text: is subjected to the bending and torsion of 
  the 
  tangential impulse-reaction forces. The 
  blade must wirhstand these stresses which are 
  generally of a vibratory and cyclic nature 
  while at high 
  temperatures. The elevated 
  temperatures at which the turbine must func- 
  for struc- 
  tion produce extreme conditions 
  tural creep and fatigue considerations. Conse- 
  quently, the engine speed and temperature op- 
  erating limits demand very careful considera- 
  tion. Excessive engine temperatures or speeds 
  may produce damage which 
  is immediately 
  apparent. However, creep and fatigue damage 
  is cumulative and even though damage may 
  not be immediately apparent by visual inspec- 
  tion, proper inspection methods (other than 
  visual) must be utilized and proper records 
  kept regarding the occurrence. 
  
  the development of high tempera- 
  ture alloys for turbines is a critical factor in the 
  develop,mcnt of high ei%ciciicy, high output 
  the tem- 
  aircraft gas turbines. The higher 
  peratute of gases entering the turbine, 
  the 
  higher can be the temperature and pressure of 
  the gases at discharge from the turbine with 
  greater exhaust jet velocity and thrust. 
  
  Actually, 