Which statement correctly describes the two main drag components affecting total drag on a wing?

• A. Skin friction drag and wave drag.
• B. Induced drag and wave drag.
• C. Induced drag and parasite drag.
• D. Profile drag and interference drag.

Answer: (C)

The two main drag components are induced drag and parasite drag. Induced drag comes from the wing producing lift—the lift creation creates downwash and wingtip vortices, which wastes energy and shows up as drag that decreases as speed increases. Parasite drag is everything else resisting the aircraft’s motion that doesn’t contribute to lift, including skin friction over surfaces, form drag from the shape, and interference drag where flows interact around joints and attachments. Wave drag is a transonic phenomenon that becomes significant at higher speeds and is generally considered part of parasite drag rather than a separate main component.

So the correct pairing reflects the broad split: lift-related drag versus all other drag sources. The other options mix in only parts of parasite drag or pair induced drag with a specialized form (like wave drag), which doesn’t capture the two overarching categories.