15.9 Lubrications And Fuels

Question 1

What are the issues with mineral based oils?

Answer 1

They suffer from excessive volatility and thermal degradation at high temperature

Question 2

What are ester based oils also known as?

Answer 2

Third generation oils

Question 3

What are the benefits of ester based oils?

Answer 3

They were developed with properties suitable for gas turbine engines such as improved thermal stability

Question 4

What are the main tasks of oils?

Answer 4

Lubrication
Cooling
Corrosion resistance
Cleaning

Question 5

What are the three types of synthetic oils?

Answer 5

Type 1 older engines
Type 2 modern gas engines
Type 3 special aircraft

Question 6

What is the largest disadvantage of synthetic oils?

Answer 6

The cost

Question 7

What is viscosity?

Answer 7

Internal resistance of a fluid against deformation

Question 8

What is pour point?

Answer 8

The lowest temperature in which oil will visibly move

Question 9

What is the pour point of type 2 oils?

Answer 9

-57 degrees

Question 10

What is viscosity in relation to temperature?

Answer 10

Higher at low temperature
Lower at higher temperature

Question 11

What is flash point?

Answer 11

The lowest temperature the oil will give off enough vapour to flash when a flame is applied

Question 12

What is the flash point of type 2 oils ?

Answer 12

250 degrees

Question 13

What is pressure resistance?

Answer 13

Oil film between moving components

Question 14

What is oxidation resistance?

Answer 14

The reaction between oil and oxygen making it thicker

Question 15

What is thermal stability?

Answer 15

Oil resistance at high temperature

Question 16

What is volatility?

Answer 16

The ease that a liquid becomes vaporous

Question 17

What is acidity?

Answer 17

Its tendency to be corrosive

Question 18

What is oil foaming?

Answer 18

Resistance of the oil to separate from entrapped air

Question 19

What is rubber swelling?

Answer 19

The amount of oil that causes rubber to swell

Question 20

What is oxidation and thermal stability?

Answer 20

The ability of oil to resist formation of high carbon and sludge

Question 21

What is corrosiveness?

Answer 21

The effect oil has on metals especially copper

Question 22

What is pressure?

Answer 22

The ability of oil to carry a load

Question 23

What is coking?

Answer 23

Carbon residue remaining in the oil after extreme heating

Question 24

What is JET A1 USA name?

Answer 24

JP1A

Question 25

What is JET A USA name?

Answer 25

JP1

Question 26

Jet B flash and freeze point?

Answer 26

Flash = -20 c Freeze = -48 c

Question 27

What is the flash and freeze point JP5?

Answer 27

Flash = 65c Freeze = -48c

Question 28

What type of fuels are jet fuels?

Answer 28

Kerosene

Question 29

What are the main requirements for fuels?

Answer 29

-low freezing point -flash point low enough to give good ignition -flash point high enough for safe handling

Question 30

What properties must fuel poses?

Answer 30

-Clear bright and visually free from contaminants -limited acidity -max viscosity at -20degrees -combustion in calorific value

Question 31

What can water build up in the tank cause?

Answer 31

-microbial growth -engine power fluctuations and flameout

Question 32

What is the fuel density of jet A?

Answer 32

0.81 kg per litre at 15 degrees Also jet a1

Question 33

How are fuel additives measured?

Answer 33

Parts per million

Question 34

What anti Ice additives are typically used?

Answer 34

PRIST

Question 35

What additives can be added to fuel?

Answer 35

Anti ice Anti microbial Anti oxidants Static dissipator Corrosion inhibitors Metal de activators

Question 36

What is important when storing oil?

Answer 36

It cannot be stored open it’s hygroscopic and absorbs moisture