A Model Study of the Hydrodynamic Characteristics of A Series of Paddle-Wheel Propulsive Devices for High-Speed Craft

摘要

The report covers an investigation of the hydrodynamic characteristics of a series of scale models of paddle wheels with fixed radial blades, designed for speeds in excess of 20 knots. The results indicate that a six-bladed wheel has higher propulsive efficiency and thrust than a twelve-bladed wheel. Peak efficiency is in the neighborhood of 41 percent and occurs at slip values of 30 to 40 percent. Thrust increases with immersion depth, within the range tested (16 percent of the wheel diameter immersed). There is a slight break in the thrust curve over a span of 10-percent slip, after which the thrust again increases with increasing slip. There is evidence of scale distortion, and it is felt that the present model, with a scale factor of 8.5 to 1, may have been too small. (Author)