15.9 Flashcards
(40 cards)
Viscosity of ester based synthetic oils
3 centistokes ( 3mm2/s at 100 degrees c )
What viscosity did thickeners raise the ester synthetic oils to
7.5 centistokes
What properties did type 1 oils need
Resistance oxidation and thermal degradation
What is type 2 oil viscosity and used for
5 mm2/s used for improved thermal stability and high load carrying ability
4 uses of oil
Lubricate
Cooling
Cleaning
Corrosion protection
How is oil used to cool
Heat of the material transferred to the oil
3 types of synthetic oil
1 - used on old gas turbine engines
2 - used on modern GTE
3 - used on special aircraft (higher thermal stability and viscosity at higher temperatures than type 2)
3 Advantages of synthetic oils
Better viscosity
Better thermal stability
High pressure resistance
Disadvantage of synthetic oils
They have a high price
What is viscosity index
Effect temperature has on viscosity of the oil
Higher number indicates least affected by temperature
What is viscosity
Most important characteristic
Internal resistance of a fluid against deformation
What happens to viscosity at high temperatures
Low and vice versa
What is pour point
Lowest temperature oil will move in a 31.75mm test tube when held for 5 seconds
Type 2 oil pour point
-57 degrees C
What is oxidation resistance
Ability of oil to not react with oxygen as it gets thicker when it does
What’s volatility
Measure of ease a liquid is converted to a vaporous state
What’s acidity
Measure of the corrosive tendencies of the oil
What’s coking
Amount of carbon residue remaining in the oil after subject to extreme heating
What is fuel main components in %
16% hydrogen 84% carbon
Most common fuel in Europe
Jet A1
(JP1A) - American name also JP5
Most common fuel in USA
Jet A
(JP1) - American name
What is jet B flash point and where is it used
-20 degrees C and used in Canada for its cold weather performance
what is JP5 flash point and freezing point
Flash point - 65 degrees C
Freezing point - 48 degrees C
Why does fuel used have to be recorded
Each fuel type has different handling and operating characteristics
