Parker variable wing

The Parker variable wing is a wing configuration in biplane or triplane aircraft designed by H.F. Parker in 1920.

[1] His design allows a supplement in lift while landing or taking-off.

At high angle of attack the flow over the lower airfoil will cause the airflow to bend up and create an upward force at the lower surface of the upper airfoil.

The flexible wing section is held at points A and B.

The trailing edge is rigid and can rotate about point B.