Powerplant - Lubrication Systems

Question 1

What is the purpose of lubricant in an aircraft engine?

Answer 1

To reduce friction between moving parts

Question 2

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

Answer 2

Viscosity

Question 3

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

Answer 3

The operating load, rotational speeds and the operating temperatures

Question 4

What are considered main oil contaminants?

Answer 4

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

Question 5

What do metallic particles on an oil screen indicate?

Answer 5

Internal failure of the engine

Question 6

What could be an indication of blocked oil cooler passages?

Answer 6

high oil temperature

Question 7

What could be an indication of an inadequate oil supply?

Answer 7

Low oil pressure and high oil temperature

Question 8

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

Answer 8

Specially developed synthetic oils

Question 9

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

Answer 9

Air cooled oil cooler and fuel cooled oil cooler

Question 10

What are the functions of engine oil in a reciprocating engine?

Answer 10

Cools various parts, seals the combustion chamber by providing a film between the cylinder walls and the rings and aids in cleaning the engine by carrying residues to the oil filter

Question 11

What is the weight of aircraft engine oil?

Answer 11

Approximately 7.5 pounds per U.S. gallon

Question 12

What is the purpose of the oil dilution system?

Answer 12

Thins the oil by inducing fuel into the lubrication system which makes cold weather starting easier

Question 13

What is straight mineral oil?

Answer 13

Natural lubricating oil that has no additives for foaming, cleaning, or viscosity.

Question 14

What is ashless dispersant oil?

Answer 14

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

Question 15

What is synthetic oil?

Answer 15

Synthetic oil that is man made through the process of chemically altering the molecular structure of petroleum oil in order to achieve the desired characteristics.

Question 16

What are the purposes of reciprocating engine oil?

Answer 16

cleans, cools, cushions, seals and lubricates parts.

Question 17

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

Answer 17

When the oil is cool it will direct it around the oil cooler. When the oil is warm it will be directed through the oil cooler.

Question 18

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

Answer 18

It is measured before it enters the system. In a dry sump lubricating system, the oil temperature bulb is located anywhere in the oil inlet line between the tank and the engine. In a wet sump system, the temperature bulb is located where is senses the temperature after the oil passes through the oil cooler.

Question 19

What could cause oil foaming?

Answer 19

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

Question 20

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

Answer 20

Airplane flight manual, pilots operating handbook

Question 21

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

Answer 21

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 22

Where are carbon seals used in turbine engines?

Answer 22

gearboxes, air turbine motor starters, and main shaft seals

Question 23

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

Answer 23

for lubrication of the main shaft bearings

Question 24

Where are the engine oil filters located?

Answer 24

Between the oil pump output and the engine bearings

Question 25

Why do reciprocating engines require high viscosity oil?

Answer 25

High viscosity oil performs better in reciprocating engines because they have large clearances, high operating temperatures, and high bearing pressures.

Question 26

What two factors impact fluid viscosity?

Answer 26

Temperature and pressure, although pressure has a very small effect on viscosity