Vertical Tail Geometric Twist Angle

Vertical tail twist is the angle of incidence of a vertical tail section, measured in a plane parallel to the XY plane. The twist is positive if the nose of the section is rotated in the positive Body Y Axis direction as shown in the graphic below.

The vertical tail twist angle refers to the twist angle at the tip chord, which is usually zero.

Note: The twist angle is taken from the quarter chord point.

See Graphic