15.9 Lubrications And Fuels Flashcards

1
Q

What are the issues with mineral based oils?

A

They suffer from excessive volatility and thermal degradation at high temperature

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2
Q

What are ester based oils also known as?

A

Third generation oils

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3
Q

What are the benefits of ester based oils?

A

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

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4
Q

What are the main tasks of oils?

A

Lubrication
Cooling
Corrosion resistance
Cleaning

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5
Q

What are the three types of synthetic oils?

A

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

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6
Q

What is the largest disadvantage of synthetic oils?

A

The cost

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7
Q

What is viscosity?

A

Internal resistance of a fluid against deformation

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8
Q

What is pour point?

A

The lowest temperature in which oil will visibly move

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9
Q

What is the pour point of type 2 oils?

A

-57 degrees

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10
Q

What is viscosity in relation to temperature?

A

Higher at low temperature
Lower at higher temperature

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11
Q

What is flash point?

A

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

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12
Q

What is the flash point of type 2 oils ?

A

250 degrees

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13
Q

What is pressure resistance?

A

Oil film between moving components

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14
Q

What is oxidation resistance?

A

The reaction between oil and oxygen making it thicker

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15
Q

What is thermal stability?

A

Oil resistance at high temperature

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16
Q

What is volatility?

A

The ease that a liquid becomes vaporous

17
Q

What is acidity?

A

Its tendency to be corrosive

18
Q

What is oil foaming?

A

Resistance of the oil to separate from entrapped air

19
Q

What is rubber swelling?

A

The amount of oil that causes rubber to swell

20
Q

What is oxidation and thermal stability?

A

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

21
Q

What is corrosiveness?

A

The effect oil has on metals especially copper

22
Q

What is pressure?

A

The ability of oil to carry a load

23
Q

What is coking?

A

Carbon residue remaining in the oil after extreme heating

24
Q

What is JET A1 USA name?

A

JP1A

25
Q

What is JET A USA name?

A

JP1

26
Q

Jet B flash and freeze point?

A

Flash = -20 c
Freeze = -48 c

27
Q

What is the flash and freeze point JP5?

A

Flash = 65c
Freeze = -48c

28
Q

What type of fuels are jet fuels?

A

Kerosene

29
Q

What are the main requirements for fuels?

A

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

30
Q

What properties must fuel poses?

A

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

31
Q

What can water build up in the tank cause?

A

-microbial growth
-engine power fluctuations and flameout

32
Q

What is the fuel density of jet A?

A

0.81 kg per litre at 15 degrees
Also jet a1

33
Q

How are fuel additives measured?

A

Parts per million

34
Q

What anti Ice additives are typically used?

A

PRIST

35
Q

What additives can be added to fuel?

A

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

36
Q

What is important when storing oil?

A

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