Which force pulls the aircraft from a straight flight path to cause a turn?

Which force pulls the aircraft from a straight flight path to cause a turn?

• A. Centrifugal force
• B. Horizontal component of lift
• C. Drag
• D. Weight

Answer: (B)

Turning an airplane comes from tilting the lift vector when you bank. Lift acts perpendicular to the wings, so when you roll into a bank, lift tilts away from perfectly vertical. The vertical component of lift continues to support the airplane’s weight, while the horizontal component points toward the inside of the turn and provides the centripetal force needed to change direction. In a level coordinated turn, the lift is increased so that its vertical component balances weight and its horizontal component equals m v^2 / r, the required centripetal force. Drag and weight don’t cause the turn by themselves—drag resists motion along the path, and weight acts downward. Centrifugal force is not an actual force acting on the aircraft in an inertial frame. So the horizontal component of lift is what pulls the aircraft from a straight path to make it turn.

Turning an airplane comes from tilting the lift vector when you bank. Lift acts perpendicular to the wings, so when you roll into a bank, lift tilts away from perfectly vertical. The vertical component of lift continues to support the airplane’s weight, while the horizontal component points toward the inside of the turn and provides the centripetal force needed to change direction. In a level coordinated turn, the lift is increased so that its vertical component balances weight and its horizontal component equals m v^2 / r, the required centripetal force. Drag and weight don’t cause the turn by themselves—drag resists motion along the path, and weight acts downward. Centrifugal force is not an actual force acting on the aircraft in an inertial frame. So the horizontal component of lift is what pulls the aircraft from a straight path to make it turn.