On Mon, 2 Jun 2008 10:11:17 -0700, "pe.rhodes" wrote:

Nice photo, Troy. You don't happen to remember the quote about the ribs on
the wings being there to put the vortex where it belongs, or something like
that...

They are wing fences. They keep the air going off the TE of wing in relatively
straight line aft, instead of sliding off along the LE. Quite a few planes have
them, especially those without LE devices. Even the old original DC-9 had a big
'potato chip' of a fence, to keep air from entering the engines at an angle
(causes stalls).

Vortex generators are small in comparison and often there are several of them,
such as those on the bottom and top of the TE of the stabilizer on a 707. In
that case, they keep the air from forming a boundry layer, making the elevator
useless. Ok, if you want to get technical, they keep a boundry layer from
forming on the elevator tab. The elevator itself isn't powered in any way.
Cheers,
jc