alu airfoil of wind turbine for DIY using purpose

our blade is modified based on NACA0021, it is drag type providing a large self-starting capability,and also a large speed-limiting capability under high wind conditions. However, these advantagesare at the expense of relative poor efficiency in steady wind conditions.after modification,the airfoil provides large working zone by permitting larger incidence angelvalues. At unsteady windflow conditions,and in silent environments(which are typical roof conditions),it is important to gain a possible large working zone.