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Regional Gliding School

Problems With Problems With The Fuel SystemThe Fuel System

Very rapid and violent burning of the fuel Very rapid and violent burning of the fuel in the cylinder.in the cylinder.

Causes overheating and damage to the Causes overheating and damage to the metal of the engine.metal of the engine.

Signs:Signs:– rapid rise in cylinder pressure, andrapid rise in cylinder pressure, and– rapid increase in cylinder head temperature.rapid increase in cylinder head temperature.

Detonation:



Causes:Causes:– incorrect fuel,incorrect fuel,– overheating (lack of airflow), andoverheating (lack of airflow), and– the setting a mixture that is too lean.the setting a mixture that is too lean.

Can be solved temporarily by making Can be solved temporarily by making the mixture richer and permanently by the mixture richer and permanently by using fuel of the octane rating specified using fuel of the octane rating specified by the engine manufacturer.by the engine manufacturer.


Premature burning of fuel mixture due to Premature burning of fuel mixture due to glowing carbon particles or “local glowing carbon particles or “local hotspots”.hotspots”.

Often confused with detonation.Often confused with detonation. Experienced when attempting to start a hot Experienced when attempting to start a hot

engine and usually results in a backfire.engine and usually results in a backfire. Can do severe damage including warped Can do severe damage including warped

pistons, and cracked cylinder heads.pistons, and cracked cylinder heads.


Pre-Ignition:


Occurs in the fuel line.Occurs in the fuel line. Caused by high atmospheric Caused by high atmospheric

temperatures, causing the fuel to temperatures, causing the fuel to vaporize and block the flow of vaporize and block the flow of liquid fuel in the line.liquid fuel in the line.


Vapour Lock:


Ignition SystemIgnition System The function of the ignition system The function of the ignition system

is to supply a spark to ignite the is to supply a spark to ignite the fuel/air mixture in the cylinders.fuel/air mixture in the cylinders.

It consists of:It consists of: two magnetos,two magnetos, two spark plugs per cylinder,two spark plugs per cylinder, ignition leads, andignition leads, and a magneto switch.a magneto switch.


The MagnetoThe Magneto If a coil of wire is rotated in a If a coil of wire is rotated in a

magnetic field, current will be induced magnetic field, current will be induced in the coil.in the coil.

This experiment demonstrates the This experiment demonstrates the inseparability of magnetism and inseparability of magnetism and electricity.electricity.

While the design of the magneto is While the design of the magneto is slightly different from that discussed slightly different from that discussed above, the principle is the same.above, the principle is the same.


The MagnetoThe Magneto Serves three functions:Serves three functions:

generates a low tension current,generates a low tension current, transforms this to a high tension, transforms this to a high tension,

andand distributes the current to the distributes the current to the

individual spark plugs at the exact individual spark plugs at the exact time it is desired to have them fire.time it is desired to have them fire.

Confirmation Confirmation StageStage

NOTE: You must use the buttons in the Confirmation Stage


Aero EnginesAero EnginesFuel problems, Ignition, and Basic Electrical System Fuel problems, Ignition, and Basic Electrical System

A

B

C

D

Prevents overheating

Connects distributor to spark plug

None of the above

Let's try a few review questions on Aero Engines:

Question #1 - What does the magneto do?

Generates a low tension current

I’m afraid that answer is incorrect

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Flying Scholarship Program


That answer is correct.

Let's move on...

The MagnetoThe Magneto Serves three functions:Serves three functions:

generates a low tension current,generates a low tension current, transforms this to a high tension, andtransforms this to a high tension, and distributes the current to the individualdistributes the current to the individual

spark plugs at the exact time it isspark plugs at the exact time it isdesired to have them fire.desired to have them fire.


A

B

C

D

Too lean a mixture

Incorrect oil

Both A and B


Question #2 - Name a cause of detonation?

Too rich a mixture



Let's try again...




Let's move on...

Problems WithProblems WithThe Fuel SystemThe Fuel System

Causes:Causes:–– incorrect fuel,incorrect fuel,–– overheating (lack of airflow), andoverheating (lack of airflow), and–– the setting a mixture that is too lean.the setting a mixture that is too lean.

Can be solved temporarilyby making theCan be solved temporarilyby making themixture richer and permanently by using fuelmixture richer and permanently by using fuelof the octane rating specified by the engineof the octane rating specified by the enginemanufacturer.manufacturer.


Dual IgnitionDual Ignition Modern aero engines are fitted with two Modern aero engines are fitted with two

spark plugs per cylinder and two magnetos.spark plugs per cylinder and two magnetos. One magneto fires one of the spark plugs One magneto fires one of the spark plugs

for each cylinder, while the second for each cylinder, while the second magneto fires the second spark plug for magneto fires the second spark plug for each cylinder.each cylinder.

Purpose is two fold:Purpose is two fold:1 safetysafety: if one system fails, the engine will : if one system fails, the engine will

still operate, andstill operate, and2 performanceperformance: improves combustion: improves combustion


Magneto SwitchMagneto Switch The magneto switch has four settings:The magneto switch has four settings:

left,left, right,right, both, andboth, and off.off.

To check magnetos, pilot watches RPMs as To check magnetos, pilot watches RPMs as he/she turns switch.he/she turns switch.

In the event of rough operation, the pilot In the event of rough operation, the pilot can switch to the smoothest operating can switch to the smoothest operating magneto.magneto.


ShieldingShielding The parts of the ignition system The parts of the ignition system

are surrounded with metal are surrounded with metal covering which is grounded.covering which is grounded.

This design is known as This design is known as shieldingshielding and is used to prevent interference and is used to prevent interference with the radio.with the radio.


Ignition TimingIgnition Timing The timing of the magneto to fire The timing of the magneto to fire

the spark plug at the proper time.the spark plug at the proper time. Firing too early can result: Firing too early can result:

– in loss of power, in loss of power, – pre-ignition, pre-ignition, – piston burning,piston burning,– scored cylinders, andscored cylinders, and– broken rings.broken rings.


A

B

C

D

Longer engine life

Prevent overheating

Both A and C


Question #3 - What is the purpose of dual ignition?

Safety



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Let's move on...

Dual IgnitionDual IgnitionModern aero engines are fitted with two Modern aero engines are fitted with two spark plugs per cylinder and two magnetos.spark plugs per cylinder and two magnetos.

One magneto fires one of the spark plugs for One magneto fires one of the spark plugs for each cylinder, while the second magneto fires each cylinder, while the second magneto fires the second spark plug for each cylinder.the second spark plug for each cylinder.

Purpose is two fold:Purpose is two fold:11safetysafety: if one system fails, the engine will : if one system fails, the engine will still operate, andstill operate, and

22performanceperformance: improves combustion: improves combustion


A

B

C

D

Surrounds cockpit

Fire wall

Metal covering


Question #4 - What is shielding?

Improves combustion



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Let's move on...

ShieldingShielding The parts of the ignition system areThe parts of the ignition system are

surrounded with metal covering whichsurrounded with metal covering whichis grounded.is grounded.

This design is known as This design is known as shieldingshielding and andis used to prevent interference with theis used to prevent interference with theradio.radio.


Electrical SystemElectrical System Supplies power to Supplies power to

start the airplane.start the airplane. Also required to Also required to

operate a multitude operate a multitude of controls of controls including:including:– flaps,flaps,– undercarriage,undercarriage,– all radios,all radios,– lights, etc.lights, etc.

Includes everything Includes everything that operates that operates electrically, except electrically, except the magnetos.the magnetos.

The ignition system The ignition system is not connected is not connected with the airplane’s with the airplane’s electrical system.electrical system.


ComponentsComponents Storage Battery:

– stores electrical energy required for engine starts.

Master Switch:– overall on/off switch for the electrical system.

Starter Motor:– turns the engine over after it receives current

from the battery.


ComponentsComponents Generator/Alternator:

– supplies current to the system and recharges the battery,– driven by the engine,– once motor is started, the alternator will take over and

transfer the energy. Voltage Regulator:

– prevents the system from being overloaded and the battery from overcharging.


ComponentsComponents Bus Bar:

– receives from the battery and the generator (or alternator) and distributes it to various circuits.

Circuit Breakers:– prevents component damage resulting from system

overloads.

Ammeter/Voltmeter:– indicates current and voltage storage and drain of the

system.


ComponentsComponents Generator Warning Light:

– indicates only of generator failure, and– aircraft without ammeter/voltmeters have this.


A

B

C

D

Voltage regulator

Circuit breaker

Ammeter


Question #5 - What prevents component damage resulting from system overloads?

Bus bar



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ComponentsComponents Bus Bar:

– receives from the battery and the generator (or alternator)and distributes it to various circuits.

Circuit Breakers:– prevents component damage resulting from system

overloads.

Ammeter/Voltmeter:– indicates current and voltage storage and drain of the

system.


A

B

C

D

Alternator

Bus bar

Ammeter


Question #6 - What stores electrical energy for engine starts?

Battery



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ComponentsComponents Storage Battery:

– stores electrical energy required for enginestarts.

Master Switch:– overall on/off switch for the electrical system.

Starter Motor:– turns the engine over after it receives current

from the battery.


Congratulations!!

You have now completed the Fuel Problems, Ignition, and Basic Electrical System lesson of the Aero Engines Module. Of course, this lesson is always available to you for future reference if required.

You are now ready to move along to the next Aero Engines lesson you have not completed or to any other module you wish. You can advance to the Self Test Module if you feel ready to challenge the final exam.

Good Luck!


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