Aeronautical Engineering Flashcards

1
Q

First successful flight

A

1903 by the Wright brothers, made from wood and muslin, aluminum engine case
- lightweight, yet not able to withstand much flight

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2
Q

Ways to increase carbon efficiency in airplanes

A

Efficient jet fuel, additive manufacturing (e.g. 3D printing), more lightweight (fuel efficiency)
- have more passengers per flight (less individual flights)
- sustainable alternatives to fuels (biofuels, battery powered, hydrogen)

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3
Q

Henry Farman

A

added ailerons to control the ROLL

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4
Q

Developments during WW1

A

Material developments: first metal frame with canvas material on wings (red barons)

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5
Q

Between WW1 developments

A

Southern Cross: uses a plywood covering the skin on the wings (first aircraft to cross the Pacific)

Dornier Do X: highly inefficient and low range.

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6
Q

The Hindenburg distastor

A

Hydrogen-filled blimp, attempted to land, caught alight and exploded.

  • exploration into different modes of transport
  • used durallium: hard, lightweight (alloys begging to be used)
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7
Q

When were alloys beginning to be added

A

Around the 1930s

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8
Q

Range and endurance of aircrafts

A

How long it can travel, how long it can spend in the air

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9
Q

WW2 Plane developments and two planes (Mosquito, Spitfire)

A

Aircraft being designed for HIGH performance, combat: high altitudes and higher speeds

De Havilland’s Mosquito: bomber, the last wooden plane remaining

Supermarine’s Spitfire: Battle of Britain,
- wing designed with two ellipses joined together
- carburetor issues: when flipped upside down, fuel could not reach the engine. Solved by adding a ring.

Vampire: back stabiliser

(Boeing B-29) Superfortress:
- Heavy bomber, used in WW2 and the Korean war
- high altitudes, drops atomic bomb

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10
Q

End of WW2 developments:

A

Switch from carburetor engines to jet engines

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11
Q

Korean War Developments

A

North American F86 Sabre
- shape of wings: swept back wings (good maneuverability)

MIG-15:
- outmaneuvered Sabre (better pilot training and expereince)
- still used in North Korea

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12
Q

De Havilland Comet

A

1950s, commercial airline, issues with pressurisation in the cabin, windown and fuselabe

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13
Q

North American X-15

A

1960s, Supersonic plane

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14
Q

Supersonic issues

A

Noise pollution

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15
Q

Vietnam War Planes

A

General Dynamics F-111 Aardvark
- swept-back wings, wings closer up: generates more lift (can take-off in a shorter runway)
- stronger development in aerodynamics

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16
Q

Stalling in aircraft

A

As the angle of attack approaches over 16 degrees, this may not allow airflow to continue over the wing and flip it over

  • not generating enough lift to counteract lift
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17
Q

Boeing 707

A

1960s, most significant commercial aircraft of its time.
- engine placed under wings
- larger take-off weight
- wider fuselag3

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18
Q

Boeing 747 (Jumbo Jet)

A

1960s, intially for military use
- carried 397 passangers (almost double the amount
- more economic

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19
Q

Saab AJ37 Thunderbolt

A

1970s:
- strange dual wing design: has ‘stol’ capabilities
- fast jet (could intercept other aircraft)
- PROBLEMS: did not have retractable wings, so couldn’t afford swept back winds
- increase of speed seen

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20
Q

Harrier Jump Jet

A

1970s, has vertical take-off capabilities (used on carrier ships)
- this can only be done at less then its maximum load weight, so is often used with a short take-off
- this is more used with landing.

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21
Q

Concorde

A

1970s:
- fatal incident, loud: noise pollution
- high attitude (difficulty landing, low visibility when landing)

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22
Q

Boeing 777

A

Modern
- extensive use of composites
Turbo-fan engines
- Twin jet
- wide-bodies
- aluminium and titanium for airframe
-

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23
Q

Advancements of electronics

A

Greater role in control of the airplane
- flight control computers, screens
- uses mechanisms e.g. actuators
- automation of flight

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24
Q

Airbus A380

A

Double Decker
- 61% made of aluminium alloys, 10% composites, etc
- first to use CFRP (carbon fibre reinforced plastics): lightweight (1.5 tonnes vs most aluminum alloys
-525 passengers: increase in passenger numbers

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25
Q

Boeing 787 Dreamliner

A
  • dependent of composite materials
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26
Q

Carbon Fibre Reinforces Polymer (CFRP benefits)

A

lightweight, and so increased fuel efficiency

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27
Q

High Bypass engines

A
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28
Q

Wing shape

A

Reduces drag

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29
Q

Modern developments

A

materials (composite materials e.g. CFRP): reducing weight for fuel efficiency

More aerodynamic design: reduce drag

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30
Q

Modern winglets benefits

A

Reduces wingtip vortices (turbulence), greater fuel efficiency,

RAKED wingtips (give % increase to wing efficiency in Boeing 787)

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31
Q

Developments in wing materials

A

Fabric -Steel - alloys/composite materials

Titanium is used in US military, however is highly expensive

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32
Q

Improving aircraft safety

A

Autopilot: reduces human error, allows holding of altitude, and follows a set navigation plan.

Materials: stronger, lighter, more durable: less risk of failure

More ‘redundancies’/analogue backups: uses difference in pressure to calculate rate of climb, altitude, etc: allows this to be still measured in case of electrical failure
- precedence of backup battery

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33
Q

Glare

A

A combination of laminated Al alloy and glass fibre/expoxy (Airbus A380)

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34
Q

CFRP

A
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35
Q

Larger widows

A
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36
Q

Composite benefits

A

Do not corrode (less maintenance, longer lasting)
Light weight (increases fuel efficiency)

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37
Q

Advanced composite or Ti turbine blades

A

Reduced mass of engine, fuel efficiency, noise pollution

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38
Q

3D printing in airplanes

A

Quicker, less expensive process
- lighter

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39
Q

Chevrons

A

Parts on engines that reduce engine noise

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40
Q

LED impacts in planes

A

Longer lasting and reduces minimal heat: passenger comfort

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41
Q

Window technology advncements

A

Dimmable windows: gel layer that can be darkened by passing through voltage (Dreamliner)

2014: concept for windowless plane (lined with video display panels): reduces weight by reducing reinforcement structures

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42
Q

Electric systems in planes

A

used for brakes, drives for hydraulics (replace air-bleed systems)
- much easier to monitor for health, less maintenance
- reduced fuel rate
- lower life-cycle costs

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43
Q

Work health and Safety

A

Work Health and Safety act (2011): minimum standards
- monitor and improve work health and safety

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44
Q

Safety issues in aviation

A

Chemical hazards
- resins used in composites, paints, etc
Noise
- Jet engine: constant exposure leads to damage
Fibre dust
Fumes entering aircraft cabins
- e.g. carbon monoxide: can be monitored with a carbon patch
- VENTILATION is imporant

45
Q

Societal impacts

A

Less travel time: used to take 6 weeks to sydney and london, now within 24 hours (more accessible, better postal)

  • connect families and culture, tourism good for economy

Regional Australia: Royal Flying doctor service brings medical facilities
- regional areas gain quicker access to emergancy services, communication

Farmers use helicopters and light planes for monitoring land, herding and crop sprating

Aircraft used for geological surveying and cartographic services

Military purposes: drones, potentially autonomous

46
Q

Environmental Impacts

A

Air pollution (piston and turbine engines with exhaust gases), fuel dumping (plane has to circle to burn fuel to reduce risks)
- more research into alternative fuels

Noise pollution:
- urban areas: has impact for people living in that area.
- curfews
- new turbine designs to reduce noise.

47
Q

Aviation carbon costs

A

Only 2% of the total carbon emissions

48
Q

Military impacts

A

Drones for medical supplies.

49
Q

Aileron

A

Controls Roll, (z axis)

50
Q

Rudder

A

Controls Yaw, at back of plane

51
Q

Elevator

A

Controls the Pitch

52
Q

Forces on an aircraft

A
  • Weight v
  • Lift ^ (upward for on wing to overcome weight)
  • Drag < (air resistance)
  • Thrust > (must overcome drag to increase speed)
53
Q

Angle of attack

A

Controlled by pitch/elevator

54
Q

Types of Airfoils

A

Early airfoils: significant undercamber, modern subsonic are more symmetric

Supersonic aircraft require different foil shapes

55
Q

Venturi effect (Fluid dynamics)

A

Venturi effect: an incompressible fluid/s velocity must increase as it passes through a constriction (principle of mass cont.)

56
Q

Bernoulli’s principle

A

increase of the speed of fluid occurs simultaneously with a decrease in static pressure.

57
Q

Incorrect lift theory

A
  1. when air meats leading edge, airflow splits. This causes
  2. Newton’s 3d lay
    - must be an equal force pushing foil upwards
  3. Venturi theory
58
Q

Correct lift theory

A

Flow turning
1. Speed is faster over top surface: lower pressure region on upper surface
2. Lower surface of the airfoil turns flow of air (but so does top surface: this is why planes can fly upside down.

Lift is related to

59
Q

Drag types

A

Induced drag and parasitic drag

60
Q

Induced drag

A

Pilot input The faster the plane, the lower the drag

61
Q

Parasitic drag: graph shape and types

A

Increases exponentially as speed increases

3 types:
- form
- skin friction
- interference (e.g. wingtip vortexes)

62
Q

Reducing drag

A
  • Reducing frontal area
  • Using smoother skin materials
  • Adding winglets to disrupt vortices
  • Reducing weight.
63
Q

Laminar vs Turbulent Flow

A

Laminar: airflow is smooth, follows shape closely (streamlined). Kostly for small angles of attack

64
Q

Lift-Drag ratio

A

Indication of aerodynamic efficiency
- higher ratio = more fuel efficient (powered) or with gliders, can fly long distances

When experiences no thrust (steadily descending): relates to angle of glide
- L/D = 1/tan(alpha)

65
Q

Hydraulic systems

A
  • operate undercarraige, flaps, and brake system.

Poarts:
- pump, regulator, reervoir, relief valve, filters, plumbing, oil, control valves, actuators, and an acccumulator

66
Q

How is Hydraulic systems controlled

A

Moves control valve, directing hyrdraulic fluid to the actuator,
This pressure then moves the actuator, mechanically operating the service

control valve -> actuator

67
Q

Air Pressure Types

A

Absolute Pressure: absolute vacumn

Atomospheric pressure: hydrostatic pressure caused by the weight of air: usually measured at sea level

Gauge Pressure: relative to atmospheric pressure. Positive for pressures above atmospheric, negative for pressures below.

Static pressure: Sum of gauge and atmospheric pressure

Dynamic pressure/velocity: additional pressure caused by movement of aur

Total: sum of dynamic and static

68
Q

Flight instrument categories

A
  1. Pressure instruments
  2. Gyroscopic
  3. Compass
69
Q

3 types of pressure instruments

A
  1. Airspeed indicator
  2. Altimeter
  3. Vertical Speed indicator
70
Q

Pitot Tube and Airspeed indicator

A

Usually located below the wings, measures dynamic + static pressure.

71
Q

Alternate Static Source

A

Side of the aircraft: away from airflow

72
Q

Pitot Heater Switch

A

If too cold: becomes blocked by icing. Thus, the heater heats the pitot tube

73
Q

Static Port

A

Allows in only the current atmospheric pressure

74
Q

4 Stages of Combustion engine

A
  1. Intake: piston moves down, creating a vacuum to suck in air
  2. Compression: squeezes the air and makes it highly combustible
  3. Power: The spark plug ignites the mixture of gas, forcing the piston downwards
  4. Exhaust: exhaust gasses are released

Valves open and close the different chambers.

75
Q

Early ice engines:

A
  • Water-cooled, used in early aircraft
  • Wright 6-70 inline 6 engine (1913)

Inline engines reached peak in WW1
The Curtiss B-8 V-8:

After 1908: water cooled

76
Q

Rotary engines (what, pros and cons)

A

PROPELLOR engine
Have a large, usually odd number of cylinders: arranged around a crank case

  • the whole engine rotates

PROS:
- more compact design, lighter, less machine parts
CONS:
- inefficient: requires more oil and lubrication (more moving parts)
-releases more emissions
- Lower thermal efficiency: doesn’t handle higher temperatures as well.

77
Q

Radial Engines

A

Similar to rotary engines, however only the propellor rotates
- entered development even before Wright brothers
- liquid cooled: lighter then inline engines
- more reliable: run smoother

HOWEVER, large frontal area creates drag
- have to taxi in a S shape, as it reduces visibility

78
Q

Planes using the Radial engine

A

Messerschmitt Me 163 Komet (up to 1130km/h)

79
Q

Turbojet stages

A
  1. Intake: air enters inlet at high speed.
  2. Compression: Compressor blades force air into an increasingly narrow chamber
  3. Combustion: Air mixed with fuel and ignited
  4. Exhausted is vented out of the nozzle, providing thrust + spinning shaft.
80
Q

How does a Jet Engine work

A

Mechanically simple system, generates high thrust by combustion, expelling an air-fuel mixture at high speeds.

81
Q

Turbojet engines pros and cons

A

Fuel: inefficient, high noise pollution

BUT achieves high speeds

82
Q

Afterburner

A

Additional fuel is sprayed into the jet pipe: ignites a second, fuel-inefficient burst of thrust
- achieve high thrust: military planes

83
Q

Turbprop engines

A

High speeds achievable by turbojet engines: not good for passenger planes: used for regional, short-haul aircraft
- combines high power and low maintenance of a turbojet with the cruising speeds of a piston engine,
- done through gear reduction: between turbine shaft and propellor shaft
- quieter

84
Q

Turbofan engines

A

Used for high altitude, long-haul flights

aka. bypass engines: produces 80% of the thrust.

Bypass air: high volume, low velocity = quieter, more efficient

CONS: size

85
Q

Ramjet vs scramjet engines

A

Ram:
Air-breathing jet engine without rotary compression: do not work at low speeds, and often need a secondary propulsion system to achieve this speed. (doesn’t work above Mach 1)
- experimental military aircraft

Scramjet:
Above Mach 5 (used for missiles, etc.)

86
Q

Rocket Propulsion

A

Exhaust fumes released by explosive chemicals are pushed out of the nozzle at high speed: generating thrust

  • using them in space: need a chemical called and oxidant
87
Q
  1. types of rocket propulsion
A

Solid:

Liquid:
- multiple steps allows for more control over turning it on/off: better performance

88
Q

Applications of rockets

A

Military aircraft, missiles and satellite launches

89
Q

German aircraft

A

Didn’t have mass manufacture capabilities: LESS planes

90
Q

Comparison of Titanium. Aluminium and Magnesium

A

Density: Ti-> Al -> Mg

Ti: excellent creep resistance and strong + ductile, yet scare + expensive

Al and Mg alloys are more susceptible to creep at lower temperatures: not good for inside of crafts
v.s. Ti alloys and Steel

91
Q

Alclad

A

A composite sheet, plate, etc. which a thin layer of almost pure Al. has been metallurgically bonded: hot-rolled into the surface.
- provided a corrosion resistant later.

Developed around late 1920s: used for skin on airframes.

92
Q

Advantages of Alclad

A

High corrosion resistance
High fatigue resistance and strength
Relatively shiny finish

HOWEVER:
Heaver then unclad Al
Difficult to weld
Requires care when cleaning and polishing

93
Q

Titanium Properties

A

moderate density
maintain mechanical properties up to 500 (can’t be used in induction part of the engine: more exhaust of fan.)
high strength
long fatigue life
good touchness
resistance to corrosion and oxidisation

94
Q

Titanium uses in aero

A

airframes, langding gear and jet engines: good more military uses

95
Q

Ti-6Al-4V

A

4x yield strength then steel
- Very high cost from titamium

96
Q

Nickel Superalloys uses and properties

A

At least 50% nickel and up to 10 other elements (e.g. Cr, Al and Mb and Mb)

Used in jet turbine engines: turbine blandes and discs, furnace parts

  • maitnain strength and creep resistance at high termpartautres
  • long fatigue life.
    BUT: high density so very heavy
  • its usage is minimised.

eg. Inconel

97
Q

Creep

A

Plastic deformation process:
- load below the elastic limit for a long time, elevated temperature
- leads to permanent extension and failure

e.g. turbine blades: eventually extends them to hit the turbine casing.

98
Q

Cobalt Alloys

A

Usually in the combustion stage of the engine (temperatures up to 1100)
- contains high level of Cr

99
Q

Grain size impacts

A

Better properties occur with smaller grain size, however, creep resistance decreases: failure occurs at grain boundaries
- Thus: for turbines, advanced manufacturing techniques are developed to reduce grain boundaries.

100
Q

Plywood in Aeornautial

A

In early aircraft fuselages, propellers and airframes

101
Q

First introduction of composites (commercial)

A

1958: Boeing
- fibreglass skins used to cover aluminum honeycomb cores on secondary control surfaces (2% of external surface area)

  • now: modern Boeing 787 dreamliners is 50% composites
102
Q

Boron

A

Lightweight composite, mostly used for military applications

103
Q

Boron fibres

A

boron fibres with a tungsten fore in a titanium matrix

104
Q

Fibre metal laminates and types

A

Alternating layers of metals and composites
Good fatigue resistance

GLARE
ARALL
CARALL

105
Q

Dreamliner construction

A

Constructed in several peices and places
Final assembly in Washington

WINGs and FUSELAGEL composite materials e.g. Torayca 3900-series CFRP prepreg tapes

106
Q

Wing construction

A

Build box structure, supports large loads eperienced during flight: wings can be used for fuel storage

  1. Prepreg is laid onto a cure table
  2. Resin is cured in prepreg: baking it through heat or pressure
  3. Panel is trimmed to size

THEN ASSEMBLY:
1. automated drilling and fastening of upper and lower panels
2. Electrical systems and hydraulics are installed
3. Wing is shipped to Washington, control surfaces and wing tips then fitted.

107
Q

primary vs secondary control system

A

control yaw pitch vs flaps, etc

108
Q

Causes of corrosion in aircraft

A

Water, bad weather

  • the environments: damn coastal areas, air pollution
  • concentration cells in small crevices and between sheets of metal, fasteners
    Dissimilar metal contact
    Aviation fuel and exhaust gases
109
Q
A