M15.3

Question 1

What is total head pressure?

Answer 1

Pressure of the air when brought to rest in front of the wing and intakes

Question 2

Where does air enter from?

Answer 2

The engine air intake

Question 3

What is it called when an inlet duct gets wider?

Answer 3

A divergent duct

Question 4

What does having a divergent duct do to the airflow?

Answer 4

The static pressure increases (Bernoulli’s principle)

Question 5

Why does air need to be smooth when entering the engine?

Answer 5

To be as efficient as it can

Question 6

What can cause air disturbance?

Answer 6

Damage inlet, damaged nose, ice build up, crosswinds at low speeds

Question 7

What is the first component of the gas turbine to contribute to generation of thrust?

Answer 7

The air inlet duct

Question 8

What should the air velocity be at the compressor inlet?

Answer 8

Mach 0.4-0.7

Question 9

What are air inlets designed to do?

Answer 9

Decelerate the airflow by converting kinetic energy to pressure energy

Question 10

What would poor air pressure and velocity distribution result in?

Answer 10

A compressor stall

Question 11

What may air from behind the intake lip suffer from?

Answer 11

Flow separation due to extreme local acceleration

Question 12

How would you reduce the risk of flow separation at the intake lip?

Answer 12

Have well rounded intake lips

Question 13

What are blow-away jets used for?

Answer 13

To blow away vortexes in front of the engine

Question 14

How would you overcome crosswind?

Answer 14

You would restrict from applying full power until a specific speed is reached

Question 15

What speed range is pitot type intake used for?

Answer 15

Low supersonic 1.5 Mach

Question 16

What is critical condition?

Answer 16

When the intake cross section must be efficient for maximum airflow

Question 17

What are the three types of shock waves at supersonic inlet ducts?

Answer 17

• normal or perpendicular
• oblique
• bow wave

Question 18

What does most of the energy turn into on a normal shockwave?

Answer 18

Unusable heat

Question 19

What speed range does a normal shockwave happen?

Answer 19

Low supersonic

Question 20

When would a oblique shockwave happen?

Answer 20

When the airflow is forced to change direction

Question 21

When a oblique shockwave happens how fast is the air going after the wave?

Answer 21

Supersonic

Question 22

When would a bow shockwave occur?

Answer 22

If the speed drops or flow deviation exceeds a maximum angle

Question 23

When would a normal shock diffuser inlet be used?

Answer 23

At low supersonic speeds where the normal sock wave isn’t too strong

Question 24

How does a oblique shock inlet work?

Answer 24

It uses oblique shockwaves before using a normal shockwave

Question 25

How does a multiple oblique shock inlet work?

Answer 25

It uses multiple oblique shock waves

Question 26

Why are small shockwaves used in front of large ones?

Answer 26

To waste less energy and have a high pressure recovery

Question 27

How does a variable supersonic inlet work?

Answer 27

It’s a equipped with an actuator operated panel to change the number of shock waves

Question 28

What happens when a variable supersonic inlet is at a flight speed below Mach 1?

Answer 28

It will be fully open with a high angle of attack

Question 29

What happens when a variable supersonic inlet is at a flight speed above Mach 1?

Answer 29

It will operate the panel actuated to adjust angles to get multiple shock waves

Question 30

What happens when a variable supersonic inlet is at a flight speed of Mach 1?

Answer 30

It only produces a single normal shockwave

Question 31

What two problems does ice cause on the inlet?

Answer 31

Flow distribution and pieces of ice going in the engine

Question 32

What would tell you the operating conditions in cold icy weather?

Answer 32

The maintenance manual

Question 33

What is the most common type of ice protection?

Answer 33

Thermal systems

Question 34

What is the thermal system for ice protection split into?

Answer 34

Bleed air and electrical heating

Question 35

Which heating sub-system can do the nose spinner?

Answer 35

Bleed air

Question 36

What can be used to protect the nose spinner from ice build up?

Answer 36

- bleed air - hot oil - rubber spike

Question 37

When would bleed air be used for ice protection?

Answer 37

It’s used on engines with high mass airflow

Question 38

Where does the bleed air for ice protection come from?

Answer 38

The high pressure compressor which gets passed through the pressure regulations bleed valves

Question 39

If bleed air is used in the nose cone where does the air go afterwards?

Answer 39

Either overboard or into the low pressure compressor

Question 40

What does pressing the engine anti-icing switch energies?

Answer 40

The thermal anti-icing valve

Question 41

What does the engine anti-ice system use?

Answer 41

Pneumatic air or bleed air

Question 42

What part of the structure does the anti-ice system protect?

Answer 42

The leading edge of the wing

Question 43

Where is electrical ice protection normally used?

Answer 43

On turbo-prop engines

Question 44

What type of flow would the electrical ice protection come in?

Answer 44

AC and DC

Question 45

How many amps is used in the continuous electrical ice protection?

Answer 45

18 amps

Question 46

How many amps is used for the cycling electrical ice protection?

Answer 46

29 amps

Question 47

What determines fast or slow on the electrical ice protection system?

Answer 47

The outside air temperature

Question 48

At what temperatures would you select fast cycle on the electrical ice protection system?

Answer 48

Between -6C and +10C

Question 49

At what temperatures would you select slow cycle on the electrical ice protection system?

Answer 49

Below -6C

Question 50

How is cycling from the electrical ice protection system indicated?

Answer 50

A light will be glowing bright then dim

Question 51

How would over heating be indicated on a heater mat?

Answer 51

Splits, wrinkling, tears, and discolouration