Most of the specs I have read are for 10 sq meters of wing and the picture I took this from is bigger than that. Someone must have gotten the scale way wrong. So for 10 square meters and say aspect ratio of 4.125 ish that would be a root chord of approximately 2.42 meters or 6.15 feet or 73-74 ish inches? The drawing is no where near this. Span would therefore be something like 21-22 feet?