Here is an article about the successful addition of wing tip stall fences:
http://www.soaridaho.com/Schreder/HP...ng_Fences.html

Wayne
http://www.soaridaho.com/


"CV" wrote in message
...

Another aerodynamic bone to toss around and chew on:

Instead of carefully crafted, expensive winglets, wouldn't
straightforward flat end plates serve nearly as well in
reducing wingtip vortices and improve performance.

Have they ever been tried, and with what results ?
CV