text: The effectiveness of flaps on a wing con- 
  figuration depend on many different factors. 
  factor is the amount of the 
  One important 
  wing area affected by 
  flaps. Since a 
  certain amount of the span is reserved for 
  ailerons, the actual wing maximum lift prop- 
  erties will be less than that of the flapped 
  two-dimensional section. 
  the basic wing 
  has a low thickness, any type of flap will be 
  less effective than on a wing of greater thick- 
  ness. Sweepback of the wing can cause an 
  additional significant reduction in the effec- 
  tiveness of flaps. 
  
  the 
  
  The slottedPap is similar to the plain flap but 
  the gap between the main section and flap 
  leading edge is given specific contours. High 
  energy air from the lower surface is ducted to 
  the flap upper surface. The high energy air 
  the slot accelerates the upper surface 
  from 
  boundary layer and delays airflow separation 
  to some higher lift coefficient. The slotted 
  flap can cause much greater increases in c,,, 
  than the plain or split flap and section drags 
  are much lower. 
  
  The Fowkr&zp arrangement is similar to the 
  the de- 
  slotted flap. The difference is that 
  flected flap segment is moved aft along a set of 
  tracks which 
  increases the chord and effects 
  an increase in wing area. The Fowler flap is 
  characterized by large increases in c,,, with 
  minimum changes in drag. ,. 