What is aerodynamic lift?

• A. The force perpendicular to the relative wind that enables the aircraft to rise, produced by pressure differences over the wing.
• B. The forward force that moves the airplane.
• C. The drag acting on the wings.
• D. The friction between the fuselage and air.

Answer: (A)

Lift is the force perpendicular to the relative wind that enables the aircraft to rise, produced by pressure differences over the wing. The wing’s shape and angle of attack speed up air over the top surface, lowering its pressure, while air beneath the wing is pushed downward, increasing bottom pressure. The resulting pressure difference creates an upward force that counteracts gravity and keeps the airplane aloft. This lift acts largely vertical when the wings are level; when the aircraft banks, the lift vector tilts with the wings. The other forces—thrust, which pushes forward; drag, which resists motion along the path; and friction on the surface—are not lift.