text: to dihedral effect. 
  
  The amount of effective dihedral necessary 
  to produce satisfactory flying qualities varies 
  greatly with 
  the type and purpose of the air- 
  plane. Generally, the effective dihedral should 
  not be too great since high roll due to side- 
  slip can create certain problems. Excessive 
  dihedral effect can lead to 
  difficult rudder coordination in rolling maneu- 
  lateral 
  vers, or place extreme demands for 
  control power during crosswind takeoff and 
  landing. Of course, the effective dihedral 
  should not be negative during the predominat- 
  ing conditions of flight, e.g., cruise, high 
  speed, etc. 
  If the airplane demonstrates satis- 
  factory dihedral effect for these conditions of 
  flight, certain exceptions can be considered 
  when the airplane is in the takeoff and landing 
  configuration. Since the effects of flaps and 
  power are destablizing and reduce the dihedral 
  effect, a certain amount of negative dihedral 
  effect may be possible due to these sources. 
  
  The unusual nature of the contribution of 
  sweepback to dihedral effect is that the con- 
  tribution 
  lift 
  coefficient as well as the angle of sweepback. 
  It should be clear that the swept wing at zero 
  lift will provide no roll due to sideslip since 