P Piston Engine Lubrication and Cooling

Question 1

Why must the engine be lubricated?

Answer 1

To reduce friction and wear

Question 2

What are the 4 secondary functions of engine oil?

Answer 2

1. Cooling - absorbs heat and disperses it to atmosphere
2. Cleaning - removes carbon deposits and metal flakes, which are then trapped by a filter
3. Protection - protects components from corrosion
4. Hydraulic operations - operates valve gear and variable pitch propellers

Question 3

What are the 3 types of aero engine oil?

Answer 3

1. Mineral oil - derived from crude oil
2. Synthetic oil - chemical based, laboratory derived
3. Compound oil - a blend of the above

Question 4

What does the engine oil grade system indicate?

Answer 4

Bigger the number the less the viscosity changes with temperature, a multi grade oil will have 2 numbers (e.g 10w30), will behave like a 10 in winter and a 30 when warm

Question 5

What is the pressure of high pressure oil in a dry sump system?

Answer 5

60-70psi

Question 6

Why does the scavenger filter have higher volumetric capacity?

Answer 6

Hot oil has expanded in the system and air may have been mixed in

Question 7

What are the advantages of liquid cooling?

Answer 7

More efficient and automatic computer controlled cooling

Question 8

How can an air cooled engine increase cooling?

Answer 8

Open the cowl flap

Question 9

What is a wet sump lubricating system?

Answer 9

Where the oil is mostly stored in the engine sump and splashes onto the engine parts