Liindgren, Johnsson and Dyne 



(8) A series of "optimum" ducted propellers analogous to the family 

 of contrarotating propellers, will be manufactured and tested (see Table 5). 



(9) The questions concerning vibratory forces, maneuverability, and 

 stopping and backing ability require further studies. 



ACKNOWLEDGMENTS 



The authors wish to express their gratitude to the Swedish Council for Ap- 

 plied Research for sponsoring the present investigation. 



The authors are indebted to Dr. Hans Edstrand, Director General of the 

 Swedish State Shipbuilding Experimental Tank, for the opportunity to undertake 

 this study, as well as for the interest he has shown. 



Thanks are also due to Mr. Eric Bjarne for his assistance with the analysis 

 of the material and to other members of the staff for their assistance in various 

 stages of the work. 



LIST OF SYMBOLS 



Aq = '!L—- = propeller disk area 



-4^ - ultimate wake area 

 A^ = developed blade area 

 B = beam of hull 



B = 33.48 A — 



, ' T 



= 13.36 ^ — 



JK. 



Taylor variables 

 (salt water) 



D = propeller diameter 



/ = camber of blade sections 



fjy = camber of duct profile 



= ' , = non dimensional blade circulation coefficient 



ttDV^ 



jyrp; = advance ratio 



1300 



