Dynamics of Hydrofoils as Applied to Naval Propellers 



form; the second, Cta j produced by the angle of attack, depends upon the inci- 

 dence and upon the thickness ratio of a particular thickness distribution. See 

 Fig. 1. -. . 



^ ^ * » 



Assuming 



Fig. 1 - Velocity increments 



and 



it follows that 





dc 



(3) 



r A'V^ A'V^ dc 



r A'v^ dc 



(4) 



(l + ^f) 



(5) 



K the structure of the two formulas (3) and (4) is considered, it is easily 

 recognized that the coefficient k f depends only upon the mean line, and that k\, 

 in practice, even though not in theory, depends almost only upon the thickness 

 distribution and the thickness ratio. 



In Figs. 2-7, values of c^^ versus tjc and f^/c are given for several 

 combinations of thickness forms and mean lines. The values shown have been 

 calculated by A. Silvestro (3), integrating numerically the velocity increments 

 tabulated in NASA Report 824. 



1023 



