On Jul 21, 2:00*pm, Home Guy wrote:
harry used improper usenet message composition style by full-quoting:

I can move air with flat blade angled at 45 degrees. *The blade
doesn't need a foil-shaped cross section - instead it can be flat.
When a flat blade is angled (any angle other than 0) and rotated,
it is pushing air out of the way as it turns.

Similarly, wind that wants to move past the blade must push it
aside, and in doing so it will rotate the hub. *The more surface
area you present to the wind (ie the wider the blade) the more
rotational force you transmit to the hub.

Explain what's wrong with my concept.

The thing you describe is a "plate or thin aerofoil"

Well ****.

If a conventional airplane wing is a foil, and if a flat plate can be a
foil, then ****, everything and anything can be a foil according to
you. *So where does that get us?

No matter which way you cut it, you're still left with capturing a
lateral force (ie = wind pressure) and convert it into rotational
energy. *A flat blade angled at 45 degrees will probably get you the
most torque and rotational speed out of a given breeze of air (but it's
totally possible that optimal blade angle is a function of RPM), and the
more surface area your blade has, the more of that wind energy it can
convert into rotational energy.

No. Not true. An oversimplification. If the blades are close
together (by being broader) each blade works in the turbulence of it's
predecessor.
Also, the most turbines have to work at a constant speed, but the wind
speed varies.

The baldes are designed to minimise this effect at the minimum wind
speed they are designed to function at. The effectis less marked at
higher windspeeds.
This is also why many have variable incidence.