Advanced Rotor Design. We have often been complemented on how attractive our turbine is, especially the rotor blades. It is a perfect example of form following function. The blades were not designed to be attractive. The design was based solely on achieving the best aerodynamics. Aerostar blades use AS 200 proprietary low reynolds number airfoils developed by Aerostar. The airfoils are optimized to produce energy at low wind speeds.
Some turbines use untwisted rectangular shaped blades, sometimes called "constant chord" blades. The primary advantage is lower cost. Unfortunately, performance can suffer. Becase the speed of a turbine blade changes with the blade radius, optimum design requires the width of the blade to vary. Inner portions of the blade move slowly so they need to be wider to extract energy from the wind. Outboard blade sections travel at high speed so they can be narrower. The angle that the wind makes with the blade also changes with blade radius so, for a blade to be efficient, it must be twisted. Sections near the root need much more twist than sections near the blade tip.
Aerostar blades are made from advanced composites for high strength and light weight. Each blade set is matched by being made from the same mold so that the blades are identical and perform exactly the same. Many wind turbine blades travel more than 125 MPH so over time, rain and airborne dirt act like a sandblaster wearing away the leading edges. The leading edges of the blades are coated with a special impact resistant urethane so that rain and flying dirt bounce off saving the blades from erosion.
Read our paper on Why Two Bladed Rotors Make Sense.
NASA Spinoff article on Aerostar blade aerodynamics.