Castagneto and Maioli 



Such a "reverse procedure" is based upon the equality of the conditions im- 

 posed by the hydrodynamic calculation, which can be expressed, section by sec- 

 tion, by the well-known relation 



C, = 



4ttD 



^x X sin (/3.) tan (/3,-/3) 



and upon the equality of the conditions imposed by the geometry of each single 

 section, which, according to the notations and relations presented in the preced- 

 ing paragraphs, are expressed by 



Cj^ = 0.75 Kf —ll+K^ ~j+ 6.00 a , 



where 0.75 is the coefficient of reduction from perfect to viscous fluid. 



The equation of equality is an implicit function only of the hydrodynamic 

 angle of advance /3i , which can be evaluated for each separate section together 

 with the ideal efficiency rj-. In this way it is possible to deduce the values of 

 the thrust T., of the ideal moment Q ,, and of the corresponding quantities in 

 actual fluid; the latter with the introduction of an appropriate value of the drag- 

 lift ratio e (in this case equal to 0.035). Table 6 gives the design and the cal- 

 culated hydrodynamic data for cases a and B ; Table 7 for the three models in 

 case c . 



Table 7 



Camber and Pitch Ratios of Models 



E.997 (Basic)-E.998-E.999 



1038 



