Bindel 

 0.20 



H 

 t = 10- 



$ ;^„ 



15 



10 



10 



15 



-.• 



. 2 



.6 



1. 



Fig. 2a - Variation of incidence on the blade 

 element due to shaft inclination, xj, = 0.20 

 and 9 = 10° (supposing u^ = Uj = 0) 



blade. This is in accordance with common experience; however, it must be 

 noted that for consideration of strength, the thickness ratio of the sections near 

 the hub is larger and therefore less sensitive to incidence variations than the 

 sections farther from the axis. 



The incidence variations increase with J, i.e., large-pitch propellers are 

 more sensitive to the phenomenon involved than low-pitch propellers. The in- 

 cidence variations increase also, of course, with 6 . It is thus normal that 

 fast ships, such as torpedo boats for example, which have generally large- 

 pitch propellers and for which is also large are the ships suffering the most 

 severe erosion near the hub (for this type of ship, 6 is approximately the angle 

 between the shaft and the hull; it may be of the order of 15°). 



1500 



