Engines Flashcards

1
Q

What is the main function of an aircraft engine?

A

To create the necessary movement for an aircraft and to provide hydraulic and electric power plus bleed air for the pneumatic system

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2
Q

What are the two types of engine?

A

-piston type
-gas turbine

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3
Q

What are the 4 types of gas turbine engines?

A

-turbojet
-turboprop
-turbofan
-turbo shaft

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4
Q

What wash the first type of engine ever used?

A

Turbojet

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5
Q

When does a turbojet engine experience issues and with what?

A

Issues with noise and fuel consumption at 0.8 mach

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6
Q

what are some advantages of a turbojet engine?

A

-relatively simple design
-capable of very high speeds
-takes up little space

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7
Q

What are some disadvantages of a turbojet engine?

A

-high fuel consumption
-loud
-poor performance @ slow speeds
-limited in range & performance

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8
Q

What was the turbofan engine developed from?

A

The turbojet engine

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9
Q

Why is the turbofan arrangement better?

A

Because of high aircraft speeds with food fuel efficiency

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10
Q

What are the two turbofan arrangements?

A

-twin spool
-triple spool

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11
Q

Define a spool?

A

A turbine driving a compressor through a shaft

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12
Q

Describe a twin spool?

A

High pressure turbine driving a high pressure compressor and a low pressure turbine driving a low pressure compressor

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13
Q

What does a triple spool add?

A

An intermediate turbine with and intermediate compressor

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14
Q

What are the advantages of a turbofan?

A

-fuel efficient
-quieter than turbojets
-streamline appearance

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15
Q

What are the disadvantages of a turbofan?

A

-heavier than turbojets
-larger frontal area than turbojets
-inefficient at very high altitudes

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16
Q

What are turboprop engines designed to do?

A

Produce shaft horsepower only to drive a propeller

17
Q

What are the principles of a turboprop engine similar to and what is the difference?

A

Turbojet principles only difference is additional turbines,a power shaft and reduction gearbox are added

18
Q

What are the advantages of turboprop engines?

A

-very fuel efficient
-most efficient at 250-400 knots
-most efficient at 18k-30k ft

19
Q

When is a turboprop most efficient? (Mid,low,high range)

A

Mid range

20
Q

What are the disadvantages of a turboprop engine?

A

-limited forward airspeed
-gearing systems are heavy & can break down

21
Q

What does a turboshaft engine prioritise?

A

Shaft power to drive machinery rather than thrust

22
Q

Describe a turboshaft engine briefly?

A

Small but powerful lightweight engine

23
Q

What is a turboshaft engine usually called?

A

An APU

24
Q

What does a turboshaft engine do for the aircraft?

A

Supplies electric & pneumatic power when engines not available

25
Q

Where is a turboshaft engine used outside of planes?

A

Helicopters

26
Q

What are the advantages of a turboshaft engine?

A

-much higher power to weight ratio than piston engines
-typically smaller than piston engines

27
Q

What are the disadvantages of a turboshaft engine?

A

-loud
-gear systems connected to the shaft can be complex and break down

28
Q

Where does intake,compression,combustion and exhaust occur on a reciprocating engine?

A

In the same combustion chamber

29
Q

Name some things a typical gas turbine engine consists of?

A

-an air inlet (fan blades)
-compressor section (low pressure compressor LPC and high pressure compressor HPC)
-combustion section (diffuser & combustor)
-turbine section (low pressure turbine LPT and high pressure turbine HPT)
-exhaust section (turbine exhaust case TEC)
-accessory section (main gearbox)

30
Q

What are the two section types in a gas turbine engine and what are they?

A

-hot (compressor to combustion chambers & exhaust)
-cold (inlets to compressors/diffusers)

31
Q

What are some advantages to the engine manufacturer for modular design?

A

-rotating module parts can be pre-balanced
-fewer spare engines are needed in stock
-more flexibility for changes to be made to a part
-main engine modules can be easily stored and transported

32
Q

What are the advantages of modular design for the engine operator?

A

-modules can be removed and replaced without disturbing the rest of the system too much
-no re-balancing it required after a module change
-most modules can be replaced whilst the engine remains in the aircraft
-less need for spare parts and the modules can be easily transported

33
Q

What is the main requirements for engine materials?

A

-it’s have strength for required purposes
-must be as light & cheap as possible

34
Q

Name some typical engine materials?

A

-aluminium alloy
-ceramic material
-composite material
-cobalt base alloy
-nickel base alloy
-corrosion resistant steel alloy
-titanium base alloy