Why is the Robin wing shaped the way it is?

The outer section of the Robin wing has dihedral, which gives increased stability in bank and in turns.

The outer wing section also has a high degree of washout, so it provides minimal lift and drag in cruise, but gives extra lift at high angles of attack, improving low speed stability and reducing the stall speed.

Note that the ailerons are located on the dihedral section, improving their efficiency in turns and retaining their effectiveness at or near the stall.

Virtually all wings, other than in some military combat types, incorporate dihedral for stability but to twist a wing that has constant dihedral to provide washout near the outer ends is complicated and, therefore, expensive, which is why you see stall strips on the inner section of some wings. Stall strips are really a cheap fudge to cause the inner part of the wing to stall before the outer part. The craftwmen-made wooden structure of the Robin (originally Jodel) wing effectively combines constructional and aerodynamic efficiency without the compromises of other designs.

 Mistral Aviation LLP, Elstree Aerodrome WD6 3AW; +44 (0)7973 691727; sales@mistralaviation.co.uk