"G.Kurek" wrote:
...
My criteria of similarities whe old beaten trainer with some
fabric, with L/D around 24 (when it was new) ...

On the web site where I found the picture, there is also a joke
saying that Wassmer (the manufacturer) claimed the same L/D as
the Blanik, but ommitted to say the comparison was made with the
Blanik flying inverted.