Vertical axis wind turbine models

This was the first model I made and I really didn't expect it to work. The blades are pieces of card bent into a crude aerofoil and glued to a plywood rotor. The rotor arm pushes over a ball bearing mounted on a length of metal stud.

In a low wind this will just feather into the wind but as the wind picks up it will start to rotate at approximately wind speed then as the wind increases it will accelerate. On the first test one of the blades flew off and the model continued to rotate with only one blade and would even self start.

There is quite a lot of vibration that tends to smooth out at high speed.