Module 15.9 Lubricants and fuels Flashcards
What are the drawbacks of mineral oils?
Lack stability and suffer from excessive volatility and thermal degradation at high temperatures
Ester based synthetic oils are now referred to as what?
Third generation oils
What are the functions of engine oil?
- Lubrication
- Cooling
- Cleaning
- Corrosion protection
What are the types of synthetic oils and uses?
Type 1 - older aircraft
Type 2 - modern GTE
Type 3 - specialised aircraft, jets
What are the advantages of synthetic oils?
- Better viscosity
- Better thermal stability
- High pressure resistance
What is viscosity index?
The effect that temp has on the viscosity
What is viscosity?
Internal resistance of fluid against deformation/flow
What is the pour point?
Lowest temperature oil will visibly move
Type 2 - -57℃
What is the flash point of type 2 oils?
250℃
What is a feature needed for oil when between moving components?
Pressure resistance
What happens to oil when it reacts with oxygen?
It gets thicker
Acidity is a measure of what?
The oil’s corrosive tendencies
What is oil foaming a measure of?
Resistance of oil to separate from entrapped air
Oil can cause rubber to do what?
Swell
What metal is particularly susceptible to oil corrosion?
Copper