Originally Posted by paulkinm
Do the use of winglets improve the wake or is it minimal? (if any)
They do reduce the strength of the vorticies, but the total wake behind a heavy aircraft would still be very strong for a light aircraft to fly behind it.
Basically, the BIG wingtip vortex is broken down into 2 smaller ones. One at the root of the winglet and the other at the tip of the winglet. So they're still there, but there is plenty of strong wake or disturbed air from all along the wing.