What would my infinitely more wise fellow sailors recommend for a foil shape on this rudder. This is going on the back of a 22' Helsen. From what I was reading, one should choose a NACA 0015-0025 shape for rudders. Also I read that for slower boats (im assuming something like a Catalina) a NACA 0018 should be used. The dimensions of the rudder are 1.5" in thick and 10.75" wide. Any constructive advice is appreciated.
Rudder foil shape
- Thread starter kirbyc1goo
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Those NACA airfoils are based on max thickness of the airfoil in percent. Your chord length is 10.75" and your max thickness is 1.5", (1.5 divided by 10.75=13.95%)then it sounds like your closest option is a NACA 0015 unless you change length of the chord. The longer the blade, the thicker it needs to be. One side will be in tension, and the other in compression (depending on the angle of attack). Highest stress will be at the pivot point. The thicker there the better.
J
check out this link:
http://www.mothboat.com/Building/foils.html
J
check out this link:
http://www.mothboat.com/Building/foils.html
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Ah gotcha. I should be able to use this percentage to figure out how far down the chord my thickest section will be. I have read some really good ideas that I feel like should be posted. One of which involves taking a router then setting it to certain depth and making a line across the board at the respective chord. This gives you the depth that you need to sand to at that point on the board. You can do this in a few places to help get that general slope down.
Im not sure how thick i should leave my trailing edge. When complete, should I wrap this wood in fiberglass for rigidity? If i make my trailing edge too thin and not wrap it, what is the possibility of it breaking under load?
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