Chapter 9 - Lubrication Oils Flashcards
Define Viscosity
The measure of oil’s resistance to flow.
Define specific gravity
The comparison of oil’s weight to the weight of an equal volume of distilled water at a specified temperature.
What determines the color of gas?
It is determined by the amount of light that passes through an oil sample in a glass container when placed in front of a light of known intensity.
What is used to measure viscosity?
Saybolt Viscosimeter
What is the viscosity index?
A standard used to identify the rate of change in viscosity for a given change in temperature.
Which oil is better for breaking in?
Straight mineral oil.
What is a disadvantage using straight mineral oil in recipricating engines?
When exposed to elevated temperatures, straight mineral oil has a tendency to oxidize.
If it becomes overly contanimated , sludge can form that can clog filters and passages and score engine components
What two techniques is used to reduce oil congealing?
Use a heater blanket
Place aircraft in hanger
What is flashpoint?
The temperature at which oil begins to emit ignitable vapors
What is pour point?
the lowest temperature at which oil flow can be poured.
Name two classifications of the lubrication system.
Wet Sump - The sump is housed within the engine
Dry Sump - A reservoir is attached to the side of the engine
What is turbine’s synthetic lubricant base?
Diester base
What sub system is the scavage a part of?
The return system
Name the three methods of lubrication.
Pressure
Splash
Spray
What is SOAP?
Spectrometric oil analysis program
A laboratory that analysis foreign particles in engine oil
What must SOAP need for trending?
It needs to be ongoing and continuous
Name the four sub systems.
Supply system - runs from the reservoir to the engine driven pump
Pressure sub system -engine driven pump to bearings, gearboxes, and oil galleries
Return System (Scavage system) -
- Dry sump system uses a pump to return oil to the bearings, geabox (Chip detector location) and to the reservoir
- Wet sump system uses gravity
Breather/Vent system
What is coking?
The tendency of mineral-based oils to leave behind carbon deposits when exposed to extremely high temperatures.
NAme two types of seals
Lybryrinth - uses bleed air
Carbon
What type of bearings are used on recipricating and turbine engines?
Plane - recips
Steel ball bearings - turbine engines
Name three main requirements for selecting oil.
Operating temperatures
Operating loads
rotational speeds of bearings
Fill in the blank
SAE No. Commercial aviation NO. AN Specification
SAE 30 Grade_______ AN ____________
SAE 40 Grade_______ AN____________
SAE 50 Grade_______ AN_____________
SAE 60 Grade_______ AN____________
SAE 70 Grade________ AN____________
Fill in the blank
SAE No. Commercial aviation NO. AN Specification
SAE 30 Grade65 AN1065
SAE 40 Grade 80 AN1080
SAE 50 Grade 100 AN 1100
SAE 60 Grade 120 AN1120
SAE 70 Grade 140 N/A
What would the “W” mean for SAE 10W30?
Winter usage
What is centistokes?
Instead of an SAE rating, synthetic oils are given a Kinematic Viscosity Rating in centistokes (cSt)
Which ATA chapter has information regarding oil servicing and handling?
Chapter 12
What are the three grades of oils?
SAE
Army Navy
Aviation Grade
Name a function of ashless-dispersant oil
It produces low content of ash, and it helps keep particles seperated so no clumps form
NAme the thre types of oil bases
Mineral or patroleum
Animal or vegetable - cannot withstand high temperatures
Synthetic - combination of both
How do you know engine break-in as occured?
Oil levels begin to settle
Name a five contaniments that the oil can pick up
Metal
Dirt
Fuel
water
rust
carbon
rubber
What temperature should a turbine engine be when being checked for oil?
Cold
NAme the weight of the items
Fuel Avgas, jet fuel, water, oil
Fuel avgas - 6lbs/gal
Jet fuel - 6.5 ibs/gal
water - 8lbs/gal
Oil - 7lbs/gal
What is the difference between oil dilution system and acceleration system?
Oil dilution system - Oil is mixed fuel to reduse the oil’s viscosity.
Acceleration System (Hopper) - speeds up heating
They are both part of the dry lubrication system
What is a standpipe?
Use to provide oil to feather propeller, feeds engine driven oil
What is a scupper?
It is used to catch spilled oil from the filler opening
What is used to increase or decrease pressure needed to open the relief valve?
Shimms
What are the components of a filter adapter?
Thermostatic control valve - it wants oil to circulate faster to reach oil temp. Valve closes, forces oil to cooler, then back
Temperature bulb
What are the filtration system classifications?
Full flow (common) - in series with bearings
Bypass flow - parallel with bearings
Name the different types of filters.
Semi Depth (most common) - pleated and covers the most surface area DISPOSABLE
Depth - prone to improper filtration
Surface - REUSABLE
Edge - “spacer & screen” - REUSABLE
Name three things that aid in engine cooling.
Exhaust
Air cooled
Oil
Spikes in oil temperatures can be caused by what?
Baffle and seal improper maintenance
Improper number of radiating fins
Oil pressure guage uses what type of measuring devise? Where does the pressure come from?
Uses a burdon tube
Pressure comes from the engine
When is it best to drain the engine oil and why?
When the engine is warm because the viscosity will be lower and flow out better
What should be written on the filter when it is being installed?
Hobbs time
date
engine number
Name five functions of the oil
Reduce metal friction
Absorbs heat
cleans
seals
cushion
Name the two steps to roughing cylinder walls.
Honging cylinders
Chrome plated
What is the function of a compensated oil pressure relief valve?
maintain a higher system pressure when the oil is cold, then after the oil warms, the valve automatically lowers pressure to the normal operating range
