrote:

ah well, that was exactly the type of feeback i was looking for
thanks.

My revised plan is to experiment with building a carbon fiber
propeller. I like the general design theory behind the wind turbine
that i specified, so I am thinking of inverting the pitch for thrust
and making the blade shorter and broader (45-50" diameter, 2-4" wide
tapering to tip). My plan is to make foam airfoil cores with a
hotwire cutter, extensively reinforce the lengthwise direction with
unidirectional carbon fiber roving, and wrap the whole blade with
carbon fiber farbric and vacuum bag. I would use a similar twisting
geometry that narrows and goes from ~20 degrees to nearly a flat pitch
at the tip and transforms from an elipitcal cross section at the hub
to an airfoil at the tip. or would it be better and simpler to have a
constant pitch, width, and airfoil and make the overall pitch ground
adjustable. Rememeber i need it to be as light and efficent as
possible this is for a paraglider fan (backpack type) not some big
beefy airplane. Any suggestions?

Sebastian, several people have fabricated composite propellers in
their shop. It isn't easy to do and the prop REALLY has to be of
sound construction in order to withstand the forces of thrust,
vibration reasonance and turbulence.

I suggest you do a search on the internet to see if you can find the
websites of those who have documented their techniques. Be prepared
to spend a LOT of time getting it right.

Propeller design is not simple.

Good luck, Corky Scott