Wing twist

The twist is the structural distortion of the wings, which seeks a favorable environment for the flight characteristics of the aircraft behavior in the event of a stall. This can be done by geometric or aerodynamic twist.

By increasing the angle of attack during the flight it comes from a certain angle to stall and the loss of the dynamic lift. The aim of the twist is to achieve a gradual loss of buoyancy - as opposed to an abrupt over the entire support surface.

It is intended that by increasing the angle of attack at first only in the region of the root rib ( wing root ) comes to stall, the wing panels outboard will still be flowing normally and generate lift. The aircraft can be controlled by the ailerons also outside. In addition, a stall which possibly occurs only on one wing tip, much more difficult to intercept.

Geometric twist

In the construction of the wing, the outer tread rib, also end rib, rotated relative to the inner tread rib, also root rib with the leading edge down. Although root and tip rib having the same profile with the same maximum angle of attack, in the wing root (inside ), this occurs first, thus finds in coating a continuous demolition, starting at the wing root instead. The advantage over the aerodynamic twist is in the simpler and therefore more cost -effective design, the disadvantage in the higher resistance increase.

Aerodynamic twist

Wing root and tip rib do not differ by an angle difference of the chord, but by choosing a different profile shape. The end rib should have a profile shape which allows a greater angle of attack. The degree of change in shape of the individual intermediate ribs can take place either linear or irregular. Although in this case also increases the total resistance of the wing, the amount is significantly less than the geometric setting. The disadvantage lies in the extra effort in building.

By twist so the performance of a certain profile is slightly affected, the slow flight characteristics of the aircraft but improved considerably.