15.9 Lubricants and Fuels Flashcards
What are the 4 main tasks of engine lubricant?
Lubricate
Cooling
Cleaning
Corrosion protection
What are the 2 types of oil?
Synthetic
Mineral
Which type of synthetic oil is used on GTE?
Type 2 (synthetic)
Name 3 advantages of synthetic oil
Better viscosity
Better thermal stability
High-pressure resistance
What can’t be done with synthetic oils?
Cannot be mixed with other manufacturers, even if the oil is the same type
Define viscosity
Ability of a fluid to resist deformation
Define pour point
Lowest temperature oil will visibly move in a 31.75mm tube held horizontally for 5 seconds.
Define flashpoint
Lowest temperature oil will give off enough vapor to flash when a flame is applied.
What is coking?
The amount of carbon residue remaining in the oil after being subjected to extreme temperatures.
What is the most commonly used jet fuel in Europe?
Jet A1
What is jet A1 flashpoint?
+38 degrees C
What is jet A1 freezing point?
-47 degrees C
What is the specific gravity for jet A1?
0.775-0.840
What are the fuel requirements, in relation to freezing point, flashpoint, and volatility?
- Low freezing point.
- Low flashpoint to allow ignition but high enough for safe handling.
- High volatility for engine starts in all conditions, ground and air.
What method is used to detect water that has dissolved in fuel?
Syringe test cartridge.
What are the two main additives used in aviation fuel?
- Anti-ice additive.
- Anti-microbial additive.
How does anti-ice additive prevent the formation of ice
Reduces the fuel’s freezing point.
What type of jet fuel is used for extreme cold climates?
Jet B (freezing point of -58 degrees C).
What are the five factors which affect oil performance?
- Oil foaming.
- Rubber swelling.
- Corrosiveness.
- Pressure.
- Coking.
How easy a liquid converts to a vapor is known as what?
Volatility.
What is the result of a higher viscosity index?
Viscosity is less affected by temperature.
What is the Pour point of type 2 synthetic oil?
-57 degrees C
Type 2 viscosity must be higher than ___ at 90°C and lower than ___ At -40°C.
5cs
13000cs
What happens to the oil viscosity as temperature increases?
Viscosity decreases.
What is meant by the pressure resistance of oil?
Ability for the oil to keep its lubricating film between components, when under loads.
What are static dissipator additives used for?
To reduce hazardous effects of static electricity generated by the high fuel flow rate through the system.
What are etal deactivators, in relation to fuel additives?
They suppress the catalytic effect that metals have on fuel oxidation.
What should you do if you ingest oil or fuel?
- Do NOT induce vomiting.
- Drink 250ml of water.
- Seek medical attention.
What should be done if your skin comes into contact with fuel?
Wash thoroughly with soap and water, as it can cause dermatitis.
What is thermal ability?
The ability to resist decomposition at high temperatures.
What is viscosity measured in?
Centistrokes (cs)
