M15.1 Fundamentals

Question 1

What is energy typically defined as?

Answer 1

Something that gives us the capacity to perform work.

Question 2

How are work and energy measured?

Answer 2

In joules.

Question 3

What are the two types of energy?

Answer 3

• Potential
• Kinetic

Question 4

Define potential energy.

Answer 4

Energy at rest or energy that is stored.

Question 5

Define kinetic energy.

Answer 5

Energy in motion.

Question 6

What is Newton’s First Law of Motion also known as?

Answer 6

The law of inertia.

Question 7

What does Newton’s Second Law of Motion express?

Answer 7

The interplay between force and motion.

Question 8

What is the formula for Newton’s Second Law?

Answer 8

Force = Mass x Acceleration.

Question 9

What is Newton’s Third Law of Motion also referred to as?

Answer 9

The law of action and reaction.

Question 10

What does the Brayton cycle describe?

Answer 10

The thermodynamic cycle of a gas turbine engine that produces thrust.

Question 11

What are the four stages of the Brayton cycle?

Answer 11

• Intake (suck)
• Compression (squeeze)
• Expansion (bang)
• Exhaust (blow)

Question 12

What happens during the intake stage of the Brayton cycle?

Answer 12

Air enters at ambient pressure and at a constant volume.

Question 13

What is isobaric heating in the Brayton cycle?

Answer 13

Heat is added to the air in the combustion chamber at constant pressure.

Question 14

What are the four ideal changes of state?

Answer 14

• Isobaric
• Isochoric
• Isothermal
• Isentropic

Question 15

Which changes of state are important for aircraft gas turbine engines?

Answer 15

• Isobaric
• Isentropic

Question 16

What does force represent?

Answer 16

The intensity of a thrust or input.

Question 17

What is the unit for force in the metric system?

Answer 17

Newtons (N).

Question 18

What is work defined as?

Answer 18

When a force is moved through a distance, in the direction of the force.

Question 19

What are the two factors involved in calculating work?

Answer 19

• Force
• Movement through a distance

Question 20

What is the SI unit of work?

Answer 20

Joule (J).

Question 21

What does power involve in relation to work?

Answer 21

The rate of doing work over time.

Question 22

What is the SI unit of power?

Answer 22

Watt (W).

Question 23

Define motion.

Answer 23

A continuing change of position or place.

Question 24

What is the difference between speed and velocity?

Answer 24

Speed does not include direction; velocity includes both speed and direction.

Question 25

What is acceleration defined as?

Answer 25

The rate of change of velocity.

Question 26

What are the two main types of aircraft engines?

Answer 26

* Piston type engines * Gas turbine engines

Question 27

What is a key advantage of gas turbine engines over piston engines?

Answer 27

Can operate at very high altitudes.

Question 28

What type of engine produces thrust in aircraft?

Answer 28

Gas turbine engines.

Question 29

What are the types of gas turbine engines used on aircraft?

Answer 29

* Turbojet engines * Turbofan engines * Turboprop engines * Turboshaft engines

Question 30

What is a significant disadvantage of turbojet engines?

Answer 30

High fuel consumption.

Question 31

What is the primary function of turbofan engines?

Answer 31

Produce thrust with better efficiency than turbojets.

Question 32

What is the advantage of turboprop engines?

Answer 32

Very fuel efficient at mid-range speeds.

Question 33

What is a turboshaft engine primarily used for?

Answer 33

To drive machinery instead of producing thrust.

Question 34

What are the main sections of a gas turbine engine?

Answer 34

* Air inlet * Compressor section * Combustion section * Turbine section * Exhaust section * Accessory section

Question 35

What does the 'cold section' of a gas turbine engine refer to?

Answer 35

Parts from the inlets up through the compressors.

Question 36

What does the 'hot section' of a gas turbine engine refer to?

Answer 36

Areas past the compressors from the combustion chambers through the exhaust.

Question 37

What are the main sections of a turbine engine?

Answer 37

Combustion section, Turbine section, Exhaust section, Accessory section ## Footnote The sections include the diffuser, combustor, Low-pressure Turbine (LPT), High-pressure Turbine (HPT), Turbine Exhaust Case (TEC), and main gearbox.

Question 38

What does the 'cold section' of a turbine engine refer to?

Answer 38

Parts of the engine from the inlets up through the compressors and/or diffusers ## Footnote This section includes components that operate at lower temperatures compared to the hot section.

Question 39

What does the 'hot section' of a turbine engine refer to?

Answer 39

Areas past the compressors from the combustion chambers through the exhaust ## Footnote This section involves components that operate at high temperatures.

Question 40

List the advantages of modular engine construction for the engine manufacturer.

Answer 40

* The rotating module parts can be pre-balanced * Fewer spare engines are needed in stock * More flexibility when changes are made to individual engine parts * Main engine modules can be easily stored and transported ## Footnote These advantages contribute to efficiency in manufacturing and inventory management.

Question 41

List the advantages of modular engine construction for the engine operator.

Answer 41

* Modules can be removed and replaced with minimum disturbance to other nearby engine parts * No re-balancing is required after a module change * Most modules can be replaced while the engine remains on the aircraft * Less need for spare parts and modules can be easily transported ## Footnote These benefits enhance maintenance efficiency and reduce downtime.

Question 42

What is a further advantage of the modular design in terms of repairs?

Answer 42

Replacement of a module is often considered a minor repair and not a shop repair ## Footnote This allows maintenance to be performed by a maintenance organization rather than requiring an engine overhaul organization.

Question 43

What is the main design aim for engine materials?

Answer 43

Materials must be strong enough for their tasks, as light and cheap as possible ## Footnote This balance is crucial for performance and cost-effectiveness in engine design.

Question 44

What are typical materials used in modern jet engines?

Answer 44

* Aluminium alloy * Ceramic material * Composite material * Cobalt base alloy * Nickel base alloy * Corrosion resistant steel alloy * Titanium base alloy ## Footnote These materials are selected for their specific properties suitable for high-performance engine components.