Date: 11/10/2009
Name: Bob McGovern
email: bobmcgov@wildblue.net
subject:NACA foil rudders
Christian is correct: making a rudder blade to NACA profiles is no more difficult than making any symmetrical shape. I used a spreadsheet to loft a NACA04 profile to a piece of graph paper, glued that to a piece of masonite, and faired to the line. From there to a 1" thick piece of UHMW polyethylene; used a router to establish fairing depths. The result (completely illegal, but it needn't be) is a nice low-drag blade that turns on a dime. Rudder assembly weighs 13# less than previous mahogany kickup. End view:http://sites.google.com/a/wildblue.net/hedgehogia/_/rsrc/1250373613568/Home/rudder7.jpg
Photos of rebuild here (scroll down):
http://www.sj21fleet1forums.org/viewtopic.php?f=2&t=112
NACA background & formulas here:
http://www.boat-links.com/foils.txt
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