Adverse yaw

Turning moment in Aircraft a label for a torque about the vertical axis (z -axis) of an aircraft.

In horizontal flight a turning moment is caused only by the operation of the rudder.

Usually undesirable, the adverse yaw, which is caused by operation of the ailerons. By aileron "rolls" the aircraft, although as desired, but also leads one of the intuitive expectation opposite motion along the vertical axis: the lowered aileron on the raised wing generates next to the increased buoyancy in addition an increased air resistance, which in turn causes a significant braking effect. Consequently, the plane in the direction of the braked giert support surface and therefore to the rolling direction "negative".

The adverse yaw moment can be counteracted by a synchronous operation of the aileron and rudder: So should be done with the actuation of the joystick to the left and to the resulting right-sided reduction of the aileron also always simultaneously (synchronously) a left-side swing of the Seitenrruders to yaw the to avoid airplane's longitudinal axis to the right. Therefore, the two rudder deflections usually occur synchronously. This applies analogously to a turn to the right.

For larger aircraft, the adverse yaw torque is automatically counteracted by springs or spoilers. Also by differential aileron is countering negative yaw constructive. In a normal aileron is the amount by which the aileron one side lifts ( inside of the curve ), equal to the amount by which lowers the other aileron ( outside of the curve ). In a differential aileron deflection of the heaving aileron is stronger than the rash of be -lowering aileron. The heaving ailerons located on the side on which the wing is lower ( buoyancy reduction ). To increase the positive and reduce the negative turning moment and air resistance on the lowered side should be increased - hence the stronger deflection of the aileron. On the side where the wings to lift (ie the outside of the curve ), to lowering the aileron indeed increase the lift of the wing, but not possible, the air resistance. The increase in resistance can be technically not be completely avoided, but is offset by the much lower deflection down.

Not to be confused is the adverse yaw with the rudder reversal effect.

• Flight control
• Gliding