Originally Posted by
chornedsnorkack
Just why is a winglet better than extending the wingtip in the same direction?
As then, without the winglet (above Boeing) or wing fences (Airbus) you'd still get the span wise flow meeting.
Basically you have to try and stop the meeting of the top and bottom air flows. Which creates the 'swirls' you see on a damp morning when acft are landing.