Powerplant Systems & Components: Lubrication Systems 🔊 Flashcards
What is straight mineral oil?
A type of natural oil that has no additives for foaming, cleaning, or viscosity
What is ashless dispersant (AD) oil?
It is a type of mineral oil with additives that evenly spread contaminates throughout the oil. The additives that are used do not form ashes.
What is synthetic oil?
It is an oil that is man-made through the process of chemically altering the molecular structure of petroleum oil to achieve desired characteristics
What is meant by multi-viscosity oil?
It has varying viscosity; cold oil have low viscosity but when it warms up the viscosity increases for better lubrication.
What are the purposes of reciprocating engine oil?
It cleans, cools, cushions, seals, and lubricates parts
What is the most important property that aircraft reciprocating engine oil must possess?
Viscosity (a measurement of frictional resistance to flow)
What factors must be considered in determining the proper grade of oil to use in a specific engine?
The operating load, rotational speeds, and operating temperatures are the most important to consider
What is the purpose of the oil flow control valve “oil cooler bypass valve”?
When the oil is cool the valve will direct it around the oil cooler, when it warms it will direct it through the oil cooler
What are come oil contaminants?
Gasoline, moisture, acid, dirt, carbon, and metallic particles
From what location on a reciprocating engine is the oil temperature usually taken?
The bulb is located where it measures oil temperature before it enters the hot sections of the engine. In a dry sump lubricating system, the bulb is located anywhere in the oil inlet line between the oil tank and the engine. Wet sump systems have the bulb located where it senses the temperature after the oil passes through the oil cooler.
What do metallic particles on an oil screen indicate?
They may indicate an internal failure of the engine
What could cause oil foaming?
Diluted oil, contaminated oil, or the oil level is too high
What would be an indication of blocked oil cooler passages?
High oil temperature
What would be an indication of an inadequate oil supply?
Low oil pressure and high oil temperature
What type of oil is used in turbine engine lubrication systems?
Specially developed synthetic oils
Where can you find the specified grade of oil for a particular aircraft?
In the Airplane Flight Manual (AFM) or the Pilot’s Operating Handbook (POH)
What are two types of oil coolers used in turbine engine lubrication systems?
Air-cooled oil cooler and fuel-cooled oil cooler
What is the meaning of oil flash point? Fire point?
Oil flash point is the temperature at which the oil will begin to give off ignitable vapors. The fire point is the temperature at which there are sufficient vapors to support a continuous flame.
What is the weight of aircraft engine oil?
Approximately 7.5 pounds per US gallon
What is the purpose of an oil dilution system?
It thins the oil by introducing fuel into the lubrication system which makes cold weather starting easier. Fuel is used because it will evaporate out of the oil and leave through the crankcase breather.
What is the primary purpose of engine oil lubricant?
To reduce friction
What is the S.O.A.P. analysis?
It is an analysis system that establishes a trend to measure engine health (Spectrometric Oil Analysis Program)
Where are carbon seals used in a turbine engine?
Gearboxes, air-turbine motor starters, and main shaft seals
What is the key purpose of lubrication in a turbine engine?
Lubrication of the main shaft bearings
Where are engine oil filters located?
Between the oil pump output and the engine bearings
Why do reciprocating engines require oil with a high viscosity index? (Small changes in viscosity over a wide temperature range)
Higher viscosity indexes allow for easier starting in cold temperatures and prevents the oil from becoming too thin at operating temperatures to protect bearings under operating loads
Why do reciprocating engines require high viscosity oil? (Oil flows slowly)
They have large clearances, high operating temperatures, and high bearing pressures
What two factors impact fluid viscosity?
Temperature and pressure
What is the purpose of ashless dispersant oil?
To prevent sludge build up and oil filters from clogging
