Aircraft SystemsAircraft Systems

Presented by:Presented by:

Carol Cushman & Kyle Carol Cushman & Kyle BlackBlack

Engine TypesEngine Types

Turbine EngineTurbine Engine– Found in transport Category aircraftFound in transport Category aircraft– Relatively costly but extremely Relatively costly but extremely

powerfulpowerful Reciprocating EngineReciprocating Engine

– Found in general aviationFound in general aviation– Economical, but still very reliable Economical, but still very reliable

Cessna EngineCessna Engine

Horizontally Horizontally OpposedOpposed

Direct DriveDirect Drive Air CooledAir Cooled 4 cylinder4 cylinder

Engine OperationEngine Operation

What are the four strokes of an What are the four strokes of an engine?engine?

Four Strokes on an Four Strokes on an EngineEngine

IntakeIntake

When the piston moves away When the piston moves away form the cylinder headform the cylinder head

Intake valve opensIntake valve opens Fuel/Air mixture is drawn into the Fuel/Air mixture is drawn into the

combustion chambercombustion chamber

CompressionCompression

Piston moves back toward the Piston moves back toward the cylinder headcylinder head

Intake valve closesIntake valve closes Fuel/Air Mixture is compressedFuel/Air Mixture is compressed

PowerPower

Compression nearly completeCompression nearly complete Spark plugs fireSpark plugs fire Compressed mixture is ignitedCompressed mixture is ignited Rapidly expanding gases drive Rapidly expanding gases drive

the piston, providing the power the piston, providing the power that rotates the crankshaftthat rotates the crankshaft

ExhaustExhaust

Expels the burned gases through Expels the burned gases through the exhaust valve, which opens at the exhaust valve, which opens at the end of the power strokethe end of the power stroke

Induction SystemInduction System

Brings outside air into the engine, Brings outside air into the engine, mixes it with fuel in the proper mixes it with fuel in the proper proportion and deliver it to the proportion and deliver it to the cylinders where combustion cylinders where combustion occurs.occurs.

ThrottleThrottle MixtureMixture Intake PortIntake Port

ThrottleThrottle

Controls Engine SpeedControls Engine Speed Regulates the amount of fuel/air Regulates the amount of fuel/air

mixture that flows into the mixture that flows into the cylinderscylinders

MixtureMixture

Controls the fuel/air ratioControls the fuel/air ratio

Intake PortIntake Port

Where outside air enters the Where outside air enters the induction systeminduction system

Normally contains an air filter to Normally contains an air filter to keep out dust and FODkeep out dust and FOD

Carburetor Carburetor

Mixes the incoming air with fuel Mixes the incoming air with fuel and delivers it to the combustion and delivers it to the combustion chamberchamber

CarburetorCarburetor

Air passes through a venturi, increases Air passes through a venturi, increases velocity and decreases pressurevelocity and decreases pressure

Fuel enters from a float chamber Fuel enters from a float chamber where it is maintained at a nearly where it is maintained at a nearly constant level by a float deviceconstant level by a float device

Discharge nozzle is located in an area Discharge nozzle is located in an area of low pressure created by the venturiof low pressure created by the venturi

Fuel is forced through the discharge Fuel is forced through the discharge nozzel by the higher atmospheric nozzel by the higher atmospheric pressure in the float chamberpressure in the float chamber

Overly Rich MixtureOverly Rich Mixture

What does it mean to have a What does it mean to have a “Rich” mixture?“Rich” mixture?– As altitude increases, the mixture will As altitude increases, the mixture will

get progressively richer due to the get progressively richer due to the decrease in air density.decrease in air density.

– Can result in engine roughness: Can result in engine roughness: excessive carbon buildup on the excessive carbon buildup on the spark plug will cause them to foul.spark plug will cause them to foul.

– High elevation airports, climb or High elevation airports, climb or cruise at high elevationcruise at high elevation

Overly Lean MixtureOverly Lean Mixture

What does it mean to have a What does it mean to have a “Lean” mixture?“Lean” mixture?– May result in high engine May result in high engine

temperatures causing excessive temperatures causing excessive wear or even failurewear or even failure

– Enrichen Mixture on descents from Enrichen Mixture on descents from high altitudeshigh altitudes

– Watch engine temperatureWatch engine temperature

Carburetor IceCarburetor Ice

Occurs due to the effect of fuel Occurs due to the effect of fuel vaporization and decreasing pressure vaporization and decreasing pressure in the venturi which causes a sharp in the venturi which causes a sharp temperature drop in the carburetortemperature drop in the carburetor

If water vapor in the air condenses If water vapor in the air condenses when the carburetor temperature is at when the carburetor temperature is at or below freezing, ice may form on or below freezing, ice may form on internal surfaces of the carburetor, internal surfaces of the carburetor, including the throttle valveincluding the throttle valve

Likely below 21C (70F), humidity Likely below 21C (70F), humidity above 80% above 80%

Carburetor IceCarburetor Ice

Carburetor IceCarburetor Ice

Carburetor Ice Carburetor Ice IndicationsIndications Why can Carburetor Ice be dangerous?Why can Carburetor Ice be dangerous? What are some indications of Carb Ice?What are some indications of Carb Ice?

– Drop in engine RPMDrop in engine RPM– Engine RoughnessEngine Roughness– Fuel starvationFuel starvation

What can we do to get rid of What can we do to get rid of carburetor ice or even prevent it from carburetor ice or even prevent it from happening in the first place?happening in the first place?– Carburetor HeatCarburetor Heat

Carburetor HeatCarburetor Heat

Carburetor ice is especially dangerous when Carburetor ice is especially dangerous when operating at low power settings, may go operating at low power settings, may go unnoticed until power is addedunnoticed until power is added

How does carburetor heat work?How does carburetor heat work?– Carburetor heat routes air across a heat source before Carburetor heat routes air across a heat source before

it enters the carburetorit enters the carburetor

How will carb heat affect engine performance?How will carb heat affect engine performance?– Causes a slight decrease in engine power (heated air is Causes a slight decrease in engine power (heated air is

less dense)less dense)– If ice is present, there will be a decrease followed by a If ice is present, there will be a decrease followed by a

gradual increase in rpmgradual increase in rpm

Carburetor HeatCarburetor Heat

Fuel InjectionFuel Injection

What is the benefit of a fuel What is the benefit of a fuel injected fuel system?injected fuel system?– No carburetorNo carburetor– More precision in metering and More precision in metering and

distributing fuel/air mixturedistributing fuel/air mixture– Injects the fuel directly into each Injects the fuel directly into each

cylinder separatelycylinder separately– Lower fuel consumption, increased Lower fuel consumption, increased

Horsepower, lower operating Horsepower, lower operating temperatures, longer engine lifetemperatures, longer engine life

Fuel InjectionFuel Injection

High Altitude FlightHigh Altitude Flight

SuperchargerSupercharger– Compresses the incoming air to the Compresses the incoming air to the

engine using a pump driven by the engine using a pump driven by the engineengine

TurbochargerTurbocharger– Pressurizes the air into the engine Pressurizes the air into the engine

using a mechanism driven by using a mechanism driven by exhaust gasesexhaust gases

TurbochargerTurbocharger

Ignition SystemIgnition System

What does the ignition system do?What does the ignition system do?– Provides spark that ignites the fuel/air Provides spark that ignites the fuel/air

mixture in the cylindersmixture in the cylinders List the parts of the ignition system.List the parts of the ignition system.

– MagnetosMagnetos– Spark PlugsSpark Plugs– Interconnecting wires Interconnecting wires – Ignition SwitchIgnition Switch

MagnetoMagneto

What is a Magneto?What is a Magneto?– Self contained, Engine drivenSelf contained, Engine driven– Supplies electrical current to the spark plugsSupplies electrical current to the spark plugs– Uses permanent magnet for electrical current Uses permanent magnet for electrical current

that is completely separate from the electrical that is completely separate from the electrical systemsystem

– Begins when you engage starter Begins when you engage starter – Operates whenever the crankshaft turnsOperates whenever the crankshaft turns– Normally two for redundancy/ improves Normally two for redundancy/ improves

combustioncombustion If you lose your battery/alternator in flight, If you lose your battery/alternator in flight,

will your engine stop working?will your engine stop working?

MagnetoMagneto

Ignition SwitchIgnition Switch

Controls the operation of the magneto Controls the operation of the magneto from the cockpitfrom the cockpit

Can select left, right or bothCan select left, right or both Engine can still fire even with the Engine can still fire even with the

battery and master switches off, if the battery and master switches off, if the magnetos are left on and the prop is magnetos are left on and the prop is moved because no outside electrical moved because no outside electrical power is requiredpower is required

Abnormal CombustionAbnormal Combustion

Name two types of Abnormal Name two types of Abnormal Combustion:Combustion:

– DetonationDetonation– Pre-ignitionPre-ignition

DetonationDetonation

What is Detonation?What is Detonation?– Explosive ignition of the fuel/air mixture Explosive ignition of the fuel/air mixture

within the cylinders combustion chamber within the cylinders combustion chamber – UncontrolledUncontrolled– Engine overheating, roughness or loss of Engine overheating, roughness or loss of

powerpower– Excessive temperatures and pressures Excessive temperatures and pressures

leading to failure of piston, cylinder or leading to failure of piston, cylinder or valvesvalves

– Engine overheat or lower than Engine overheat or lower than recommended fuel graderecommended fuel grade

Pre-IgnitionPre-Ignition

What is Pre-Ignition?What is Pre-Ignition?– Fuel/Air mixture is ignited in advance of Fuel/Air mixture is ignited in advance of

the normal timed ignitionthe normal timed ignition– Detonation can lead to pre – ignitionDetonation can lead to pre – ignition– Caused by a residual hot spot in the Caused by a residual hot spot in the

cylinder such as a small carbon deposit on cylinder such as a small carbon deposit on a spark plug , cracked ceramic spark plug a spark plug , cracked ceramic spark plug insulator, or any damage around the insulator, or any damage around the combustion chambercombustion chamber

Fuel SystemFuel System

What are the two different types What are the two different types of fuel systems found on small of fuel systems found on small airplanes?airplanes?

1. Fuel-Pump System1. Fuel-Pump System

2. Gravity Feed2. Gravity Feed

Fuel-Pump SystemFuel-Pump System

Engine Driven Engine Driven PumpPump

Electric Fuel pumpElectric Fuel pump Provides fuel under Provides fuel under

pressure from the pressure from the fuel tanks to the fuel tanks to the engineengine

Low wing airplanesLow wing airplanes

Fuel-Pump SystemFuel-Pump System

Fuel Pressure GaugeFuel Pressure Gauge– Gives and exact reading of the Gives and exact reading of the

pressure the fuel pump is providing pressure the fuel pump is providing the enginethe engine

– Helpful in detecting fuel pump Helpful in detecting fuel pump malfunctionsmalfunctions

Fuel-Pump System Fuel-Pump System

What is Vapor Lock?What is Vapor Lock?– When the fuel in the lines of a fuel When the fuel in the lines of a fuel

injected engine vaporizes due to injected engine vaporizes due to excessive heat, and prevents the excessive heat, and prevents the flow of fuel to the engineflow of fuel to the engine

– Common on a hot day in fuel Common on a hot day in fuel injected aircraftinjected aircraft

Gravity – Feed SystemGravity – Feed System

Fuel flows to the engine by Fuel flows to the engine by gravity from the fuel tanksgravity from the fuel tanks

High wing aircraftHigh wing aircraft

PrimerPrimer

What do we use a primer for?What do we use a primer for?– Used to pump fuel directly into the Used to pump fuel directly into the

intake system prior to engine startintake system prior to engine start– Useful in cold weather when fuel in the Useful in cold weather when fuel in the

carburetor is difficult to vaporizecarburetor is difficult to vaporize How do you prime a carbureted How do you prime a carbureted

engine?engine? How does this process differ in a fuel How does this process differ in a fuel

injected engine?injected engine?

Fuel TanksFuel Tanks

Where are the fuel tanks in most Where are the fuel tanks in most aircraft?aircraft?– Usually located in the wingsUsually located in the wings– Vented to allow for changes in Vented to allow for changes in

pressure inside the tank, prevents pressure inside the tank, prevents vacuum vacuum

Fuel Quantity GaugesFuel Quantity Gauges

Located on the instrument panelLocated on the instrument panel Shows the amount of fuel in each Shows the amount of fuel in each

fuel tankfuel tank

Fuel Selector ValveFuel Selector Valve

Allows you to select fuel from Allows you to select fuel from various tanksvarious tanks

Some may only have Left, Right Some may only have Left, Right and OFF – must monitorand OFF – must monitor

Fuel StrainerFuel Strainer

What is the Fuel Strainer use for?What is the Fuel Strainer use for?– Removes moisture and other sediments Removes moisture and other sediments

that might be in the systemthat might be in the system– In cold weather, moisture is hazardous In cold weather, moisture is hazardous

because it can freeze and block fuel linesbecause it can freeze and block fuel lines– In warm weather, it can flow into the In warm weather, it can flow into the

carburetor and stop the enginecarburetor and stop the engine Tanks should be filled each evening to Tanks should be filled each evening to

prevent condensationprevent condensation

Re- FuelingRe- Fueling

Red: 80/87 octaneRed: 80/87 octane Green: 100/130Green: 100/130 Blue: 100LLBlue: 100LL Clear: JetClear: Jet In emergency, always use next In emergency, always use next

higher grade (but never jet)higher grade (but never jet)

Oil SystemOil System

What are some functions of oil in What are some functions of oil in a reciprocating engine?a reciprocating engine?– LubricatesLubricates– CleansCleans– SealsSeals– Cools Cools – ProtectsProtects

Dry- Sump SystemDry- Sump System

Oil is contained in a separate tankOil is contained in a separate tank Circulated through the engine by Circulated through the engine by

pumpspumps

Wet Sump SystemWet Sump System

Oil is carried in a sumpOil is carried in a sump Integral part of the engineIntegral part of the engine Found on most small general Found on most small general

aviation aircraftaviation aircraft

Wet Sump Oil SystemWet Sump Oil System

Oil Pressure GaugeOil Pressure Gauge

Provides direct indication of the oil Provides direct indication of the oil system operationsystem operation

Below normal pressure may mean that Below normal pressure may mean that the oil pump is not putting out enough the oil pump is not putting out enough pressure to circulate oil throughout the pressure to circulate oil throughout the engine. engine.

Above normal may indicate a clogged Above normal may indicate a clogged oil lineoil line

Shut down engine if oil pressure does Shut down engine if oil pressure does not begin to rise within 30 seconds for not begin to rise within 30 seconds for warm starts/60 seconds cold startswarm starts/60 seconds cold starts

Oil Temperature GaugeOil Temperature Gauge

Measures temperature of the oil Measures temperature of the oil as it enters the engineas it enters the engine

Slow changesSlow changes

Cooling SystemsCooling Systems

Excessively high engine temperatures Excessively high engine temperatures can result in a loss of power, high oil can result in a loss of power, high oil consumption and engine damage.consumption and engine damage.

Internal cooling is done by oil, but Internal cooling is done by oil, but more is needed to maintain normal more is needed to maintain normal temperaturestemperatures

Remaining heat dissipated by exhaust Remaining heat dissipated by exhaust and through outside air flowing around and through outside air flowing around the enginethe engine

Cowl FlapsCowl Flaps

Create a large path for air to Create a large path for air to escape from the engine escape from the engine compartmentcompartment

Flaps that open on the bottom of Flaps that open on the bottom of the engine cowlingthe engine cowling

Increases cooling air flowIncreases cooling air flow

Cowl FlapsCowl Flaps

Cylinder Head Cylinder Head Temperature GaugeTemperature Gauge Usually in airplanes with Cowl Usually in airplanes with Cowl

FlapsFlaps Direct temperature reading from Direct temperature reading from

one of the cylindersone of the cylinders Reducing Engine TemperaturesReducing Engine Temperatures

– Enrichen mixtureEnrichen mixture– Reduce rate of climbReduce rate of climb– Increase airspeedIncrease airspeed– Decrease power settingDecrease power setting

Exhaust SystemExhaust System

Vent burned gasesVent burned gases Provide heat for cabinProvide heat for cabin Directs exhaust out below the engine Directs exhaust out below the engine

compartment through a muffler and compartment through a muffler and tailpipe tailpipe

As the hot exhaust gases heat the As the hot exhaust gases heat the muffler, metal shrouds around the muffler, metal shrouds around the muffler capture the heat and duct it to muffler capture the heat and duct it to the cabin. the cabin.

PropellersPropellers

Provides thrust to propel the Provides thrust to propel the airplane through the air.airplane through the air.

Each blade is an airfoil that acts Each blade is an airfoil that acts like a rotating winglike a rotating wing

Amount of thrust produced is a Amount of thrust produced is a function of shape, rotation speed function of shape, rotation speed and position relative to the and position relative to the relative windrelative wind

PropellersPropellers

Each small section of blade is set Each small section of blade is set at a different angle to the plane at a different angle to the plane of rotationof rotation

Gradual decrease in blade angle Gradual decrease in blade angle gives twisted appearancegives twisted appearance

Allows the propeller to provide Allows the propeller to provide more uniform thrust throughout more uniform thrust throughout most of the length of the blademost of the length of the blade

PropellersPropellers

Climb PropellerClimb Propeller

Low blade angleLow blade angle Best performance for takeoff and Best performance for takeoff and

climbclimb

Cruise PropellerCruise Propeller

High blade angleHigh blade angle High speed cruiseHigh speed cruise High altitude flightHigh altitude flight

Fixed – Pitch PropellerFixed – Pitch Propeller

Blade angle is selected on the Blade angle is selected on the basis of what is best for the basis of what is best for the primary function of the airplaneprimary function of the airplane

Cannot be changed by the pilotCannot be changed by the pilot

Constant Speed Constant Speed PropellerPropeller Pilot can adjust the blade angle Pilot can adjust the blade angle

for the most efficient operationfor the most efficient operation

Electrical SystemElectrical System

Electrical System Electrical System DefinitionsDefinitions Amp: flow rateAmp: flow rate Volt: measure of electromagnetic Volt: measure of electromagnetic

force. Volts are pressure that force. Volts are pressure that push amps to give powerpush amps to give power

Volts X Amps = WattsVolts X Amps = Watts

Alternators v. Alternators v. GeneratorsGenerators AlternatorsAlternators

– Produces sufficient Produces sufficient amount of electrical amount of electrical current at slower RPM current at slower RPM by producing AC by producing AC current that is current that is converted to DCconverted to DC

– More constant at More constant at different ranges of different ranges of engine speedsengine speeds

– Lighter weightLighter weight– Less costly to maintainLess costly to maintain– Less prone to Less prone to

overloadingoverloading

GeneratorsGenerators– Do not produce Do not produce

enough electrical enough electrical current at low engine current at low engine RPM to operate RPM to operate entire electrical entire electrical system.system.

– Electrical needs often Electrical needs often rely on battery, rely on battery, which is quickly which is quickly depleteddepleted

AlternatorAlternator

Engine DrivenEngine Driven Supplies engine when running Supplies engine when running

with electrical supplywith electrical supply Usually 14-28 voltUsually 14-28 volt

Alternating Current Alternating Current (AC)(AC) Type of current produced by an Type of current produced by an

alternatoralternator Current that changes directionCurrent that changes direction

Direct Current (DC)Direct Current (DC)

Current that flows in one directionCurrent that flows in one direction Aircraft run off of direct currentAircraft run off of direct current AC must be converted to DCAC must be converted to DC Battery is DC currentBattery is DC current

BatteryBattery

Main purpose is to provide a Main purpose is to provide a means of starting the enginemeans of starting the engine

Limited operation of electrical Limited operation of electrical components (Clock, hourmeters)components (Clock, hourmeters)

Source of standby or emergency Source of standby or emergency electrical power in case of electrical power in case of alternator malfunctionalternator malfunction

AmmeterAmmeter

Used to monitor the electrical current Used to monitor the electrical current in amperes within the systemin amperes within the system

Positive value means battery is being Positive value means battery is being chargedcharged

Negative value means you are drawing Negative value means you are drawing off of the batteryoff of the battery

Two typesTwo types– One reflects current flowing to or from the One reflects current flowing to or from the

batterybattery– Other type displays the load placed on the Other type displays the load placed on the

alternator and is often called a loadmeteralternator and is often called a loadmeter

AmmeterAmmeter

Two Types:Two Types:– One reflects current flowing to or One reflects current flowing to or

from the batteryfrom the battery– One displays the load placed on the One displays the load placed on the

alternator and is often called a load alternator and is often called a load metermeter

Master SwitchMaster Switch

Controls the entire electrical Controls the entire electrical systemsystem– Except battery and magnetosExcept battery and magnetos

Battery and Alternator SwitchesBattery and Alternator Switches– Similar to MasterSimilar to Master– You can turn of the Alternator in the You can turn of the Alternator in the

event of failure, at which point all event of failure, at which point all current will be drawn the battery. At current will be drawn the battery. At that point, you will need to load shedthat point, you will need to load shed

Circuit Breakers/FusesCircuit Breakers/Fuses

Protect various components from Protect various components from overloadsoverloads

Resetting a breaker will usually Resetting a breaker will usually re-activate the circuitre-activate the circuit

In the event of an alternator In the event of an alternator failure, you may have to reduce failure, you may have to reduce the load on the battery by pulling the load on the battery by pulling certain non – essential circuit certain non – essential circuit breakers.breakers.

Circuit BreakersCircuit Breakers

Bus BarsBus Bars

Tie Bus

Avionics (40) Non – Essential (40)l Main Bus (60)

AP Com. 1 Rec. lts Heater Strobe Pitot

Voltage Regulator Voltage Regulator

Controls the rate of charge to the Controls the rate of charge to the battery by stabilizing battery by stabilizing generator/alternator electrical generator/alternator electrical output.output.

Alternator voltage is normally Alternator voltage is normally slightly higher than battery slightly higher than battery (otherwise, the battery would be (otherwise, the battery would be charging the alternator)charging the alternator)

Overvoltage RelayOvervoltage Relay

Located in alternatorLocated in alternator Takes the alternator offline if the Takes the alternator offline if the

output exceeds a predetermined output exceeds a predetermined valuevalue

QuestionsQuestions

Any questions?Any questions?