text: The lagging tab arrangement shown in figure 
  4.18 employs a linkage between the fixed sur- 
  face and the tab surface. The geometry is 
  such that upward deflection of the control 
  surface displaces the tab down relative to the 
  control surface. Such relative displacement 
  of the tab will aid in deflection of the control 
  surface and thus reduce the hinge moments due 
  to deflection. An obvious advantage of this 
  device is the reduction of deflection hinge 
  moments without a change in aerodynamic 
  balance. 
  
  A bobweighr will have an effect on the 
  maneuvering stick force gradient since the bob- 
  weight mass is subjected to the same accelera- 
  tion as the airplane. Thus, the bobweight will 
  provide an increment of stick force in direct 
  proportion to the maneuvering acceleration of 
  the airplane. Because of the linear contribu- 
  tion of the bobweight, the bobweight can be 
  applted to Increase the maneuvering stick force 
  if the basic airplane has too low a 
  stability 
  value or develops a decreasing gradient at high 
  lift coefficients. 
  
  The leading tab arrangement shown in figure 
  4.18 also employs a linkage between the fixed 
  surface and the tab surface. However, 
  the 
  geometry of the linkage is such that upward 
  deflection of the control surface displaces the 
  tab up relative to the control surface. This 
  relationship serves to increase the control sur- 
  face hinge moments due to deflection of the 
  surface. 