I had to make a run to South Texas yesterday and it was the first time I’d seen the windmills running with a significant breeze. The surface winds were around 15 knots (17 mph).
I’m not sure of the exact blade length of these. Some generators run blades nearly 150 feet in length and are supported by 200' towers. Aeronautical charts for the area show minimum safe altitudes over 500 feet.
No matter. It’s still an amazing feat to have that much flex in something that big that’s spinning 10 to 15 rpm with a tip speed over 120 mph.