Lubrication Flashcards
What are the functions of lubricating oil in reciprocating engines
To reduce friction between moving parts and remove heat
Name two important characteristics of aircraft engine oil
Oil must be light enough to circulate freely but heavy enough to provide the proper oil film at engine operating temperatures
What could happen to an oil that is too low in viscosity at normal engine operating temperatures
becomes thin and the oil film between moving parts is easily broken, resulting in premature wear
What are some of the factors that must be considered by an engine manufacturer in determining the proper grade of oil for particular engine
Operating load and temperature as well as the rotational speed
Why do aircraft reciprocating engines use a relatively high viscosity oil
large operating clearance and operate at high temperatures and pressure
Name some oil contaminants
Metal particles, dirt, carbon, moisture and acids
What is possible indication of low oil pressure together with high oil temperature
A low oil supply
Why do oil reservoirs have expansion space
To provide for oil foaming, thermal expansion, and air in the return oil
What could cause oil foaming
Diluted oil, contaminated oil, and the oil level is too high
What controls oil pressure in a gear type oil pressure pump
Oil pressure relief valve
What function does an oil cooler bypass valve perform
It directs the oil either through the cooler or around it in order to maintain proper operating oil temperatures
What could be a possible indication if the oil cooler passage becomes obstructed
A high oil temperature
Where is the oil temperature bulb usually located
At the engine oil inlet
What type of oil is used in a turbine engine oil system
Synthetic oil
Where is the most critical point of lubrication in a gas turbine engine
At the turbine bearing
What should be done if metal particles are found in an engine oil filter
Follow engine manufacturers maintenance instructions
Name two types of turbine engine oil coolers
Air and fuel cooled
What does the presence of metal particles in an engine oil filter indicate
usually indicates abnormal wear and possible engine internal failure
What is the weight of aircraft engine oil
Approximately 7.5 pounds per U.S gallons
What is the primary purpose of engine oil lubricate
To reduce friction.
What is straight mineral oil
It is a lubricating oil and does not have any additives
Is automotive oil suitable for aircraft engines
No
Where can you find the grade of engine oil specified for a particular aircraft
Aircraft flight manual or pilots operating handbook for the aircraft
What two instruments show the condition of a reciprocating engine lubrication system
Oil pressure and oil temperature gauge
What type of oil quantity indicator is used in most aircraft engines
Dipstick that measures the quantity of the oil in the tank sump
When should the engine oil quantity be checked on a turbine engine
As soon as possible after engine is shut down
A reciprocating engine is found to have excessive oil consumption without evidence of any oil leaks. Heat is the likely cause
Piston rings are worn or broken
