The sail elements are based on a catenary and mirrored section of a 'satenary' curve
 
A look at the catenary and satenary 'alpha curves'
 
the positive limb of the satenary chosen is reflected on the x axis
 
The satenary curves are further modified to add strength
 
The airfoil form is based on a parametric function modified from that for a circle
 
Near the rail-ring, the cross sections of the sail are graduated to a stronger shape
 
31 March 2010
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