Posted for "Martin Hollmann" <aircraft@mbay.net>:

 Dear Mr. Kaye,
 
 I have just read the letter posted on your website: Alert. NACA64212. I and
Rick McWilliams designed the Lancair IV wing and here is my response.
 
 Yes, the NACA64212 has a sharp stall. However, the wing is designed with the
RXM5-217 airfoil, a very gentle stalling airfoil, at the root and the
NACA64212 airfoil at the tip. The wing is washed out so that the root stalls
first. The wing tip is not designed to stall and as such the question of how
it stalls is not relevant. The NACA64212 airfoil was chosen for the tip
because it has a high lift coefficient and it is very effective with an
aileron. I use this wing design on my Stallion and both the Stallion and the
Lancair IV have a very gentle stall.
 
 While Rick McWilliams and I designed the wing of the Lancair IV, I also
designed structure for the wing of the Rigel AA300, a two place jet trainer.
The wing airfoils for that airplane had been selected by Harry Riblett. When I
superimposed the root airfoil and tip airfoil of both wings, the airfoils were
almost identical. I really felt good since I know that Riblett uses the Eppler
code and McWilliams used the Oshkosh Airfoil Program and neither of these two
people talk to each other. Both had come up with the same wing airfoil design.
I felt great.
 
 Then something happened that really turned my stomach. Shortly after the
Lancair IV flew, Harry Riblett sent a letter to my good friend Paul Poberezny
(EAA), all major airframe manufactures, NASA directors stating that the
Lancair IV had the wrong airfoils and wing design. [...snip...] Needless to say, I
realized that Riblett was not only suffering from the NIH (not invented here)
syndrome and visions of grandeur, [...snip...].
 
 I hope that this clears things up and if you have any questions, call me at
831-649-6212. Martin Hollmann