Powerplant - Lubrication Systems Flashcards
What is the purpose of lubricant in an aircraft engine?
To reduce friction between moving parts
What is the most important property that an aircraft reciprocating engine oil must possess?
Viscosity
What factors must be considered in determining the proper grade of oil to use in a specific engine?
The operating load, rotational speeds and the operating temperatures
What are considered main oil contaminants?
Gasoline, moisture, acid, dirt, carbon deposits and metallic particles
What do metallic particles on an oil screen indicate?
Internal failure of the engine
What could be an indication of blocked oil cooler passages?
high oil temperature
What could 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
What are two types of oil coolers used in turbine engine lubrication systems?
Air cooled oil cooler and fuel cooled oil cooler
What are the functions of engine oil in a reciprocating engine?
Cools various parts, seals the combustion chamber by providing a film between the cylinder walls and the rings and aids in cleaning the engine by carrying residues to the oil filter
What is the weight of aircraft engine oil?
Approximately 7.5 pounds per U.S. gallon
What is the purpose of the oil dilution system?
Thins the oil by inducing fuel into the lubrication system which makes cold weather starting easier
What is straight mineral oil?
Natural lubricating oil that has no additives for foaming, cleaning, or viscosity.
What is ashless dispersant oil?
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?
Synthetic oil that is man made through the process of chemically altering the molecular structure of petroleum oil in order to achieve the desired characteristics.
What are the purposes of reciprocating engine oil?
cleans, cools, cushions, seals and lubricates parts.
What is the purpose of the oil flow control valve “oil cooler bypass valve”?
When the oil is cool it will direct it around the oil cooler. When the oil is warm it will be directed through the oil cooler.
From what location on a reciprocating engine is the oil temperature usually taken?
It is measured before it enters the system. In a dry sump lubricating system, the oil temperature bulb is located anywhere in the oil inlet line between the tank and the engine. In a wet sump system, the temperature bulb is located where is senses the temperature after the oil passes through the oil cooler.
What could cause oil foaming?
Diluted oil, contaminated oil, or the oil level is too high
Where can you find the specific grade of oil for a particular aircraft?
Airplane flight manual, pilots operating handbook
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.
Where are carbon seals used in turbine engines?
gearboxes, air turbine motor starters, and main shaft seals
What is the key purpose of lubrication in a turbine engine?
for lubrication of the main shaft bearings
Where are the engine oil filters located?
Between the oil pump output and the engine bearings
Why do reciprocating engines require high viscosity oil?
High viscosity oil performs better in reciprocating engines because they have large clearances, high operating temperatures, and high bearing pressures.
What two factors impact fluid viscosity?
Temperature and pressure, although pressure has a very small effect on viscosity
