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To counter adverse yaw, an aircraft has aileron/rudder coupling. In a right turn, the left aileron goes (1) _____, the right aileron goes (2) _____, and the rudder automatically moves to the (3) _____.
  • A
    (1) down; (2) up; (3) right.
  • B
    (1) up; (2) up; (3) right.
  • C
    (1)down; (2) down; (3) left.
  • D
    (1) up; (2) down; (3) left.

Adverse yaw is a yawing motion opposite to the turning/rolling motion of the aircraft. Adverse yaw is caused by the drag on the down-going aileron being greater than that on the up-going aileron. This imbalance in drag causes the yawing motion around the normal/vertical axis. Since this yaw is adverse (i.e., in a banked turn to the left, the yaw is to the right), it is opposing the turn, which is detrimental to the aircraft's performance.

  • To counter adverse yaw, some aircraft incorporate aileron/rudder coupling which is a system that automatically applies a rudder input in a turn to counter the adverse yawing moments generated by the ailerons.
  • In a right turn, the left wing lift is increased by lowering the aileron. As we have described above, increased lift, increases induced drag, which generates a yawing moment in the opposite direction. As a result, the aircraft will be in an unbalanced turn. To re-balance the turn, right rudder must be applied.

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