What is the typical cause of form drag in an aircraft?

Form drag, also known as pressure drag, primarily arises from the shape of an aircraft as it moves through the air. The design and contour of the aircraft influence how air flows around it. A well-shaped aircraft allows the air to flow smoothly over its surface, which minimizes turbulence and reduces drag. Conversely, a poorly shaped aircraft will cause the airflow to separate from the surface, leading to increased turbulence and, consequently, increased form drag.

While surface imperfections can contribute to increased drag by disrupting smooth airflow, form drag itself is more directly related to the overall shape of the aircraft rather than minor irregularities. Weight distribution and control surface movement are important factors in aircraft performance and handling, but they do not significantly influence the formation of form drag in the same fundamental way that aircraft shape does. The efficiency of the aircraft's design is crucial in understanding and managing drag in flight.