Reciprocating Engines Overview

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Questions and Answers

What describes the arrangement of cylinders in an opposed reciprocating engine?

Cylinders are arranged directly opposed each other on the crankshaft. (correct)

Cylinders are set in a V-shape.

Cylinders are arranged in a circular manner.

Cylinders are lined up in one row.

Which stage is NOT part of the 4-stroke operating cycle of a reciprocating engine?

Exhaust

Ignition (correct)

Intake

Power

What happens when carburetor heat is applied during carburetor icing?

RPM decreases steadily.

There is no change in RPM.

RPM increases immediately.

RPM drops and then increases slowly. (correct)

What is the primary function of the ignition system in a reciprocating engine?

To provide the spark that ignites the fuel/air mixture. Signup and view all the answers

Which component is responsible for supplying electrical current to the spark plugs?

Magnetos Signup and view all the answers

What is detonation in the context of abnormal combustion?

Uncontrolled explosive ignition of the fuel/air mixture. Signup and view all the answers

What is an effective method to achieve sea-level performance at high altitudes?

Using superchargers or turbochargers. Signup and view all the answers

Which factor does NOT contribute to detonation?

Using high-grade fuel. Signup and view all the answers

What type of induction system allows outside air to enter the engine?

Intake port Signup and view all the answers

Which of the following is a characteristic of a dual ignition system?

Improved engine performance. Signup and view all the answers

What is the primary function of oil in an engine?

Cools Signup and view all the answers

What distinguishes a dry sump system from a wet sump system?

Oil is contained in a separate tank Signup and view all the answers

What does the oil temperature gauge measure?

Temperature of the oil Signup and view all the answers

Which of the following components is responsible for regulating the temperature within the engine compartment?

Cowl flaps Signup and view all the answers

What is the main source of electrical power in a modern light airplane?

Alternator Signup and view all the answers

What is a primary purpose of the bus bar in an electrical system?

Distributes electrical power Signup and view all the answers

What is essential to prevent when dealing with exhaust gases in the cabin?

Carbon monoxide leakage Signup and view all the answers

What type of propeller has a fixed blade angle?

Fixed-pitch propeller Signup and view all the answers

What is the function of the ammeter/load meter in an electrical system?

Measures current flowing in or out of the battery Signup and view all the answers

What important consideration should a pilot keep in mind when positioning the cowl flaps?

Cylinder head temperature (CHT) Signup and view all the answers

What is a possible cause of pre-ignition in an engine?

Residual hotspots caused by carbon deposits Signup and view all the answers

Which system is primarily used in low-wing airplanes for fuel delivery?

Fuel pump system Signup and view all the answers

What is the function of a fuel selector valve?

To select fuel from various tanks Signup and view all the answers

What is the major hazard during refueling an aircraft?

Possible combustion by a spark Signup and view all the answers

How can you decrease engine temperature effectively?

Reduce power and enrich the mixture Signup and view all the answers

What is a common characteristic of a gravity-fed fuel system?

Fuel flows by gravity from the tanks to the engine Signup and view all the answers

What role does engine oil play in the lubrication system?

Carries away contaminants and cools the engine Signup and view all the answers

What is a vital task for fuel management?

Checking for water and contaminants Signup and view all the answers

How can moisture condensation in fuel tanks be prevented?

Fill tanks after the last flight of the day Signup and view all the answers

What color represents 100LL aviation fuel?

Blue Signup and view all the answers

Study Notes

Engine Categories

Reciprocating engines are a type of engine that uses pistons.

Types of Reciprocating Engines

Opposed engines have cylinders arranged directly across from each other on the crankshaft.
Radial engines have cylinders arranged in a circular pattern.
V-type engines have cylinders arranged in a V-shape.
In-line engines have cylinders arranged in a single row.

Parts of a Reciprocating Engine

The crankshaft converts linear motion of the pistons into rotational motion.
The connecting rods connect the pistons to the crankshaft.
The pistons move up and down in the cylinders, converting the pressure from combustion into linear motion.
The cylinders are the housings where the pistons move.
The valves control the flow of air and exhaust gases into and out of the cylinders.

Engine Power Cycle

The engine power cycle, also known as the four-stroke operating cycle, is a continuous process of energy creation.
Intake: Air is drawn into the cylinder through the intake valve.
Compression: The intake valve closes, and the piston compresses the air-fuel mixture.
Power: The spark plug ignites the air-fuel mixture, creating an explosion that pushes the piston down.
Exhaust: The exhaust valve opens, and the piston pushes the burned gases out of the cylinder.

Induction System

The induction system draws air into the engine, mixes it with fuel, and delivers it to the cylinders.
The carburetor mixes fuel with air and delivers it to the engine.
The throttle controls the amount of air and fuel mixture entering the cylinders.
The mixture control adjusts the ratio of air to fuel.
The carburetor heat system helps prevent icing in the carburetor.

Indications of Carburetor Icing

A drop in RPM followed by a slow increase when carb heat is applied signals icing.
RPM increases further when carb heat is turned off.
This indicates melting ice in the carburetor.

Intake Port

The intake port allows outside air to enter the induction system.
An air filter prevents dust and foreign objects from entering the engine.
The air filter is located in front of the engine compartment.

Superchargers/Turbochargers

Superchargers and turbochargers help achieve sea-level performance at high altitudes by increasing the air density.

Ignition System

The ignition system provides the spark that ignites the fuel-air mixture in the cylinder.

Parts of an Ignition System

Magnetos are engine-driven units that generate electrical current for the spark plugs.
Spark plugs deliver the ignition spark to the air-fuel mixture.
Wires connect the ignition switch, magnetos, and spark plugs.
The ignition switch controls the operation of the magnetos.

Dual Ignition System

A dual ignition system uses two magnetos, providing improved combustion efficiency for better engine power and performance.
It also acts as a safety factor in case one magneto fails.

Abnormal Combustion

Detonation refers to an uncontrolled explosion of the fuel-air mixture within the combustion chamber.
Detonation can damage the engine, leading to excessive temperature, pressure, and potential failure of pistons, cylinders, or valves.
Detonation can also cause engine overheating, roughness, or power loss.
Pre-ignition refers to the uncontrolled ignition of the fuel-air mixture before the spark ignites it.
Pre-ignition is often sparked by detonation and can be caused by hotspots in the cylinder from carbon deposits.

Causes of Detonation

Use of low-grade fuel.
Fuel-air mixture being too lean.
Mixture temperature being too high.
High cylinder head temperature.
Abruptly opening the throttle when the engine is at low speed.

Reducing Engine Temperature

Reduce power.
Increase airspeed.
Enrich the mixture (add more fuel).

Fuel System

The fuel system stores and delivers fuel to the carburetor or fuel injection system at the correct pressure.

Fuel System Types

Gravity-fed systems rely on gravity to deliver fuel from the tanks to the engine.
Fuel pump systems are commonly found in low-wing airplanes where the fuel tank may be below the engine. They use a pump to deliver fuel under pressure.

Primer

The primer is a manually-operated pump that delivers fuel directly into the intake system.
It is helpful in cold weather when fuel in the carburetor is difficult to vaporize.

Fuel Tanks

Fuel tanks are typically located in the wings.
Fuel tanks have a vent to equalize air pressure.
They also have an overflow drain to prevent rupture from fuel expansion.

Fuel Quantity Gauges

Fuel quantity gauges show the amount of fuel in the tanks.

Fuel Selector Valve

The fuel selector valve allows the pilot to choose fuel from different tanks.
Common settings include: OFF, BOTH, LEFT, RIGHT.

Vapor Lock

Vapor lock occurs when air enters the fuel system, preventing proper fuel flow.

Refueling Hazards

Static electricity can build up during refueling and cause ignition.
A ground wire is essential to dissipate static electricity.

Filling Fuel Tanks

Filling tanks after the last flight of the day prevents moisture condensation in the tank.

Fuel Grades and Colors

80 (mogas) - Red
100LL (avgas) - Blue
100 (unleaded) - Green
Turbine fuel or Jet A-1 - Colorless

Lubrication System

Engine oil serves multiple functions: it lubricates moving parts, cools the engine, seals cylinder walls, and removes contaminants.

Types of Lubrication Systems

Dry sump systems use a separate tank to store oil, which is circulated through the engine by pumps.
Wet sump systems store oil in a sump that is an integral part of the engine.

Components of Lubrication Systems

Dipstick is used to measure the oil level.
Oil pressure gauge indicates the pressure of the oil supplied to the engine.
Oil temperature gauge measures the temperature of the oil.

Cooling System

The cooling system maintains the engine temperature within specified limits.
Outside air enters the engine compartment through an inlet behind the propeller hub.
Baffles direct the air to the hottest parts of the engine, primarily the cylinders.

Cowl Flaps

Cowl flaps regulate engine compartment temperature.
They can be fixed or adjustable.
The pilot uses cylinder head temperature (CHT) as the primary factor in deciding where to position the cowl flaps.

Electrical System

Modern light aircraft typically use direct current (DC) electrical systems.
Electrical power is supplied by an alternator when the engine is running or a battery or external power source when the engine is not running.

Electrical System Components

The alternator is the primary source of electrical power.
The battery provides emergency power and power for engine start.
The bus bar acts as the main conductor and distribution center for the electrical system.
The ammeter or load meter measures electrical current.
The master switch controls the entire electrical system, except the ignition system, which draws power directly from the engine-driven magneto.
Fuses and circuit breakers protect electrical equipment from overloads.

Exhaust System

The exhaust system removes burned gases from the engine cylinders.
It is crucial to prevent leakage of exhaust gases into the cabin, as they contain carbon monoxide.
The exhaust system can provide heat for the cabin and carburetor.

Propellers

Propellers are rotating airfoils that produce thrust.

Types of Propellers

Fixed-pitch propellers have blades with a fixed angle.

Climb Propellers

Climb propellers have low blade angles, providing high performance during takeoff and climb.

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Description

Dive into the world of reciprocating engines with this quiz that covers various types, parts, and the power cycle associated with these engines. Test your knowledge on how components like crankshafts, pistons, and valves work together in different engine configurations.