| 摘要 |
1472179 Screw propellers INDUSTRIEELE ONTWIKKELINGS MAATSCHAPPIJ NV 14 Aug 1974 [22 Aug 1973] 35820/74 Heading B7V [Also in Division B1] A marine screw propeller comprises a plurality of helical ridges around the hub, shaped so that on a cross-section normal to the rotational axis, the distance A shown in Fig. 2 is at least onethird of the distance B. The ridges and the troughs between them preferably have profiles (as seen in sections as in Fig. 2) formed of arcs of circles of radius at least one-third of the distance B. The outline of the propeller in axial crosssection preferably tapers in the forward direction, as seen in Fig. 1. |
