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

9.02 Cooling, Oil and Fuel Engine Cooling

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.

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.

9.02 Cooling, Oil and Fuel Engine Oil

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

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.

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

9.02 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

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.

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

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.

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.

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.

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.

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.

Confirmation Exercise 9.02 Cooling, Oil and Fuel Confirmation Exercise

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 ______________________ ______________________ ______________________ ______________________ ______________________ ______________________

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 ______________________ ______________________

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 ______________________ ______________________ ______________________ ______________________

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 ______________________ _____________________ ______________________ ______________________ ______________________ ______________________

9.02 Cooling, Oil and Fuel Fuel & Fuel Systems

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.

9.02 Cooling, Oil and Fuel Gravity-Feed System

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.

9.02 Cooling, Oil and Fuel Forced-Feed System

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

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

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

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

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

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

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

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

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

9.02 Cooling, Oil and Fuel Review Questions

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

How are octane ratings of fuels calculated? BC Online Ground School 9.02 Cooling, Oil and Fuel How are octane ratings of fuels calculated? Ratio of octane and heptane

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