text: flaps shown on 
  figure 1.19 causes a reduction of drag coeffi- 
  cient at 
  coefficient. This drag 
  reduction improves the acceleration of the 
  airplane. 
  
  (2) The retraction of 
  
  that  lift 
  
  flaps requires an 
  increase in angle of attack to maintain the 
  same lift coefficient. Thus, if airplane accel- 
  eration is low 
  the flap retraction 
  speed range, angle of attack must be in- 
  creased to prevent the airplane from sinking. 
  This situation is typical after takeoff when 
  gross weight, density altitude, and tempera- 
  ture are high. However, some aircraft have 
  such high acceleration through the flap re- 
  traction speed that 
  the rapid gain in air- 
  speed requtres much less noticeable attitude 
  change. 
  
  (3) The retraction of 