52 RCACS Ground School Engines PO 407 EO 2 “Cooling, Fuel and Lubrication Systems”

Introduction Teaching Points Teaching Points Review Review Reference: Reference: FTGU Chapter 3 FTGU Chapter 3 Section A Pages Section A Pages Section B Pages Section B Pages 59-61

Cooling System In an internal combustion engine, fuel is burned, causing much heat. This heat is absorbed partly by all the metal engine parts. Some method of cooling must occur. Air- cooled engines are most common, some use antifreeze liquid cooling. In an internal combustion engine, fuel is burned, causing much heat. This heat is absorbed partly by all the metal engine parts. Some method of cooling must occur. Air- cooled engines are most common, some use antifreeze liquid cooling.

Methods of Cooling FINS: FINS: Metal plates on the outside of the cylinders that increases the surface area exposed to the air. Metal plates on the outside of the cylinders that increases the surface area exposed to the air. COWL FLAPS: COWL FLAPS: They vary the size of the opening at the front of the engine cowling. They control the amount of air entering the engine, so controlling the amount of DRAG produced. They vary the size of the opening at the front of the engine cowling. They control the amount of air entering the engine, so controlling the amount of DRAG produced. COOLING FANS: COOLING FANS: Powered by crankshaft, they increase airflow over the engine. Powered by crankshaft, they increase airflow over the engine. AUGMENTOR TUBES: AUGMENTOR TUBES: Jet pumps powered by escaping exhaust gases, they increase airflow over the engine. Jet pumps powered by escaping exhaust gases, they increase airflow over the engine.

Lubrication System Lubrication oil has 4 important functions: Cooling: Cooling: Carries away excessive heat generated by the engine. Carries away excessive heat generated by the engine. Sealing: Sealing: Provides a seal between the piston rings and cylinder walls, preventing "blow-by" loss of power and excessive oil consumption. Provides a seal between the piston rings and cylinder walls, preventing "blow-by" loss of power and excessive oil consumption. Lubrication: Lubrication: Prevents wear and tear of metal parts by maintaining a film to reduce friction. Prevents wear and tear of metal parts by maintaining a film to reduce friction. Flushing: Flushing: Cleans and flushes engine interior of contaminants that enter of are formed during combustion. Cleans and flushes engine interior of contaminants that enter of are formed during combustion.

REQUIREMENTS OF THE OIL VISCOSITY: VISCOSITY: Resistance to flow. Resistance to flow. HIGH FLASH POINT: HIGH FLASH POINT: Temperature at which to oil burns. Temperature at which to oil burns. LOW CARBON CONTENT: LOW CARBON CONTENT: Less carbon, less deposit in engine. Less carbon, less deposit in engine. LOW POUR POINT: LOW POUR POINT: Temperature at which oil solidifies. Temperature at which oil solidifies.

Pour Point Test

METHODS OF LUBRICATION DRY SUMP (FORCED FEED) DRY SUMP (FORCED FEED) Oil is injected into the crankcase through hoses by pump. Oil reservoir is a tank separate from the engine. Oil is injected into the crankcase through hoses by pump. Oil reservoir is a tank separate from the engine. WET SUMP (SPLASH) WET SUMP (SPLASH) Oil is kept in a pan below the engine. Crankshaft sits in oil and churns it into a heavy mist that covers all parts of the engine. Oil is kept in a pan below the engine. Crankshaft sits in oil and churns it into a heavy mist that covers all parts of the engine.

TYPES OF FUEL SYSTEMS GRAVITY FEED: GRAVITY FEED: Used in high-wing aircraft (when fuel tanks are above engine). Gravity does the work. Used in high-wing aircraft (when fuel tanks are above engine). Gravity does the work. FUEL PUMP: FUEL PUMP: Used in low wing aircraft (when tanks are not above engine). Electric and/or engine driven pump does the work. Used in low wing aircraft (when tanks are not above engine). Electric and/or engine driven pump does the work.

COMPONENTS OF THE FUEL SYSTEM Fuel Tanks: Fuel Tanks: carry aircraft’s fuel carry aircraft’s fuel vary in size and shape vary in size and shape usually located in the wings usually located in the wings Fuel Selector Control: Fuel Selector Control: permits the pilot to select which tank he wishes to draw fuel permits the pilot to select which tank he wishes to draw fuel Fuel Line and Filters: Fuel Line and Filters: connecting the fuel tanks to the carburetor - fuel is filtered by one or several filters. connecting the fuel tanks to the carburetor - fuel is filtered by one or several filters.

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