Deploying flaps has what effect on lift, stall speed, and parasite drag?

• A. Increases stall speed
• B. Increases parasite drag and lowers stall speed
• C. Decreases lift
• D. Flaps increase lift, lower stall speed, increase parasite drag, change stall characteristics and pitch stability

Answer: (D)

Deploying flaps increases the wing’s camber and effectively the wing’s surface area, so it can generate more lift at lower speeds. That higher lift means you can reach the desired lift with a slower airspeed, hence the stall speed is reduced. The flip side is that more surface area and a longer aerodynamic surface create more parasite drag, so the drag rises when flaps are extended. The change in lift distribution and moment from the extended flaps also alters how the wing stalls and how the aircraft behaves in pitch, i.e., stall characteristics and pitch stability are affected.