"Jock Proudfoot" wrote in message ...
Anyone know in round numbers, what % increase in L/D garden-variety
winglets give?


Back in 1997, when winglets were entering the soaring scene, an article was published in the Free Flight magazine's April edition entitled "Do Winglets Work?" It can be found on page 16 of the following link. (http://www.wgc.mb.ca/sac/freeflight/97_04.pdf)

As for percentage of improvement, US racing handicaps are adjusted from as little as 0.002 to 0.010 in the case of the Discus 2b.

Wayne
HP-14 "6F"