text: The curve of drag or thrust required versus 
  velocity shows the variation of induced, para- 
  Induced drag predomi- 
  site, and total drag. 
  nates at low speeds. When the airplane is 
  operated at maximum lift-drag ratio, (L/D)-, 
  the total drag is at a minimum and the induced 
  and parasite drags are equal. For the specific 
  airplane of figure 2.1, (,L/D),, and minimum 
  total drag are obtained at a speed of 160 knots. 
  The curve of power required versus velocity 
  shows the variation of induced, parasite, and 
  total power 
  required. As before, induced 
  power required predominates at low speeds and 
  parasite power required predominates at high 
  speeds and the induced and parasite power are 
  equal at (L/D),,. 
  However, the condition of 
  (L/D&- 
  defines only the point of minimum 
  drag and does not define the point of minimum 
  pozver required. Ordinarily, 
  the point of mini- 
  mum power required will occur at a speed 
  which is 76 percent of the speed for minimum 
  drag and, in the case of the airplane configura- 
  tion of figure 2.1, the speed for minimum power 
  required would be 122 knots. The total drag 
  at the speed for minimum power required is 15 
  percent higher than the drag at (L/D)- 
  but the 
  minimum power required is 12 percent lower 
  than the power required at (L/D)-. 