If you check out this link to the Polish designed PZL-130 "Orlik" advanced miltary turboprop trainer, I think you'll be impressed by the wing tips: http://www.pzl-okecie.com.pl/orlik.htm This type of wing planform (although the aspect ratio is obviously stretched considerably) is often used in high performance gliders where streamlining and drag reduction is crucial. This is one very efficient low drag wing tip and overall wing planform. Cool looking plane in my opinion!