15.04

Question 1

What material is the fan rotor disc made from

Answer 1

Titanium alloy

Question 2

Which type of compressor axial or centrifugal is more efficient

Answer 2

Axial

Question 3

Where would you most likely find a centrifugal flow compressor

Answer 3

Small gas turbine engine e.g APU

Question 4

Why does a cone have a spiral or white markings

Answer 4

To scare birds away

Question 5

Which type of compressor axial or centrifugal has a good efficiency over a wide speed range

Answer 5

Centrifugal

Question 6

What is the first part of a compressor stage

Answer 6

The rotor

Question 7

What unit can the moment weigh of a blade be given in

Answer 7

Gram/inches
cmg
Oz inches

Question 8

What type of fan blade attachment is used on most engines

Answer 8

Dovetail fitting

Question 9

What makes up the compressor stage

Answer 9

Rotor & stator

Question 10

What two ways can you compress air in engines

Answer 10

Decrease the volume by a piston

Make use of Bernoulli Principal

Question 11

What happens when the impeller rotates

Answer 11

Air is sucked horizontally near the centre of the impeller

Question 12

What is the spinner cone also known as

Answer 12

Compressor inlet cone or nose cone

Question 13

What is the forward part and aft part of a dual spool engine called

Answer 13

LP compressor N1 and HP compressor N2

Question 14

When can a compressor stall

Answer 14

Speed of engine is too far BELOW the design speed

Question 15

What pressure ratio can the centrifugal flow compressor give

Answer 15

About 5:1

Question 16

What is the rear drum of a rotor assembly bolted to

Answer 16

Rear hub

Question 17

What is the advantage of wide chord fan blade than to conventional blades

Answer 17

More efficient

Question 18

How are the stator vanes installed on a split stator case

Answer 18

Two stator halves bolted together afterward

Question 19

What axis does airflow in an axial flow compressor flow along

Answer 19

Horizontal axis

Question 20

Can fan blades be manufactured to have the same moment weights

Answer 20

NO!!

Question 21

What would you do if one blade is damage

Answer 21

Change the pair instead of one blade

Question 22

What is the fan blade containment made of

Answer 22

Honeycomb construction covered by Kevlar

Question 23

How are the stator vanes fitted on a closed stator case

Answer 23

Fitted to the shrouds between the rotor stages

Question 24

Which compressor axial or centrifugal has a very high pressure rise per stage

Answer 24

Centrifugal

Question 25

Which compressor axial or centrifugal is cheaper to manufacture

Answer 25

Centrifugal

Question 26

Which compressor axial or centrifugal needs less power for engine start and weight less

Answer 26

Centrifugal

Question 27

How many compressor stages does a modern engine have

Answer 27

9 up to 14

Question 28

What is the best method to change the engine fan blade

Answer 28

Replace the fan blade with a new blade with the moment weight as close to the old blade

Question 29

What are the main components of a centrifugal flame w compressor

Answer 29

Diffuser Impeller Compressor manifold

Question 30

What is another name for a low pressure compressor rotor

Answer 30

Booster rotor

Question 31

What is the pressure ratio of each stage of an axial flow compressor

Answer 31

1:3:1

Question 32

How many stages of pressure increase can you have in a centrifugal flow compressor

Answer 32

2 As pressure decrease when airflow goes from first stage to second stage

Question 33

What two main components does a compressor have

Answer 33

Compressor rotor | Compressor stator

Question 34

What is a double faced compressor

Answer 34

Two impeller mounted face to face

Question 35

If the moment is larger than specific by manufacturer what can be used

Answer 35

Balance weights

Question 36

How can you identify fan blade one

Answer 36

Index mark or offset hole

Question 37

How is the labyrinth seal made

Answer 37

By knife edges on the rotor drum and the opposing shrouds of the stator assembly

Question 38

How can you get a smooth airflow on an axial compressor

Answer 38

Make sure angle of attack on rotor blade is small

Question 39

What do the compressor inlet/outlet cases support

Answer 39

Give support for the compressor rotor bearings

Question 40

Which compressor axial or centrifugal causes less drag on engines

Answer 40

Axial as it has a smaller frontal area

Question 41

What do the OGV improve

Answer 41

The airflow into the fan nozzle

Question 42

What are the three methods used to prevent compressor stall and surge

Answer 42

1. Use compressor bleed valve 2. Use dual or triple spool rotors instead of single 3. Use variable compressor stator vanes (most modern)

Question 43

What are the two types of compressor

Answer 43

The axial flow compressor | The centrifugal flow compressor

Question 44

Compressor with high compression ratios will have what

Answer 44

VSV In the first stages

Question 45

What are the bells held in place by

Answer 45

Blade retainers

Question 46

What do IGV improve

Answer 46

The airflow into the first compressor stage

Question 47

Where is bleed air supplied through in a compressor

Answer 47

Supplied through hollow stator vanes or through holes in the outer platform of the stator vane

Question 48

What does a labyrinth seal do

Answer 48

Prevents reverse air flow

Question 49

What is a severe form of compressor stall

Answer 49

Compressor surge

Question 50

What happens when the air passes through the diffuser

Answer 50

Velocity decreases and pressure increases

Question 51

What three ways can you fit blades onto a HP compressor

Answer 51

Blade retainers Locking lug Bolts