Duportj Viscontij and Mevte 



VIII. CONCLUSION 



A general method of approach has been briefly described, this 

 applying to the hydraulic design studies of jet propellers for high 

 speed surface ships. The validity of this method where internal and 

 external flows are to a large extent separately considered had to be 

 proven, at least for application to short ducted straight flow jet 

 propellers. 



The tests of a 50 knot , 800 Kw prototype propulsion unit in 

 the high speed towing tank of CEAT in Toulouse has shown a good 

 accordance between the prototype performances and the predicted 

 characteristics which had been derived from the proposed approach 

 method. The descrepancies are within the limits of the expected 

 scale effect which is normally observed when dealing with reduced 

 model approachs. 



We have also proposed some simple dimensionless parameters 

 for the sake of comparison of various types of propellers applicable 

 to rapid surface -ships. The prototype test proved the high perfor- 

 mances of the Straight-Flow-Jet Propeller unit, and its potential 

 interest in this field of application. 



22 



