Dear Scott,

If you'll contact me directly with a valid email address I can attach a
DeltaCAD drawing of the Clark Y15 - 48 to the return message.

But it's easy enough to dig out for yourself.

Use Google or other search engine to locate 'Profili,' a popular
airfoil profiling program written by an Italian fellow and offered free
to the aviation community. (The program was apparently written
specifically for MODEL airplane builders, so think big :-)

Once you find it and get it installed on your computer, use the task
bar to locate the Airfoil Library, click on that then simply go down
the list until you find the Clark Y-15 (which is there; keep looking
:-)

Once you have it, Profili will print it out for you in any chord (be
sure to select 'inches;' output is normally in millimeters).

If you select .dxf as the output file type you can enter the result
directly into DeltaCAD, which is also available free, at least for a
time-crippled copy.

Once you have the airfoil in DeltaCAD you can do ANYTHING YOU WANT with
it, such as drawing in the verticals & diagonals, figuring out the best
shape of the gussets and so forth.

To make up your rib jig simply print the airfoil full-scale (DeltaCAD
allows any scale), glue it to your board, give it a coat of varnish and
there it is.

Since it will print-out on several sheets, to aid in their alignment I
usually overlay a 2" grid of light blue lines. I use them to align the
sheets on a light-table (or sliding glass door) BEFORE gluing them to
the board.

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You're message is pretty good evidence that you don't have Profili
installed. (And maybe not even DeltaCAD, although it has become a de
facto standard for homebuilders.) In that case, it may sound like a
lot of trouble.

Trust me here, Scott. Profili is a useful tool for the homebuilder.
It's always something of a pain in the ass when you have to learn to
use a new tool, especially one you may need to use only once, which is
why I offered to send you the .dxf file. But once you have a tool
available you tend to find uses for it, such as laying out symmetrical
airfoils for fairings and the like, which takes only a moment when you
have Profili and DeltaCAD.

-R.S.Hoover

PS -- For those not familiar with the airfoils of Virginius Clark, the
Clark-Y is approximately 12% thickness (11.73) whilst the Clark-Y15 is
the same airfoil but a full 15% depth.