RE: F104g 1:4 scale
Enrique,
To select the section of bar I calculate the force on wing @ 10g, I check what my aluminum supplier has and his material then I make some finite elements analysis to obtain @ 10g the maximum stress lower then yeld.
The used material is EN AW 6082 T6, Rp =250 Mpa and Rm =310 Mpa 20x15 mm thickness=1.3mm.
2 bars are little bit over dimensioned (max stress obtained in traction is about 190MPa), this is not the ideal section, but it is the best solution that I find from my alu supplier!
This kind of calculation was done before starting to engineers the model, the same methodology was used to calculate the gears support.
About the details of splitting, this evening I make some photos!
damiano