Powerplant Part 1

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Author:
robsok
ID:
100416
Filename:
Powerplant Part 1
Updated:
2011-09-07 22:52:20
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Powerplant
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Description:
Reciprocating Engines
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  1. Which statement is true regarding bearings used in high-powered reciprocating aircraft engines?
    There is less rolling friction when ball bearings are used than when roller bearings are employed.
  2. A condition that can occur in radial engines but is unlikely to occur in horizontally opposed engines is
    Hydraulic Lock
  3. Which condition would be the least likely to be caused by failed or failing engine bearings?
    Low Oil Temperatures
  4. What is the principal advantage of using propeller reduction gears?
    To enable the engine rpm to be increased with an accompanying increase in power and allow the propeller to remain at a lower, more efficient rpm.
  5. Which of the following will decrease volumetric efficiency in a reciprocating engine?

    3. Improper valve timing.
    4. Sharp bends in the induction system.
    5. High carburetor air temperatures.
    3, 4, and 5
  6. Which of the following is a characteristic of a thrust bearing used in most radial engines?
    Deep-groove ball
  7. Which bearing is least likely to be a roller or ball bearing?
    Master Rod Bearing (Radial Engine)
  8. The operating temperature valve clearance of a radial engine as compared to cold valve clearance is
    Greater
  9. A nine-cylinder engine with a bore of 5.5 inches and a stroke of 6 inches will have a total piston displacement of
    1,283 Cubic Inches.
  10. The five events of a four-stroke cycle engine in the order of their occurrence are
    Intake, Compression, Ignition, Power, Exhaust
  11. The primary concern in establishing the firing order for an opposed engine is to
    Provide for balance and eliminate vibration to the greatest extent possible.
  12. If fuel/air ratio is proper and ignition timing is correct, the combustion process should be completed
    Just after top center at the beggining of the power strike.
  13. Grinding the valves of a reciprocating engine to a feather edge is likely to result in
    Preignition and burned valves.
  14. Which statement is correct regarding engine crankshafts?
    Moveable counterweights serve to reduce the torsional vibrations in an aircraft reciprocating engine.
  15. On which strokes are both valves on a four-stroke cycle reciprocating aircraft engine open?
    Exhaust and intake.
  16. Master rod bearings are generally what type?
    Plain.
  17. The actual power delivered to the propeller of an aircraft engine is called
    Brake horsepower.
  18. Cam-ground pistons are installed in some aircraft engines to
    Provide a better fit at operating temperatures.
  19. Using the following information, determine how many degrees the crankshaft will rotate with both the intake and exhaust valves seated.

    Intake opens 15°: BTDC.
    Exhaust opens 70°: BBDC.
    Intake closes 45°: ABDC.
    Exhaust closes 10°: ATDC.
    245 Degrees
  20. Some aircraft engine manufacturers equip their product with choked or taper-ground cylinders in order to
    Provide a straight cylinder bore at operating temperatures.
  21. An aircraft reciprocating engine using hydraulic valve lifters is observed to have no clearance in its valve-operating mechanism after the minimum inlet oil and cylinder head temperatures for takeoff have been reached. When can this condition be expected?
    During Normal Operation
  22. What tool is generally used to measure the crankshaft rotation in degrees?
    Timing disk
  23. If an engine with a stroke of 6 inches is operated at 2,000 RPM, the piston movement within the cylinder will be
    At maximum velocity 90 degrees after TDC.
  24. If the intake valve is opened too early in the cycle of operation of a four-stroke cycle engine, it may result in
    Backfiring into the induction system.
  25. Some cylinder barrels are hardened by
    Nitriding
  26. Which statement is correct regarding a four-stroke cycle aircraft engine?
    The intake valve closes on the compression stroke.
  27. On which part of the cylinder walls of a normally operating engine will the greatest amount of wear occur?
    Near the top of the cylinder
  28. During overhaul, reciprocating engine exhaust valves are checked for stretch
    With a contour or radius gauge
  29. When is the fuel/air mixture ignited in a conventional reciprocating engine?
    Shortly before the piston reaches the top of the compression stroke.
  30. Ignition occurs at 28° BTDC on a certain four-stroke cycle engine, and the intake valve opens at 15° BTDC. How many degrees of crankshaft travel after ignition does the intake valve open? (Consider one cylinder only.)
    373 Degrees
  31. What is the purpose of the safety circlet installed on some valve stems?
    To prevent valves from falling into the combustion chamber.
  32. Valve overlap is defined as the number of degrees of crankshaft travel
    During which both valves are off their seats.
  33. The valve clearance of an engine using hydraulic lifters, when the lifters are completely flat, or empty, should not exceed
    A specified amount above zero.
  34. If the exhaust valve of a four-stroke cycle engine is closed and the intake valve is just closed, the piston is on the
    Compression Stroke
  35. How many of the following are factors in establishing the maximum compression ratio limitations of an aircraft engine?

    1. Detonation characteristics of the fuel used.
    2. Design limitations of the engine.
    3. Degree of supercharging.
    4. Spark plug reach.
    Three
  36. Full-floating piston pins are those which allow motion between the pin and
    Both the piston and small end of the connecting rod.
  37. The primary purpose in setting proper valve timing and overlap is to
    Obtain the best volumetric efficiency and lower cylinder operating temperatures.
  38. If the hot clearance is used to set the valves when the engine is cold, what will occur during operation of the engine?
    The valves will open late and close early.
  39. The purpose of two or more valve springs in aircraft engines is to
    Eliminate Valve Spring Surge
  40. During overhaul, the disassembled parts of an engine are usually degreased with some form of mineral spirits solvent rather than water-mixed degreasers primarily because
    Water-mixed degreaser residues may cause engine oil contamination in the overhauled engine.
  41. Why does the smoothness of operation of an engine increase with a greater number of cylinders?
    The power impulses are spaced closer together.
  42. Compression ratio is the ratio between the
    Cylinder volume with piston at bottom dead center and at top dead center.
  43. If the crankshaft runout readings on the dial indicator are plus .002 inch and minus .003 inch, the runout is
    .005 Inch
  44. (1) Cast iron piston rings may be used in chrome-plated cylinders.
    (2) Chrome-plated rings may be used in plain steel cylinders.Regarding the above statements,
    Both No.1 and No.2 are true
  45. How is proper end-gap clearance on new piston rings assured during the overhaul of an engine?
    By placing the rings in the cylinder and measuring the end-gap with a feeler gauge.
  46. The volume of a cylinder equals 70 cubic inches when the piston is at bottom center. When the piston is at the top of the cylinder, the volume equals 10 cubic inches. What is the compression ratio?
    7:1
  47. When cleaning aluminum and magnesium engine parts, it is inadvisable to soak them in solutions containing soap because
    Some of the soap will become impregnated in the surface of the material and subsequently cause engine oil contamination and foaming.
  48. What is the purpose of a power check on a reciprocating engine?
    To determine satisfactory performance.
  49. What will be the likely result if the piston ring gaps happen to be aligned when performing a differential-pressure compression check on a cylinder?
    A worn or defective ring (s) indication.
  50. Which of the following will be caused by excessive valve clearance of a cylinder on a reciprocating aircraft engine?
    Reduced valve overlap period.
  51. The floating control thermostat, used on some reciprocating engine installations, helps regulate oil temperature by
    Controlling air flow through the oil cooler.
  52. Which of the following would indicate a general weak-engine condition when operated with a fixed-pitch propeller or test club?
    Lower than normal static RPM, full throttle operation.
  53. What is required by 14 CFR Part 43 Appendix D when performing an annual/100-hour inspection on a reciprocating engine aircraft?
    Cylinder compression check
  54. After spark plugs from an opposed engine have been serviced, in what position should they be reinstalled?
    Next in firing order to the one from which they were removed and swapped bottom to top.
  55. As the pressure is applied during a reciprocating engine compression check using a differential pressure tester, what would a movement of the propeller in the direction of engine rotation indicate?
    The piston was positioned past top dead center.
  56. Excessive valve clearance results in the valves opening
    late and closing early.
  57. During routine inspection of a reciprocating engine, a deposit of small, bright, metallic particles which do not cling to the magnetic drain plug is discovered in the oil sump and on the surface of the oil filter. This condition
    May be a result of abnormal plain type bearing wear and is cause for further investigation.
  58. A characteristic of dyna-focal engine mounts as applied to aircraft reciprocating engines is that the
    Shock mount pivots toward the engine's center of gravity.
  59. If metallic particles are found in the oil filter during an inspection,
    The cause should be identified and corrected before the aircraft is released for flight.
  60. If the oil pressure gauge fluctuates over a wide range from zero to normal operating pressure, the most likely cause is
    Low Oil Supply
  61. What special procedure must be followed when adjusting the valves of an engine equipped with a floating cam ring?
    Eliminate cam bearing clearance when making valve adjustment.
  62. Which of the following is most likely to occur if an overhead valve engine is operated with inadequate valve clearances?
    The valves will not seat positively during start and engine warmup.
  63. Excessive valve clearances will cause the duration of valve opening to
    Decrease for both Intake and Exhaust Valves
  64. What does valve overlap promote?
    Better scavenging and cool characteristics.
  65. At what speed must a crankshaft turn if each cylinder of a four-stroke cycle engine is to be fired 200 times a minute?
    400 RPM
  66. Engine crankshaft runout is usually checked

    1. during engine overhaul.

    3. after a 'prop strike' or sudden engine stoppage.
    1 and 3
  67. Before attempting to start a radial engine that has been shut down for more than 30 minutes,
    Turn the propeller by hand three to four revolutions in the normal direction of rotation to check for liquid lock.
  68. An engine misses in both the right and left positions of the magneto switch. The quickest method for locating the trouble is to
    Check for one or more cold cylinders.
  69. A hissing sound from the exhaust stacks when the propeller is being pulled through manually indicates
    Exhaust valve blow-by
  70. If the oil pressure of a cold engine is higher than at normal operating temperatures, the
    Engine's lubrication system is probably operating normally.
  71. If an engine operates with a low oil pressure and a high oil temperature, the problem may be caused by a
    Leaking oil dilution valve.
  72. Which fuel/air mixture will result in the highest engine temperature (all other factors remaining constant)?
    A mixture leaner than a manual lean mixture of .060.
  73. If an engine cylinder is to be removed, at what position in the cylinder should the piston be?
    Top Dead Center
  74. The horsepower developed in the cylinders of a reciprocating engine is known as the
    Indicated Horsepower
  75. Engine operating flexibility is the ability of the engine to
    run smoothly and give the desired performance at all speeds.
  76. Standard aircraft cylinder oversizes usually range from 0.010 inch to 0.030 inch. Oversize on automobile engine cylinders may range up to 0.100 inch. This is because aircraft engine cylinders
    Have relatively thin walls and may be nitrided.
  77. If the ignition switch is moved from BOTH to either LEFT or RIGHT during an engine ground check, normal operation is usually indicated by a
    Slight Drop in RPM
  78. During ground check an engine is found to be rough-running, the magneto drop is normal, and the manifold pressure is higher than normal for any given RPM. The trouble may be caused by
    A dead cylinder
  79. What is the best indication of worn valve guides?
    High oil consumption
  80. By use of a differential pressure compression tester, it is determined that the No. 3 cylinder of a nine-cylinder radial engine will not hold pressure after the crankshaft has been rotated 260° from top dead center compression stroke No. 1 cylinder. How can this indication usually be interpreted?
    A normal indication.
  81. When does valve overlap occur in the operation of an aircraft reciprocating engine?
    At the end of the exhaust stroke and the beginning of the intake stroke.
  82. What is an advantage of using metallic-sodium filled exhaust valves in aircraft reciprocating engines?
    Reduced valve operating temperatures.
  83. Valve clearance changes on opposed-type engines using hydraulic lifters are accomplished by
    Push Rod Replacement
  84. What is likely to occur if a reciprocating engine is operated at high power settings before it is properly warmed up?
    Oil Starvation of bearings and other parts.
  85. An increase in manifold pressure with a constant RPM will cause the bearing load in an engine to
    Increase
  86. Direct mechanical push-pull carburetor heat control linkages should normally be adjusted so that the stop located on the diverter valve will be contacted
    Before the stop at the control lever is reached in both HOT and COLD positions.
  87. Reduced air density at high altitude has a decided effect on carburetion, resulting in a reduction of engine power by
    Excessively enriching the fuel/air mixture.
  88. Increased water vapor (higher relative humidity) in the incoming air to a reciprocating engine will normally result in which of the following?
    Decreased engine power at a constant RPM and manifold pressure.
  89. (1) Preignition is caused by improper ignition timing.
    (2) Detonation occurs when an area of the combustion chamber becomes incandescent and ignites the fuel/air mixture in advance of normal timed ignition.Regarding the above statements,
    Niether No.1 nor No.2 is true.
  90. Which of the following engine servicing operations generally requires engine pre-oiling prior to starting the engine?
    Engine Installation
  91. During the inspection of an engine control system in which push-pull control rods are used, the threaded rod ends should
    be checked for the amount of thread engagement by means of inspection holes.
  92. Which of the following conditions would most likely lead to detonation?
    Use of fuel with too low an octane rating.
  93. An unsupercharged aircraft reciprocating engine, operated at full throttle from sea level, to 10,000 feet, provided the RPM is unchanged, will
    Lose power due to the reduced density of the air drawn into the cylinders.
  94. Which of the following would most likely cause a reciprocating engine to backfire through the induction system at low RPM operation?
    Lean Mixture.
  95. How may it be determined that a reciprocating engine with a dry sump is pre-oiled sufficiently?
    Oil will flow from the engine return line or indicator port.
  96. What is the basic operational sequence for reducing the power output of an engine equipped with a constant-speed propeller?
    Reduce the manifold pressure, then the RPM.
  97. Which statement pertaining to fuel/air ratios is true?
    The mixture ratio which gives the best power is richer than the mixture ratio which gives maximum economy.
  98. Backfiring through the carburetor generally results from the use of
    An excessively lean mixture.
  99. Which of these conditions will cause an engine to have an increased tendency to detonate?
    1. High manifold pressure.
    2. High intake air temperature.
    3. Engine overheated.
    1, 2, 3
  100. When will small induction system air leaks have the most noticeable effect on engine operation?
    At low RPM.
  101. To reduce the power output of an engine equipped with a constant-speed propeller and operating near maximum BMEP, the
    Manifold pressure is reduced with the throttle control force before the RPM is reduced with the propeller control.
  102. One of the best indicators of reciprocating engine combustion chamber problems is
    Spark Plug Condition
  103. What could cause excessive pressure buildup in the crankcase of a reciprocating engine?
    Plugged Crankcase Breather
  104. Excessive valve clearance in a piston engine
    Decreases Valve Overlap
  105. To what altitude will a turbo charged engine maintain sea level pressure?
    Critical Altitude
  106. If air is heard coming from the crankcase breather or oil filler during a differential compression check, what is this an indication of?
    Piston Ring Leakage
  107. One cause of afterfiring in an aircraft engine is
    An excessively rich mixture.

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