Sharp VAWT Bird Windmill

A nice wind toy that demonstrates the principle and capabilities of vertical axis wind turbines with pitch control (VAWTs).

The toy consists of a simple lightweight planar wing mounted on a string. When exposed to wind, the wing demonstrates its self-starting capabilities - it begins to tumble and eventually starts to perform circular motions orbiting a virtual vertical axis. The design of the wing includes a counterweight mounted on a outrigger at the leading edge of the wing. The counterweight experiences a centrifugal force as the wing orbits. This force counteracts the torque generated by the wing. The result is a passive self-balancing system for the angle of attack, which dramatically improves the performance of the wing throughout the entire rotation. This system also contributes to the wing's ability to compensate for gusty winds.

Unfortunately we had almost no wind the last few days. So I made a video of the wing in operation inside the house using a small fan.

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