Powerplant Part 2

Card Set Information

Powerplant Part 2
2011-09-08 23:00:11

Turbine Engines
Show Answers:

  1. At what point in an axial-flow turbojet engine will the highest gas pressures occur?
    At the compressor outlet.
  2. One function of the nozzle diaphragm in a turbine engine is to
    Direct the flow of gases to strike the turbine blades at the desired angle.
  3. What is the profile of a turbine engine compressor blade?
    A cutout that reduce the blade tip thickness.
  4. The fan rotational speed of a dual axial compressor forward fan engine is the same as the
    Low pressure compressor
  5. The abbreviation Pt7 used in turbine engine terminology means
    The total pressure at station No.7
  6. The blending of blades and vanes in a turbine engine
    Should be performed parallel to the length of the blade using smooth contours to minimize stress points.
  7. What turbine engine section provides for proper mixing of the fuel and air?
    Combustion Section
  8. In a gas turbine engine, combustion occurs at a constant
  9. Which statement is true regarding jet engines?
    At the higher engine speeds, thrust increases rapidly with small increases in RPM.
  10. Some high-volume turboprop and turbojet engines are equipped with two-spool or split compressors. When these engines are operated at high altitudes, the
    Low-pressure rotor will increase in speed as the compressor load decreases in the lower density air.
  11. Turbine nozzle diaphragms located on the upstream side of each turbine wheel, are used in the gas turbine engine to
    Increase velocity of the heated gases flowing past this point.
  12. Where is the highest gas pressure in a turbojet engine?
    In the enterance of the burner section
  13. An exhaust cone placed aft of the turbine in a jet engine will cause the pressure in the first part of the exhaust duct to
    Increase and the velocity to decrease.
  14. What is the function of the stator vane assembly at the discharge end of a typical axial-flow compressor?
    To straighten airflow to eliminate turbulence.
  15. The turbine section of a jet engine
    Drives the compressor section.
  16. When starting a turbine engine,
    A hot start is indicated if the exhaust gas temperature exceeds specified limits.
  17. In the dual axial-flow or twin spool compressor system, the first stage turbine drives the
    N(2) Compressor
  18. During inspection, turbine engine components exposed to high temperatures may only be marked with such materials as allowed by the manufacturer. These materials generally include

    1. layout dye.
    2. commercial felt tip marker.
    4. chalk.
    1, 2, 4
  19. When starting a turbine engine, a hung start is indicated if the engine
    Fails to reach Idle RPM
  20. What are the two basic elements of the turbine section in a turbine engine?
    Stator and Rotor
  21. The function of the exhaust cone assembly of a turbine engine is to
    Straighten and collect the exhaust gases into a solid exhaust jet.
  22. What are the two functional elements in a centrifugal compressor?
    Impeller and diffuser
  23. What must be done after the fuel control unit has been replaced on an aircraft gas turbine engine?
    Retrim the engine.
  24. If, during inspection at engine overhaul, ball or roller bearings are found to have magnetism but otherwise have no defects, they
    must be degaused before use.
  25. A turbine engine compressor which contains vanes on both sides of the impeller is a
    double entry centrifugal compressor
  26. What is the first engine instrument indication of a successful start of a turbine engine?
    A rise in the exhaust gas temperature
  27. Some engine manufacturers of twin spool gas turbine engines identify turbine discharge pressure in their maintenance manuals as
  28. Who establishes the recommended operating time between overhauls (TBO) of a turbine engine used in general aviation?
    The engine manufacturer
  29. The basic gas turbine engine is divided into two main sections: the cold section and the hot section.
    (1) The cold section includes the engine inlet, compressor, and turbine sections.
    (2) The hot section includes the combustor, diffuser, and exhaust sections.Regarding the above statements,
    Neither No.1 nor No.2 is true.
  30. (1) Welding and straightening of turbine engine rotating airfoils does not require special equipment.
    (2) Welding and straightening of turbine engine rotating airfoils is commonly recommended by the manufacturer.Regarding the above statements,
    Neither No.1 nor No.2 is true.
  31. Turbine engine components exposed to high temperatures generally may NOT be marked with

    3. wax or grease pencil.

    5. graphite lead pencil.
    3 and 5
  32. Who establishes mandatory replacement times for critical components of turbine engines?
    The engine manufacturer
  33. Main bearing oil seals used with turbine engines are usually what type(s)?
    Labyrinth and/or carbon rubbing
  34. How does a dual axial-flow compressor improve the efficiency of a turbojet engine?
    Higher compression ratios can be obtained.
  35. Three types of turbine blades are
    impulse, reaction, and impulse reaction
  36. Which statements are true regarding aircraft engine propulsion?
    1. An engine driven propeller imparts a relatively small amount of acceleration to a large mass of air.
    2. Turbojet and turbofan engines impart a relatively large amount of acceleration to a smaller mass of air.
    1 and 2
  37. An advantage of the axial-flow compressor is its
    High peak efficiency
  38. What is one purpose of the stator blades in the compressor section of a turbine engine?
    Control the direction of the airflow.
  39. What is the purpose of the diffuser section in a turbine engine?
    To increase pressure and reduce velocity
  40. Where do stress rupture cracks usually appear on turbine blades?
    Across the leading or trailing edge at a right angle to the edge length.
  41. In which type of turbine engine combustion chamber is the case and liner removed and installed as one unit during routine maintenance?
  42. The diffuser section of a jet engine is located between
    The compressor section and the burner section.
  43. When the leading edge of a first-stage turbine blade is found to have stress rupture cracks, which of the following should be suspected?
    Overtemperature Condition
  44. Turbine blades are generally more susceptible to operating damage than compressor blades because of
    Exposure to high temperatures.
  45. Which of the following is the ultimate limiting factor of turbine engine operation?
    Turbine inlet temperature.
  46. The recurrent ingestion of dust or other fine airborne particulates into a turbine engine can result in
    Erosion Damage to the compressor and turbine sections.
  47. Which of the following engine variables is the most critical during turbine engine operation?
    Turbine Inlet Temperature.
  48. Reduced blade vibration and improved airflow characteristics in gas turbines are brought about by
    Shrouded turbine rotor blades.
  49. Which turbine engine compressor offers the greatest advantages for both starting flexibility and improved high-altitude performance?
    Split-spool, axial-flow
  50. Jet engine turbine blades removed for detailed inspection must be reinstalled in
    The same slot
  51. An advantage of the centrifugal-flow compressor is its high
    Pressure rise per stage.
  52. The highest heat-to-metal contact in a jet engine is the
    Turbine inlet guide vanes.
  53. Which two elements make up the axial-flow compressor assembly?
    Rotor and Stator.
  54. The two types of centrifugal compressor impellers are
    Single entry and Double entry
  55. Between each row of rotating blades in a turbine engine compressor, there is a row of stationary blades which act to diffuse the air. These stationary blades are called
  56. Standard sea level pressure is
    29.92" HG
  57. Using standard atmospheric conditions, the standard sea level temperature is
    59 Degrees Farenheit
  58. When aircraft turbine blades are subjected to excessive heat stress, what type of failures would you expect?
    Stress Rupture
  59. In an axial-flow compressor, one purpose of the stator vanes at the discharge end of the compressor is to
    Straighten the airflow and eliminate turbulence.
  60. Compressor field cleaning on turbine engines is performed primarily in order to
    Prevent engine performance degradation, increased fuel cost, and damage or corrosion to gas path surfaces.
  61. Hot section inspections for many modern turbine engines are required
    on a time or cycle basis
  62. A purpose of the shrouds on the turbine blades of an axial-flow engine is to
    Reduce vibration
  63. In a dual axial-flow compressor, the first stage turbine drives
    N(2) Compressor
  64. What should be done initially if a turbine engine catches fire when starting?
    Turn off the fuel and continue engine rotation with the starter.
  65. What is the proper starting sequence for a turbojet engine?
    Starter, ignition, and fuel
  66. A weak fuel to air mixture along with normal airflow through a turbine engine may result in
    A lean die-out
  67. What is used in turbine engines to aid in stabilization of compressor airflow during low thrust engine operation?
    Variable guide vanes and/or compressor bleed valves.
  68. In a turbine engine with a dual-spool compressor, the low speed compressor
    Seeks it's own best operating speed.
  69. What is the function of the inlet guide vane assembly on an axial-flow compressor?
    Directs the air into the first stage rotor blades at the proper angle.
  70. Hot spots on the tail cone of a turbine engine are possible indicators of a malfunctioning fuel nozzle or
    A faulty combustion chamber.
  71. The stator vanes in an axial-flow compressor
    Convert velocity energy into pressure energy.
  72. The velocity of subsonic air as it flows through a convergent nozzle
  73. The velocity of supersonic air as it flows through a divergent nozzle
  74. The pressure of subsonic air as it flows through a convergent nozzle
  75. The pressure of supersonic air as it flows through a divergent nozzle
  76. Anti-icing of jet engine air inlets is commonly accomplished by
    Engine bleed air ducted through the critical areas.
  77. Generally, when starting a turbine engine, the starter should be disengaged
    After the engine has reached self-accelerating speed.
  78. What is the primary advantage of an axial-flow compressor over a centrifugal compressor?
    Greater pressure ratio.
  79. The purpose of a bleed valve, located in the beginning stages of the compressor, in an aircraft gas turbine engine is to
    Vent some of the air overboard to prevent a compressor stall.
  80. What is meant by a double entry centrifugal compressor?
    A compressor with vanes on both sides of the impeller.
  81. What is the major function of the turbine assembly in a turbojet engine?
    Supplies the power to turn the compressor.
  82. Stator blades in the compressor section of an axial-flow turbine engine
    Decrease the air velocity and prevent swirling
  83. A gas turbine engine comprises which three main sections?
    Turbine, compressor and combustion
  84. What type of turbine blade is most commonly used in aircraft jet engines?
  85. What is the primary factor which controls the pressure ratio of an axial-flow compressor?
    Number of stages in compressor.
  86. The non-rotating axial-flow compressor airfoils in an aircraft gas turbine engine, are called
    Stator vanes.
  87. (1) In a turbine engine axial-flow compressor, each consecutive pair of rotor and stator blades constitutes a pressure stage.
    (2) In a turbine engine axial-flow compressor, the number of rows of stages is determined by the amount of air and total pressure rise required.Regarding the above statements,
    Both No.1 and No.2 are true.
  88. The air passing through the combustion chamber of a turbine engine is
    Used to support combustion and to cool the engine.
  89. The stators in the turbine section of a gas turbine engine
    Increase the velocity of the gas flow.
  90. The compressor stators in a gas turbine engine act as diffusers to
    Decrease the velocity of the gas flow.
  91. The procedure for removing the accumulation of dirt deposits on compressor blades is called
    Field cleaning
  92. Which of the following may be used to accomplish internal inspection of an assembled turbine engine?

    3. A borescope.
  93. What is the possible cause when a turbine engine indicates no change in power setting parameters, but oil temperature is high?
    Engine main bearing distress.
  94. Newton's First Law of Motion, generally termed the Law of Inertia, states:
    Everybody persist in its state of rest, or of motion in a straight line, unless acted upon by some outside force.
  95. A turbine engine hot section is particularly susceptible to which kind of damage?
  96. Dirt particles in the air being introduced into the compressor of a turbine engine will form a coating on all but which of the following?
    Turbine blades
  97. Severe rubbing of turbine engine compressor blades will usually cause
  98. Which of the following influences the operation of an automatic fuel control unit on a turbojet engine?
    Burner Pressure
  99. If a turbine engine is unable to reach takeoff EPR before its EGT limit is reached, this is an indication that the
    Compressor maybe contaminated or damage
  100. The Brayton cycle is known as the constant
    Pressure cycle.
  101. Continued and/or excessive heat and centrifugal force on turbine engine rotor blades is likely to cause
  102. If the RPM of an axial-flow compressor remains constant, the angle of attack of the rotor blades can be changed by
    changing the velocity of the airflow.
  103. The compression ratio of an axial-flow compressor is a function of the
    Number of compressor stages.
  104. Which of the following variables affect the inlet air density of a turbine engine?

    1. Speed of the aircraft.
    4. Altitude of the aircraft.
    5. Ambient temperature.
    1, 4, 5
  105. Which of the following factors affect the thermal efficiency of a turbine engine?

    1. Turbine inlet temperature.
    2. Compression ratio.
    5. Turbine and compressor efficiency.
    1, 2, 5
  106. Why do some turbine engines have more than one turbine wheel attached to a single shaft?
    To extract more power from the exhaust gases than a single wheel can absorb.
  107. The exhaust section of a turbine engine is designed to
    Impart a high exit velocity to the exhaust gases.
  108. Which of the following types of combustion sections are used in aircraft turbine engines?
    Multiple-can, annular, and can-annular
  109. A cool-off period prior to shutdown of a turbine engine is accomplished in order to
    Allow the turbine wheel to cool before the case contracts around it.
  110. What type igniter plug is used in the low tension ignition system of an aircraft turbofan engine?
    Self ionizing or shunted gap type plug.
  111. What is meant by a shrouded turbine?
    The turbine blades are shaped so that their ends form a band or shroud.
  112. What term is used to describe a permanent and cumulative deformation of the turbine blades of a turbojet engine?
  113. What is the purpose of the dump valve used on aircraft gas turbine engines?
    The fuel is quickly cut off to the nozzles and the manifolds are drained preventing fuel boiling off as a result of residual engine heat.
  114. At what stage in a turbine engine are gas pressures the greatest?
    Compressor Outlet.
  115. In what section of a turbojet engine is the jet nozzle located?
  116. (1) Accumulation of contaminates in the compressor of a turbojet engine reduces aerodynamic efficiency of the blades.
    (2) Two common methods for removing dirt deposits from turbojet engine compressor blades are a fluid wash and an abrasive grit blast.Regarding the above statements,
    Both No.1 and No.2 are true.
  117. Hot spots in the combustion section of a turbojet engine are possible indicators of
    Malfunctioning fuel nozzles.
  118. Which of the following can cause fan blade shingling in a turbofan engine?

    1. Engine overspeed.

    4. FOD.
    1, 4
  119. Compressor stall is caused by
    A high angle of attack airflow through the first stages of compression.
  120. A condition known as 'hot streaking' in turbine engines is caused by
    A partially clogged fuel nozzle