View Single Post
Old 12-30-09, 12:19 AM   #9
Bicycle Bob
Suncatcher
 
Join Date: Sep 2008
Location: Spiritwood, Northern Saskatchewan
Posts: 42
Thanks: 0
Thanked 1 Time in 1 Post
Default Blade Bias

Quote:
Originally Posted by Christ View Post
So I kind of wonder if there is any efficiency difference with bullet-nose cones in the middle of a turbine, etc... I also wonder if the airfoil design is really that much more efficient than just using a tilted blade at a fixed angle?

By "that much more efficient" I mean: Should I go out and buy a 3 blade plane prop to make a windmill, or should I just make 3 sticks from old boards with tapered edges and a fixed pitch to the wind?
If you buy blades, get windmill parts. Airplane props would be the equivalent of flying a cambered wing upside down. If you don't mind some extra stress on the tower and bearings, you don't need precision blades, just longer ones. One fellow has some really crude-looking 4-blade designs that gain overspeed protection by the inherent aero properties of the inefficiencies existing.
Bicycle Bob is offline   Reply With Quote