15.10 Lubrication Systems Flashcards
What is the purpose of lubrication systems?
To distribute oil to bearing compartments and gearboxes.
What are the 2 types of lubrication sumps used?
Wet and dry sumps.
Where does a wet sump store oil?
In the engine.
Where does a dry sump store oil?
An external supply tank mounted on/near the engine.
What are the 2 classifications of lubrication systems?
Full flow.
Constant pressure.
What can be said about oil pressure in a full flow system?
It can’t be regulated.
What changes oil pressure in a full flow system?
Rotor speed and oil temp.
What drives the supply pump in a full flow system?
N2 rotor
What effect does a leakage have on oil pressure?
Decreases it.
Where is a pressure relief valve installed in a full flow system?
Between the delivery and suction side of the supply pump.
What can be said about the oil pressure of a constant pressure system?
It is regulated.
What valve does the constant pressure system have that the full flow system doesn’t?
Pressure regulating valve.
What effect do changes in oil temp have on oil pressure?
No effect.
What lubrication system is most common?
Full flow.
What are the advantages of a full flow system?
Simplicity.
No adjustments are necessary during maintenance.
What are the negatives of a full flow system?
Needs relatively high oil pressure when engine is at idle.
There’s a rise in oil temp after a power reduction.
What is the critical point of the lubrication system due to high temperatures.
Exhaust turbine bearing.
What is used to cool oil?
An oil cooler.
What is an oil tank made of?
Aluminium coated in silicone for fire resistance.
What surrounds a filler to catch oil spillage during servicing?
A scupper.
Where does a scupper drain spilt oil?
To the engine drain mast.
What is a strainer?
A filter
What is an oil pump designed to do?
To supply oil under pressure.
What are the 2 types of oil pumps?
Gear and gerotor.
