text: where 
  
  D,, = parasite drag corresponding to some orig- 
  
  inal altitude density ratio, 0, 
  
  D,,=parasite drag corresponding to some new 
  
  altitude density ratio, (ra 
  
  (and f, V are constant) 
  
  This relationship 
  implies that parasite drag 
  would decrease at altitude, e.g., a given air- 
  plane in flight at a given T.4.Y at 40,COO ft. 
  (e=O.29 would have one-fourth the parasite 
  drag when at sea level (u=l.OO). 
  This effect 
  results when the lower air density produces 
  less dynamic pressure. However, if the air- 
  plane is flown at a constant EAS, the dynamic 
  pressure and, thus, parasite drag do not vary. 
  In this case, the TASwould be higher at altitude 
  to provide the same EAS. 
  
  EFFECT OF SPEED. The effect of speed 
  
  alone on parasite drag is the most important. 
  If all other factors are held constant, the effect 
  of velocity on parasite drag is expressed as: 
  
  &, V,*
  -=- 
  (3 
  D,, V 
  
  where 
  
  D,,=parasite drag corresponding to some orig- 
  
  inal speed, Vi 