text: SCALE EFFECT. Since the boundary layer 
  friction and kinetic energy are dependent on 
  the characteristics of 
  layer, 
  Reynolds Number is important in correlating 
  aerodynamic characteristics. The variation of 
  the aerodynamic characteristics with Reynolds 
  Number is termed “scale effect” and is ex- 
  tremely important in correlating wind tunnel 
  test data of scale models with the actual flight 
  characteristics of the full size aircraft. The 
  two most important section characteristics 
  affected by scale effects are drag and maximum 
  lift-the 
  effect on pitching moments usually 
  being negligible. From the known variation 
  of boundary layer characteristics with Rey- 
  nolds Number, certain general effects may be 
  anticipated. With increasing Reynolds Num- 
  ber, it may be expected that the section maxi- 
  mum lift coefficient will 
  the 
  higher energy turbulent boundary layer) and 
  that the section drag coefficient will decrease 
  (similar to that of the smooth plate). These 
  effects are illustrated by the graphs of figure 
  1.27. 
  
  the boundary 
  
  In order to prevent separation of a boundary 
  layer in the presence of an adverse pressure 
  gradient, the boundary layer must have the 
  highest possible kinetic energy. 
  If a choice is 
  available, the turbulent boundary layer would 
  be preferable to the laminar boundary layer 
  because the turbulent velocity profile shows 
  higher 
  local velocities next to the surface. 
  lift devices (slots, 
  The most effective high 
  slotted flaps, BLC) utilize various techniques 