During the COVID-19 1st lock down I eventually got motivated to build a copy of Wolfgang Matt's Rubin. This is the model that he won the European Championships with in 1992 and 1994. A few clicks of aileron trim and a bit more elevator trim was needed. There was a strong cross wind so it was difficult to slow it down for landing. Maidened May 2020 at WimborneMAC field.
Fuselage. A very simple box with thick sheets of balsa on top of the nose in front of the canopy. Turtle decks cut from white foam and skinned with 1/16 balsa using Gorilla Glue. I was not looking forward to cutting these, but they were a lot easier to make than expected. Once glued to the fuselage and carved/sanded to shape you get a very strong but light fuselage. Fin and rudder made in the same way. The top of the fin is a sandwich of 2 sheets of light balsa with a 1/32 ply filling. This allows me to sand it down to a taper and a) retain strength and b) allows me to sand each side equally down to the ply.
Hot wire cut foam for Wing and skins made from six sheets of 4" balsa and 1 sheet of 3". This is for just one half, so a total of 12 x 4" and 2 x 3" sheets in total...it's a big wing!
Full build blog here https://wimbornemac.org/forum/kits-and-scratch-build/2426-rubin?start=0