text: The plainjap shown in figure 1.17 is a simple 
  hinged portion of the trailing edge. The effect 
  of the camber added well aft on the chord 
  causes a significant increase in cbr. 
  In addi- 
  tion, 
  the zero lift angle changes to a more 
  negative value and the drag increases greatly. 
  The split flap shown in figure 1.17 consist of 
  plate deflected from the lower surface of the 
  section and produces a slightly greater change 
  than the plain flap. However, a much 
  in c ImoT 
  larger change in drag results from the great 
  turbulent wake produced by this 
  flap. 
  The greater drag’may not be such a disadvan- 
  rage when ir is realized that it may be advan- 
  tageous to accomplish steeper landing ap- 
  proaches over obstacles or require higher power 
  from the engine during approach (to minimize 
  engine acceleration time for waveoR). 
  
  loads on the structure and pitching moments 
  the horizontal 
  that must be controlled with 
  tail. Unfortunately, 
  the flap types producing 
  the greatest increases in c,,- usually cause the 
  greatest twisting moments. The Fowler flap 
  causes the greatest change in twisting moment 
  while 
  flap causes the least. This 
  factor-along with mechanical complexity of 
  the installation-may 
  complicate the choice 
  of a flap configuration. 
  
  the split 