Powerplant Systems & Components: Lubrication Systems 🔊

Question 1

What is straight mineral oil?

Answer 1

A type of natural oil that has no additives for foaming, cleaning, or viscosity

Question 2

What is ashless dispersant (AD) oil?

Answer 2

It is a type of mineral oil with additives that evenly spread contaminates throughout the oil. The additives that are used do not form ashes.

Question 3

What is synthetic oil?

Answer 3

It is an oil that is man-made through the process of chemically altering the molecular structure of petroleum oil to achieve desired characteristics

Question 4

What is meant by multi-viscosity oil?

Answer 4

It has varying viscosity; cold oil have low viscosity but when it warms up the viscosity increases for better lubrication.

Question 5

What are the purposes of reciprocating engine oil?

Answer 5

It cleans, cools, cushions, seals, and lubricates parts

Question 6

What is the most important property that aircraft reciprocating engine oil must possess?

Answer 6

Viscosity (a measurement of frictional resistance to flow)

Question 7

What factors must be considered in determining the proper grade of oil to use in a specific engine?

Answer 7

The operating load, rotational speeds, and operating temperatures are the most important to consider

Question 8

What is the purpose of the oil flow control valve “oil cooler bypass valve”?

Answer 8

When the oil is cool the valve will direct it around the oil cooler, when it warms it will direct it through the oil cooler

Question 9

What are come oil contaminants?

Answer 9

Gasoline, moisture, acid, dirt, carbon, and metallic particles

Question 10

From what location on a reciprocating engine is the oil temperature usually taken?

Answer 10

The bulb is located where it measures oil temperature before it enters the hot sections of the engine. In a dry sump lubricating system, the bulb is located anywhere in the oil inlet line between the oil tank and the engine. Wet sump systems have the bulb located where it senses the temperature after the oil passes through the oil cooler.

Question 11

What do metallic particles on an oil screen indicate?

Answer 11

They may indicate an internal failure of the engine

Question 12

What could cause oil foaming?

Answer 12

Diluted oil, contaminated oil, or the oil level is too high

Question 13

What would be an indication of blocked oil cooler passages?

Answer 13

High oil temperature

Question 14

What would be an indication of an inadequate oil supply?

Answer 14

Low oil pressure and high oil temperature

Question 15

What type of oil is used in turbine engine lubrication systems?

Answer 15

Specially developed synthetic oils

Question 16

Where can you find the specified grade of oil for a particular aircraft?

Answer 16

In the Airplane Flight Manual (AFM) or the Pilot’s Operating Handbook (POH)

Question 17

What are two types of oil coolers used in turbine engine lubrication systems?

Answer 17

Air-cooled oil cooler and fuel-cooled oil cooler

Question 18

What is the meaning of oil flash point? Fire point?

Answer 18

Oil flash point is the temperature at which the oil will begin to give off ignitable vapors. The fire point is the temperature at which there are sufficient vapors to support a continuous flame.

Question 19

What is the weight of aircraft engine oil?

Answer 19

Approximately 7.5 pounds per US gallon

Question 20

What is the purpose of an oil dilution system?

Answer 20

It thins the oil by introducing fuel into the lubrication system which makes cold weather starting easier. Fuel is used because it will evaporate out of the oil and leave through the crankcase breather.

Question 21

What is the primary purpose of engine oil lubricant?

Answer 21

To reduce friction

Question 22

What is the S.O.A.P. analysis?

Answer 22

It is an analysis system that establishes a trend to measure engine health (Spectrometric Oil Analysis Program)

Question 23

Where are carbon seals used in a turbine engine?

Answer 23

Gearboxes, air-turbine motor starters, and main shaft seals

Question 24

What is the key purpose of lubrication in a turbine engine?

Answer 24

Lubrication of the main shaft bearings

Question 25

Where are engine oil filters located?

Answer 25

Between the oil pump output and the engine bearings

Question 26

Why do reciprocating engines require oil with a high viscosity index? (Small changes in viscosity over a wide temperature range)

Answer 26

Higher viscosity indexes allow for easier starting in cold temperatures and prevents the oil from becoming too thin at operating temperatures to protect bearings under operating loads

Question 27

Why do reciprocating engines require high viscosity oil? (Oil flows slowly)

Answer 27

They have large clearances, high operating temperatures, and high bearing pressures

Question 28

What two factors impact fluid viscosity?

Answer 28

Temperature and pressure

Question 29

What is the purpose of ashless dispersant oil?

Answer 29

To prevent sludge build up and oil filters from clogging