Hello Larry:

It's hard to add anything to the expert advice given by Dr.'s Drela &
Pfeiffer, and the practical value of an experienced
pilot/builder/engineer like Steve Leonard.

However, you might glance at :
http://www.appledor.net/tsillas/soaring/pikt7/pikt7.htm

As is so often the case, Dick Johnson has "been there, done that". A
couple of key points from this work with the related FX 17% section:

1) The practical eyeball approach yielded two serious failures when
Dan Somers found pressure waves in the NASA Langely tunnel
2) The final results give you some idea of what you *might* gain for
the work involved.

I enjoyed meeting and flying with you at Hobbs in '98. One of these
days, I might enter another contest.

Best Regards,
Gary Osoba


Larry Goddard wrote in message ...
Many thanks to everyone who has (will?) responded!!!! The technical info
is great. I now have a copy of Xfoil and am trying to figure out how to
use it. The "realistic" advice is also well taken.


Steve wrote:

Since the good Doctors are done explaining how it should be done in
the electronic world, here is a bit of advice for you to ponder,
Larry.

It was good enough for NACA to have the leading edge be above and
ahead of the origin of the coordinates system (Remember, Aero
specialists. Leading edge radius and slope on the old sections, hmm?)


Steve, et. al., did NACA _actually_ intend that the leading edge be above
and ahead of coordinate origin?? Or is that simply how we choose to
conveniently spline it currently? Seems like that messes up the whole
"chord" reference mechanism...

Thanks again to all... this is really interesting!

Larry Goddard
"01" USA