Module 15.10 Lubrication systems Flashcards
Lubrication systems distribute oil to what?
- Bearing compartments
- Gearboxes
Where do wet sump engine lubrication systems store the oil?
In the engine
What do dry sumps use to store oil?
External supply tank
What are the two types of oil/lubrication systems?
- Full flow
- Constant pressure
The supply pump is driven by what rotor system?
N2 (High pressure turbine, which drives the accessory gearbox)
In full flow systems, oil pressure changes with what?
- N2 rotor speed
- Temperature
- Flow area
A leak in the oil system leads to what?
- Decrease in pressure
- Increase in the total flow area
On full flow, what would a pressure relief valve be installed between on the pump?
Between the delivery and the suction side
The constant pressure system is also called what?
Regulated pressure system
What valve type does a constant pressure system have?
Pressure regulating valve
What does the pressure regulating valve do?
Holds oil pressure at a given value at all N2 speeds from idle to full
Does oil temperature affect pressure in the constant pressure system?
No
Why is the full flow system most common?
- Simple
- No adjustments during maintenance
What are the two disadvantages of full flow?
- High oil pressure at idle
- Significant rise in oil temperature at power reduction
Why is the exhaust turbine bearing a critical lubrication point?
High temperature
What is used to cool oil?
Oil coolers
What are aluminium alloy oil tanks coated with to give fire resistance?
Silicon
What are the two refilling methods?
- Gravity
- Pressure
What prevents discharge of oil and air if the cap is not fitted properly?
Check valve\
Where does the scupper drain, drain oil to?
Engine drain mast
What is the purpose of the scupper drain?
To catch spilt oil
What is after the oil pump in the delivery system? and what is the safety feature?
Filter, with a pressure differential switch that operates a bypass valve
After the filter, where does the oil flow?
First to the air cooled oil cooler, then to the fuel cooled oil cooler
What are the filters after the heat exchangers called?
Last chance filters