horiz tail airfoil observations

Brad wrote:
I've been perusing Fred Thomas's Sailplane Design book lately. I am
curious, why do most of the modern sailplanes use a non-symetrical
airfoil for the horiz surface, and most of the "older" sailplanes use a
symetrical airfoil?

I was looking at a Krokus at the Pensacola airshow over the weekend,
made in the 80's, it is definately using somthing like the Wortman
71-150/30 while my glider, and Apis uses an airfoil that is not
symetrical.

Is the fixed portion symmetrical but with a control surface that has a
slight undercamber on the bottom? That's what my ASH 26 elevator is
like, and I believe that is normal.

If the fixed portion is not symmetrical, is the flatter part on the top
or bottom?


--
Eric Greenwell - Washington State, USA
Change "netto" to "net" to email me directly

"Transponders in Sailplanes" on the Soaring Safety Foundation website
www.soaringsafety.org/prevention/articles.html

"A Guide to Self-launching Sailplane Operation" at www.motorglider.org