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Course: Physics
The Physics of Flight
Notes for learners
Level: National 4 and 5
April 2013
This advice and guidance has been produced for teachers and other staff who
provide learning, teaching and support as learners work towards qualifications.
These materials have been designed to assist teachers and others with the
delivery of programmes of learning within the new qualifications framework.
These support materials, which are neither prescriptive nor exhaustive,
provide suggestions on approaches to teaching and learning which will
promote development of the necessary knowledge, understanding and skills.
Staff are encouraged to draw on these materials, and existing materials, to
develop their own programmes of learning which are appropriate to the needs
of learners within their own context.
Staff should also refer to the course and unit specifications and support notes
which have been issued by the Scottish Qualifications Authority.
http://www.sqa.org.uk
Acknowledgements
© Crown copyright 2013. You may re-use this information (excluding logos) free of charge in
any format or medium, under the terms of the Open Government Licence. To view this licence,
visit http://www.nationalarchives.gov.uk/doc/open-government-licence/ or e-mail:
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This document is also available from our website at www.educationscotland.gov.uk.
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Contents
Introduction and aims
4
The dynamics of flight
5
Lift vs weight
7
Generating lift (Newton’s third law)
9
Flight control surfaces
14
Investigation: Building a model glider
18
Investigation: Weight distribution
21
Investigation: Angle of attack
24
Investigation: Additional lift
28
Investigation: The banked turn
30
The ‘loop-the-loop’ challenge
35
The jet engine
37
Navigation
42
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INTRODUCTION AND AIMS
Introduction and aims
The aviation industry is a huge worldwide industry that employs thousands of
people in many fields, from pilots who fly planes to aeronautical engineers
who design them. This investigation will enable you to learn about the
importance of forces and Newton’s laws of motion in allowing planes to fly in a
controlled manner.
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THE DYNAMICS OF FLIGHT
The dynamics of flight
When a plane is flying through the air, there are four main forces acting on it.
These are as follows:
 Weight: This force acts downwards, due to gravity, pulling the plane
down to the ground. Any object in the air will have this force acting on it.
 Lift: This force acts upwards, and is generated by the wings of the plane.
It acts against gravity to lift the plane into the air and keep it there.
 Drag: This force acts against the forward motion of the plane, just like air
resistance acts on us when we ride a bike. It slows the plane down.
 Thrust: This force is produced by the engines of the plane to propel the
plane forward. It acts against drag to make the plane go faster.
Aircraft image courtesy of NASA: http://www.grc.nasa.gov/WWW/k-12/airplane/forces.html
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THE DYNAMICS OF FLIGHT
Exercise: The balancing act
1.
Explain in your own words the effect of the four different forces that act
on a plane in flight.
2.
Consider a plane that is flying at a constant speed. What can be said
about the relative size of the thrust and drag forces?
3.
Consider a plane that is flying at a constant height (altitude). What can
be said about the relative size of the weight and lift forces?
4.
Which of Newton’s three laws of motion did you apply to answer
questions 2 and 3?
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LIFT VS WEIGHT
Lift vs weight
In order for a plane to get into the air, it needs an upward force to lift it into the
air. This force is called lift and it is generated by the wings of the plane.
Newton’s first law of motion
Isaac Newton changed our understanding of the universe with his three laws
of motion. They can be used to describe how a plane stays in the air.
Newton’s first law of motion states that:
An object will remain at rest or move with a constant speed unless an
unbalanced force acts upon it.
In other words, an object will remain still until you apply a force, such as a
push, to it.
Object on a table
Consider a vase sitting on a tabletop. According to
Newton’s first law, there is no unbalanced force
acting because the vase is not moving. However,
there are forces that are acting on the vase:
 weight: this force is caused by gravity and it acts
to pull the vase down to the ground
 reaction: this force is produced by the table and it
acts to push the vase upwards.
For the vase on the table both of these forces are said
to be balanced – they are equal to each other. If the
forces are equal, then the overall (resultant or
unbalanced) force is zero. The vase will not move.
Image of vase:
Ilovebutter/Flickr Creative
Commons
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LIFT VS WEIGHT
Lift
Cruising at a constant height
A plane cruising at a constant height is very
similar to the vase sitting on the table. The height
does not change, so the forces acting up and
down must be balanced. The two forces acting
up and down on a plane are weight and lift, shown opposite.
Weight
Exercise: Find the weight and lift
Shown below are the masses of some popular aircraft.
1.
Use the following formula to calculate the weight of each aircraft:
weight = mass × 9.8
W = mg
2.
For each aircraft, calculate the lift produced by the wings to maintain a
constant altitude.
Boeing 747-400
Mass = 178,756 kg
Airbus A380-800
Mass = 276,800 kg
Boeing 757-200
Mass = 57,840 kg
Airbus A330-300
Mass = 124,500 kg
You may wish to visit the following website to see images of some of these planes:
www.airliners.net
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GENERATING LIFT (NEWTON’S THIRD LAW
Generating lift (Newton’s third law)
In order for a plane to stay in the air, the downward force of weight must be
balanced by the upward force of lift. The lift is provided by the wings of the
aircraft. Remember, according to Newton’s first law, for the plane to remain at
a constant altitude then the downward and upward forces must be balanced.
Newton’s third law of motion
Newton’s third law of motion states:
For every action, there will be an equal and opposite reaction.
In other words, if you apply a force to an object in one direction, then the
object will apply a force to you in the opposite direction.
Imagine pushing the sharp end of a pin with your
thumb. You apply a force to the pin (called an action
force). The pin applies an equal and opposite force
(called a reaction force) which pushes the pin into
your thumb. You will also feel a small amount of pain!
This is why you feel a force when you push on objects
– the object is pushing back on you with the same force
but in an opposite direction.
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GENERATING LIFT (NEWTON’S THIRD LAW
Newton’s third law also applies when you go swimming. You push the water
backwards with your hand (action force) so the water pushes you forwards
(reaction force). In the same way, if you fire a paintball gun, the action force
shoots the paintball forwards. The gun recoils into your shoulder as a result of
the reaction force.
Action force
Reaction force
Swimmer pushes
water in backward
direction.
Water exerts a
force on the
swimmer.
Image: Jim Bahn/Flickr Creative Commons
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GENERATING LIFT (NEWTON’S THIRD LAW
Exercise: Which way?
For each of the objects below, draw a diagram to show the
direction of the action and reaction forces.
Air forced back
Air forced back
Air forced down
Air forced down
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GENERATING LIFT (NEWTON’S THIRD LAW
Generating lift with a wing
An aeroplane wing generates lift by forcing air downwards (action force). This
results in the wing being pushed upwards (reaction force) – the force of lift.
Air must flow across the wing so in order to produce lift, so the aircraft must be
moving through the air. This theory is based on Newton’s third law of motion
that every action has an equal and opposite reaction.
Lift
Downward
force on the
air
Image: Theresa Knott/Wikimedia Commons
http://en.wikipedia.org/wiki/File:Angle_of_attack.svg
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GENERATING LIFT (NEWTON’S THIRD LAW
Exercise: Generating lift
Consider the structure of a wing, shown in the diagram below.
What factors do you think will affect the amount of lift that the
wing will generate?
Discuss in small groups and write a short report on what factors you believe
will affect the amount of lift generated by a wing.
Image: Pearson Scott Foresman/Wikimedia Foundation
http://en.wikipedia.org/wiki/File:Alieron_A-44_(PSF).png
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FLIGHT CONTROL SURFACES
Flight control surfaces
To manage flight direction, aircraft use control surfaces. A plane can move
about three axes as shown in the diagram below, changing the roll, pitch and
yaw.
Image courtesy of NASA
http://commons.wikimedia.org/wiki/File:Roll_Pitch_Yaw.JPG
A plane uses four basic control surfaces to control the flight – elevation,
rudder, ailerons and flaps. These four surfaces are explained below. You will
investigate their effects in detail later using a model glider.
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FLIGHT CONTROL SURFACES
Elevator – controlling the pitch
An elevator is a control surface that makes the front of the plane (the nose)
pitch up and down. Elevators are usually found at the back of the plane, on a
part called the horizontal stabiliser. When the elevator points downwards,
it causes the nose to point downwards. When the elevator points upwards
(pitch up), it causes the nose to point upwards (pitch down).
Image courtesy of R/C Airplane World: http://www.rc-airplane-world.com/how-airplanes-fly.html
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FLIGHT CONTROL SURFACES
Rudder – controlling the yaw
The rudder of the plane is used to move the nose to the left or the right (yaw).
The rudder is located on the back edge of the vertical stabiliser or fin. The
air flowing over the rudder pushes harder on one side than the other, which
forces the nose of the plane to yaw either to the left or the right. When the
rudder turns to the left the plane will yaw to the left. When the rudder turns
to the right, the plane will yaw to the right.
Image courtesy of R/C Airplane World: http://www.rc-airplane-world.com/how-airplanes-fly.html
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FLIGHT CONTROL SURFACES
Ailerons – controlling the roll
Ailerons work in pairs to control the plane's roll. Each aileron moves at the
same time but in opposite directions. When the left aileron moves up, the right
aileron moves down and vice versa. This causes a decrease in lift on the
wingtip with the upward-moving aileron and an increase in lift on the
wingtip with the downward-moving aileron. These opposite changes in lift
cause the plane to roll either to the left or the right.
Flaps – increasing drag and generating extra lift
Flaps are located on the back edge of each wing, usually between the
fuselage and the ailerons. They extend downwards (and often outwards)
from the wing. One purpose of the flaps is to generate more lift at slower
speeds. They also generate more drag, which slows the plane down. You will
notice that flaps are usually deployed on take-off to help the plane get airborne
and while landing to help slow the plane down. You can see these control
surfaces if you look at modern aircraft – the next time you fly, look out for them
on the plane you fly in.
Images courtesy of R/C Airplane World: http://www.rc-airplane-world.com/how-airplanes-fly.html
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INVESTIGATION: BUILDING A MODEL GLIDER
Investigation: Building a model glider
The Wright brothers1 (Wilbur and Oliver) built model gliders to learn and
understand the importance of weight and balance in aircraft. If the weight is
not positioned properly, the plane will not fly. For example, too much weight at
the front (nose) will cause the plane to dive towards the ground. Small weights
can be used with a model glider to change its weight distribution. Test flights
can then be carried out to determine the effects of this on the glider’s flight.
Wilbur and Orville also learned that the design of a plane was very important.
Experimenting with models of different designs showed that planes fly best
when the wings, fuselage and tail are designed and balanced to interact with
each other. The Wright Flyer was the first plane to complete a controlled takeoff and landing. It was produced as a result of many experiments conducted
by the Wright brothers.
Gliders are still used in aviation design today. At NASA, model aircraft are
used to test ideas in aviation, developing new concepts and trialling new
designs. Some models fly in the air using remote control, while others are
tested in wind tunnels. The goals of NASA research are to make planes fly
more safely, perform better and become more efficient.
In this investigation, you are going to construct a model glider to investigate
the effects of weight distribution and control
surfaces on the flight of a plane.2 The gliders
will be made from polystyrene with paper clips
or bulldog clips used to control the weight.
1
See photos of the Wright Brothers: http://faculty.etsu.edu/gardnerr/wrightbrothers/huffaker.htm
2 Glider based on NASA Right Flight Glider,
http://www.nasa.gov/audience/foreducators/topnav/materials/listbytype/Right_Flight.html
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INVESTIGATION: BUILDING A MODEL GLIDER
Follow the instructions below to construct your model glider.
You will need:






two styrofoam trays
glider template
sellotape
scissors
sharp knife
emery board.
1.
Use scissors to cut the outer
edges off the glider template so
that it will fit on the inside of the
tray.
2.
Stick the template down onto the
styrofoam tray using sellotape.
3.
Using a sharp knife, carefully cut
around the outline of the glider.
This can also be done using a pin
or a sharp pencil to make lots of
close together holes along the
outline of the glider.
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INVESTIGATION: BUILDING A MODEL GLIDER
4.
After cutting around the template,
turn the tray over and use the
knife to complete the cutting
where necessary. Then carefully
push the components out of the
tray.
5.
Using a piece of sandpaper or an
emery board, carefully remove the
rough edges from around the
wings, fuselage and horizontal
stabiliser.
6.
Gently push the wings through the
hole in the fuselage. Ensure the
wings are equal lengths on both
sides of the fuselage. Repeat with
the horizontal stabiliser.
7.
Your glider is now ready to fly.
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INVESTIGATION: WEIGHT DISTRIBUTION
Investigation: Weight distribution
In order for the model glider to fly
properly, it is necessary for its weight
to be correctly balanced.
The initial test flights are going to
investigate the distribution of the weight
of the glider to optimise its flight. This will
require several test flights, each with
different amounts and positions of
weights.
Paper clips or blu-tac can be used to add weight to the glider. The distribution
of weight can be changed by changing the position of the clips/blu-tac.
What factor or factors of the flight of the glider will you use to compare
how good each flight was?
______________________________________________________________
______________________________________________________________
______________________________________________________________
Flight 1 – No additional weight
Firstly, try to fly the glider with no
additional weights added.
Describe the flight of the glider. Use the
terms roll, pitch and yaw (see the section
on flight ‘control surfaces’ for more detail).
You may use a diagram to help your
description.
______________________________________________________________
______________________________________________________________
______________________________________________________________
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INVESTIGATION: WEIGHT DISTRIBUTION
Flight 2 – Adding weight to the nose
Add a paper clip or blu-tac to the nose of
the plane (as shown in the photograph).
Now try flying the plane again.
Describe the flight of the glider, again
using the terms roll, pitch and yaw. In
your description include the following:
 Was this flight improved over flight 1?
 What effect did the addition of the weight have? (Hint: Think about how the
pitch of the plane has changed between flight 2 and flight 1.)
______________________________________________________________
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Flight 3 – Additional weight
Add a second paper clip or more blu-tac
to the front of your glider (as shown in the
photograph). Repeat your test flight and
watch carefully the flight path of the glider.
Describe the flight path using the terms
roll, pitch and yaw. In your description
consider the following:
 Has the additional weight improved the flight?
 Is the glider flying ‘level’ yet? (Think about the pitch of the glider.)
 How could you improve the glider further?
______________________________________________________________
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______________________________________________________________
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INVESTIGATION: WEIGHT DISTRIBUTION
Finding the optimum weight distribution
Carry out an investigation to find the optimum weight distribution for your
glider.
Use the space below to record the results of your investigation. The glider
diagrams can be used to note the positions of the weights.
Flight 4
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Flight 5
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_________________________________________
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Flight 6
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Optimum weight distribution
On the diagram opposite sketch the position of
the weight or weights used for optimum weight
distribution.
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INVESTIGATION: ANGLE OF ATTACK
Investigation: Angle of attack
In order to generate lift, the wing of the glider must force air downwards. By
Newton’s third law this will result in an equal and opposite force upwards,
which is called lift. The amount of lift provided by the wing depends on its
angle of attack.
Angle of attack
Image: Pearson Scott Foresman/Wikimedia Foundation
http://commons.wikimedia.org/wiki/File:Angle_of_attack_(PSF).png
The angle of attack (pitch) of the glider can be changed by using the
elevators on the horizontal stabiliser (at the rear of the glider). The
elevators can move upwards or downwards and change the lift generated at
the back of the glider.
Image courtesy of NASA: http://www.grc.nasa.gov/WWW/k-12/airplane/elv.html
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INVESTIGATION: ANGLE OF ATTACK
When the elevator tilts upwards, it reduces the lift at the back of the plane.
This causes the nose to rise which increases the angle of attack. When the
elevator tilts downwards, it increases the lift at the back of the plane. This
causes the nose to lower which reduces the angle of attack.
Angle of attack
Carry out an investigation into the effects of the elevators on the angle of
attack of the glider. Use the space below to record the results of your
investigation. Remember to describe the flight path of the glider using the
terms pitch, roll and yaw.
Flight 1 – Elevators level
_________________________________
_________________________________
_________________________________
_________________________________
Flight 2 – Elevators raised
_________________________________
_________________________________
_________________________________
_________________________________
Flight 3 – Elevators lowered
_________________________________
_________________________________
_________________________________
_________________________________
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INVESTIGATION: ANGLE OF ATTACK
When a plane is taking off and gaining altitude, what position should the
elevators be set to? Explain your answer.
______________________________________________________________
______________________________________________________________
______________________________________________________________
Extra: Stalled wings
We have seen in the above investigation that if you increase the angle of
attack, you can increase the lift generated by the wings. However, there is a
certain angle of attack that you must never go above – this is known as the
critical angle of attack. Above this angle, the wing will ‘stall’. This means that
the wing no longer produces lift and when this happens the glider or plane will
fall out of the sky.
To produce lift, there must be smooth flow of air over the wings, as shown in
the diagram below.3 This is known as ‘clean airflow’. The wing forces the air
downwards. By Newton’s third law, the wing is forced upwards with an equal
but opposite force, which is the lift.
3
GrahamUK/Wikimedia Common: http://en.wikipedia.org/wiki/File:Deep_Stall.png
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INVESTIGATION: ANGLE OF ATTACK
If the angle of attack it too great, the airflow over the wing breaks up and
becomes turbulent. This is known as ‘dirty airflow’. As air is no longer being
forced cleanly downwards, there is no resultant upward force. In other words,
there is no lift.
Carry out an investigation into the effects of changing the angle of attack on
the flight of your glider. Use the elevators to change the angle of attack. What
happens to the flight path of the glider when the wings stall? Use the space
below to record the results of your investigation.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
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INVESTIGATION: ADDITIONAL LIFT
Investigation: Additional lift
The majority of the lift is produced by the
plane’s wings.4 Changes to the shape
and size of the wing will affect the lift.
One of the main ways of changing the
shape of the wing is to use flaps. These
are on the back of the wing (closest to
fuselage on your glider). They extend
outwards and downwards from the wing
and increase lift at slow speeds.
To deploy the flaps on your glider, start at one side and carefully bend them
downwards. If the flap snaps, sticky tape can be used to reattach it.
The effects of the flaps
Carry out an investigation into the
effects of deploying the flaps on your
glider.
Use the space below to record the
results of your investigation. Remember
to describe the flight path of your glider
using the terms roll, pitch and yaw.
Extra: Try launching the glider at different speeds and investigate the effects
of the flaps at both low and high speeds.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
_____________________________________________________________
4
Image: NASA at http://virtualskies.arc.nasa.gov/aeronautics/3.html
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INVESTIGATION: ADDITIONAL LIFT
Planes usually deploy the flaps when they are taking off. Why do you think this
is so?
______________________________________________________________
______________________________________________________________
When flying at high speed, planes usually have the flaps retracted (not
deployed). Why would planes not fly with the flaps deployed all the time?
______________________________________________________________
______________________________________________________________
Extra: The effects of wing area
Carry out an investigation into the
effect of changing the wing area on
the lift of your glider. You will need to
make an additional wing, with a
larger area, using a new piece of
styrofoam.
Use the space below to record the results of your investigation. Ensure you
keep the launch speed constant.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
_
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INVESTIGATION: THE BANKED TURN
Investigation: The banked turn
When an aircraft wants to turn to the left or right, it flies a banked turn,5 which
is controlled by both the ailerons and the rudder. This is a more advanced
application of the changes of lift to the wings.
Ailerons are used to make the aircraft roll. This is also known as making the
aircraft ‘bank’. They work using the same principles as flaps to change the lift
of a wing. The ailerons on your glider can be deployed in the same way as the
flaps – gently bend the aileron either up or down starting at one of the edges.
5
Image: NASA at http://www.grc.nasa.gov/WWW/k-12/airplane/turns.html
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INVESTIGATION: THE BANKED TURN
To increase the lift on one of the wings the aileron should be pointed
downwards. Then to reduce the lift on the other wing the aileron should be
pointed upwards.
Image courtesy of NASA: http://www.grc.nasa.gov/WWW/k-12/airplane/alr.html
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INVESTIGATION: THE BANKED TURN
The effects of the ailerons
Carry out an investigation into the
effects of the ailerons on the flight
of your glider.
Use the space below to record
the results of your investigation.
Remember to describe the flight
path of your glider using the
terms roll, pitch and yaw. Include in your description the relevant Newton’s
laws to describe the effects of the flight in terms of the weight and lift
generated by the wing.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
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______________________________________________________________
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INVESTIGATION: THE BANKED TURN
To complete a banked turn, the aircraft must also yaw in the direction of the
turn.
The rudder is used to make the plane to yaw to the left or right. When the
ailerons and rudder are used together, the glider can be made to fly a
banked turn. The moving air pushes with more force on one side of the rudder
than the other, which causes the nose of the plane to yaw to the left or right.
You can adjust the rudder on your glider by gently pushing it to one side or the
other, starting at the top and working downwards.
Making a banked turn
Adjust the rudder and the ailerons
such that the glider will fly a
banked turn. You can choose
in which direction you wish your glider
to fly.
Once you have achieved the
banked turn, describe how you set
the control surfaces of the glider and draw a diagram of the flight path.
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INVESTIGATION: THE BANKED TURN
The rudder and Newton’s third law
We have seen from the investigation above that moving the rudder will cause
the glider to yaw to the left or right.
Explain, using Newton’s third law of motion, the action of the rudder on the
flight of the glider. You may wish to consider the following:
 When the side of the rudder is in the air stream, it will experience a force
pushing it on one direction.
 Newton’s third law states that for every action force, there is an equal and
opposite reaction force.
A diagram may also help your description.
Can you explain how changing the position of the rudder will change the
amount by which the glider will yaw in a given direction?
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THE ‘LOOP-THE-LOOP’ CHALLENGE
The ‘loop-the-loop’ challenge
So far you have optimised the weight distribution of your glider and
investigated the effects of the ailerons and the flaps on the flight path. This
challenge involves changing the control surfaces to achieve a ‘loop-the-loop’
with your glider.6
6
Davynin/Flickr Creative Commons
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THE ‘LOOP-THE-LOOP’ CHALLENGE
Loop-the-loop
Adjust the flight control surfaces on your glider to achieve a loop-the-loop.
Think about the following:
 The lift required – which control surfaces generate additional lift?
 The position of the ailerons – the plane is flying straight.
 Launch speed and angle.
Once you have achieved the loop-the-loop, describe in the space below what
changes you made to the control surfaces. Explain why these changes
resulted in a loop-the-loop. You can use a diagram to help with your
explanation.
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THE JET ENGINE
The jet engine
A large number of aircraft are powered by the jet engine. Some aircraft have
two, others have four and a small proportion of heavy aircraft have six. The jet
engine has made long-distance flight a reliable and quick experience – flying
from London to New York typically takes just 7–8 hours, and in the days of
Concorde took as little as 5 hours as the plane flew at twice the speed of
sound. Without doubt, the jet engine revolutionised air travel and as such
revolutionised global travel and had a big impact on the world’s economy.
An afterburner glows on an F-15 Eagle engine following a repair during an engine test run November 10,
2010, at the Florida Air National Guard base in Jacksonville International Airport, Fla. Shelly Gill/Wikimedia
Commons. http://en.wikipedia.org/wiki/File:F100_F-15_engine.JPG
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THE JET ENGINE
How a jet engine works
The diagram below7 shows how a jet engine sucks in cold air from the fan
blades at the front and ejects it out of the exhaust. Air is forced to flow in one
direction through the engine. The core of the engine is where the combustion
takes place – fuel is injected into the hot air and burns. This turns the turbines
and the front fan to suck in more air.
Explain, using the Newton’s second and third laws, how a jet engine works to
propel an aircraft forward. In your explanation, consider how the engine can
produce different amounts of thrust (forward force).
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7
K.Ainsqatsi/Wikimedia Commons: http://en.wikipedia.org/wiki/File:Turbofan_operation_lbp.svg
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THE JET ENGINE
Fan blades8
Conduct an experiment to investigate the effect of fan blades on the
movement of air. You should consider the shape of the blade and investigate
how changing the speed of rotation of the fan blades affects the movement of
air.
Describe the experiment that you carried out in the space below, recording
your results and the conclusions you can draw from them.
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8
Image of blades from Olivier Cleynan/Wikimedia Commons:
http://en.wikipedia.org/wiki/File:Outer_nozzle_of_GEnx-2B_turbofan_engine.jpg
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THE JET ENGINE
Reverse thrust
When an aircraft lands, it can use the thrust from its engines to help slow it
down on the runway. However, the engine’s fan direction cannot be reversed
so there must be another method to force the air forwards. One design to
force air forwards (known as reverse thrust) is shown in the photograph
below.9
Explain, using Newton’s third law, why the above design can be used to help
slow a plane down on the runway. Consider in your explanation the direction
the air is forced in by the doors.
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9
Bryan from Las Vegas/Wikimedia Commons: http://en.wikipedia.org/wiki/File:Boeing_737200_thrust_reverser.jpg
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THE JET ENGINE
Applying Newton’s second law
We have seen that a jet engine produces thrust by forcing air through it in one
direction. The thrust of an engine is measured in kilo Newtons (kN). As most
planes have either two or four engines, the total thrust can be found by
multiplying the single engine thrust by the number of engines.
This allows the acceleration of the plane to be predicted using Newton’s
second law:
F  ma
Assuming there are no frictional forces acting, calculate the initial acceleration
of each of the following aircraft. You will need to research the engine thrust
and maximum take-off weights for each aircraft. The internet can be used
for this task.
(a) Boeing 787 Dreamliner
(b) Boeing 777-200
(c) Boeing 747
(d) Airbus A330-300
(e) Airbus A340-600
(d) Airbus A380-800
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NAVIGATION
Navigation
Air traffic control are responsible for giving directions to all aircraft both when
they are in flight and when they are on the ground. They ensure that aircraft
do not come too close to each other and are given the correct flight path to
their destination.
Vectors are key to navigation for aircraft. When air traffic control issue a pilot
with a direction, they issue it as a vector. Sometimes a pilot will request a
vector to a specific airport. Vectors are essential as they give both a
magnitude (size of velocity or distance) and a direction. Both pieces of
information are vital to the pilot.
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NAVIGATION
Vectoring aircraft
You are in charge of issuing aircraft with a vector from Edinburgh Airport to
different airports around Europe. You must issue the pilot with a
displacement vector to their destination as the crow flies (single straight
line between starting point and destination). Use the map below to help you.10
Do the same for these other flight paths:
(a)
Glasgow to London Heathrow:
_________________________
(b)
Glasgow to Paris Charles de Gaulle:
_________________________
(c)
Glasgow to Berlin Schonelfeld:
_________________________
(d)
Glasgow to Milan Malpensa:
_________________________
10
Blank_map_of_Europe_(polar_stereographic_projection)_cropped.svg/Wikimedia Commons:
http://en.wikipedia.org/wiki/File:Europe_polar_stereographic_Caucasus_Urals_boundary.svg
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NAVIGATION
Real-time air traffic control
The following website allows you to watch commercial aircraft in real time:
www.flightradar24.com
Clicking on any of the aircraft will give information about it, its starting point
and its destination. It will also tell you its speed and heading (its velocity
vector), its altitude and whether or it is descending or ascending.
Investigate aircraft that are flying near your school. Where are they flying to,
and where have they flown from? On a clear day, can you spot the aircraft in
the sky?
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