What are the two main types of aerodynamic drag?

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

Answer: (A)

The question tests your understanding of the two broad categories of aerodynamic drag. Induced drag is the portion that comes from generating lift; it arises from wingtip vortices and is tied to how much lift you need. Parasite drag is all the drag not directly related to lift, and it includes skin friction (viscous drag on the surface), form drag (shape-related pressure drag), and interference drag (effects where components interact).

Why this is the best answer: you’re being asked to name the two main types of drag, and the standard classification is induced drag plus parasite drag. The other options mix induced drag with specific subtypes of parasite drag (skin friction, form drag, interference drag), which are not themselves considered separate top-level categories. So the pair that correctly identifies the two primary drag types is induced drag and parasite drag.

Context to help understanding: induced drag decreases as speed increases (since required lift coefficient drops), while parasite drag increases with speed (roughly with the square of velocity). At low speeds, induced drag dominates; at high speeds, parasite drag dominates. This interplay shapes performance like fuel burn and optimum cruise speed.