15.9 Flashcards
(28 cards)
Why are mineral oils not used on engines
Excessive volatility and thermal degradation
What oils are used in engines
Ester based synthetic oils
What is the take or oil
Lubrication
Cooling
Cleaning
Corrosion protection
What is a type 2 oil
Mostly used on gas turbine
What is a type 3
Special aircraft (military)
Where is type 1 oil used
Older gas turbine engines
What are the advantages and disadvantages of turbine fuel
Good viscosity
Thermal stability
High pressure resistance
Expensive
What is the viscosity index
Effect temp has on viscosity
Higher number indicates least effected by change in temp
What is viscosity
Internal resistance of fluid against deformation
What is the pour point
Lowest temp there is viable movement
What is the flash point of type 2 oil
250C
Flash point definition
Lowest temp vapour will burn
Acidity
Corrosive tendency
What is oxidation resistance
Reaction between oil and oxygen
Increases viscosity
What is oil foaming
Resistance of oil to separate form air
What is rubber swelling
Amount oil will cause rubber to swell
What is coking
Amount of carbon residue after oil has been subjected to extreme heat
Jet A1
JP1A
+38 FLASH
- 47 FREEZE
Jet A
JP1
+38 FLASH
-40 FREEZ
Jet B
JP4
-20 FLASH
-58 FREEZ
JP5
+65 flash
-48 FREEZ
Military (aircraft carriers)
Idael Jet fuel properties
Low freezing point
Low enough flash point to provide good ignition but not to low
Must have volatility as to be able to vaporise
Why are additives used
To give high tendency to vaporise at high altitudes
What metal does fuel act corrosively
Cooper and silver
