Foil Design

The foil design was carried out in a similar way to the hull design. The current ideas were studied and small improvements were made.

5.1 Section Choice.

The foils sections are Tom Spears H105 sections. The horizontal foils are cambered 4% (need to check this) and the vertical foil has no camber. This section was chosen over NACA 64 012 series sections because it has been optimised for use as a hydrofoil. Pressure peaks have been smoothed out so the foil is less likely to ventilate. A second bonus is the drag is less for the same thickness of foil. This allows stronger structures of the same drag to be made.

Comments

What's your experience with the H105 section?

I assume you used the NACA 64-012 as centerboard and rudder section?

I personally didn't sail the boat enough to really evaluate the performance of the foils, however the H105 section has being adopted by other builders so the performance seems to be good. The Cl/Cd curves certainly are good. My limited experience of the foils indicated they worked well. 

I used the 64-012 as the centreboard for its low drag at small angle of attach, but used a NACA 0012 section for the rudder. The 0012 section has a higher stall point, so was a better choice for a foil that may be required to operate at high AoA. Maybe an uncambered H105 section may be good for the rudder as the pressure distribution is more even across the cord? You could perhaps conact TSpeer on the boatdesign.net forums about this.

 

hope this helps 

Chris 

:)