Originally Posted by Giulietta
That's not the reason the blades are twisted.
They are twisted to ensure that lift at the tip is equal to lift at the root.
This is achived by twisting as you say, thus reducing angle of attack and aspect ratio, guaranteeing that lift os proportaional and the same along the lenght of the blade.
If this was not so, the blade would colapse and fold, due to the greater lift present at the tips.
Much thanks for the explain. But I did think apparent wind was also at play. In multielement wing sails for C-cats, they introduce twist in the top to prevent stallage that would otherwise occur. Apparent wind is higher at the top of the mast (as in all sails) and from a different direction because of wind gradient.But with rotating blades maybe this is less important than the lift loading issues.