ON THE DESIGN OF THE PROPULSION SYSTEMS WITH 

 « Z » DRIVES FOR HYDROFOIL SHIPS 



A. A. Rousetsky 



Kryloff Ship Research Institute 



Leningradj U.S.S.R. 



ABSTRACT 



The design features of propeller with "Z" power 

 drive are described. The data on the velocity field 

 produced by the propulsion pod are given and re- 

 commendations for choice of the elements of pro - 

 peller and propulsion pod adapted to velocity field 

 are given. 



Information on the hydrofoil "Typhoon" propulsion 

 system design are set forth. 



The propeller powered through an inclined shaft is the most 

 extensively employed propulsion system for hydrofoil ships. Such 

 propulsion systems distinguished by simple design are used for most 

 hydrofoil ships now in operation. However, this system has some 

 disadvantages. The oncoming flow obliquity due to the propeller shaft 

 inclination results in the periodic change of the incident angles of the 

 propeller elements, the amplitude being increased with the decrease 

 in the relative radius. The variation of the incident angles prevents 

 from designing the optimum propeller, from the point of view of pro- 

 pulsion qualities, and forces the designers to make a certain compro- 

 mise, while choosing the propeller elements, to avoid the intensive 

 erosion damages on the propeller blades. The method of designing 

 the propellers adapted to the oblique flow is described in papers 

 [1] . [2] • 



The experience obtained in calculating such propellers shows 

 that with the oblique flow angles exceeding 14° - 15° the design of 

 the ship propeller displaying satisfactory erosion characteristics has 

 failed. At the same time the improvment of the hydrofoil ship seakeepinj 



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