text: Control system friction can create very un- 
  forces. Figure 
  desirable effects on control 
  4.14(D) 
  force 
  that 
  illustrates 
  versus airspeed is a band rather than a line. 
  A wide friction 
  force band can completely 
  mask the stick force stability when the stick 
  force stability 
  is low. Modern flight control 
  systems require precise maintenance to mini- 
  force band and preserve 
  friction 
  mize the 
  proper feel to the airplane. 
  
  the control 
  
  The most direct appreciation of the ma- 
  neuvering stability of an airplane is obtained 
  from a plot of stick force versus load factor 
  such as shown in figure 4.15. The airplane 
  with positive maneuvering stability should 
  demonstrate a steady increase in stick force 
  The 
  increase in load factor or “G”. 
  with 
  maneuvering stick 
  stick 
  force gradient-or 
  force per G-must be positive but should be 
  force 
  of 
  gradient must not be excessively high or the 
  airplane will be difficult and tiring to maneuver. 
  Also, the stick force gradient must not be too 
  low or the airplane may be overstressed in- 
  advertently when light control forces exist. 
  A maneuvering stick force gradient of 3 to 8 
  lbs. per G is satisfactory for most fighter and  MANEUVERING STABILITY. When an 
  airplane is subject to a normal acceleration, 
  the flight path is curved and the airplane is 
  subject to a pitching velocity. Because of 
  the pitching velocity 
  in maneuvering flight, 
  the longitudinal stability of the airplane is 
  slightly greater than in steady flight condi- 
  tions. When an airplane is subject to a pitch- 
  1 ing velocity at a given lift coefficient, the air- 
  plane develops a pitching moment resisting 