Hilton wrote:
Greg Esres wrote:
No, for subsonic flight, it's perpendicular to the *local* relative
wind, the relative wind that is modified by wingtip vortices. If lift
were perpendicular to the chordline, you would have induced drag in a
wind tunnel, and you don't.

Come on Greg, you're telling me that wings in wind tunnels have no induced
drag? That's ridiculous. How about if the wind tunnel was 1000 miles
long
by 10 miles high - would the wings in that wind tunnel have induced drag?
(I seem to remember this same argument a few months ago)

Just to follow-up my own post, here is a line from the NASA web site:
"During the winter, with the aid of their wind tunnel, they began to
understand the role of high induced drag on their aircraft's poor
performance."

http://www.grc.nasa.gov/WWW/Wright/airplane/drag1.html

Sorry Greg, "no induced drag in a wind tunnel" is simply not true.

Hilton