Thanks Blue Skyy. The Germans in many of their advanced gliders have been using a multi step swept leading edge terminating in a raked tip giving the wing a "scimitar" look. This Scheumann planform is noted for its high efficiency. I've even seen some airliners employing this wing type - I think it was one of the newest Fokkers or a Dornier. What you see with the PZL is similar but simpler. Bizjets are another example where you see some pretty slick aerodynamics. If you look at Lancair and Dymond airplane wing tips they're pretty slick as well. That new Nemesis is an excellent example of very advanced aerodynamic design. The newer carbon fiber design wing seems to employ a flexible trailing edge skin! Wow - I'm sure that's been done on military prototypes but I've not seen it done like that before! I look at some of the more advanced propellor shapes, like APC props, being a good example of optimised airfoil design. Trouble with a lot of these shapes is their not easy to accurately build, that's why we see the move to glass and carbon fibre molds. I guess if you have lots of time and patience, anything can be carved from balsa!