Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Module 15 > 15.13 > Flashcards

15.13 Flashcards

(90 cards)

Start Studying
1
Q

When might you want to motor the engine without ignition?

A

When doing maintenance checks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

When might you only want to ingite the engine?

A

In flight after a flame out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are gas turbine engines started by?

A

The HP compressor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why would you want to accelerate the compressor?

A

To provide sufficient air to support combustion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Until when must the starter assist the engine?

A

Until it has reached above a self accelerating speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How much torque should the motor create?

A

Excess to overcome compressor inertia and friction)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

When is ignition turned on, then following after fuel suppled?

A

When the starter has accelerated compressor to the point where air is flowing though

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

When is the fuel flow rate not sufficient for the engine to accelerate?

A

At low (cranking) speeds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Are the starter and the ignitor switched off automatically or manually?

A

Automatically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is a hot or hung false start?

A

When the starter doesn’t assist the acceleration so theres a delay in the starting cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the cartridge stater?

A

A small impulse type engine that is driven by high velocity gases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Where do the high velocity gases needed to drive the impulse type engine in the cartridge starter come from?

A

A burning cartridge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The power output from the turbine is passed through what two things before it rotates the engines?

A

A reduction gearbox (increases torque with lower rpm)

An automatic means of disconnection (when you don’t need the starter anymore)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What initiates the burning of the cartridge?

A

An electrically fired denoter. (cordite charge)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does the cartridge system work?

A

Putting in a voltage (electricity) to start the ignition of the cartridge causes a release of hot gases. These hot gases go through a breech to a nozzle with allows flow to the turbine. This causes the turbine to rotate (under overboard exhaust collector)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens when the pressure rises above the preset maximum?

A

The air goes through a pressure relief valve which bypasses it through the hot air nozzle. (Want the two separate pressures to mix at the end to trim the pressure)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Advantages of air starter system?

A

Lighter, simple and more economical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What two things are consisted in an air starter system?

A

A reduction gearbox and a clutch which drives an output shaft connected to an engine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What air is used to start the starter turbine?

A

GPU air
APU
Crossfeed from running engine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What PSI is used at a time to start an air driven starter turbine?

A

30-50

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

When does the clutch automatically disengage?

A

When the engine accelerates to idling RPM and the starter motor ceases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What type of clutch is involved in a air starter?

A

A sprag clucth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

When does the sprag clutch engage automatically?

A

When the rotor starts to turn

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

When does the sprag clutch disengage?o

A

As soon as the drive coupling turns more rapidly than rotor (It doesn’t need the starter motor anymore as it has reached self accelerating speed)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
When does the ouput assemble and the drive coupling turn?
As long as the engine is on
26
What is set to open the turbine switch when the starter reaches cut out point?
A rotor switch actuator (Closes the valve and stops air supply to starter
27
What does a turbine rotor containment ring do?
Dissipate energy Discharge energy coming off of the blades through the exhaust duct (in event of overspeed of turbine
28
What does the transmission housing also provide?
Lubrication
29
What is in the drain opening that allows you to see inside?
A sight glass
30
What does a magnetic drain plug do?
Picks up any ferrous metals that may be in the oil for the turbine (used to start the starter)
31
What 3 things are involved in maintenance?
Leaks Oil level Magnetic drain plug
32
What can be added through a port in the air starter?
Oil to the transmission housing sump
33
When is the sump vented?
During normal flight
33
The slope of the cam track is designed to provide what?
Small initial travel but high torque
34
If air starter valve fails to open (to allow air in to start) what must you do?
Manual over ride
35
What are the two types of electric starter systems?
Direct cranking Starter generator
36
What type of electricity does the direct cranking electric starter use?
DC
37
What does the clutch do when the engine reaches the a self sustaining speed on an electric starter system?
Automatically disengages
38
The electrical supply is automatically cancelled when what?
When the starter motor is reduced after the engine has started efficiently or when the time cycle is completed
39
Where are direct cranking systems used mostly?
On small turbine engines like APU's or turboshaft engines
40
How do direct cranking electrical systems work?
High or low voltages passed through a series of relays or resistance to allow voltage to build up as the starter gains speed.
41
What does the direct cranking system also provide?
Power for ignition
42
What is the difference between the starter generator and the direct cranking systems (The two electrical systems)
The starter generator can be used as a generator too (Don't need an IDG) after the engines have reached self sustaining speed. (STARTER AND GENERATOR )
43
In what type of starter motor is the shaft permanently engaged with the starter motor?
The starter generator
44
What type of generator is a starter generator? What do they produce
Shunt generator (strong field and high torque)
45
What is the C field used for in starter genrators?
Starting
46
What is the shunt used for in a starter generator?
For voltage generation in the generator
47
What does the undercurrent controller do?
controls the starter generator when it is used as a starter to provide positive action (To keep it running until the engine is running at a good speed)
48
How many relays does the control block of the undercurrent relay
49
What is the igniter used for?
To ignite the fuel then switches off
50
What is different about the continuous ignition mode?
It uses a lower voltage and lower power
51
When is continous ignition used?
If there is a possibility of engine flame out to relight the fuel and keep the engine from stopping
52
What situation is continous ignition used in?
Take off, landing and some weather conditions (abnormal or emergancy)
53
What is ignition cooled down with?
Fan airflow
54
What type of ignition are most turbine engines equipped with?
Electronic type
55
How many ignition sources do capacitor type systens consit of?
2 operating at operating from common DC source
56
What are the DC sources used for ingition?
115VAC The battery Permenant magnetic generator
57
What is the generator turned by?
The gearbox so produced power every time the engine is running
58
Because of high altitudes, what can this cause the spark to do?
Become high intensity
59
What is a safety factor ignition systems?
A dual system designed to fire two igniter plugs
60
Before the electrical energy reaches the exciter unit, what does it pass through?
A filter that prevents noise voltage entering fuel electrical systems
61
What drives the multi lobe
A multi-lobe/single lobe cam
62
What are breaker points acctuated by?
Cams (multi/single)
63
Once combustion is started what is the flame considered as?
Continuous
64
What is the benefit of the ignitor being hermetically sealed?
Protects components from adverse operating conditions Eliminate possibility of flashover (due to pressure change) Sheilding against high frequency voltage
65
What is the energy in the capacitor discharge exciter unit stored in?
Capacitor
66
How many storage capacitors are there in discharge circuits?
2 (in the exciter unit)
67
What happens to the resistance when the ignitor plug fires?
Drops to allow the larger capacitor to discharge across the gap
68
What is the dual purpose of the spark?
Igniting abnormal fuel mixtures Burning off deposits
69
What is an exciter plug?
A dual unit that produces sparks for both igniter plugs
70
A continuous series of sparks is produced until when?
The engine starts
71
Why are exciters air cooled?
To prevent overheating during long use of continuous ignition
72
When is an exception for the sparks being produced after the engine has started?
When continuous ignition
73
Where are spark plugs used?
Reciprocating engine system
74
What is the main difference between spark plugs and igniter plugs?
Igniter plugs' electrode need to capable of withstanding a higher energy
75
What causes electrode errosion?
High energy current
76
How can you minimise electrode errosion?
Short periods of operation
77
Why is the electrode gap larger in a igniter plug than a spark plug?
Operating pressures lower (in spark plug) Spark can arc more easily (In igniter plug)
78
What does a long reach ignitor mean?
It protrudes into the combustion chamber slightly for more effective results
79
Where is a gap plug used?
Turbine engines
80
What does a gap plug not do and what does this ensure?
Extend into the combustion chamber so it has a cooler operating temperature
81
In a gap plug igniter plug, where does the spark arc?
Beyond the face of the combustion chamber liner
82
How can the igniter be checked?
Hearing a clicking noise as the engine begins to start driven by the starter Removing it and activating the start cycle and looking for a visible spark across it
83
What does the ignition system wire insulation need to be?
Flexible with no evidence of arcing
84
What must you do to the leads?
Clean them with a solvent and perform continuity checks
85
When handling hot parts what PPE must you wear?
Hand PPE
86
What is the most probable reason for accidental discharge of an ignitor plug?
Touching the ignitor
87
What type of tools must be used?
Insulated
88
Coupling nuts or connectors should not be what?
Touched with bare hands
89
At what end must you disconnect igniter lead couplings first at?
The exciter end

Module 15 (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions