Jeppesen Oral- Chapter 9 (Lubrication Systems) Flashcards
faulty piston rings
Clean, cushion, cool, reduce friction, hydraulic medium
Light enough to circulate freely Viscous enough to provide cushioning
Becomes too thin, cause more damage
Operating load and temperature as well as rotational speed
To provide sufficient cushioning for momentary loads, To provide sufficient thickness for containment entrapment
Metal particles, dirt, carbon, moisture and acids
low oil supply
Causes slugging materials to repel each other and remain in suspension long enough to be trapped by oil filter or drained
To provide for oil foaming, thermal expansion and air in the oil return
Diluted oil, contaminated oil, and oil level being to high
Oil pressure relief valve
Directs oil either through the cooler or around it in order to maintain proper operating oil temperatures
high oil temperature
At the engine oil inlet
Indicates abnormal wear and imminent engine failure
Follow engine manufactures maintenance instruction
Turbine bearings
Synthetic oil
main oil pressure system, scavenge system and just before oil jet (last chance filter)
Air cooled Fuel cooled
It may become so thin, film is not thick enough and metal to metal contact happens
Is the oil temperature shown on the aircraft instrument panel the temperature of the oil entering the engine or of the oil leaving the engine?
It is the temperature of the oil entering the engine.
What is the purpose of oil dilution in a reciprocating engine?
When very cold weather is anticipated, gasoline can be mixed with the lubricating oil before the engine is shut down. This reduces the viscosity of the oil and makes starting easier. When the engine is running, the gasoline evaporates out of the oil.
What is the function of the hopper in the oil tanks used with some reciprocating engines?
Hoppers are a part of the oil dilution system. Only the oil in the hopper is diluted. This speeds up dilution and requires less gasoline.
What happens to the gasoline that is used to dilute the oil in the crankcase of an aircraft reciprocating engine?
When the engine is sunning and the oil is warm, the gasoline evaporates out of it.
What is the purpose of the sludge plugs in the crankshaft of a reciprocating engine?
They trap sludge that is in the oil and hold it until the engine is disassembled at overhaul.
Which pump is the larger in a dry-sump lubricating system, the pressure pump or the scavenger pump?
The scavenger pump has the greater volume.
Why do full-flow oil filters have a spring-operated bypass valve in them?
In case the filter should plug up so it cannot pass any oil, the bypass valve will open and allow unfiltered oil to flow through the system.
Where are the last chance filters located in a turbojet engine?
They are located inside the engine just ahead of the nozzles that spray oil onto the bearings.
