Oscillating -bladed Propellers 



y 



/ 



V= 

 Y-- ) 



Fig. 9b - Cavitation inception curves for 

 oscillating -bladed propeller, d - 15° 



could take place near the hub (in the case of the propeller tested), better re- 

 sults would perhaps be obtained with a nonsinusoidal oscillation, the oscillation 

 being successively in phase with the variation of incidence in order to delay 

 cavitation near the mean line of the propeller, and in advance of phase to delay 

 cavitation on the leading edge. Of course, the oscillation mechanism system 

 would then be more complicated. 



5. A sophisticated theory, taking into accoxmt the blade width and the vari- 

 ations of the induced velocities, seems also necessary for a better understand- 

 ing of the phenomenon. 



ACKNOWLEDGMENT 



The author is greatly indebted to V. Adm. Brard, director of Bassin 

 d'Essais des Carenes, for having supported this investigation, and to Mr. Riou 

 for having carried out the tests. 



1515 



