Dave Shaddock wrote:
NACA0012 profile, if he’s carrying 150 lbs of bulb underneath a carbon
or glass skinned fin—a profile with 12% of its chord at max width will
withstand side loads
Well, actually, the NACA 0012 I spec'ed was for the rudder.
At the risk of incurring the wrath of the listee's who are darned sick
of this thread, I would like to prolong it with
2 more issues (where else is one going to find resources like both Dave
Sh's, Mark, Peter, Keith and Phil and anyone
else whom I may have inadvertently failed to include, on one internet
forum that is comparatively non-contentious,
friendly and not full of abrasive know-it-alls, I ask you?)
- section for the keel...the 0012 I mentioned is for my rudder....so,
stick with the 0012 section for the keel? (I already have the templates
but it's a relatively minor job to make new ones) Go with a more robust
foil 0013? The bulb will end up being approx
165-170 (I need a bit more RM because my crew is lighter)...tip to root
length, keel foil is approx 60 inches. Keel foil
is 13.5 root chord, 12 inches tip chord. Laminated 1.25 inch sections of
white oak, skinned with e-glass.
- ok, and this is where it gets really murky...trailing edge
shape/trailing edge width. There was a pretty long thread about this
on SA (I cant find the darn thread, though) on this topic. J24
measurer's look at keel trailing edges VERY closely. As I understand it,
a squared off trailing edge is fast (as oppposed to one that comes to a
point), but only fast to the extent that the width of the edge
(measured perpendicularly to the keel chord) is the proper
dimension...some percentage of the max profile maybe? This is where
I cant find much info.
Remember the design is a box rule and the keel and rudder design are
completely at the discretion of the builder/designer...which
makes it both fun and a bit frightening...the downside is, like the
first TP52's, the first boats are likely to be slower than the later
builds as the faster stuff shakes down and become part of the lore of
the class.
Thanks again for contributing to a project that is not particularly C27
related.
For anyone who's undies are in a knot over this thread, I can make it a
sub-list and continue the discussion there-OR-take
it to boatdesign.com and suffer some abuse there.
tf
