text: An additional factor to consider is the aero- 
  dynamic drag of the airplane during the land- 
  ing roll. Because of the reduced induced drag 
  when in ground effect, aerodynamic braking 
  will be of greatest significance only when 
  partial stalling of the wing can be accom- 
  plished. The reduced drag when in ground 
  effect accounts for the fact that 
  the brakes 
  are the most effective source of deceleration 
  the majority of airplane configurations. 
  for 
  the takeoff pharc of flight ground 
  effect produces some important relationships. 
  Of course, the airplane leaving ground effect 
  encounters just the reverse of the airplane 
  entering ground effect, i.e., the airplane leaving 
  (1) require an increase in 
  ground effect will 
  angle of attack 
  the same lift 
  to maintain 
  coefficient, (2) experience an increase in in- 
  duced drag and thrust required, (3) experience a 
  decrease in stability and a nose-up change in  The rotor of the helicopter experiences a 
  similar restraint of induced flow when in prox- 
  imity to the ground plane. Since the induced 
  rotor power required will predominate at low 
  flight speeds, ground effect will produce a con- 
  siderable effect on the power required at low 
  speeds. During hovering and flight at low 
  speeds, the elevation of the rotor above the 
  ground plane will be an important factor de- 
  termining the power required for flight. 
  
  During 