Which term describes parasite drag caused by the shape of the aircraft and airflow around it?

• A. Skin friction drag
• B. Interference drag
• C. Form drag
• D. Induced drag

Answer: (C)

Form drag is the parasite drag that comes from the pressure differences around the aircraft as air flows past its shape. When the flow encounters the nose, sides, and tail, it must accelerate and decelerate, creating high pressure in some regions and lower pressure in others. This pressure distribution around the body produces drag that is tied to the overall shape and cross-sectional area facing the flow. It’s distinct from skin friction drag, which arises from viscous shear along surfaces; from interference drag, which comes from flow interactions at junctions; and from induced drag, which is tied to lift generation rather than the body’s shape in the flow. So the term describing parasite drag caused by the aircraft’s shape and the surrounding airflow is form drag.