Tim, as far as foil design, if it were me (and may well be some day) I'd start with a template off the fastest Melges 24, 30, 32 I could find, identify that foil (or close) and work from there Just my $3.26 worth Mark Want to keep your WHOLE PAYCHECK? PLEASE VISIT http://www.fairtax.org ----- Original Message ----- From: "tim ford" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Wednesday, March 19, 2008 9:00 AM Subject: Re: catalina27-talk: Keel Design-OT-OT-OT
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 -- Internal Virus Database is out-of-date. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.21.4/1310 - Release Date: 3/4/2008 8:35 AM
