Why do windmills have only 3 blades?
The energy generated by a “windmill” (or wind turbine) is based on a few things. Wind speed, air density, blade area, and blade design all affect the energy that can be captured. The number of blades (and the size and shape) determines the speed and torque that the blade assembly will operate at a given windspeed. The more blades generally result in more torque, but slowed speed. When the engineers design the wind turbine, they have to evaluate what speed and torque would be best for the generator they are using. Odd numbers of blades are common, but for a different reason that efficiency. The wind it normally faster at higher altitudes. Thus the blade at the top is “pushed” more than the one at the bottom. If there were an even number of blades, the entire blade structure would be flexed alot, and would eventually wobble and fail.
