text: flight speeds where the dynamic 
  pressure is low, the relationship between aero- 
  dynamic force buildup and torsional deflection 
  is ‘stable. However, the change in lift per 
  angle of attack is proportional 
  to ‘vz but the 
  structural 
  torsional stiffness of the wing re- 
  implies 
  mains constant. This relationship 
  that at some high speed, the aerodynamic force 
  
  At  low 