text: The effect of a change in weight on the thrust 
  and power required is illustrated by figure 2.2. 
  1 The primary effect of a weight change is a 
  change in the induced drag and induced power 
  required at any given speed. Thus, the great- 
  est changes in the curves of thrust and power 
  required will 
  take place in the range of low 
  speed flight where the induced effects pre- 
  dominate. The changes in thrust and power 
  required in the range of high speed flight are 
  relatively slight because parasite effects pre- 
  dominate at high speed. The induced effects 
  at high speed are relatively small and changes 
  in these items produce a small effect on the 
  total thrust or power required.  The same situation exists with respect to the 
  curves of power required where a change in 
  weight requires a change of speed to maintain 
  flight at a particular CL. For example, if the 
  15,000-lb. airplane achieves minimum power 
  required at 122 knots, an increase in weight to 
  22,500 Ibs. increases the speed for minimum 
  power required to 149 knots. 
  
  0f course, the thrust and power required at 
  specific lift coefficients are altered by changes in 
  weight. At a specific C,, any change in weight 
  causes a like change in thrust required, e.g., a 
  50-percent increase in weight causes a 50-per- 
  cent increase in thrust required at the same C,. 
  The effect of a weight change on the power re- 
  quired at a specific CL is a bit more complex be- 
  cause a change in speed accompanies the change 