It may be beneficial to taper the blade for structural reasons. The above graph represents how this would affect CP. In this example the root chord was kept constant at 0.4m. Low taper ratios result in improved CP values at low velocities but reduced performance at higher velocities. Increasing the taper ratio towards unity, corresponding to a uniform chord, results in improved performance at higher velocities but results in a reduction in CP at low inflow speeds. For our turbine geometry, employing a taper ratio of 0.75 would gain performance below about 2.6m/s, sacrificing performance above when compared to a turbine with uniform blades.
