Ignition starting system pt. 1 ⭐️

50問 • 1年前

問題一覧

A safety feature usually employed in direct cranking starters that is used to prevent the starter from reaching burst speed is the

stator nozzle design that chokes airflow and stabilizes turbine wheel speed.

In a four-stroke cycle aircraft engine, when does the ignition event take place?

Before the piston reaches TDC on compression stroke.

What likely effect would a cracked distributor rotor have on a magneto?

Ground the secondary circuit through the crack.

Sharp bends should be avoided in ignition leads primarily because

weak points may develop in the insulation through which high tension current can leak.

Using a cold spark plug in a high-compression aircraft engine would probably result in

normal operation

The purpose of an undercurrent relay in a starter generator system is to

disconnect power from the starter-generator and ignition when sufficient engine speed is reached

How does high-tension ignition shielding tend to reduce radio interference?

Receives and grounds high-frequency waves coming from the magneto and high-tension ignition leads.

Ignition check during engine run-up indicates a slow drop in RPM. This is usually caused by

incorrect ignition timing or valve adjustment.

The secondary coil of a magneto is grounded through the

primary coil

When installing a magneto on an engine, the

piston in the No. 1 cylinder must be a prescribed number of degrees before top center on the compression stroke.

A certain nine-cylinder radial engine used a non-compensated single-unit, dual-type magneto with a four-pole rotating magnet and separately mounted distributors. Which of the following will have the lowest RPM at any given engine speed?

Distributors

A defective primary capacitor in a magneto is indicated by

burned and pitted breaker points.

When the ignition switch of a single (reciprocating) engine aircraft is turned to the OFF position.

the primary circuits of both magnetos are grounded.

The capacitor-type ignition system is used almost universally on turbine engines primarily because of its high voltage and

high-heat intensity

What test instrument could be used to test an ignition harness for suspected leakage?

A high tension lead tester.

The greatest density of flux lines in the magnetic circuit of a rotating magnet-type magneto occurs when the magnet is in what position?

Full alignment with the field shoe faces.

Failure of an engine to cease firing after turning the magneto switch off is an indication of

an open P-lead to ground.

In a turbine engine dc capacitor discharge ignition system, where are the high-voltage pulses formed?

At the triggering transformer

Ignition check during engine run-up indicates excessive RPM drop during operation on the right magneto. The major portion of the RPM loss occurs rapidly after switching to the right magneto position (fast drop). The most likely cause is

faulty or fouled spark plugs.

When internally timing a magneto, the breaker points begin to open when the rotating magnet is

a few degrees past the neutral position.

When a magneto is disassembled, keepers are usually placed across the poles of the rotating magnet to reduce the loss of magnetism. These keepers are usually made of

soft iron

What components make up the magnetic system of a magneto?

Rotating magnet, the pole shoes, the pole shoe extensions, and the coil core.

Magneto timing drift is caused by erosion of the breaker points and

wear of the cam followers

What would be the result if a magneto breaker point mainspring did not have sufficient tension?

The points will float or bounce.

Magneto breaker point opening relative to the position of the rotating magnet and distributor rotor (internal timing) can be set most accurately

during assembly of the magneto before installation on the engine.

(1) The platinum and iridium ground electrodes used on fine wire spark plugs are extremely brittle and can be broken if they are improperly handled or adjusted. (2) When gapping massive-electrode spark plugs, a wire gauge should be inserted between the center and ground electrodes while moving the ground electrode in order to avoid setting the gap too close. Regarding the above statements.

only No. 1 is true.

Magneto pole shoes are generally made of

laminations of high-grade soft iron.

What will be the result of using too hot a spark plug?

Pre-ignition

Hot spark plugs are generally used in aircraft powerplants

with comparatively low operating temperatures.

In an aircraft ignition system, one of the functions of the capacitor is to

facilitate a more rapid collapse of the magnetic field in the primary coil.

Inspection of pneumatic starters by maintenance technicians usually includes checking the

oil level and magnetic drain plug condition.

Which of the following statements regarding magneto switch circuits is NOT true?

In the BOTH position, the right and left magneto circuits are grounded.

The spark occurs at the spark plug when the ignition’s

primary circuit is broken.

Spark plug fouling caused by lead deposits occurs most often

when cylinder head temperatures are relatively low.

Generally, when removing a turbine engine igniter plug, in order to eliminate the possibility of the technician receiving a lethal shock, the ignition switch is turned off and

the igniter lead is disconnected from the plug and the center electrode grounded to the engine after disconnecting the transformer-exciter input lead and waiting the prescribed time.

What is the electrical location of the primary capacitor in a high-tension magneto?

In parallel with the breaker points.

The numbers appearing on the ignition distributor block indicate the

sparking order of the distributor.

When performing a magneto ground check on an engine, correct operation is indicated by

a slight drop in RPM.

The type of ignition system used on most turbine aircraft engines is

capacitor discharge.

It is found that a shielded ignition system does not adequately reduce ignition noise, it may be necessary to install

a filter between the magneto and magneto switch.

In a typical starter-generator system, under which of the following starting circumstances may it be necessary to use the start stop button?

Hung start

A spark plug is fouled when

its spark grounds without jumping electrodes.

When internally timing a magneto, the breaker points begin to open when

the magnet poles are a few degrees beyond the neutral position.

What is the purpose of a safety gap in some magnetos?

To discharge the secondary coil’s voltage if an open occurs in the secondary circuit.

What is the radial location of the two north poles of a four-pole rotating magnet in a high-tension magneto?

180° apart

Magneto breaker points must be timed to open when the

greatest magnetic field stress exists in the magnetic circuit.

What are two parts of a distributor in an aircraft engine ignition system? 1. Coil 2. Block 3. Stator 4. Rotor 5. Transformer

2 and 4

If an aircraft ignition switch is turned off and the engine continues to run normally, the trouble is probably caused by

an open ground lead in the magneto.

When removing a shielded spark plug. Which of the following is most likely to be damaged?

Core insulator

The constrained-gap igniter plug used in some gas turbine engines operates at a cooler temperature because

the construction is such that the spark occurs beyond the face of the combustion chamber liner.

Airlaw (PCAR, AFCAR, Airframe check & Publications) (2)

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Airlaw (PCAR, AFCAR, Airframe check & Publications) (2)

47問 • 1年前

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Reciprocating Engines pt.1 ⭐️

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Reciprocating Engines pt.1 ⭐️

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Reciprocating Engines pt.2 ⭐️

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Induction and Airflow System

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Engine Instrument System

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Fuel Metering System

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Turbine Engines pt. 1 ⭐️

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Turbine Engines pt. 2 ⭐️

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Powerplant (Propellers) pt. 1 ⭐️

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Powerplant (Propellers) pt. 2 ⭐️

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Powerplant (Auxiliary power unit)

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Engine Lubrication ⭐️

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Assembly and Rigging ⭐️

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78問 • 1年前

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問題一覧

A safety feature usually employed in direct cranking starters that is used to prevent the starter from reaching burst speed is the

stator nozzle design that chokes airflow and stabilizes turbine wheel speed.

In a four-stroke cycle aircraft engine, when does the ignition event take place?

Before the piston reaches TDC on compression stroke.

What likely effect would a cracked distributor rotor have on a magneto?

Ground the secondary circuit through the crack.

Sharp bends should be avoided in ignition leads primarily because

weak points may develop in the insulation through which high tension current can leak.

Using a cold spark plug in a high-compression aircraft engine would probably result in

normal operation

The purpose of an undercurrent relay in a starter generator system is to

disconnect power from the starter-generator and ignition when sufficient engine speed is reached

How does high-tension ignition shielding tend to reduce radio interference?

Receives and grounds high-frequency waves coming from the magneto and high-tension ignition leads.

Ignition check during engine run-up indicates a slow drop in RPM. This is usually caused by

incorrect ignition timing or valve adjustment.

The secondary coil of a magneto is grounded through the

primary coil

When installing a magneto on an engine, the

piston in the No. 1 cylinder must be a prescribed number of degrees before top center on the compression stroke.

Distributors

A defective primary capacitor in a magneto is indicated by

burned and pitted breaker points.

When the ignition switch of a single (reciprocating) engine aircraft is turned to the OFF position.

the primary circuits of both magnetos are grounded.

The capacitor-type ignition system is used almost universally on turbine engines primarily because of its high voltage and

high-heat intensity

What test instrument could be used to test an ignition harness for suspected leakage?

A high tension lead tester.

The greatest density of flux lines in the magnetic circuit of a rotating magnet-type magneto occurs when the magnet is in what position?

Full alignment with the field shoe faces.

Failure of an engine to cease firing after turning the magneto switch off is an indication of

an open P-lead to ground.

In a turbine engine dc capacitor discharge ignition system, where are the high-voltage pulses formed?

At the triggering transformer

faulty or fouled spark plugs.

When internally timing a magneto, the breaker points begin to open when the rotating magnet is

a few degrees past the neutral position.

When a magneto is disassembled, keepers are usually placed across the poles of the rotating magnet to reduce the loss of magnetism. These keepers are usually made of

soft iron

What components make up the magnetic system of a magneto?

Rotating magnet, the pole shoes, the pole shoe extensions, and the coil core.

Magneto timing drift is caused by erosion of the breaker points and

wear of the cam followers

What would be the result if a magneto breaker point mainspring did not have sufficient tension?

The points will float or bounce.

Magneto breaker point opening relative to the position of the rotating magnet and distributor rotor (internal timing) can be set most accurately

during assembly of the magneto before installation on the engine.

only No. 1 is true.

Magneto pole shoes are generally made of

laminations of high-grade soft iron.

What will be the result of using too hot a spark plug?

Pre-ignition

Hot spark plugs are generally used in aircraft powerplants

with comparatively low operating temperatures.

In an aircraft ignition system, one of the functions of the capacitor is to

facilitate a more rapid collapse of the magnetic field in the primary coil.

Inspection of pneumatic starters by maintenance technicians usually includes checking the

oil level and magnetic drain plug condition.

Which of the following statements regarding magneto switch circuits is NOT true?

In the BOTH position, the right and left magneto circuits are grounded.

The spark occurs at the spark plug when the ignition’s

primary circuit is broken.

Spark plug fouling caused by lead deposits occurs most often

when cylinder head temperatures are relatively low.

Generally, when removing a turbine engine igniter plug, in order to eliminate the possibility of the technician receiving a lethal shock, the ignition switch is turned off and

the igniter lead is disconnected from the plug and the center electrode grounded to the engine after disconnecting the transformer-exciter input lead and waiting the prescribed time.

What is the electrical location of the primary capacitor in a high-tension magneto?

In parallel with the breaker points.

The numbers appearing on the ignition distributor block indicate the

sparking order of the distributor.

When performing a magneto ground check on an engine, correct operation is indicated by

a slight drop in RPM.

The type of ignition system used on most turbine aircraft engines is

capacitor discharge.

It is found that a shielded ignition system does not adequately reduce ignition noise, it may be necessary to install

a filter between the magneto and magneto switch.

In a typical starter-generator system, under which of the following starting circumstances may it be necessary to use the start stop button?

Hung start

A spark plug is fouled when

its spark grounds without jumping electrodes.

When internally timing a magneto, the breaker points begin to open when

the magnet poles are a few degrees beyond the neutral position.

What is the purpose of a safety gap in some magnetos?

To discharge the secondary coil’s voltage if an open occurs in the secondary circuit.

What is the radial location of the two north poles of a four-pole rotating magnet in a high-tension magneto?

180° apart

Magneto breaker points must be timed to open when the

greatest magnetic field stress exists in the magnetic circuit.

What are two parts of a distributor in an aircraft engine ignition system? 1. Coil 2. Block 3. Stator 4. Rotor 5. Transformer

2 and 4

If an aircraft ignition switch is turned off and the engine continues to run normally, the trouble is probably caused by

an open ground lead in the magneto.

When removing a shielded spark plug. Which of the following is most likely to be damaged?

Core insulator

The constrained-gap igniter plug used in some gas turbine engines operates at a cooler temperature because

the construction is such that the spark occurs beyond the face of the combustion chamber liner.