Flaps

1. Plain flap
   • Increases camber of the wing
   • Creates drag
   • Moves center of pressure backwards
   • Creates nose-down pitching moment
2. Split flap
   • Deflects
   • More lift than a plain flap
   • Same amount of drag as plain flap
3. Slotted flap
   • Most common type of flap
   • Like a split flap, but there's a gap between the wing and the flap
   • Slot energizes boundary layer behind the flap, which delays the critical AoA before stall
   • Can have multiple slots
4. Fowler flap
   • Flaps which "slide" down and back from the wing
   • Common on airliners
   • Increase wing surface area
   • Small deflection adds lift
   • End of the deflection is mostly drag
5. Slotted fowler flap
   • Combines the advantages of fowlers and slotted flaps

Pilot's Handbook of Aeronautical Knowledge pg. 3-6