One wing: a Stephenson six-bar

Complete right wing

Enlarged shoulder and crank

Count rigid bodies, not separate wooden pieces

Dark gray dashed: target wing position
Light gray solid (ending at T): actual wing position

  1. Frame O–S: the only stationary link.
  2. Crank O–A–D: blue shoulder arm and orange elbow arm locked to one shaft; one moving link. The blue triangle groups them.
  3. Shoulder coupler A–B (blue).
  4. Inner wing S–B–E: rocker and inner spar rigidly connected; one moving link.
  5. Elbow coupler D–Q.
  6. Outer wing E–Q–T: red output lever and pale outer spar rigidly connected. T is the wingtip, not a joint.

Why Stephenson?

The three-joint links O–A–D and S–B–E do not share a joint. They connect through other links. In a Watt chain, the two three-joint links share a joint directly.

There is no fixed triangular link here. O and S are fixed points, but their attached triangles rotate about them.