LOL ... I got tired of replacing the windsock at the end of my runway, so I found a better idea .....

I have a tachogenerator with some gearing in the fuse part. In a 15 mph wind, the tach spins just over 1850 rpm which puts out 9.3 volts DC at just under 35 mA. This may not sound like a lot, but it's connected to a 6 volt 5 Ah battery, and I use that to charge my 4.8 volt packs. It turns with the direction of the wind, and it's made of aluminum, so it won't rot.