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Powerplant Writtens > Lubrication Systems > Flashcards

Lubrication Systems Flashcards

1
Q

What will be the result of operating an engine in extremely high temperatures using a lubricant recommended by the manufacturer for a much lower temperature?

A

The oil pressure will be lower than normal.

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2
Q

(1) Gas turbine and reciprocating engine oils can be mixed or used interchangeably.

(2) Most gas turbine engine oils are synthetic.

A

Only 2 is true.

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3
Q

An oil separator is generally associated with which of the following?

A

Engine-driven vacuum pump.

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4
Q

The time in seconds required for exactly 60 cubic centimeters of oil to flow through an accurately calibrated orifice at a specific temperature is recorded as a measurement of the oil’s what?

A

viscosity.

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5
Q

Upon what quality or characteristic of a lubricating oil is its viscosity index based?

A

its rate of change in viscosity with temperature change.

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6
Q

Lubricating oils with high viscosity index ratings are oils…

A

in which the viscosity does not vary much with temperature change.

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7
Q

Compared to reciprocating engine oils, the types of oils used in turbine engines…

A

have less tendency to produce lacquer or coke.

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8
Q

The oil used in reciprocating engines has a relatively high viscosity due to what?

A

large clearances and high operating temperatures.

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9
Q

If all other requirements can be met, what type of oil should be used to achieve theoretically perfect engine lubrication?

A

The thinnest oil that will stay in place and maintain a reasonable film strength.

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10
Q

Which of these characteristics is desirable in turbine engine oil?

A

High flash point.

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11
Q

The viscosity of a liquid is a measure of its what?

A

resistance to flow.

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12
Q

What type of oil system is usually found on turbine engines?

A

Dry sump, pressure, and spray.

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13
Q

Which of the following helps determine the proper grade of oil to use in a particular engine?

A

Operating speeds of bearings.

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14
Q

Specific gravity is a comparison of the weight of a substance to the weight of an equal volume of what?

A

distilled water at a specific temperature.

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15
Q

Which of the following has the greatest effect on the viscosity of lubricating oil?

A

Temperature.

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16
Q

What advantage do mineral base lubricants have over vegetable oil base lubricants when used in aircraft engines?

A

Chemical stability.

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17
Q

The recommended aircraft engine lubricants are what?

A

mineral or synthetic base.

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18
Q

High tooth pressures and high rubbing velocities, such as occur with spur-type gears, require the use of what?

A

An EP lubricant.

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19
Q

Manufacturers normally require turbine engine oil servicing within a short time after engine shutdown primarily to what?

A

prevent overservicing.

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20
Q

What type of oil do most engine manufacturers recommend for new reciprocating engine break-in?

A

Straight mineral oil.

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21
Q

What type of oil do most engine manufacturers recommend after new reciprocating engine break-in?

A

Ashless dispersant oil.

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22
Q

The type of oil pump most commonly used on turbine engines are classified as…

A

positive displacement.

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23
Q

As a general rule, the mixture setting on a reciprocating engine operating at or near takeoff power that provides the best cooling is what?

A

FULL RICH

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24
Q

The engine oil temperature regulator is usually located between which of the following on a dry sump reciprocating engine?

A

The scavenger pump outlet and the oil storage tank.

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25
Q

What will happen to the return oil if the oil line between the scavenger pump and the oil cooler separates?

A

The return oil will be pumped overboard.

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26
Q

At cruise RPM, some oil will flow through the relief valve of a gear-type engine oil pump. This is normal as the relief valve is set at a pressure which is what?

A

lower than the pressure pump capabilities.

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27
Q

(1) Fuel may be used to cool oil in gas turbine engines.

(2) Ram air may be used to cool oil in gas turbine engines.

A

Both 1 and 2 are true.

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28
Q

In a reciprocating engine oil system, the temperature bulb senses oil temperature…

A

at a point after the oil has passed through the oil cooler.

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29
Q

The oil dampened main bearing utilized in some turbine engines is used to what?

A

provide an oil film between the outer race and the bearing housing in order to reduce vibration tendencies in the rotor system, and to allow for slight misalignment.

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30
Q

What is the purpose of the last-chance oil filters?

A

to filter the oil immediately before it enters the main bearings.

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31
Q

In a jet engine which uses a fuel/oil heat exchanger, the oil temperature is controlled by a thermostatic valve that regulates the flow of what?

A

oil through the heat exchanger.

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32
Q

What prevents pressure within the lubricating oil tank from rising above or falling below ambient pressure (reciprocating engine)?

A

Oil tank vent.

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33
Q

In an axial-flow turbine engine, compressor bleed air is sometimes used to aid in cooling the what?

A

turbine, vanes, blades, and bearings.

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34
Q

Oil picks up the most heat from which of the following turbine engine components?

A

Turbine bearing.

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35
Q

Which of the following is a function of the fuel/oil heat exchanger on a turbojet engine?

A

Increases fuel temperature.

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36
Q

According to the Federal Aviation Regulations, oil tank fillers on turbine engines must be marked with the word…

A

“oil”

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37
Q

Oil tank fillers on reciprocating engines are marked with the word…

A

“oil,” in accordance with 14 CFR Part 25

38
Q

After making a welded repair to a pressurized type turbine engine oil tank, the tank should be pressure checked to what?

A

not less than 5 psi plus the maximum operating pressure of the tank.

39
Q

Why are fixed orifice nozzles used in the lubrication system of gas turbine engines?

A

To provide a relatively constant oil flow to the main bearings at all engine speeds.

40
Q

Possible failure related ferrous-metal particles in turbine engine oil cause an (electrical) indicating-type magnetic chip detector to indicate their presence by what?

A

bridging the gap between the detector center (positive) electrode and the ground electrode.

41
Q

What would be the probable result if the oil system pressure relief valve should stick in the open position on a turbine engine?

A

Insufficient lubrication.

42
Q

What is the primary purpose of the fuel/oil heat exchanger?

A

Cool the oil.

43
Q

What unit in an aircraft engine lubrication system is adjusted to maintain the desired system pressure?

A

Oil pressure relief valve.

44
Q

Low oil pressure can be detrimental to the internal engine components. However, high oil pressure…

A

should be limited to the engine manufacturer’s recommendations.

45
Q

What is the primary purpose of the oil breather pressurization system that is used on turbine engines?

A

Provides a proper oil spray pattern from the main bearing oil jets.

46
Q

The purpose of directing bleed air to the outer turbine case on some engines is to what?

A

provide optimum turbine blade tip clearance by controlling thermal expansion.

47
Q

Some larger reciprocating engines use a compensating oil pressure relief valve to what?

A

provide a high engine oil pressure when the oil is cold and automatically lower the oil pressure when the oil warms up.

48
Q

In order to relieve excessive pump pressure in an engine’s internal oil system, most engines are equipped with a what?

A

relief valve.

49
Q

What is the source of most of the heat that is absorbed by the lubricating oil in a reciprocating engine?

A

Pistons and cylinder walls.

50
Q

How are the teeth of the gears in the accessory section of an engine normally lubricated?

A

By splashed or sprayed oil.

51
Q

What is the purpose of the check valve generally used in a dry sump lubrication system?

A

To prevent the oil from the supply tank from seeping into the crankcase during inoperative periods.

52
Q

Which of the following factors has the least effect on the oil consumption of a specific engine?

A

Mechanical efficiency.

53
Q

How is the oil collected by the piston oil ring returned to the crankcase?

A

Through holes drilled in the piston oil ring groove.

54
Q

Which of the following lubrication system components is never located between the pressure pump and the engine pressure system?

A

Fuel line for oil dilution system.

55
Q

As an aid to cold-weather starting, the oil dilution system thins the oil with what?

A

gasoline.

56
Q

The basic oil pressure relief valve setting for a newly overhauled engine is made…

A

in the overhaul shop.

57
Q

Where is the oil temperature bulb located on a dry sump reciprocating engine?

A

Oil inlet line.

58
Q

Cylinder walls are usually lubricated by what?

A

splashed or sprayed oil.

59
Q

If an oil filter element becomes completely clogged, the what?

A

bypass valve will open, and the oil pump will supply unfiltered oil.

60
Q

Oil accumulation in the cylinders of an inverted inline engine and in the lower cylinders of a radial engine is normally reduced or prevented by what?

A

extended cylinder skirts.

61
Q

What is the primary purpose of changing aircraft engine lubricating oils at predetermined periods?

A

The oil becomes contaminated with moisture, acids, and finely divided suspended solid particles.

62
Q

What determines the minimum particle size which will be excluded or filtered by CUNO (staked disc, edge filtration) filter?

A

The spacer thickness.

63
Q

What is the primary purpose of the hopper located in the oil supply tank of some dry sump engine installations?

A

To reduce the time required to warm the oil to operating temperatures.

64
Q

The purpose of the flow control valve in a reciprocating engine oil system is to what?

A

direct oil through or around the oil cooler.

65
Q

Where are sludge chambers, when used in aircraft engine lubrication systems, usually located?

A

In the crankshaft throws.

66
Q

Why is an aircraft reciprocating engine oil tank on a dry sump lubrication system equipped with a vent line?

A

To prevent pressure buildup in the oil tank.

67
Q

Excessive oil is prevented from accumulating on the cylinder walls of a reciprocating engine by…

A

oil control rings on the pistons.

68
Q

(1) Wet sump oil systems are most commonly used in gas turbine engines.

(2) In most turbine engine oil tanks, a slight pressurization of the tank is desired to ensure a positive flow of oil.

A

Only 2 is true.

69
Q

The pumping capacity of the scavenger pump in a dry sump aircraft engine’s lubrication system…

A

is greater than the capacity of the oil supply pump.

70
Q

In which of the following situations will the oil cooler automatic bypass valve be open the greatest amount?

A

Engine oil below normal operating temperature.

71
Q

In order to maintain a constant oil pressure as the clearances between the moving parts of an engine increase through normal wear, the supply pump output…

A

remains relatively constant (at a given RPM) with less oil being returned to the pump inlet by the relief valve.

72
Q

The valve assemblies of opposed reciprocating engines are lubricated by means of a what?

A

pressure system.

73
Q

What will result if an oil filter becomes completely blocked?

A

Oil will flow at the normal rate through the system.

74
Q

A turbine engine dry sump lubrication system of the self-contained, high-pressure design…

A

consists of pressure, breather, and scavenge subsystems.

75
Q

Lube system last-chance filters in turbine engines are usually cleaned…

A

during overhaul.

76
Q

How are the piston pins of most aircraft engines lubricated?

A

By oil which is sprayed or thrown by the master or connecting rods.

77
Q

The vent line connecting the oil supply tank and the engine in some dry sump engine installation permits what?

A

the oil tank to be vented through the normal engine vent.

78
Q

An engine lubrication system pressure relief valve is usually located between the what?

A

pump and the internal oil system.

79
Q

Where is the oil of a dry sump reciprocating engine exposed to the temperature control valve sensing unit?

A

Oil cooler inlet.

80
Q

Under which of the following conditions is the oil cooler flow control valve open on a reciprocating engine?

A

When the temperature of the oil returning from the engine is too low.

81
Q

The purpose of a relief valve installed in the tank venting system of a turbine engine oil tank is to what?

A

prevent oil pump cavitation by maintaining a constant pressure on the oil pump inlet.

82
Q

In a reciprocating engine, oil is directed from the pressure relief valve to the inlet side of the what?

A

pressure pump.

83
Q

If the oil in the oil cooler core and annular jacket becomes congealed, what unit prevents damage to the cooler?

A

Surge protection valve.

84
Q

The primary source of oil contamination in a normally operating reciprocating engine is what?

A

combustion deposits due to combustion chamber blow-by and oil migration on the cylinder walls.

85
Q

A drop in oil pressure may be caused by what?

A

foreign material under the relief valve.

86
Q

The main oil filters strain the oil at which point in the system?

A

Just as it leaves the pressure pump.

87
Q

Which of the following prevents oil from entering the main accessory case when the engine is not running?

A

Check valve.

88
Q

An oil tank having a capacity of 5 gallon must have an expansion space of what?

A

2 quarts.

89
Q

As a general rule, a small amount of small fuzzy particles or gray metallic paste on a turbine engine magnetic chip detector…

A

is considered to be the result of normal wear.

90
Q

Why is expansion space required in an engine oil supply tank?

A

For oil enlargement and collection of foam.

91
Q

The purpose of a dwell chamber in a turbine engine oil tank is to provide what?

A

separation of entrained air from scavenged oil.

92
Q

Which of the following bearing types must be continuously lubricated by pressure oil?

A

Plain.

Powerplant Writtens (28 decks)

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