text: (2) Sweepback will reduce the magnitude 
  of change in the aerodynamic force coeffi- 
  cients due to compressibility. Any change 
  in drag, lift, or moment coefbcients will be 
  reduced by the use of sweepback. Various 
  sweep angles applied to wings of moderate 
  aspect ratio will produce these approximate 
  effects in transonic flight. 