PURPOSE:To remarkably improve the characteristic of a water-jet propeller by setting inlet angles of vane inlet edges on a casing side to a same and small value of possibly nearest value of 0 deg. over all of the length. CONSTITUTION:In an impeller 11, inlet edges 1 of vanes 12 which are smoothly laid along a recessed circular arc curve of a boss side shroud 11a and a boss shroud shape 11b on the side of cylindrical vane inlet substantially parallel to a rotary shaft, are so arranged as to have substantial same inlet angles of possibly nearest value of 0 deg. at any position. Corners are thus eliminated from the intersections of inlet pressure faces of the vanes 12 and the boss shroud 11a, so that the vane inlet edges 1 show a part of substantial circle. Front half of the vane 12 of the impeller 11 functions as inducer at a high speed rotation. It is therefore possible to improve cavitation ability and suppress the loss of the impeller inlet to the minimum.
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