text: High lift devices applied to the leading edge 
  of a section consist of slots, slats, and small 
  amounts of local camber. The fixed slot in a 
  wing conducts flow of high energy air into the 
  boundary layer on the upper surface and delays 
  airflow separation to some higher angle of 
  attack and 
  lift coefficient. Since the slot 
  alone effects no change in camber, the higher 
  maximum lift coefficient will be obtained at a 
  higher angle of attack, i.e., the slot simply 
  delays stall to a higher angle of attack. An 
  automatic slot arrangement consists of a 
  leading edge segment (slat) which 
  is free to 
  move on tracks. At low angles of attack the 
  slat is held flush against the leading edge by 
  the high positive local pressures. When the 
  section is at high angles of attack, the high 
  local suction pressures at the leading edge 
  create a chordwise force forward 
  to actuate 
  the slat. The slot formed then allows the 
  section to continue to a higher angle of attack 
  and produce a clno. greater than that of the 