text: (C) The point of minimum total drag occurs 
  at a speed of 163 knots. Since this speed in- 
  curs the least total drag for lift-equal-weight 
  the airplane is operating at (L/D)ma,. 
  flight, 
  Because of the particular manner in which 
  parasite and induced drags vary with speed 
  (parasite drag directly as the speed squared; 
  induced drag inversely as the speed squared) 
  the minimum total drag occurs when the in- 
  duced and parasite drags are equal. The speed 
  for minimum drag is an important reference for 
  many items of airplane performance. One 
  item previously ,presented related glide per- 
  formance and lift-drag ratio. At the speed of 
  163 knots this airplane incurs a total drag of 
  778 lbs. while producing 12,000 lbs. of lift. 
  These figures indicate a maximum lift-drag 
  ratio of 15.4.and relate a glide ratio of 15.4.~ 
  In addition, if this airplane were jet powered, 
  the airplane would achieve maximum en- 
  durance at this airspeed for ‘the specified alti- 
  If this airplane were propeller powered, 
  tude. 
  the airplane would achieve maximum range at 
  this airspeed for the specified altitude. 