Lift & Drag Devices

Lift & Drag Devices

1. Lift Devices

   • Hinged/pivoted or sliding profiles near trailing edge
   • Mainly used for landing to increase lift and drag
   • Used for take-off on large aircraft to increase lift
   • Plain Flap
     • Looks like a control surface
     • Flaps on two wings linked, move down together
     • 55% lift increase
   • Split Edge Flap
     • 65% lift increase
     • Flat metal plate which is hinged along its forward edge
   • Slotted Flap
     • 70% lift increase
     • Allows air from lower side of wing to upper side
       • Helps prevent early flow seperation
   • Fowler Flap
     • 95% lift increase
     • Rolls bac on a track when extended
     • Increases effective wing area and lowers trailing edge
     • Fits into lower contour of trailing edge when retracted
   • Slat
     • Moveable leading edge of the wing
     • Forms a slot when extended
     • 35% lift increase

2. Drag Devices

   • Spoilers
     • Located on upper surface of the wing close to the trailing edge
     • Increases drag
     • Reduces lift
   • Air Brakes
     • Located in areas where structure is strong enough to withstand heavy air-loads
     • Some civil aircraft, tail cone is separated to increase total drag without affecting lift
     • Some military aircraft, located on the upper surface
     • Some aircraft located on the left and right sidewalls