The Aerodynamics of Sails 



REPLY TO DISCUSSION 



Jerome H. Milgram 



I wish to thank Mr. Thieme for his comments and valuable references. 

 Some interesting results can be obtained by comparing theory with the data 

 presented in Mr. Thieme' s discussion. For given normalized load distributions 

 and lift coefficients, theory predicts that the coefficient of induced drag is pro- 

 portional to the area of the lifting surfaces divided by the square of the span. 

 This ratio is 0.30 for the 7KR YACHT, 1.70 for PAMIR, and 1.92 for DYNA. 

 The fact that the drag coefficients for DYNA are less than those for PAMIR 

 attests to the high efficiency of her rig which has equal sail areas on spans 

 of equal height. 



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