What is Dutch Roll?

Out-of-Phase Aircraft Motion

Definition

Dutch roll is an aircraft motion characterized by an out-of-phase combination of tail-wagging yaw and rocking from side to side (roll). It occurs when the aircraft rolls in one direction while yawing in the opposing direction.

Origin of the Name

The term "Dutch roll" derives from the distinctive motion of a classic sailing vessel, where the ship would alternately roll and yaw in a synchronized manner.

Characteristics

Dutch roll is a series of decreasing oscillations on both the rolling and yawing axes. As the aircraft attempts to stabilize itself on both axes, it undergoes a damped yaw oscillation accompanied by a roll.

Causes

Dutch roll typically arises from a lack of stability in the aircraft's yaw and roll axes. Factors such as insufficient fin area, low dihedral angle, or improper rudder sizing can contribute to this instability.

Consequences

Dutch roll can impair aircraft control and handling, lead to pilot discomfort, and potentially contribute to accidents. It is therefore essential for pilots to be aware of the potential for Dutch roll and to take appropriate corrective actions.

Corrective Measures

Pilots can mitigate the effects of Dutch roll by maintaining proper airspeed, using rudder to counteract yaw oscillations, and applying opposite aileron inputs to stabilize roll.