Engines Ch8

  1. The tendency of a fuel to vaporize refers to its ________
  2. Define flashpoint
    The minimum temperature at which a combustible liquid emits a sufficient quantity of vapor that ignition will occur during a momentary application of a flame.
  3. What type of fule is used during shipboard operations? Why?
    JP-5, less volatile, higher flashpoint.
  4. An increase in temperature will cause what change, if any, in volatility? In flashpoint?
    Increase the volatility. Flashpoint always remains constant.
  5. What are the major considerations in designing a fuel system?
    • Operation at low atmospheric pressures.
    • Complexity of the piping system.
    • Cold weather starting
    • High fuel flow pressure
  6. What controls the amount of fuel delivered to the combustion chamber?
    the FCU
  7. How does the pilot communicate with the FCU?
    Through the PCL
  8. List the various operational parameters the FCU must process to deliver the proper fuel flow to the engine.
    • PCL inputs
    • Compressor inlet temperature
    • Compressor rpm (high pressure RPM in dual spool)
    • Turbine inlet temperature
  9. Why is a boost pump included in the aircraft fuel system?
    Pilot controls amount of fuel supplied to the burner and the rate of application. Pilot must monitor the engines critical limits.
  10. Why is a boost pump included in the aircraft fuel system?
    To avoid vapor lock or engine fuel pump cavitation.
  11. What part does the FCU play during engine starts?
    Sends a pressure signal to close the dump valve. Schedules fuel flow for start.
  12. What is the position of the pressurizing and dump valve during an engine start? During normal engine operation? During engine shutdown?
    • dump valve closed
    • dump valve closed
    • open
  13. What cuts off fuel flow during engine shutdown?
    the FCU
  14. Where does metered fuel begin in the aircraft fuel system?
    After the FCU
  15. What is military rated thrust?
    The maximum thrust for a specified limited period of time (30 minutes)
  16. What component measures the proper amount of fuel flow to the afterburner?
    Afterburner FCU
Card Set
Engines Ch8
Chapter 8 book questions