| 摘要 |
A blade (9) for a paddle intended for paddling a canoe or corresponding water-craft, which paddle comprises a paddle shaft and a blade arranged on at least one end of the paddle shaft and intended to be inserted fully or partially into the water with the main-extension plane of the blade located substantially transversally to the longitudinal axis of the canoe or like watercraft during a so-called paddle stroke for forward propulsion of the canoe, where the one side (12'') of the blade, which is intended to face forwards relative to the intended direction of travel, the front face (12'') of the blade, is curved. The cross-sectional shape of the blade (9) throughout substantially the whole of the blade, substantially perpendicular to the longitudinal axis of the paddle shaft, had a configuration such that the blade, in addition to normally occurring pressure forces, also utilizes suction forces resulting from the passage of the water over the surface of the blade upon lateral displacement of the blade (9) through the water substantially in the direction of the main-extension plane, with the plane forming a given angle with the direction of paddle displacement and substantially transversally to the longitudinal axis of the paddle shaft, and for avoiding the formation of turbulence or eddy currents around the blade, where the blade (9) is formed so that the forces counter-act rearward displacement of the blade (9) through the water during a paddle stroke and where the cross-sectional profile of the blade (9) is asymmetric, substantially similar to the cross-sectional profile of the wing or the like of an aeroplane, where a first edge part (10) of the cross-sectional profile intended during the aforementioned lateral displacement to form the leading edge part (10) remote from the canoe herewith corresponds to the leading edge of a wing, and where the cross-sectional profile of both sides (12+40, 12'') of the blade (9) between the two edge parts (10,11) of the cross-sectional profile, are completely devoid of outwardly projecting turbulence-creating portions, such as ridges and the like in order to avoid turbulent flow. |
