Theory of Rotary Wing Flight Practice Test 2026 - Free Helicopter Flight Theory Questions and Study Resource

Lift and drag are the two components of the total aerodynamic force on a wing or rotor blade moving through air. When air flows past a surface, pressure differences and viscous effects produce a force that can be resolved into two orthogonal components relative to the oncoming air: lift, which acts perpendicular to the relative wind, and drag, which acts parallel to the relative wind and opposite to the direction of motion. The total aerodynamic force is simply the vector sum of lift and drag.

Lift provides the vertical support or contributes to the vertical load, while drag resists forward motion and increases with speed. The other options mix in forces that come from propulsion (thrust and torque) or refer to non-force quantities (pressure, velocity) or a non-force pair (speed and lift), so they don’t describe the two components of the aerodynamic force.