How does an aircraft's configuration affect its drag?

The impact of an aircraft's configuration on drag is significant because changing its configuration can alter both the shape of the wings and the total surface area exposed to the airflow. When an aircraft's flaps, slats, or landing gear are deployed, for example, these adjustments modify the wing's profile, increasing the boundary layer and creating additional turbulent flow. This, in turn, raises the drag experienced by the aircraft due to the increased surface area and changes in airflow patterns over the wings.

In a clean configuration (with flaps retracted, landing gear up, etc.), an aircraft can achieve lower drag levels, enhancing efficiency and performance. Conversely, when configurations are adjusted for landing or takeoff, which typically involve deploying flaps or extending gear, drag increases to provide the necessary lift at lower speeds, but at the cost of increased resistance to forward motion.

Drag is a critical aspect to consider in flight operations, particularly during phases of flight where configurations are altered, emphasizing the importance of understanding how wing shape and surface area affect aerodynamic drag.