Adverse yaw during a turn entry is caused by?

Adverse yaw during a turn entry occurs primarily due to the differences in drag experienced by the wings as the aircraft begins to bank. When the pilot initiates a turn, the aileron on the wing that is lowered (the wing that is turning downward) is deflected downward, while the aileron on the raised wing goes upward.

This downward deflection of the aileron increases the camber of the lowered wing, resulting in an increase in lift but also in induced drag. Conversely, the upward deflection of the aileron on the raised wing decreases its lift and reduces the induced drag on this wing. The resulting imbalance between the two wings causes the aircraft to yaw toward the wing with the reduced lift and increased drag—hence, the term "adverse yaw."

In summary, the phenomenon is directly related to the changes in induced drag: the increased induced drag on the lowered wing due to its higher lift production and the decreased induced drag on the raised wing leads to the undesirable yawing motion that pilots need to compensate for during the turn. Understanding this concept is crucial for flight instructors to teach students effective handling techniques during turns.