Roll-Yaw Interaction

Coupled Motion

Roll and Yaw are rarely isolated.

• Roll causes Yaw: Sideslip towards the low wing -> Weathercock stability yaws nose into the slip. Also adverse yaw.
• Yaw causes Roll: Outer wing moves faster -> More Lift -> Rolls into the turn.

Adverse Yaw (Review)

• Cause: Induced drag differential from aileron deflection.
• Effect: Nose yaws opposite to the turn entry.
• Correction: Coordinated rudder input into the turn.

Sideslip

Movement of the aircraft where the relative wind is not aligned with the longitudinal axis.

• Essential for Crosswind Landings: Prevents drift while keeping nose aligned (or checking drift).
• Induced by: Rudder input without bank, or bank without turn (slipping turn).