Questions and Answers - Aircraft Reciprocating Engine (Part 2) | Aircraft Systems

Questions and Answers - Aircraft Reciprocating Engine (Part 2)

Multiple Choices Questions

56. Excessive valve clearance results in the valves opening
a. late and closing early.
b. early and closing late.
c. late and closing late.

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
a. may be a result of abnormal plain type bearing wear and is cause for further investigation.
b. is probably a result of ring and cylinder wall wear and is cause for engine removal and/or overhaul.
c. is normal in engines utilizing plain type bearings and aluminum pistons and is not cause for alarm.

58. A characteristic of dyna-focal engine mounts as applied to aircraft reciprocating engines is that the
a. shock mounts eliminate the torsional flexing of the powerplant.
b. engine attaches to the shock mounts at the engine's center of gravity.
c. shock mounts point toward the engine's center of gravity.

59. If metallic particles are found in the oil filter during an inspection,
a. it is an indication of normal engine wear unless the particles are nonferrous.
b. the cause should be identified and corrected before the aircraft is released for flight.
c. it is an indication of normal engine wear unless the deposit exceeds a specified amount.

60. If the oil pressure gauge fluctuates over a wide range from zero to normal operating pressure, the most likely cause is
a. low oil supply.
b. broken or weak pressure relief valve spring.
c. air lock in the scavenge pump intake.

61. What special procedure must be followed when adjusting the valves of an engine equipped with a floating cam ring?
a. Adjust valves when the engine is hot.
b. Adjust all exhaust valves before intake valves.
c. 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?
a. The valve will not seat positively during start and engine warmup.
b. The further decrease in valve clearance that occurs as engine temperatures increase will cause damage to the valve-operating mechanism.
c. The valves will remain closed for longer periods than specified by the engine manufacturer.

63. Excessive valve clearances will cause the duration of valve opening to
a. increase for both intake and exhaust valves.
b. decrease for both intake and exhaust valves.
c. decrease for intake valves and increase for exhaust valves.

64. What does valve overlap promote?
a. Lower intake manifold pressure and temperatures.
b. A backflow of gases across the cylinder.
c. Better scavenging and cooling 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?
a. 800 RPM.
b. 1,600 RPM.
c. 400 RPM.

66. Engine crankshaft runout is usually checked
1. during engine overhaul.
2. during annual inspection.
3. after a "prop strike" or sudden engine stoppage.
4. during 100-hour inspection.

a. 1, 3 and 4.
b. 1 and 3.
c. 1, 2 and 3.

67. Before attempting to start a radial engine that has been shut down for more than 30 minutes,
a. turn the propeller by hand three or four revolutions in the opposite direction of normal rotation to check for liquid lock.
b. turn the ignition switch on before energizing the starter.
c. 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
a. check for one or more cold cylinders.
b. perform a compression check.
c. check each spark plug.

69. A hissing sound from the exhaust stacks when the propeller is being pulled through manually indicates
a. a cracked exhaust stack.
b. exhaust valve blow-by.
c. worn piston rings.

70. If the oil pressure of a cold engine is higher than at normal operating temperatures, the
a. oil system relief valve should be readjusted.
b. engine's lubrication system is probably operating normally.
c. oil dilution system should be turned on immediately.

71. If an engine operates with a low oil pressure and a high oil temperature, the problem may be caused by a
a. leaking oil dilution valve.
b. sheared oil pump shaft.
c. clogged oil cooler annular jacket.

72. Which fuel/air mixture will result in the highest engine temperature (all other factors remaining constant)?
a. A mixture leaner than a rich best-power mixture of .085.
b. A mixture richer than a full-rich mixture of .087.
c. 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?
a. Bottom dead center.
b. Top dead center.
c. Halfway between top and bottom dead center.

74. The horsepower developed in the cylinders of a reciprocating engine is known as the
a. shaft horsepower.
b. indicated horsepower.
c. brake horsepower.

75. Engine operating flexibility is the ability of the engine to
a. deliver maximum horsepower at a specific altitude.
b. meet exacting requirements of efficiency and low weight per horsepower ratio.
c. run smoothly and give the desired performance at all speeds.

76. Standard aircraft cylinder oversizes usually range from 0.01 0 inch to 0.030 inch. Oversize on automobile engine cylinders may range up to 0.100 inch. This is because aircraft engine cylinders
a. have more limited cooling capacity.
b. have relatively thin walls and may be nitrided.
c. operate at high temperatures.

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
a. large drop in RPM.
b. momentary interruption of both ignition systems.
c. 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. several spark plugs fouled on different cylinders.
b. a leak in the intake manifold.
c. a dead cylinder.

79. What is the best indication of worn valve guides?
a. High oil consumption.
b. Low compression.
c. Low oil pressure

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. A normal indication.
b. Exhaust valve blow-by.
c. A damaged exhaust valve or insufficient exhaust valve clearance.

81. When does valve overlap occur in the operation of an aircraft reciprocating engine?
a. At the end of the exhaust stroke and the beginning of the intake stroke.
b. At the end of the power stroke and the beginning of the exhaust stroke.
c. At the end of the compression stroke and the beginning of the power stroke.

82. What is an advantage of using metallic-sodium filled exhaust valves in aircraft reciprocating engines?
a. Increased strength and resistance to cracking.
b. Reduced valve operating temperatures.
c. Greater resistance to deterioration at high valve temperatures.

83. Valve clearance changes on opposed-type engines using hydraulic lifters are accomplished by
a. rocker arm adjustment.
b. rocker arm replacement.
c. 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?
a. Oil starvation of bearings and other parts.
b. Excessive thinning of the engine oil.
c. Accelerated oil breakdown and oxidation.

85. An increase in manifold pressure with a constant RPM will cause the bearing load in an engine to
a. decrease.
b. remain relatively constant.
c. 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
a. before the stop at the control lever is reached in both HOT and COLD positions.
b. before the stop at the control lever is reached in the HOT position and after the stop at the control lever is reached in the COLD position.
c. after 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
a. excessively enriching the air/fuel mixture.
b. excessively leaning the air/fuel mixture.
c. reducing fuel vaporization.

88. Increased water vapor (higher relative humidity) in the incoming air to a reciprocating engine will normally result in which of the following?
a. Decreased engine power at a constant RPM and manifold pressure.
b. Increased power output due to increased volumetric efficiency.
c. A leaning effect on engines which use non-automatic carburetors.

(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,
a. only No. 1 is true.
b. both No. 1 and No. 2 are true.
c. neither 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?
a. Engine oil and filter change.
b. Engine installation.
c. Replacement of oil lines.

91. During the inspection of an engine control system in which push-pull control rods are used, the threaded rod ends should
a. not be adjusted in length for rigging purposes because the rod ends have been properly positioned and staked during manufacture.
b. be checked for thread engagement of at least two threads but not more than four threads.
c. be checked for the amount of thread engagement by means of the inspection holes.

92. Which of the following conditions would most likely lead to detonation?
a. Late ignition timing.
b. Use of fuel with too high an octane rating.
c. 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
a. lose power due to the reduced volume of air drawn into the cylinders.
b. produce constant power due to the same volume of air drawn into the cylinders.
c. 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?
a. Idle mixture too rich.
b. Clogged derichment valve.
c. Lean mixture.

95. How may it be determined that a reciprocating engine with a dry sump is preoiled sufficiently?
a. The engine oil pressure gauge will indicate normal oil pressure.
b. Oil will flow from the engine return line or indicator port.
c. When the quantity of oil specified by the manufacturer has been pumped into the engine.

96. What is the basic operational sequence for reducing the power output of an engine equipped with a constant-speed propeller?
a. Reduce the RPM, then the manifold pressure.
b. Reduce the manifold pressure, then retard the throttle to obtain the correct RPM.
c. Reduce the manifold pressure, then the RPM.

97. Which statement pertaining to fuel/air ratios is true?
a. The mixture ratio which gives the best power is richer than the mixture ratio which gives maximum economy.
b. A rich mixture is faster burning than a normal mixture.
c. The mixture ratio which gives maximum economy may also be designated as best power mixture.

98. Backfiring through the carburetor generally results from the use of
a. an excessively lean mixture.
b. excessively atomized fuel.
c. an excessively rich 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.
4. Late ignition timing.

a. 1, 4.
b. 1, 2, 3.
c. 1, 2, 3, 4.

100. When will small induction system air leaks have the most noticeable effect on engine operation?
a. At high RPM.
b. At maximum continuous and takeoff power settings.
c. At low RPM.

101. To reduce the power output of an engine equipped with a constant-speed propeller and operating near maximum BMEP, the
a. manifold pressure is reduced with the throttle control before the RPM is reduced with the propeller control.
b. manifold pressure i s reduced with the propeller control before the RPM is reduced with the throttle control.
c. RPM is reduced with the propeller control before the manifold pressure i s reduced with the throttle control.

102. One of the best indicators of reciprocating engine combustion chamber problems is
a. excessive engine vibration.
b. starting difficulties.
c. spark plug condition.

103. What could cause excessive pressure buildup in the crankcase of a reciprocating engine?
a. Plugged crankcase breather.
b. Improper warmup operation.
c. An excessive quantity of oil.

104. Excessive valve clearance in a piston engine
a. increases valve overlap.
b. increases valve opening time.
c. decreases valve overlap.

105. To what altitude will a turbo charged engine maintain sea level pressure?
a. Critical altitude.
b. Service ceiling.
c. Pressure 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?
a. Exhaust valve leakage.
b. Intake valve leakage.
c. Piston ring leakage.

107. One cause of afterfiring in an aircraft engine is
a. sticking intake valves.
b. an excessively lean mixture.
c. an excessively rich mixture.