15.1 Fundamentals Flashcards

1
Q

Newton’s first law denotes what?

A

A body at rest will remain at rest and a body at motion continues to move at motion until acted upon by an external force

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2
Q

Equation for Newton’s second law?

A

Force=Mass x Acceleration

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3
Q

4 stages of an engine?

A
  1. Intake (Suck)
  2. Air compression (squeeze)
  3. Combustion (Bang)
  4. Expansion/Exhaust (Blow)
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4
Q

Newton’s third law denotes what?

A

Every action has a equal and opposite reaction

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5
Q

Within the compressor does the static pressure?
A- Increase
B- Decrease
C- Stay the same

A

A- Increase

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6
Q

The process of adding heat into the compressor at a constant pressure is known as what?

A

Isobaric Heating

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7
Q

What is the main function of an engine?

A

Provide thrust

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8
Q

Apart from thrust, what are three other functions of aircraft engines?

A

Supply hydraulic power
Supply electrical power
Supply bleed air for pneumatic systems

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9
Q

An engine which uses jet propulsion can also be known as what?

A

A reaction engine

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10
Q

Performance of piston engines decrease when and why?

A

Decrease at high altitude due to there being less airflow/dynamic pressure

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11
Q

To accelerate air, air pressure must what?

A

Increase

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12
Q

All gas not used to drive compressor, does what?

A

Used as thrust

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13
Q

Turboprop engines produce the majority of their thrust how?

A

Small acceleration of a large quantity of air with a propeller

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14
Q

Turboprop engines convert all gas energy to what?

A

Torque

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15
Q

Compressors are made up of what?

A

Rotors and stators

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16
Q

What is the bypass ratio?

A

Ratio of air that passes through the fan duct compared with what passes through the core engine

17
Q

The fan produces what percent of thrust

A

80%

18
Q

On modern aircraft the bypass ratio is what?

A

Between 4:1 and 9:1

19
Q

Advantage of prop fan over turbo fan?

A

Up to 20% less fuel as they have bypass ratio of 90:1

20
Q

Characteristics of non modular construction?

A

Saved weight
Design is complicated and hard to get to
Engine has to be removed for access
Found on old a/c

21
Q

Characteristics of modular construction?

A

Whole engine is split into a set of separate major modules
Engine modules pre assembled and balanced
Further divided into sub modules

22
Q

Advantages of modular construction for manufacturer

A

Rotating module parts can be pre balanced
Less spare engines are needed in stock
More flexibility when changes are made to individual parts
Main engine modules can be easily stored and transported

23
Q

Advantages of modular construction for operator?

A

No rebalancing required
Most modules can be replaced while the engine remains of the aircraft
Less spare parts while engine is on AC

Replacements of modules are considered minor so can be done by a maintenance organisation

24
Q

Characteristics of engine materials

A

Must be strong for individual tasks
Light and cheap

25
Q

Aluminium alloy is mainly used for what?

A

Gearbox housing
Fan stator casings

26
Q

Where are ceramic coatings used and why?

A

In the combust or and pressure turbine
Serve as heat and corrosion protection

27
Q

Where are steel alloys used?

A

Used in shaft, engine bearings and main structural frames

28
Q

Cobalt base alloys are highly heat resistant, where would they be found?

A

Found in stators and first stage of HP turbine

29
Q

Characteristics of titanium?

A

As strong as steel but half the weight
Withstand high centrifugal loads
Expensive

30
Q

Where is titanium used?

A

Mainly used in fan
Low pressure compressor
And front stages of high compressor

31
Q

Characteristics of nickel base alloys?

A

Withstand high centrifugal loads at high temperatures

32
Q

Where are nickel based alloys used?

A

Used in High pressure compressor
Combustion section and high and low pressure turbines

33
Q

What are two forms of mechanical energy?

A

Potential energy
Kinetic energy

34
Q

What is the brayton cycle

A

The working cycle of a gas turbine engine

35
Q

How is power defined?

A

Work done/ time