Abstract
In flight, many birds increase their height by flapping their wings. When it flaps the whole wing moves flexibly. This movement produces a difference in air resistance: the air is caught when the wing is moved in a downward direction and released when the wing is moved upward. We applied this mechanism to the wing of a wind turbine. This paper describes the result of a wind tunnel test on the CFRP Feather model which is the fifth model and uses a thin narrow plate of Carbon Fiber Reinforced Plastics (CFRP) instead of stainless steel. The power coefficient of the model is less than that of the fourth model. The possibility of vibration being one of the causes of the performance deterioration is shown. However, it is clarified that the output increases when the clearance of the middle wing is closed. Also, the middle wing which is near the rotational shaft greatly contributes to the output.
