Chp 3 (Oil System) Flashcards
Frictional force
Resistance to movement that is felt when one surface is moved across another surface.
Purpose of Lubricant
-Friction
-Wear
-Aids Cooling
Stages of Lubrication
a).Boundary Lubrication
b). Film Lubrication
Explain Boundary Lubrication
-Oil film may be only a few molecules thick
-A condition bordering on seizure. The oil film between the surfaces under load is reduced to almost nothing.
Explain Film Lubrication
As rotation commences oil pressure will keep the surfaces apart, supporting the shaft.
Static
Metal to Metal contact
Commencing Rotation
Boundary Lubrication
Working speed
Film Lubrication
Lightly-loaded ball used for:
Shafts
What is used to remove heat from the engine
Oil and Air
Type of oil used in oil system
Synthetic oil (OX–)
Characteristics of Synthetic oil (OX–)
-highly corrosive
-react with natural rubber compounds
-can withstand high temperatures
-injurious to the human body
What is needed to create flow which will provide adequate lubrication, protection, and cooling for gears and bearings.
Free flowing with Low viscosity oil, low pressure only is needed.
Oil system
Substances used to minimize friction and wear
Types of Seals
a). Carbon
b). Labyrinth
c). Lip
d). Brush
Why is labyrinth seal important?
Uses air to stop leakage.
Methods of lubrication
a).Oil jet
b).Oil mist
Which method of lubrication is better and why?
Oil jet
-simple
-reliable
-supplys correct amount of oil
Types of systems:
a).Recirculatory
b). Expendable
Two types of Recirculatory oil system.
a). Pressure Relief Valve System
b). Full flow system
With PRV system at idle and max RPM, what happens to pressure:
Pressure is less than optium.
Advantages of Full Flow System
-suitable pressure
-correct at all engine speeds
-suitable oil flow
Oil System Flow Diagram
Oil tank
⬇️
Pressure pump
⬇️
PRV
⬇️
Filter
⬇️
Check valve
⬇️
Fine filter
⬇️
Engine
⬇️
Mag plugs
⬇️
Filter
⬇️
Scavenge pumps
⬇️
Oil cooler with ByPass
⬇️
Oil Tank
Two ways to remove air from labyrinth seal:
-Baffles.
-Centrifugal Breather.
Baffles
Oil returning hit plates and runs over them thus separating the air from the oil.
Centrifugal Breather
The returning oil/air mix enters the component and runs over de-aerator segments that are spinning.
Separates the heavier oil from the air,which then drains back down into the tank. Air is vented to atmosphere
Oil system maintenance
-Hazard/maintenance info
-SDS
-Monitoring oil consumption
-Maintaining the correct level of oil
-monitoring probes (WDM)
-periodic replacement of the oil filter
-checking the system leaks
-Inspecting the pipes
Negative effects of Aircraft oil
-Check SDS
-Dont handle FLAP without permission
-use barrier cream
-wash hands after handling
-with incident. Immediately get emergency assistance.
FLAP
Fuel
Lubricate
Associative
Products
