text: fuselage and nacelles of high 
  well faired canopies, and thin wing sections 
  which have very smooth uniform pressure dis- 
  tributions. 
  -Low aspect ratios and sweepback 
  are favorable in delaying and reducing the 
  compressibility drag rise. 
  inter- 
  ference effects are quite important in transonic 
  and supersonic flight and the airplane cross 
  section area distribution must be controlled 
  to minimize local velocity peaks which could 
  create premature strong shock wave formation. 
  The modern configuration of airplane will 
  illustrate 
  the features required to effect very 
  high speed performance-low 
  aspect ratio, 
  sweepback, thin low drag sections, etc. These 
  same features produce flight characteristics at 
  low airspeeds which necessitate .proper flying 
  technique. 
  
  fineness ratio, 
  
  as great a speed or one-fourth as much parasite 
  drag at half the original speed. This fact may 
  be appreciated by the relationship of dynamic 
  pressure with speed-twice as much V, four 
  times as much 4, and four times as much D,. 
  This expressed variation of parasite drag with 
  speed points out that parasite drag will be of 
  greatest importance at high speeds and prac- 
  tically 
  insignificant in flight at low dynamic 
  pressures. To illustrate this fact, an airplane 
  in flight just above the stall speed could have a 
  parasite drag which is only 25 percent of the 
  total drag. However, this same airpfane at 
  maximum level flight speed at low altitude 
  would have a parasite drag which’ 
  is very 
  nearly 100 percent of the total drag. The 
  predominance of parasite drag at high flight 
  speeds emphasizes the necessity for great aero- 
  dynamic cleanness (low j) to obtain high speed 
  performance. 