text: The form of the turbine blades may be a com- 
  bination of two distinct 
  types. The imp&c 
  type turbine relies upon the nozzle vanes to 
  accomplish the conversion of combustion gas 
  static pressure to high velocity 
  jets. The 
  impulse turbine blades are shaped to produce 
  a large deflection of the gas and develop the 
  tangential force by the flow direction change. 
  In such a design, negligible velocity and pres- 
  the flow across the tur- 
  sure drop occurs with 
  bine rotor blades. The reaction type turbine 
  differs in 
  large velocity and pressure 
  changes occur across the turbine rotor blades. 
  In the reaction turbine, rhe stationary nozzle 
  vanes serve only to guide the combustion gas 
  onto the turbine rotor with negligible changes 
  in velocity and pressure. The reaction tur- 
  bine rotor blades are shaped to provide a pres- 
  sure drop and velocity 
  increase across the 
  blades and the reaction from this velocity in- 
  force on the 
  crease provides the tangential 
  wheel. Generally, 
  turbine design is a 
  the 
  form utilizing some feature of each of the two 
  types. 
  
  that 
  
  The tur6inc section is the most critical element 
  of the turbojet engine. The function of the 
  turbine is to extract energy from the combus- 
  tion gases and furnish power to drive the com- 
  pressor and accessories. In the case of the 
  turboprop engine, the turbine section must ex- 
  tract a very large portion of the exhaust gas 