Induced drag and how does it relate to speed and wing loading?

Induced drag and how does it relate to speed and wing loading?

• A. Induced drag arises from lift generation; decreases with increasing airspeed and increases with higher lift demand and lower aspect ratio
• B. Induced drag arises from skin friction; increases with speed
• C. Induced drag is independent of lift, speed
• D. Induced drag is only present at transonic speeds

Answer: (A)

Induced drag is a byproduct of how lift is produced by the wing. When the wing generates lift, air streams around the wingtips create trailing vortices and a downward flow (downwash). Energy spent to sustain those vortices shows up as drag, so induced drag is fundamentally linked to lift generation. Its magnitude changes with speed and wing geometry. At higher airspeeds, the wing can produce the same lift with a smaller lift coefficient, so the induced drag drops as speed increases. When the lift demand is higher—due to heavier weight or a smaller wing area—the wing must generate more lift, which increases induced drag. The wing’s aspect ratio also matters: lower aspect ratio (shorter, stubbier wings) strengthens the wingtip vortices and raises induced drag, while higher aspect ratio wings spread out lift more efficiently and reduce induced drag. So induced drag arises from lift, decreases with increasing speed, and increases with higher lift demand and with lower aspect ratio.

Induced drag is a byproduct of how lift is produced by the wing. When the wing generates lift, air streams around the wingtips create trailing vortices and a downward flow (downwash). Energy spent to sustain those vortices shows up as drag, so induced drag is fundamentally linked to lift generation.

Its magnitude changes with speed and wing geometry. At higher airspeeds, the wing can produce the same lift with a smaller lift coefficient, so the induced drag drops as speed increases. When the lift demand is higher—due to heavier weight or a smaller wing area—the wing must generate more lift, which increases induced drag. The wing’s aspect ratio also matters: lower aspect ratio (shorter, stubbier wings) strengthens the wingtip vortices and raises induced drag, while higher aspect ratio wings spread out lift more efficiently and reduce induced drag.

So induced drag arises from lift, decreases with increasing speed, and increases with higher lift demand and with lower aspect ratio.