During a level coordinated turn in smooth air, wing loading depends upon which factor?

During a level coordinated turn in smooth air, wing loading depends upon which factor?

• A. aircraft weight
• B. angle of bank
• C. air density only
• D. altitude only

Answer: (B)

In a level coordinated turn the lift must do two jobs at once: support the weight and provide the centripetal force for turning. To keep altitude, the vertical component of lift must balance weight, so L cos(phi) = W, where phi is the bank angle. Solving gives L = W / cos(phi) = W sec(phi). Wing loading is lift per unit wing area, L/S, so with fixed weight and wing area, wing loading becomes (W/S) sec(phi). That means wing loading grows as the bank angle increases, because more lift is required to maintain the level turn. Weight or altitude/density don’t set how wing loading changes with bank in this scenario; the bank angle is the controlling factor.

In a level coordinated turn the lift must do two jobs at once: support the weight and provide the centripetal force for turning. To keep altitude, the vertical component of lift must balance weight, so L cos(phi) = W, where phi is the bank angle. Solving gives L = W / cos(phi) = W sec(phi). Wing loading is lift per unit wing area, L/S, so with fixed weight and wing area, wing loading becomes (W/S) sec(phi). That means wing loading grows as the bank angle increases, because more lift is required to maintain the level turn. Weight or altitude/density don’t set how wing loading changes with bank in this scenario; the bank angle is the controlling factor.