Abstract
The tip speed ratio Cp will be low as the pitch angle β is high. Meantime it becomes slow decline after 11° with 1.5 of Cp. The Cp difference of 5° and 15° is much smaller than that of 15° and 25°. The more difficult happens with increasing β so that promoting Cp with it is more difficult in terms of this study. This is a key in this conclusion of this research. If it is smaller than 10° it is more convenient for design and use simply than high angle. So we should think over the cost increasing to proceed the high pitch angle work for its high power and low cost at different condition. It is discussed in former other paper. Cp will be slow declining to be below 1 after λ is 55.
