The June 4, 2009 issue of Machine Design has a Sparrow Hawk glider on
the cover. The article does a very good job of covering all three of
Windward Performance's current sailplane projects. The Sparrow Hawk
13m ultralight, the Duck Hawk 15m racing plane and the Perlan
(designed to break the world altitude record). If you don't receive a
copy of Machine Design you can see the entire article on line at:

http://machinedesign.com/article/win...n-to-set-altit