Lindgren, Johnsson and Dyne 



ffO- 



6 ^ 



Q3 



OA 



0.5 



0.6 



0.7 



Fig. 6 - Family of contrarotating propellers. Radial distributions of 

 maximum camber of blade sections. See further Table 1 (D = forward 

 and aft propeller diameter, respectively). 



5 ^ 



5 L 



O Conventional propellers 

 A Contra - rotating propellers 

 V Ducted propellers 



Note. For contrarot. props, pitch ratio 

 of forward prop, is used 



Fig. 7 - Difference in number of revs, between calculations and 

 open-water tests for different types of propellers 



1274 



