Hello; Tyvek is definately heavier than mono-ultracote, but the strength it gives the spindly wing is worth the weight. I scratch built my speedy Bee from plans while I was recovering the use of my right arm, so I concentrated on lightness. I built it using carpenter's glue and contest grade balsa. Finished it weighed 3 1/2 pounds ready to fly. lots of differential in the ailerons, little down lots of up, or it'll adverse roll.

I had a pair of floats doing nothing so I elastic banded the Bee to one float and flew it at the lake.