| 摘要 |
PURPOSE:To enhance the propulsion efficiency of a propeller by a structure wherein fins locating at the side, at which the blade of the propeller moves upward, are also twisted respectively so as to have larger setting angles at the position nearer to the tip of the fins in order to effectively generate rotating currents, the direction of rotation of which is opposite to that of the currents caused by the blades of the propeller. CONSTITUTION:The fins 12a-12c located at the port side, at which the blade of the propeller moves upward, are fitted in such a manner that the trailing edge of the fin is lower than the leading edge. Furthermore, each fin is so twisted as to have a larger setting angle alpha at the position nearer to the tip of the fin. Owing to the structue as described above, the attack angle of each fin toward current is kept constant throughout the entire length of the fin, resulting in effectively generating rotating currents and in enhancing the propulsion efficiency of the propeller. |
