Reciprocating Engine Ignition System Flashcards

1
Q

Which of the two types of cams has a uniform distance between cam lobes?

A

uncompensated

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2
Q

The number of spark plugs legally required for a cylinder

A

Two

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3
Q

The magnetic poles switch position every

A

180 degrees

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4
Q

Alnico is comprised of

A

Aluminium, nickel and cobalt

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5
Q

Condition in which spark of magneto to jump to the wrong electrode

A

Flash over

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6
Q

The purpose of a secondary ignition coil

A

Steps up voltage which is needed to create a spark

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7
Q

The components of the magnetic circuit of a magneto

A

Permanent magnet, pole shoes, coil core

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8
Q

The two types of cams used in current day magneto systems are

A

compensated cams, uncompensated cams

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9
Q

How a pressurized magneto prevents high altitude flash-over

A

It’s more difficult for a spark to jump through denser air

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10
Q

The name of the position for when the magnetic poles are aligned with the pole shoes

A

Full register

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11
Q

The components of the primary circuit in a magneto system

A

Primary winding, contact breakers and a capacitor

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12
Q

The most commonly used cam in magneto systems

A

uncompensated cams

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13
Q

The specific number of degrees beyond the neutral point is termed

A

the efficiency gap

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14
Q

Where flash over is more likely to occur

A

High altitude

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15
Q

The issue of flash over is more a problem with which type of magneto

A

high tension

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16
Q

Difference between a battery ignition system and a high tension system in a piston engine

A

Battery system uses a battery for voltage generation and the high tension uses a permanent magnet generator

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17
Q

Carbon tracking is a consequence of______ _____and happens inside the_____.

A

flash over, distributor

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18
Q

The name of the position when the magnetic poles have no flux lines through them

A

Neutral position

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19
Q

The reasons for why the pole shoes are laminated

A

To reduce eddy currents and cools the magneto

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20
Q

Average number of turns in a primary coil winding of a magneto system

A

180 turns

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21
Q

The system component which directs stepped-up voltage to the spark plugs

A

Distributor

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22
Q

The 3 circuits of a magneto system

A

Magnetic, primary and secondary

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23
Q

Flash over leads to a condition called

A

carbon tracking

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24
Q

14 CFR Part 33 states that each spark ignition system must have a minimum of

A

Two spark plugs

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25
Q

Another word for a capacitor

A

Condenser

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26
Q

The material rotating magnets are constructed of

A

Alnico

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27
Q

Permalloy is used in the construction of

A

Permanent magnets

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28
Q

Compensated cams are usually found on which type of piston engine?

A

radial

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29
Q

At full register position the magnetic field strength is

A

The strongest

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30
Q

The average amount of turns/ winding in the secondary circuit

A

13,000

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31
Q

The component in which current flows through, after the secondary winding, and just before reaching the distributor

A

Spring-loaded carbon brushes

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32
Q

Where the spring-loaded carbon brush is mounted to in a magneto system

A

center of the distributor

33
Q

The name of the position in which the breaker points open

34
Q

Current flow through the primary coil is interrupted by

A

The contact breakers opening

35
Q

The location where the current jumps the air gap between center and ground electrodes

A

spark plug

36
Q

The speed of the distributor rotor in the magneto

A

half the crankshaft speed

37
Q

The two factors affecting the speed of rotation of the rotating magnet

A
  1. number of poles 2. number of engine cylinders
38
Q

The formula for magneto shaft speed

A

Number of cylinders/ 2 x number of poles

39
Q

The term for the rotational speed necessary for the magneto to fire a spark plug

A

Coming-in speed

40
Q

Typical coming-in speed range for a magneto

A

Between 100 and 200 r.p.m.

41
Q

The reason why the coming-in speed is insufficient during engine start up

A

Starter motor cannot crank the crankshaft fast enough

42
Q

4 types of auxiliary ignition systems used in piston engine aircraft

A
  1. Shower of sparks 2. Impulse coupling 3. Booster magneto 4. Induction vibrators
43
Q

The 3 components of an impulse coupling

A
  1. Housing 2. fly weights 3. spring
44
Q

Function of an Impulse coupling

A

Intensify and retard the ignition spark at low engine speed to facilitate engine starting

45
Q

The condition of both magnetos when the cockpit ignition switch is positioned to the OFF position

A

Both magneto circuits are shorted though the iggntion switch to ground

46
Q

Any time a tech perfroms maintenance on an ignition system, what should be done with the switch?

A

Operational check

47
Q

Steps in an operational check of the magneto

A
  1. Run engine between 1500 and 1700 r.p.m.
  2. Move iggnition switch from BOTH to LEFT (Observe slight rpm drop)
  3. Move switch back to BOTH
  4. Move switch from BOTH to RIGHT (Observe slight RPM drop)
  5. Move switch from RIGHT to BOTH
  6. Throttle to idle
  7. Move switch to OFF
48
Q

An open P-lead on a Magneto system or a faulty igntion switch will be evidenced by

A

Engine continuing to run with IGNITION Switch in the OFF position

49
Q

In retaining the magnetism of the rotating magnet of a Magneto, place soft_____ _______ accross the poles

A

How soft iron keepers are placed

50
Q

Another word for a Magnetometer

A

Another word for a gauss meter

51
Q

The use for a Magnetometer

A

Machine which test for the strength of a magnet

52
Q

The part of the entire magneto assembly which is subject to the most wear

A

Contact breakers

53
Q

How excessive wear between the Magneto distributor gear teeth is found

A

place a drill bit inbetween magneto distributor gear teeth

54
Q

First step in internal timing of a Magneto

A

Finding the neutral position by rotating the magnet shaft by hand until you feel the magnet pull into alignment

55
Q

The reason why magneto housing would be vented

A

Arcing in the magneto cases corrosive gasses,

condensation and water vapor needs to find its way out of the magneto case

56
Q

What the induction vibrator in a Magneto system does

A

Provides pulsing direct current (DC) to the primary winding of the magneto coil

57
Q

The names of the two most commonly used magnetos in gernal aviation

A
  1. Bendix Magnetos
  2. Slick Magnetos
58
Q

Piror to Magneto installation on an engine, the crankshaft must:

A

Crank shaft must be positioned with the number 1 piston in firing position

59
Q

Tools required for engine magneto installation

A
  1. Piston stop
  2. Propeller protractor (Flower pot)

or just a

Time-rite indicator

60
Q

In preparing the engine for magneto installation, moving the piston backward beyond the ignition timing mark and then foreard to the firing positon ensures compensation for “ Backlash”. What is Backlash

A

Backlash is lost motion in the gear train due to gaps between the teeth

61
Q
A
  1. Single Magneto
  2. Dual Magneto
62
Q
A
  1. Distributor Gear
  2. High output coil
  3. Impulse coupling
  4. Magnet
  5. Pinion gear
  6. Ball Bearing
  7. Cam
  8. Capacitor
  9. Distributor block
63
Q

The typical root cause of excessive contact breaker wear

A

A defective capacitor

64
Q

The type of voltage used to test a capacitor for electical leakage

65
Q

The type of voltage used to test a capacitor for capacity

66
Q

The presence of engine oil in a magneto will indicate failure of

A

Failure of oil seal in the magneto

67
Q

The 3 times that the magneto-to-engine timing must be checked

A
  1. Overhaul
  2. 100 hour inspection
  3. Annual inspection
68
Q

The 2 sizes of ignition leads used for aircraft magneto systems

A
  1. five millimeter
  2. seven millimeter
69
Q
A

Propeller timing indicator

70
Q

Term for the smallest gear in a gear system

A

Pinion gear

71
Q

Identify

A
  1. Outter race
  2. Inner race
72
Q

The final step in magneto assembly

A

Internal magneto timing

73
Q

The procedure for servicing a cracked magneto case

A

Replace the unit

74
Q

The differnce between high-tension and low-tension magnetos systems

A

Low tension magneto systems have transformers at each sprak plug to step up the voltage before spark

High tension systems has the voltage stepped up before the distributor

75
Q

The greatest amount of magnetic field stress exist when and why?

A

Just after neutral point because this is when magetic field polarity starts to reverse

(magetic field resist change in direction)

76
Q

Why do the contact breakers open at E-gap?

A

They open to colapse the field ASAP, since polarity reverse past neautral position and the magnetic field resist direction change

77
Q

What does P-lead stand for in a magneto system

A

Primary lead

78
Q

If the P-lead in a magneto system breaks what will be the most likely condtion of the engine?

A

Will be “HOT” and ready to fire with just a small turn of the propeller

79
Q

What type of shorts can you have in the magneto system leads

A

Conductor can short to shielding

Conductor can short to airframe or engine