[l], [2], and [3] may be written: 



2 L = q S^ L; 1- q Sjj (l; - e D^) = L^ - W 



= 



hi ^W ^^ "■ °W ^W ^H -^ % ^W ^W 



H 



+ ^^ ^H ^H 



[la] 



[2a] 





'h ^ 



Sjj hjj [3a] 



Equations [2a] and [3a] do not include the moment due to 

 the body.'s weight- in-water. It is intended, however , to specify 

 the location of the ballast so as to place the effective center 

 of the gravitational forces directly below the towpoint when 

 the depressor assumes the design condition;, = 0, in tow. 



In the preliminary choice of the dimensions of the depressor, 

 the drag was neglected and various ratios of S to S^^, aspect 

 ratios, and wing-tail separations were tested until a suitably 

 compact configuration was obtained. Moderately large gap-to- 

 span ratios, G/b, and gap-to-chord ratios, G/C were chosen to 

 minimize biplane interference effects. Also, biplanes of 

 equal span and area and with zero stagger were selected . On 

 this basis, a preliminary configuration was obtained and the 

 values of the areas, aspect ratios, and overall length and height 

 fixed. At this stage, camber and wing and stabiliser incidence 



GO 



