Which of the following is NOT an advantage of a nonsymmetrical airfoil?

Which of the following is NOT an advantage of a nonsymmetrical airfoil?

• A. More lift at a given AOA
• B. Increased lift/drag radius
• C. Better stall characteristics
• D. Higher drag at a given angle of attack

Answer: (D)

Camber in a nonsymmetrical airfoil shifts the lift curve so you get more lift at the same angle of attack, because the curved upper surface creates a stronger suction and a different pressure distribution between the surfaces. That means you can generate the needed thrust or lift at lower speeds, which is a clear advantage in takeoff, hover, and low-speed flight. The camber also tends to allow higher allowable lift before stall and often yields a more favorable stall behavior, with a smoother, more controllable drop in lift. In many flight regimes, the overall lift-to-drag performance is improved compared with a symmetric section, contributing to better efficiency. The aspect that is not an advantage is higher drag at a given angle of attack; the drag penalty from camber is the trade-off, so it’s not something you count as an advantage.

Camber in a nonsymmetrical airfoil shifts the lift curve so you get more lift at the same angle of attack, because the curved upper surface creates a stronger suction and a different pressure distribution between the surfaces. That means you can generate the needed thrust or lift at lower speeds, which is a clear advantage in takeoff, hover, and low-speed flight. The camber also tends to allow higher allowable lift before stall and often yields a more favorable stall behavior, with a smoother, more controllable drop in lift. In many flight regimes, the overall lift-to-drag performance is improved compared with a symmetric section, contributing to better efficiency. The aspect that is not an advantage is higher drag at a given angle of attack; the drag penalty from camber is the trade-off, so it’s not something you count as an advantage.