Foil thoughts
Starting to do some research into foil shapes. The standard approach is to use NACA0010 / 0012 for the rudder and think about of the NACA six digit series for the daggerboard.
Laminar flow sections are faster underwater, but have issues getting the water to flow at higher angle of attacks. As I sail in an often light air venue I may end up building two daggerboards, one nice and forgiving for light air sailing and the other aimed at higher speeds.
http://airfoiltools.com/ provides some great comparisons of different sections. After some time spent in here I've pretty much discarded the idea of the laminar flow NACA section and am contemplating an RC sailplane section EH 0.0/9.0.
A problem I hit pretty quickly was that my girder was build 2mm too thin. This then makes the daggerboard slot too thin! At the time I knew it was slightly too thin (but don't remember thinking as much as 2mm - so I don't think I thought about that properly) but didn't properly think through the implications.
Folks - build your girder the right thickness! It'll help your boat fair better and give you a better daggerboard trunk!
My current thought is to sand out the trunk very slightly and get one of those mm back but I haven't followed through on this yet (and I'm not sure when I'd do this as it'll be pretty tricky to sand well). The other option it to build slightly smaller foils. I can fit one that has a chord of about 9" rather than the 9.5" that would be more ideal for a 9% chord CB.
To be continued!
Laminar flow sections are faster underwater, but have issues getting the water to flow at higher angle of attacks. As I sail in an often light air venue I may end up building two daggerboards, one nice and forgiving for light air sailing and the other aimed at higher speeds.
http://airfoiltools.com/ provides some great comparisons of different sections. After some time spent in here I've pretty much discarded the idea of the laminar flow NACA section and am contemplating an RC sailplane section EH 0.0/9.0.
A problem I hit pretty quickly was that my girder was build 2mm too thin. This then makes the daggerboard slot too thin! At the time I knew it was slightly too thin (but don't remember thinking as much as 2mm - so I don't think I thought about that properly) but didn't properly think through the implications.
Folks - build your girder the right thickness! It'll help your boat fair better and give you a better daggerboard trunk!
My current thought is to sand out the trunk very slightly and get one of those mm back but I haven't followed through on this yet (and I'm not sure when I'd do this as it'll be pretty tricky to sand well). The other option it to build slightly smaller foils. I can fit one that has a chord of about 9" rather than the 9.5" that would be more ideal for a 9% chord CB.
To be continued!
Comments
Post a Comment