Beppe, if you are looking at a R/C model you need to check out the April 2002 "Flying Scale Models" magazine. There is an article of a 54 1/2 inch span for a 30-40 engine drsigned by Pete Miller. Has build photos, reduced sized plans and 3 views. Also an article and photos of the full size.
I know about the article, but don't think to be of any use to me, I'm designing a tow plane for 62 c.c. gas engine. The small 3-views sent by David is enough......till a good one can be found, but I think I'll have my model flying by then. I think it's odd not to find more information an this plane. Anyway, thanks for your time.
The Fletcher FD-25 pictured above, N240FD was the second prototype "D" model built but was the third FD-25 off the production line as prior to this aircraft a twin, tandem seat, "A" model had been built however it crashed during spin testing killing its pilot and this version was abandoned. Demonstrated to US Army officials the "D" failed to attract interest and as a consequence only three FD-25 were built in the US. Production rights were sold to the Japanese Toyo Company who is reputed to have build around two dozen of the aircraft in 1954 for the Vietnamese and Cambodian Air Forces but it is believed that the aircraft's magnesium components did not fare well in the harsh tropical climate and their service was brief. At least one Japanese built FD-25A exists to this day in a Tokyo technical museum