text: dry hard surface runways will require particular 
  techniques to obtain minimum 
  landing dis- 
  tance. Generally, the technique involves low- 
  ering the nose wheel to the runway and retract- 
  ing the flaps to increase the normal force on 
  the braking surfaces. While the airplane drag 
  is reduced, the greater normal force can pro- 
  vide greater braking 
  force to com- 
  pensate for the reduced drag and the net retard- 
  ing force is increased. 
  
  friction 
  
  The technique necessary for minimum land- 
  ing distance can be altered~ to some extent in 
  certain situations. For example, low aspect 
  ratio airplanes with high longitudinal control 
  power can create very high drag at the high 
  speeds immediate to landing touchdown. 
  If 
  the 
  flap or 
  landing gear configuration or 
  incidence setting precludes a large reduction 
  of CL, the normal force on the braking surfaces 
  and braking friction 
  force capability are rela- 
  tively small. Thus, in the initial high speed 
  part of the landing roll, maximum deceleration 
  would be obtained by creating the greatest 
  possible aerodynamic drag. By the time the 
  aircraft has slowed to 70 or 80 percent of the 
  touchdown speed, aerodynamic drag decays 
  but braking action will 
  then be effective. 
  Some form of this technique may be necessary 
  to achieve minimum distance for some con- 
  the coefficient of braking 
  figurations when 
  icy runway) and the 
  friction 
  is reduced 
  braking 
  relative to airplane aerodynamic drag. 