15.12, 15.13, 15.16,

Question 1

Define internal air system

Answer 1

No effect on thrust

Question 2

4 functions of internal air system

Answer 2

Internal cooling , nacelle cooling, engine anti ice , customer air supply

Question 3

Air used to cool nozzle guide vanes

Answer 3

Compressor air

Question 4

Where is film cooling used

Answer 4

Turbine blades

Question 5

Method to cool engine accessories

Answer 5

Fan air

Question 6

Air used to cool turbine discs

Answer 6

Compressor air

Question 7

Where’s bleed air tapped from

Answer 7

Compressor

Question 8

How is tip clearance control maintained

Answer 8

ACC ( active clearance control )

Question 9

Starter for turbo prop

Answer 9

Electric

Question 10

Benefits of combined starter generator

Answer 10

Light weight

Used on corporate jets and some APUs

Question 11

First step when starting APU

Answer 11

Turn battery switch on

Question 12

What voltage is used in a high tension ignition plug to create ionisation of the air gap

Answer 12

20,000 volts

Question 13

Where are DC starter motors used on large aircraft

Answer 13

“ heavy duty aircraft “ older turbo props

Question 14

Where are starter generators usually used

Answer 14

Light business jets

Question 15

Pressures or air starter

Answer 15

30 to 45 psi

Question 16

Rotational speed of a starter

Answer 16

60 to 80,000RPM

Question 17

How is a manual start achieved

Answer 17

Open butterfly valve with Allen key or spanner

Question 18

3 purposes of ignition system

Answer 18

Ground start up , in flight start up ,

Question 19

What part of ignition system is usually cooled

Answer 19

Igniter sleeve

Question 20

2 forms of turbo prop engines

Answer 20

Free turbine

Single shaft

Question 21

How are turbo props coupled with engine

Answer 21

• Free turbine : shaft is independent to that used to drive compressor
• single shaft : coupled to reduction gears from same shaft as compressor and turbine

Question 22

Benefits of free turbine

Answer 22

Can go in feathered position on engine shut down

Prop and turbine can run at same speed

Question 23

Where are spider and planet gears used

Answer 23

Reduction gear system

Question 24

What prevents turbo prop over speed

Answer 24

Over speed governor

Question 25

Combustion chamber on turbo props

Answer 25

Annular reverse flow

Question 26

Type of reduction gears for turbo props

Answer 26

Parallel spur gear type

Epicylical type ( planetary gear)

Question 27

Alpha mode

Answer 27

In flight