aircraft system M3 Flashcards by RAFA BRENDA DELDIG

brings in air from the outside, mixes it with fuel, and

delivers the fuel-air mixture to the cylinder where combustion occurs.

induction system

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Outside air enters the induction system through an intake port on the front of
the _________

engine cowling

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This port normally contains an air filter that inhibits the

entry of dust and other foreign object

intake port

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The engine used in light aircraft is usually equipped with either a ______ or a ________

carburetor, fuel-injection system

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two types of induction systems that are commonly used in small aircraft engines.

carburetor, fuel injection system

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It mixes the fuel and air in the carburetor before this

the mixture enters the intake manifold.

carburetor system

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It mixes the fuel and air immediately before entry into

each cylinder or injects fuel directly into each cylinder.

the fuel injection system

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It is responsible for bringing together and mixing the air and fuel.

carburetor

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Aircraft carburetors are separated into two categories:

float-type carburetor and pressure-type carburetor

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It is complete with idling, accelerating, mixture control, idle
cutoff, and power enrichment systems

float-type carburetor

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the most common of the two carburetor types

float-type carburetor

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are usually not found on small aircraft.

pressure-type carburetor

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In the operation of the float-type carburetor system, the outside air first ____________, usually located at an air intake in the front part of the
engine cowling.

the outside air first flows through an air filter

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a narrow throat in the carburetor.

venturi

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Process of the float-type carburetor system

In the operation of the float-type carburetor system, the outside air first flows
through an air filter, usually located at an air intake in the front part of the
engine cowling.

This filtered air flows into the carburetor and through a venturi, a narrow
throat in the carburetor.

The fuel-air mixture is then drawn through the intake manifold and into the
combustion chambers where it is ignited.

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Acquires its name from a float that rests on fuel within the float chamber.

float-type carburetor

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READ 3 TIMES

A needle attached to the float opens and closes an opening at the bottom of the carburetor bowl.

READ 3 TIMES

A needle attached to the float opens and closes an opening at the bottom of the carburetor bowl.

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This meters the amount of fuel entering the carburetor, depending upon
the position of the float, which is controlled by the level of fuel in the float
chamber.

needle attached to the float

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When the level of the fuel forces the float to rise,___________closes the
fuel opening and shuts off the fuel flow to the carburetor.

the needle valve closes

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• A needle attached to the float opens and closes an opening at the bottom of
the carburetor bowl.
• This meters the amount of fuel entering the carburetor, depending upon
the position of the float, which is controlled by the level of fuel in the float
chamber.
• When the level of the fuel forces the float to rise, the needle valve closes the
fuel opening and shuts off the fuel flow to the carburetor

float type carburator

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It opens again when the engine requires additional fuel.

the needle valve: fuel type carburetor

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The flow of the fuel-air mixture to the combustion chambers is regulated by ____

the throttle valve

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the throttle valve is controlled by the ______ in the flight deck.

throttle

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The float-type carburetor distinct disadvantages:

they do not function well during abrupt maneuvers.
the discharge of fuel at low pressure leads to incomplete vaporization and difficulty in discharging fuel into some types of supercharged systems.
The chief dis advantage of the float-type carburetor, however, is its icing tendency

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It discharges fuel into the airstream at a pressure well above atmospheric pressure.

pressure- type carburetor

PRESSURE-TYPE CARBURETOR/ READ This results in better vaporization and permits the discharge of fuel into the airstream on the engine side of the throttle valve.

PRESSURE-TYPE CARBURETOR/ READ This results in better vaporization and permits the discharge of fuel into the air stream on the engine side of the throttle valve.

PRESSURE-TYPE CARBURETOR/ READ With the discharge nozzle in this position fuel vaporization takes place after the air has passed through the throttle valve and at a point where the drop in temperature is offset by heat from the engine. Thus, the danger of fuel vaporization icing is practically eliminated.

The ratio of fuel-to-air that enters the engine manifold is termed the ______ and is controlled via a lever in the cockpit.

mixture

mixture is controlled via a _____ | in the cockpit.

lever

Mixture levers are almost always painted___ in color and are usually placed to the ____t of the throttle lever.

red, right

The volume of the air-fuel mixture entering the intake manifold and the ratio of air-to-fuel in this mixture is controlled by the ______ and the ____ respectively.

throttle, mixture control levers

is incorporated into the carburetor to allow the engine to idle.

idle passage

This is a passageway which bypasses the venturi and provides a path for the fuel to flow directly from the float chamber to the low-pressure side of the throttle valve

idle passage

occurs due to the effect of fuel vaporization and the decrease in air pressure in the venturi, which causes a sharp temperature drop in the carburetor.

carburetor ice

It forms when the air passing through the carburetor venturi mixes with vaporized fuel causing a large temperature drop within the carburetor.

carburetor ice

The moisture in the air can form ice, restricting the air and fuel flow to the engine and resulting in a partial or total loss of engine power.

carburetor icing

is an anti-icing system that preheats the air before it reaches the carburetor and is intended to keep the fuel-air mixture above freezing to prevent the formation of carburetor ice.

carburetor heat

It can be used to melt ice that has already formed in the carburetor if the accumulation is not too great. Using it as a preventative measure is the better option.

carburetor heat

should be checked during the engine run-up

carburetor heat

It is imperative for a pilot to recognize carburetor ice when it forms during flight to prevent a __________. These symptoms may sometimes be accompanied by __________

loss in power, altitude, and/or airspeed; vibration or engine roughness.

The use of carburetor heat causes a _______ in engine power, sometimes up to 15 percent, because the heated air is ___ dense than the outside air that had been entering the engine. This enriches the mixture

decrease, less

UTILIZING CARB HEAT DOES NOT COME WITHOUT A COUPLE OF CONSIDERATIONS, THOUGH: Since that “heated” air entering the carburetor is much warmer and less dense, your engine now acts as though it’s at a higher altitude because warmer air is less dense. There will be a ______ associated with the introduction of carb heat.

slight power loss

Carb heart will __________, so additional engine leaning may | be needed as appropriate.

richen the fuel/air mixture

READ! UTILIZING CARB HEAT DOES NOT COME WITHOUT A COUPLE OF CONSIDERATIONS, THOUGH: The air is not flowing through the air filter which is typically positioned just before the air enters the carburetor. The carb heat air is usually unfiltered.

UTILIZING CARB HEAT DOES NOT COME WITHOUT A COUPLE OF CONSIDERATIONS, THOUGH: • Since that “heated” air entering the carburetor is much warmer and less dense, your engine now acts as though it’s at a higher altitude because warmer air is less dense. There will be a slight power loss associated with the introduction of carb heat. • Carb heart will richen the fuel/air mixture, so additional engine leaning may be needed as appropriate. • The air is not flowing through the air filter which is typically positioned just before the air enters the carburetor. The carb heat air is usually unfiltered.

``` READ Since the use of carburetor heat tends to reduce the output of the engine and to increase the operating temperature, carburetor heat should not be used when full power is required (as during takeoff) or during normal engine the operation, except to check for the presence of, or to remove, carburetor ice. ```

``` CARBURETOR HEAT/ READ AGAIN • Since the use of carburetor heat tends to reduce the output of the engine and to increase the operating temperature, carburetor heat should not be used when full power is required (as during takeoff) or during normal engine the operation, except to check for the presence of, or to remove, carburetor ice. ```

Most aircraft are also equipped with an _____ (OAT) | gauge calibrated in both degrees Celsius and Fahrenheit.

outside air temperature

It provides the outside or ambient air temperature for calculating true airspeed is useful in detecting potential icing conditions.

air temperature (OAT)

In a ________, the fuel is injected directly into the cylinders, or just ahead of the intake valve

fuel injection system

The air intake for the ___________ is similar to that used in a carburetor system, with an alternate air source located within the engine cowling.

fuel injection system

this system has many advantages over a conventional carburetor system. There is less danger of induction system icing since the drop in temperature due to fuel vaporization takes place in or near the cylinder.

The fuel-injection system

fuel injected components (6)

* Engine-driven fuel pump * Fuel-air control unit * Fuel manifold (fuel distributor) * Discharge nozzles * Auxiliary fuel pump * Fuel pressure/flow indicators.

It provides fuel under pressure from the fuel tank to the fuel-air control unit.

Engine-driven fuel pump

This control unit, which essentially replaces the carburetor, meters fuel based on the mixture control setting and sends it to the fuel manifold valve at a rate controlled by the throttle

fuel control unit

After reaching the fuel manifold valve, the fuel is distributed to the individual _________. They are located in each cylinder head, and inject the fuel-air mixture directly into each cylinder intake port.

fuel discharge nozzles

It provides fuel under pressure to the fuel-air control unit for engine starting and/or emergency use.

auxiliary fuel pump

indicates the pressure of the fuel entering the system.

fuel pressure indicators

advantages of fuel injected (6)

``` ADVANTAGES : • Reduction in evaporative icing • Better fuel flow • Faster throttle response • Precise control of mixture • Better fuel distribution • Easier cold weather starts ```

disadvantages of fuel injected (3)

``` DISADVANTAGES : • Difficulty in starting a hot engine • Vapor locks during ground operations on hot days • Problems associated with restarting an engine that quits because of fuel starvation ```

THE DIFFERENCE BETWEEN CARBURETOR AND FUEL INJECTED IN THE OPERATION OF AIRCRAFT: STARTING

In carbureted engines, the fuel/air mixture meets in the carburetor. The mixture then goes to each cylinder through the air intake. Carbureted engines undoubtedly take less talent to get started. In the fuel-injected engine, the fuel and air do not mix until they reach the cylinder. Since fuel injection systems shoot fuel directly into the cylinders, they are easier to flood (too much fuel) when starting. For this reason, starting procedures for fuel-injected engines vary a good bit depending on the aircraft/engine combination.

To increase an engine’s horsepower, manufacturers have developed forced induction systems. They both compress the intake air to increase its density, the key difference lies in the power supply. (2)

supercharger and turbosupercharger systems

an engine-driven air pump or compressor that provides compressed air to the engine to provide additional pressure to the induction air so that the engine can produce additional power.

supercharger

It increases manifold pressure and forces the fuel-air mixture into the cylinders. Higher manifold pressure increases the density of the fuel-air mixture and increases the power an engine can produce.

supercharger

THE DIFFERENCE BETWEEN CARBURETOR AND FUEL INJECTED IN THE OPERATION OF AIRCRAFT: CRUISING (read and understand)

Though they are easier to start, carbureted engines are less efficient during flight. Since the fuel/air mixture in carbureted systems meet at the carburetor, the mixture is less precise for each cylinder. Fuel injectors are calibrated to force the same amount of fuel into each cylinder. Because of their precision, most fuel injection systems also permit monitoring of each cylinder’s EGT (Exhaust Gas Temperature). EGT probes on each cylinder allow the pilot to create the ideal engine performance; saving fuel, as well as reducing wear on the engine. For these reasons, as well as many others, fuel injected engines are standard on most new aircraft.

Carbureted systems are simple: fewer parts, less complexity, less maintenance. In fact, our carbureted Cessnas do not need fuel pumps since the fuel tanks are high (in the wings ) and push the fuel all the way to the carburetor. One thing carbureted engines do need is carb heat. When activated, carb heat allows air to flow around the exhaust (to heat up) and then into the carburetor - bypassing the induction filter. The hot air melts/prevents ice buildup around the throttle valve. Fuel-injected engines do not need carb heat, but they do need electric fuel pumps as a starting flow, as well as a backup for the engine-driven fuel pump.

The most efficient method of increasing horsepower in an engine is by using a _________

turbosupercharger or turbocharger

Installed on an engine, this booster uses the engine’s exhaust gases to drive an air compressor to increase the pressure of the air going into the engine through the carburetor or fuel injection system to boost power at higher altitude

turbocharger

aircraft system M3 Flashcards

(68 cards)