Engineering

1. Air + Plane
AST 406

2. Challenge
 To design and make a better airplane;
 To understand the atmosphere better;
 To understand how air flows;
 To understand how weather affects air
travel;

3. Activity: Make a Plane
 Take a piece of paper and make an airplane
that you think will fly the farthest;
 What makes a plane fly farther?
 What makes a plane fly straighter?
 Suggest characteristics of a good paper
airplane

4. Paper Airplane Rubric
Property Desired
Design Aerodynamic – delta shape
Control of air movement over wings
Helps plane move in desired direction
Wing Area Maximum
Mass Minimal
Weight is balanced throughout
Material Keeps shape
Launch Throw forward/up from centre of gravity

5. Dihedral Angle

6. How To:

7. Wing Angle

8. Anhedral Angle Paper Airplane
Good for distance

9. Lifting Body (Cylinder) Planes
 The $6M Man
 The History: Lifting Body Planes
 The Real History: The real $6M Man
 Plans Video:
 Plans # 2

10. Atmosphere
 The atmosphere is the layer of air
surrounding the earth;
 Air is the mixture of gases that make up the
atmosphere;
 Air is ~80% Nitrogen gas (N2) and ~20%
oxygen (O2).
 There are also small amounts of the gases:
Water Vapour (H2O), Carbon Dioxide (CO2),
and Argon (Ar);

11. Challenge Flight
 In teams of 2, design a paper airplane.
 Material: 1 sheet paper, 8x11 only.
 : Nothing else, no tape, glue,
staples, etc.
 Challenge: Speed & Distance & Overall

12. Atmospheric Pressure
 Air has mass;
 Atmospheric pressure is the weight, or force
down, of the air in the atmosphere;
 Pressure = Force/Area (Pascal or Pa);
 1 Pa = 1 Newton of Force on 1 m2;
 Atmospheric pressure is about 101300 Pa
or 101.3 kPa (kiloPascal);

13. High and Low Pressure
 Greater atmospheric pressure means that
there are more particles in a volume of air;
 Less particles = less pressure;
 Warmer air rises, the particles move faster
and farther apart; thus it has a lower
pressure than cooler air;
 Air particles move from zones of higher
pressure (with lots of particles) to zones of
lower pressure (fewer particles)

14. Layers of Air

15. Functions of the Atmosphere
 Troposphere:
– Most weather here; Higher alt., lower temp.
 Stratosphere
– Contains ozone layer that absorbs UV
 Mesosphere
– Middle, coldest layer – almost no air
 Thermosphere
– Absorbs most of Sun’s radiation, thus hottest
 Exosphere
– Satellites out here

16. Activity
 Air pressure demonstration with candle in
beaker
 Workbook, Page 117 – 118

17. Air Circulation
 Air masses move around because of the
different densities and temperatures of air
masses around the world due to:
– Location – above water/land
– Season
– Time of day
– Rotation of the Earth
 This causes patterns to emerge;
 Air circulates in specific global movements;

18. Weather Patterns
 Globally – prevailing wind currents
 Continentally – warm/cold air masses move
in as fronts depending on pressure
 Locally – Air heats up and rises, cool air
takes its place creating breezes.

19. Depression/Anti-Cyclone
 Depression - D
– low air pressure - L
– cloudy skies
– precipitation – rain, snow
 Anti-cyclone - A
– high air pressure – H
– clear skies
– sunny, drier weather

20. Cold/Warm Fronts

21. A Mighty Wind
 Prevailing winds are major air currents that
blow in a given direction according to global
patterns of movement;
 An air mass is a large expanse of the
atmosphere with the same temperature,
pressure and humidity (water content);
 Anti-cyclone: an area of air circulation
surrounding a high pressure centre.
 Depression: an area of air circulation
surrounding a low pressure centre;
 Cyclone: a tropical storm with violent winds
revolving around an area of low pressure;

22. Air Cells
 Air that has been warmed at the Equator becomes
lighter and less dense;
 It moves towards the North and South Poles;
 Air that has been cooled at the Poles moves
closer to the Earth’s surface and replaces the
warmer air;
 These circulation loops are called cells;

23. Issues in Atmosphere Research
 Wind energy
 Smog = Smoke + Fog
 Thinning of the Ozone layer
 Pollution of the atmosphere
 Greenhouse Gas Effect
 Climate change/Global warming
 Ottawa Valley Weather Change

24. Liquid Air
 Air can be thought of as a liquid;
 Both are considered fluids – and form the
basis of fluid dynamics;
 They both flow;
 The greater the depth, the greater the
pressure
 Higher density = higher pressure and v.v.

25. Gas
 In a contained gas, the pressure depends
on the number of collisions between the gas
particles and the container;
 The more collisions, the greater the
pressure;
Effect on Pressure Closed Container Open Container
As Temp increases Pressure increases Pressure decreases

26. Activity
 Workbook, page 123-124;
 Textbook, page 233-239;
 Balloon blow up!

27. Pascal’s Principle
 An increase in the pressure in an enclosed
fluid is transmitted in all directions;
 E.g. the pressure of air in a car tire is the
same everywhere against the walls of the
tire;
 The brake system of a car uses Pascal’s
principle when the fluid is pushed from the
pedal to the brakes;

28. Hydraulic Lift

29. Hydraulic Force Change

30. Pressure
 Pressure is a force applied over an area.
 Pressure (Pascal) = Force (Newtons)
 Area (m2)
 P = F
 A
 What is the pressure of 5 Newtons of Force
applied over a 4 m2 area?
 P = 5.0 N = 1.25 Pa
 4 m2

31. So What is Force?
 Force is a push or pull that can change the
motion of an object;
 It can:
– move a stopped object;
– slow down a moving object – deccelerate;
– speed up a moving object - accelerate;
– it can change the direction of an object;
– it can support an object;

32. Force of Gravity, Fg
 Fg = mg
 where m is mass of object in kg
 where g is the attraction due to gravity
 g = 9.81 N/kg (m/s2)
 E.g. Weight of 5 kg curling stone
 Fg = mg = 5 kg x 9.81 N/kg
 = 49.05 N down

33. Resultant Force
 When you add two or more forces together,
the overall force, or net force is called the
Resultant Force.
 Net Force =
 20N up
– 20 N down
0 N

34. Force Arrows
 can be represented by arrows;
 The Resultant Force = 5N Left;

35. Bernoulli’s Principle
 The higher the speed of a fluid, the lower the
pressure and vice versa;
 Air particles that pass over an airplane wing
have to move faster than air particles below
the wing in order to avoid a vacuum;
 These faster air particles exert less pressure
down compared to the pressure up;
 This creates an overall upwards force or a
Buoyant Force, Fb – or LIFT.

36. Bernouilli Creates Lift

37. Archimedes’ Principle
 An object immersed in a fluid is subjected to
a buoyant (floating) force, Fb, EQUAL to the
weight of the fluid displaced by the object;
 The fluid can be air, so:
– An object floats UP if its weight is less than Fb
– An object remains at level if its weight = Fb
– An object sinks if its weight is more than Fb

38. Archimedes Lifts Up

39. The Big Explanation
 Airplanes fly because the shape of the wing
causes air to pass more quickly over the upper
side of the wing(s);
 The faster flowing air creates an area of lesser air
pressure;
 Since this is less than the normal air pressure,
LIFT is created;
 This creates a Buoyant Force that lifts the plane
up;
 Various control mechanisms add stability to a
plane.

40. Airplane Deviations

41. Airplane Controls

42. Activity
 Textbook: Chapter 7 Review: pp 246-249:
 Q. 1-9, 12-14, 21-32
 Workbook: Page 121-122
 Construct Paper Airplanes:
 Plan A:  Plan A
 Plan B:  Plan B
 Plan C:  Plan C

43. Design a Better Plane
 With our class Rubric, make your plane;
 Calculate the total area of wing space on
your airplane;
 Determine the mass of the plane;
 Calculate the wing area : mass ratio;
 Each student will make a Multi-View drawing
of his/her plane with side, front and
overhead views;

44. The Classic

45. Activity
 Workbook: pages 45-46;
 Textbook: pages 79-87;
 Complex Tasks
 Boat race Mouse Trap Car
 Desertification
 Carbon Tax
 Global Warming – UN
 Skeptical Science