Hovey Whing Ding II (WD-II) (USA) Single-seat ultra-light biplane, plans of which are available to amateur constructors: more than 6,000 sets sold by 1979.
Two examples of the Hovey Whing Ding II ultra-lightweight homebuilt biplane
Hovey Whing Ding II ultra-lightweight homebuilt biplane, with optional steel-tube landing gear
A practical demonstration of the light weight and mobility of the Hovey Whing Ding II