Dihedral

[Nesh]

What is the perfect dihedral for a plane?

[jander14indoor]

theoretically, an eliptical dihedral
Practically, just enough dihedral to maintain stability and not so much as to induce dutch roll.
Single V diheral works fine, two break (tips only up) is a little better but harder to build, three break (center and tips) better still, but again harder.

BUT, the increase in efficiency is NOT one of your big worries unless you are excessive (dutch rolling) or unstable (plane wants to flip over and can't stop.
Spend time on other aspects of your plane first.

Jeff Anderson
Livonia, MI