text: Thus, wirh rhe higher lift coefficienr available, 
  less dynamic pressure is required to provide 
  the necessary lift. 
  
  angle of attack is unaffected. At any parricu- 
  lar altitude, the indicated stall speed is a func- 
  tion of weight and load factor. An increase 
  in altitude will produce a decrease in density 
  and increase the true airspeed at stall. Also, 
  an increase in altitude will alter compressibility 
  and viscosity effects and, generally speaking, 
  cause the 
  increase. 
  in,&ztcd stall speed to 
  This parti&lar 
  consideration is usually sig- 
  nificant only above altitudes of 20,000 ft. 
  
  Because of the stated variation of stall speed 
  with C-, 
  large changes in CL- are necessary 
  to produce significant changes in stall speed. 
  This effect is illustrated by the graph in figure 
  1.16 and certain 
  typical values are shown 
  below: 
  
  Percent increase  in CL.  .~.  2 10 so  loo 300 
  
  Recovery from stall involves a very simple 
  concept. Since stall 
  is precipitated by an 
  excessive angle of attack, the angle of attack 
  must be dccmmd. This is a fundamental princi- 
  ple which is common to any airplane. 