Module 15.13 Start & ignition

Question 1

What do some aircraft use for engine starting?

Answer 1

• Electric
• Gas pressure
• Hydraulic

Question 2

What are there two separate systems to start a GTE?

Answer 2

• Provisions to rotate the compressor to induce sufficient airflow through the engine
• Provision for fuel ignition

Question 3

A cartridge starter uses what type of turbine blades?

Answer 3

Small impulse type

Question 4

Cartridge starters are driven by high velocity air driven by what?

Answer 4

A burning cartridge

Question 5

What is the power output of the turbine passed through?

Answer 5

Reduction gearbox

Question 6

How is the cartridge ignited?

Answer 6

Applying a voltage through connector at the end of the breech handle

Question 7

What are the benefits to air starters?

Answer 7

Light, simple to operate and economical

Question 8

How does the clutch disengage?

Answer 8

Automatically, if it is a sprag clutch it will disconnect at a certain centrifugal force

Question 9

What psi is required for an air starter?

Answer 9

30-50 psi

Question 10

What type of clutch does an air starter have?

Answer 10

Sprag

Question 11

Does the starter motor have its own oil system?

Answer 11

Yes, separate from the engines

Question 12

How is the air starter motor switched off?

Answer 12

Close the starter valve

Question 13

What type of drain plug is in the starter transmission?

Answer 13

Magnetic, to catch particles in the oil

Question 14

What gear system is used in a starter motor?

Answer 14

Reduction gear system

Question 15

How can the engine be started if the start valve is inoperative?

Answer 15

Manual valve override

Question 16

What are the types of electrical starter on a GTE?

Answer 16

• Direct cranking
• Starter-generator

Question 17

What current is a a direct cranking starter supplied by?

Answer 17

Direct

Question 18

What engines are direct cranking starters used on?

Answer 18

• Small turbine (APU)
• Small turboshaft

Question 19

How does a starter generator work?

Answer 19

Acts like a direct cranking starter but once the engine has started there is a secondary series of windings which allow for generation

Question 20

Does the starter-generator system have a clutch?

Answer 20

No, it is permanently mounted to the gearbox

Question 21

What is the advantage of a starter generator?

Answer 21

Saves weight

Question 22

How long are igniters lit for usually?

Answer 22

A short period

Question 23

What can be said about the igniter voltage during continuous ignition?

Answer 23

Lower

Question 24

When would continuous ignition be used?

Answer 24

• Takeoff, landing
• Abnormal conditions/ emergency

Question 25

How are the igniter leads cooled?

Answer 25

Fan air

Question 26

What are the two igniter types?

Answer 26

• Capacitance
• Electronic

Question 27

What are the 3 electrical systems that power ignitors?

Answer 27

• 115 vac
• Aircraft battery
• Permanent magnet generator

Question 28

What does a typical ignition system consist of?

Answer 28

• Two exciter units
• Two transformers
• Two intermediate ignition leads
• Two high tension leads

Question 29

What is eliminated by hermetically sealing the igniter box?

Answer 29

Eliminate flashover possibility

Question 30

How many capacitors are in a capacitor discharge unit?

Answer 30

2

Question 31

What is the discharge of the second capacitor?

Answer 31

Low voltage, high energy

Question 32

What can the high energy of the spark plug cause?

Answer 32

Electrode erosion

Question 33

What igniter plugs protrude into the chamber liners?

Answer 33

Annular gap

Question 34

What igniter plug operates at a much cooler temperature?

Answer 34

Constrained gap plug

Question 35

Does a constrained gap plug protrude into the chamber?

Answer 35

No, hence the cooler operating temperature

Question 36

What drops the resistance in the Capacitor discharge exciter unit, to allow for the high energy low voltage spark?

Answer 36

The first capacitor sparking