"Berry" wrote in message ...
In article ,
BruceGreeff wrote:

When asked what airfoil he used on his HP winglets, Dick Schreder
replied "I use the ROF-POB airfoil. Questioned further he elaborated
"Round on front-pointy on back".


I am aware of a lot of Schreder sailplanes with winglets; however, I haven't come across any with Dick's plywood slabs described above bolted to the wingtip rib. Almost all the HP/RS-15 winglets are based on (copies of) the winglets described in the Free Flight page 6 article by Peter Masak.(http://www.wgc.mb.ca/sac/freeflight/92_02.pdf)

HP pilots note that winglets definitely improve aileron effectiveness resulting in higher roll rates.

Wayne
http://www.soaridaho.com/Schreder