ClipArt ETC
A dihedral board on an aeroplane, or airplane, for stability. The boards are raised on short legs over the ribs with a spirit level on top of the board. Dihedral boards are used as a last result due to inaccuracy in stability.

Dihedral Board Aeroplane

A dihedral board on an aeroplane, or airplane, for stability. The boards are raised on short legs over…