Theory 🥱

Question 1

Newton’s third law

Answer 1

For every action there is an equal and opposite reaction

Question 2

Newton’s second law

Answer 2

Force = mass x acceleration
F = ma

Question 3

Boyle law

Answer 3

For a fixed amount of an ideal gas kept at a fixed temperature, Pressure (P) and volume (V) are inversely proportional

PV = k where k is a constant
This means that as pressure increases, temperature decreases and vice versa

Question 4

Charles law

Answer 4

When the pressure on a sample of a dry gas is held constant, the kelvin temperature and volume will be in direct proportion

V/T = K

Question 5

Parts of engine core

Answer 5

Compressor
Combustion chamber/burner
Turbine

Question 6

Bernoulli theorem

Answer 6

In the streamline flow of an ideal fluid, the sum of the variables is a constant

Question 7

Meaning of ideal fluid

Answer 7

Not viscous nor compressible
Air below 10,000ft and 250kts is an ideal fluid

Question 8

What happens to converging subsonic air

Answer 8

Velocity increases
Static pressure, temperature and density decreases

Question 9

What happens to divergent subsonic air

Answer 9

Velocity decreases
Static pressure, temperature and density increases

Question 10

What happens to convergent air at supersonic speeds

Answer 10

Velocity decreases
Static pressure, temperature and density all increase

Question 11

What happens to divergent air at supersonic speeds

Answer 11

Velocity increases
Static pressure, temperature and density all decrease

Question 12

What is the octane number of AVTUR

Answer 12

15

Question 13

Two types of fixed turbine turboprop

Answer 13

Direct drive
Compound compressor

Question 14

How much of the total thrust does a propeller provide

Answer 14

90%

Question 15

What did George Bayton develop

Answer 15

The constant pressure cycle

Question 16

Characteristics of a fixed direct drive turbine

Answer 16

Prop connected via reduction gear box to turbines and the shaft connected to the compressor
Prop driven directly from the spool
Fine pitch setting required on the ground

Question 17

Fixed turbine compound compressor characteristics

Answer 17

Two spools
Low pressure spool turns prop gearbox

Question 18

Free turbine characteristics

Answer 18

Prop driven by the turbine and independent from the engine meaning engine can be running with prop stationary

Question 19

Types of turbofan engines

Answer 19

Conventional and geared

Question 20

Core of turbofans

Answer 20

Compressor
Combustion chamber
Turbine

Question 21

How does air pass through a Turbo fan

Answer 21

All air enters passed the fan with 90% of this bypassing the core

Question 22

What is a spool

Answer 22

Compressor -shaft-turbine combination

Question 23

In turbofans which spool is connected to the fan

Answer 23

Low pressure spool (N1)

Question 24

What happens to air velocity in each section of the engine

Answer 24

Compressor- stable
Combustion chamber - stable
Turbine-fluctuates
Exhaust -increases

Question 25

What happens to air pressure in each stage of the engine

Answer 25

Compressor -rises Combustion chamber - falls slightly Turbine- falls Exhaust - falls slightly

Question 26

What happens to the temperature of air in each stage of the engine

Answer 26

Compressor - rises Combustion chamber - rises Turbine -falls Exhaust -falls