1. 9.02 Cooling, Oil and Fuel
Aero Engines
Cooling, Oil, and Fuel.

2. 9.02 Cooling, Oil and Fuel
Engine Cooling

3. Air Cooling 9.02 Cooling, Oil and Fuel
Air moving over the engine removes heat.
Addition of cooling fins increases surface area and heat removal rate.
Most engines use a fan mounted at the front of the engine to force air backwards.

4. Liquid Cooling Typically done with oil and/or water.
9.02 Cooling, Oil and Fuel
Liquid Cooling
Typically done with oil and/or water.
Oil moves inside cylinder block.
Water cooled engines use a radiator to disperse heat.

5. 9.02 Cooling, Oil and Fuel
Engine Oil

6. 4 Functions of Oil Lubricating Sealing Cooling Flushing
9.02 Cooling, Oil and Fuel
4 Functions of Oil
Lubricating
Sealing
Cooling
Flushing

7. 9.02 Cooling, Oil and Fuel
4 Functions - Cooling
Engine oil circulating through the engine will carry away excess heat.
Oil coolers are found in any internal combustion engine.

8. 4 Functions - Lubrication
9.02 Cooling, Oil and Fuel
4 Functions - Lubrication
Maintaining a film of oil between moving parts will:
Reduce wear on parts
Reduce heat generation due to friction

9. 9.02 Cooling, Oil and Fuel
4 Functions - Flushing
Circulating engine oil will remove any foreign objects from the engine block.
Contaminants include:
Fuel deposits
Metal filings

10. 9.02 Cooling, Oil and Fuel
4 Functions - Sealing
Engine oil provides an air-tight barrier between the piston rings and cylinder wall.
Maintaining this seal will reduce engine wear and increase power output.

11. 9.02 Cooling, Oil and Fuel
Circulation – Dry Sump
Engine oil is contained in a tank, then pumped through engine block.
Gravity collects oil in a sump, where it is filtered and cooled before being used again. E

12. Circulation – Wet Sump 9.02 Cooling, Oil and Fuel
Essentially the same as a dry sump except for the removal of the oil tank.
Advantage: small, compact and simple.
Disadvantage: limited oil capacity.

13. 9.02 Cooling, Oil and Fuel
Qualities of Good Oil
Viscosity: oil must be thick enough to lubricate parts, but not too thick as it will increase oil pressure.
High Flash Point: temperature which the oil ignites at. Good oil has a high flash point.

14. 9.02 Cooling, Oil and Fuel
Qualities of Good Oil
Low Pour Point: The temperature at which the oil solidifies. Lower pour point means oil can operate at colder temperatures.
Low Carbon Content: the less carbon in the oil, the less deposits it will leave in the engine.

15. 9.02 Cooling, Oil and Fuel
Oil Grades
Oil is graded on its viscosity. The higher the grade, the less viscous it is.
Lower grade oil is useful in colder operations.

16. Oil Additives Detergents: improve engine cleanliness.
9.02 Cooling, Oil and Fuel
Oil Additives
Detergents: improve engine cleanliness.
Oxidization Inhibitors: improve oil stability.
Anticorrosion Additives: deter engine corrosion.
Pour Point Depressants: lower freezing temperature.

17. Confirmation Exercise
9.02 Cooling, Oil and Fuel
Confirmation Exercise

18. Label the functions of oil and methods of lubrication with the following word
Cooling Sealing Lubrication Flushing
Force feed Splash
Maintains an oil film between moving parts, preventing wear through metal to metal contact
Cleans contaminants from the interior of the engine which enter or are formed during combustion:
Prevents blow-by loss of power and excessive oil consumption
Carries away excessive heat generated by the engine
Oil contained in sump at the bottom of the engine. The revolving crankshaft churns oil into mist moving over the various engine parts
Pressure from and oil pump sends oil through the hollow crankshaft, lubricating the parts of the engine in a fine mist
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19. 9.02 Cooling, Oil and Fuel
Label the functions of oil and methods of lubrication with the following word
Dry sump lubrication Wet sump lubrication
Oil is contained in a separate tank and is forced under pressure from a pressure pump through the hollow crankshaft to lubricate the engine by the force feed method. Oil pressure is monitored by an oil pressure gauge
Engine oil is in a sump ( or pan) under the crankcase. The oil passes through a filtered screen in the bottom of the sump into the suction side of a gear type pressure pump. The pump moves the oil around the outside of its gears. The pressure pump is engine driven
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20. 9.02 Cooling, Oil and Fuel Select True or False
Viscosity gives proper distribution of oil through the engine and prevents rupturing of the oil film which lubricates the engine parts over the wide range of temperatures
Oil of too high a viscosity being used for existing climatic temperatures will cause low oil pressure
Flash point is the temperature beyond which a fluid will not ignite
Low carbon content. To leave as little carbon as possible oil should work past the scraper ring and burn. Good oil should have a high wax content
Low pour point. The temperature at which a fluid solidifies, especially used during cold weather starting
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21. 9.02 Cooling, Oil and Fuel Select True or False
Detergents decrease engine cleanliness
Oxidation inhibitors improve oil stability
Anti-corrosion additives promote corrosion
Pour point depressants decrease the pour point.
Higher Sayblot Universal Viscosity (S.A.E) numbered oil should be used during colder weather.
The life and reliability of the engine will not be impaired if the engine manufacturer limits are not strictly observed
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22. 9.02 Cooling, Oil and Fuel
Fuel & Fuel Systems

23. Types of Fuel System – Gravity Fed
9.02 Cooling, Oil and Fuel
Types of Fuel System – Gravity Fed
Fuel tanks typically located in wings.
Because engine is below tanks, fuel will flow from top to bottom, into engine.
Advantage: simple.
Disadvantage: no inverted flight.

24. 9.02 Cooling, Oil and Fuel
Gravity-Feed System

25. Types of Fuel System – Forced
9.02 Cooling, Oil and Fuel
Types of Fuel System – Forced
Fuel tanks typically located below engine.
Fuel must be pumped against gravity towards engine.
Advantage: inverted flight.
Disadvantage: more complex.

26. 9.02 Cooling, Oil and Fuel
Forced-Feed System

27. Aviation Fuels 9.02 Cooling, Oil and Fuel
Gasoline is classified based on the Octane Rating (relative quantity of Octane to Heptane)
Octane : A substance which possesses minimum detonating qualities
Heptane: A substance which possesses maximum detonating qualities 27

28. Aviation Fuels 9.02 Cooling, Oil and Fuel
Octane numbers only go as high as 100.
Number above 100 is the anti-knock value.
Fuel grades are expressed by two performance numbers. 28

29. Aviation Fuels First number: octane rating at lean mixture conditions
9.02 Cooling, Oil and Fuel
Aviation Fuels
First number: octane rating at lean mixture conditions
Second number: octane rating at rich mixture conditions 29

30. Grade 100 / 130 9.02 Cooling, Oil and Fuel
Lean mixture performance number of 100
Rich mixture performance number of 130
Octane ratings are calculated by the ratio of octane to heptane 30

31. Aviation Fuels Aviation engines burn gasoline
9.02 Cooling, Oil and Fuel
Aviation Fuels
Aviation engines burn gasoline
Aviation Gasoline (AVGAS)
Automobile Gasoline (MOGAS)
MOGAS can only be used if approved in some types of aircraft. 31

32. Aviation Fuels 9.02 Cooling, Oil and Fuel
Aviation Fuels have distinctive colors (dyes)
AVGAS 80/87 RED
AVGAS 100LL BLUE
AVGAS 100/130 Green
Jet Fuel STRAW 32

33. Fuel - Rules of Thumb 9.02 Cooling, Oil and Fuel
Never use a fuel with a lower Octane rating than that recommended by the engine manufacturer
Overheating
Detonation
Serious Engine Damage 33

34. Fuel System Problems 9.02 Cooling, Oil and Fuel Detonation
Abnormally rapid combustion
“Pinging”
Indications:
Loss of power
Rapid rise in engine temperature
Causes:
Use of incorrect fuel
Overheating
Too lean mixture
Cures
Use proper Fuel
Use Richer mixture 34 34

35. Fuel System Problems 9.02 Cooling, Oil and Fuel Pre-ignition
Sometimes confused with detonation
Premature ignition of mixture due to glowing carbon particles or “hot spots”
Indications
Loss of power
Rough Running Engine
Causes
Hot Spots in cylinder (carbon deposits)
Results from poor maintenance
Cures
Fix the engine
Vapour Lock
Caused by high atmospheric temps
Fuel vaporizes and blocks flow of liquid fuel 35 35

36. 9.02 Cooling, Oil and Fuel
Review Questions

37. 9.02 Cooling, Oil and Fuel
What fuel feed system does an aircraft with low wing configuration use?
Force Feed System

38. How are octane ratings of fuels calculated?
BC Online Ground School Cooling, Oil and Fuel
How are octane ratings of fuels calculated?
Ratio of octane and heptane

39. The abnormal rapid combustion of fuel
9.02 Cooling, Oil and Fuel
What is detonation?
The abnormal rapid combustion of fuel