Inlet

Question 1

How does air enter engine

Answer 1

Via intake

Question 2

2 parts of an intake

Answer 2

Intake nose & inlet duct

Question 3

What is a divergent

Answer 3

Shape when inlet duct gets wider

Question 4

What does a divergent do

Answer 4

Increase static pressure of air moving through the duct

Question 5

What does intake nose do

Answer 5

Smoothens airflow

Question 6

Why does all air enter the inlet from the front

Answer 6

Ram air effect at high speeds

Question 7

What velocity to the ensure flow through compressor is smooth

Answer 7

0.4-0.7 Mach

Question 8

What is a intake designed to do and how

Answer 8

Decelerate flow & convert kinetic energy into pressure energy

Question 9

How is a subsonic air inlet shaped

Answer 9

To deliver air to front of compressor which gives even pressure distribution

Question 10

What’s the consequences of poor air pressure and velocity

Answer 10

Compressor stall

Question 11

What happens to ram pressure as ram velocity increases

Answer 11

Decreases

Question 12

What happens to air while the aircraft is stationary

Answer 12

Air in duct is accelerated to velocity required by compressor

Question 13

What does a rounded inlet lip do

Answer 13

Gives it a thicker radius which reduces risk of separation

Question 14

At high speed what shape inlet lip do we want

Answer 14

Thin

Question 15

What is a transonic duct practical speed

Answer 15

Up to Mach 1.5

Question 16

What does a transonic duct use to decelerate supersonic airflow

Answer 16

Shock diffuser

Question 17

What happens in a normal shockwave

Answer 17

Pressure and temperature increases while velocity decreases to subsonic

Question 18

What is critical condition

Answer 18

Cross section of the inlet is sufficient to allow max airflow requirements of the engine

Question 19

What is sub critical

Answer 19

The shockwave is detached from the lip and moves upstream which reduces Mach number

Question 20

What is super critical

Answer 20

The shockwave is swallowed which makes the airflow in the inlet become supersonic which is unacceptable flow into the compressor

Question 21

What is diffuser buzz or intake buzz

Answer 21

When extreme pressure fluctuations can severely damage the engine

Question 22

What happens to kinetic energy in a supersonic inlet duct

Answer 22

Large amount of it turns into unusable heat

Question 23

What happens in a oblique shockwave

Answer 23

Forced to change direction , the shockwave is inclined at oblique angle which is determined by upstream velocity

Question 24

Disadvantage of shock diffuser in supersonic duct

Answer 24

Abrupt loss of efficient as Mach number increases such as 30% at Mach 2

Question 25

What does a oblique shock diffuser do

Answer 25

Reduces supersonic flow progressively by wing , in a series of oblique shock waves

Question 26

In a normal duct what will an inefficiency of 1% do

Answer 26

Thrust loss between 1% and 4%

Question 27

Efficiency of pilot design

Answer 27

96-99% efficient

Question 28

Efficiency of wing root design

Answer 28

87-95% efficient

Question 29

Efficiency of side design

Answer 29

80-89% efficient

Question 30

Efficiency of turbo prop annular (Dart)

Answer 30

74-82% efficient

Question 31

In a transonic duct what lip shape do you want

Answer 31

As thin as possible

Question 32

In a variable intake what’s the maximum amount of shockwaves

Answer 32

4 , 3 oblique 1 normal

Question 33

How can we prevent intake buzz

Answer 33

Bleed door

Question 34

How do we cool the engine bay

Answer 34

With Air bled from ramps used for engine bay cooling

Question 35

Problems with snow and ice

Answer 35

Cause turbulent flow which can stall

Question 36

What anti ice system is used

Answer 36

Jet engines have thermal anti - ice systems

Question 37

What are antennas heated with

Answer 37

Warm air

Question 38

What’s the purpose of anti ice valves

Answer 38

Protect against over pressurisation

Question 39

How are anti ice valves operated

Answer 39

Automatically via ice detection system or manually in flight deck

Question 40

What happens to the air used for anti-icing

Answer 40

Ejected over board via small grills

Question 41

What are the 2 methods of ice protection

Answer 41

Bleed air & electrical heating

Question 42

How is the thermal anti ice valve energised

Answer 42

Engine anti-ice switch/ light

Question 43

When does the amber light turn off

Answer 43

When LP sensor duct pressure is more then 5psi

Question 44

Where is duct over pressure signalled to

Answer 44

EICAS/ECAM

Question 45

Why is caution necessary when testing thermal anti Ice system on ground

Answer 45

Air is still hot no personnel should be in the area

Question 46

Where is electrical ice protection employed

Answer 46

Turbo prop engined aircraft

Question 47

Are mats supplied with AC or DC

Answer 47

Both

Question 48

What’s the purpose of the continuously heated element

Answer 48

Prevent formation of ice on leading edge or aircraft engine air intake lip and propeller spinners

Question 49

Where is a intermittently de-icing element located

Answer 49

Behind continuous heated element

Question 50

What type of system is a continuous heated element

Answer 50

Anti - icing

Question 51

What type of system is a intermittent heated element

Answer 51

De -icing

Question 52

In an intermittently heated element why are they divided into separate segments

Answer 52

To ensure ice breaks away easily

Question 53

What happens on the FAST cycle

Answer 53

ON/OFF for 2 minutes OAT between -6 & 10 degrees

Question 54

What is the SLOW cycle

Answer 54

ON/OFF for 6 minutes OAT below -6 degrees

Question 55

Why does the cycling light glow dim and bright

Answer 55

Indicate timer is rotating

Question 56

What is a heated mat examined for

Answer 56

Splits , tears , wrinkling and discolouration which happens due to overheating security of the attachment or general condition

Question 57

Where are anti-corrosion strips placed

Answer 57

Any sign of splitting or corrosion

Question 58

When should you replace a heated mat

Answer 58

any damage which exposes the heated element

Question 59

When does a continuity and resistance check need to be completed

Answer 59

Following any repair to heated mats , resistnace valves must be within limits

Question 60

Why do we need to do insulation resistance checks

Answer 60

To determine any breakdown of insulation between heater mats Insulation resistance to earth must be checked

Question 61

What should