Lecture 23 Flashcards
What type of oil is used in gas turbine engines?
Low viscosity synthetic oil
How is gas turbine oil similar to piston engine oil?*
Reduce friction
Absorb heat
Protect metal parts against corrosion
Pick up and carry contaminants into filters
Routed through an oil-to-fuel heat exchanger
What are the two grades of synthetic oil?
Type I
Type II
Can you combine Type I and Type II oil in a gas turbine engine?
Can you switch brands?
Why or why not?
No, Type I should not be added to Type II
Different brands of oil should not be mixed
Proprietary additives may not be compatible
May degrade its superior characteristics
What can occur if you come in contact with synthetic oil without safety items?
What can happen to aircraft finishes?
Skin irritation
Parkinson’s and neurological disorders
Soften and damage aircraft finishes
Dissolve paints and enamels
What are the two classifications of lubrication systems?
Which is most common?
Wet-sump
Dry-sump
Dry-sump
What is a wet-sump lubrication system?
Pressurized oil is used to lubricate the turbine rotor coupling and rotor-shaft bearings
Accessory drive gears are splash-lubricated
What is a dry-sump lubrication system?
After performing lubrication and cooling, oil is returned to an oil tank by scavenger pumps
Oil is applied to specific parts
What are the three lubrication system subsystems?*
Pressure Subsystem
Scavenge Subsystem
Vent Subsystem
What does the pressure subsystem do?*
Supplies correct amount of clean lubrication oil at the proper pressure and temperature
What does the scavenge subsystem do?*
Picks up the oil after it has performed it functions
Returns the oil to the oil tank
What does the vent subsystem do?*
Provide slight pressure on the oil in the oil tank to assure a positive flow of oil
Vents bearing compartments and gear boxes to the oil tank to maintain uniform air pressure at the oil jets
What is the main difference in lubrication between gas turbine and piston engines?
Gas turbine engines supply a precise amount of oil at the precise location
Piston engines have oil everywhere
Where is oil filtered in the gas turbine lubrication system?
Right after the pressure pump and again just before being sprayed (in the pressure subsystem)
What happens if a filter is clogged in a gas turbine lubrication system?
A ball-type bypass valve will open and unfiltered oil will flow through the engine
Cold oil flows through the bypass valve without entering the engine until oil warms up
Red indicator button on the filter housing will indicate a clogged filter when popped up
