Experimental vertical axis wind turbines (VAWT)

I made this because I had some strips of wood that would make very light blades. The blades were carved by eye to a symmetrical airfoil section and are about 18% thick. This video at the bottom is a bit deceiving as it was taken on one of the very few times the turbine actually achieved any speed. It would easily blow around at less than wind speed with the tell-tales blowing back on the downwind section, but in a gust it would only slowly accelerate. I initially made the radius at 30cm but kept trimming down the arms to increase the solidity in an attempt to get it to self start. On the occasions it did run with the generator connected it only achieved cut in speed and accelerated no further.

In a stronger steady wind this could possibly had been more successful, but with only a 6.5cm chord the blades are operating at very low Reynolds numbers and the solidity is low. The airfoil section was carved by eye and despite careful sanding was probably not that smooth. The inertia of the rotor was quite high meaning it was slow to accelerate in gusts. The support arms and attachments probably contributed quite a lot of drag.