Form drag is defined as:

• A. The drag created by skin friction on the surface.
• B. The drag caused by induced drag.
• C. The drag created because of the shape of a component or the aircraft.
• D. The drag due to weather conditions.

Answer: (C)

Form drag arises from the way the airflow has to flow around the aircraft’s shape, creating pressure differences and flow separation that produce a wake behind the vehicle. It’s a type of parasite drag tied to the form of the body or its components; a streamlined shape helps the flow stay attached and reduces this drag, while bluff or irregular shapes increase it. This is distinct from skin friction drag, which comes from the viscous shear along the surface, and from induced drag, which is generated by lift and wingtip vortices. Drag due to weather conditions isn’t a separate drag type. So the best description is the drag created because of the shape of a component or the aircraft.