I'm designing an true ultralight floatplane with a square aluminum tube fuselage and it has proven to be almost impossible to find useful information regarding ultralight design. So I was wondering if anybody could help me out and tell me some good books that are actually geared towards design of an ultralight or classic airplane. I have been looking for about six months now and all I can find is for designing a modern plane. The most informative book I have found thus far isn't even for airplane design at all. if anyone could please help me out with this it would be very much appreciated