The yawing moment due to side force on the vertical tail refers to the rotational force created around the aircraft’s center of gravity when the aircraft experiences sideslip. This moment (Nv) is directly proportional to the side force (Yv) generated by the vertical tail. The lever arm (lv) represents the distance from the center of gravity to the vertical tail, influencing the effectiveness of the yawing moment. The formula to calculate Yawing moment as follows:
Where:
- Nv is the Yawing moment of Vertical tail in Nm,
- Yv is the Side force in N.
- lv is the  Vertical tail moment arm in m.