text: If the airplane shown in figure 4.34 were in 
  some flight condition where the inertia axis 
  and the aerodynamic axis are alined, no inertia 
  coupling would result from rolling motion. 
  However, if the inertia axis is inclined to the 
  aerodynamic axis, rotation about the aero- 
  dynamic axis will create centrifugal forces and 
  this case, a 
  cause a pitching moment. 
  rolling motion of the aircraft induces a pitch- 
  the action of inertia 
  ing moment through 
  and is 
  coupling” 
  forces. This 
  illustrated by part B of figure 4.34. 
  
  In 
  
  is “inertia 
  
  the 
  inertia axis no inertia coupling will exist but 
  aerodynamic coupling will be present. Part 
  C of figure 4.34 shows the airplane after rolling 
  90” about the inertia axis. The inclination 
  the angle of attack (a) is 
  which was initially 
  now the angle of sideslip (-6). 
  Also the 
  original zero sideslip has now become zero 
  angle of attack. The sideslip induced by this 
  rate 
  90° displacement will affect the roll 
  
  When the airplane  is rotated about 