Crazy glider

Crazy glider
Teachers‘
Guide
Crazy
Crazy
Glider
Glider
Dear Teacher,
this guide provides you with all the necessary information to
successfully plan, prepare and conduct the glider challenge
in your classroom. In combination with the students’ guide
you will quickly realize what potential this projects may hold
to enrich your lesson plan.
No expert aviation knowledge is required for the successful
outcome of this project!
Objective
The motivation driving students to complete the glider challenge is partially triggered by the fascinating field of aviation but mainly related to students’ desire to engage in this
unique format of a project. This motivation can be harnessed
to convey to the students that the subjects of physics and
mathematics hold many exiting practical applications not
only in everyday life but also in a professional career.
The glider challenge is made up of two phases. The students
are building one glider in each phase. The first glider is built
from a template while the second glider will be freely designed by the students. At the end of each phase the students
test their gliders in the glider challenge.
A trailer video of the glider challenge, complimentary projects, and additional information is provided on the Fly High
website. Feel free to contact the designated Fly High partner
in your country as they will be happy to assist you with your
questions:
www.flyhigh-321.eu
Glider
Glider
Chall
CHallenge
Group size and age
This glider challenge is designed for students from 13-19
years of age. We recommend a group size of 20 students
for a single teacher. The group size should not exceed 30
students unless an additional instructor and extra room for
testing the gliders is available.
Time table:
Phase 1
30 min. Construction
10 min. Training
10 min. Instruction
10 min. Training
30 min. Challenge
Break
30 min.
Phase 2
30 min. Planing
30 min. Constructing
30 min. Tuning
30 min. Challenge
Duration
The estimated time the glider challenge takes including the
setup und the clean up is approximately 5 hours including
a 30 min. break. The time table will guide you through the
project.
This project is not instructor centered, however the instructor must strictly guide the project through a predetermined
time table. This is not only important to keep the students
energized and focused on the current task but also key to a
fair challenge. The following time table is designed for
approximately 20 students working in groups of two.
Increasing the number of students mainly affects the
duration of the two challenge segments.
All segments of the time table shall be clearly communicated and binding for every team. Especially during the
second phase students tend to spend extensive time on
planing if the instructor does not urge them to start
construction. The tuning segment of the free design will
involve extensive testing, modifying, redesigning,
repairing, training, etc. Therefore students should not
extend the construction segment at the expense of tuning.
Motivated by the limitation of time Students tend to work
very intensely on the task. For that reason a break of 30 min.
between the two phases shall be allowed for.
3
Glider
Glider
Chall
CHallenge
Materials
DEPRON®
The only item in the list of materials that might be unfamiliar to you is probably DEPRON® board. DEPRON® is a brand
of model building board made of polystyrene. The characteristics of these large sheets are very advantageous to model
building and are often used as insulation as well. Being very
light, durable, smooth and easily cut, this material is the
essential ingredient to this project. You may wander why a
traditional paper glider cannot be used instead. Paper gliders
lack not only stability but are also not reproducible to the
extend that they would be a suited demonstration object for
the physics of flight.
Most hardware stores will not distribute DEPRON® and model making shops usually sell single sheets at a high price.
We recommend ordering DEPRON® online at an established
resell platform of your choice (eg. amazon). The price for
3mm DEPRON® board (without bonding course!) is approximately 3EUR/m2 when bought in bulk. One sheet of DEPRON® (70x100 cm) will be enough material for four
teams.
Divide the large sheet of DEPRON® into pieces measuring
35x 60cm. Each team must build the Crazy Glider and the
custom glider from this material.
Weights
Paper clips, washers, and lock nuts can serve as weight for
trimming the gliders besides the listed small coins. Usually
students are very creative in finding additional weights.
However, a single one-cent-coin per Crazy Glider is required.
Tape
The tape should only be used to attach the weight to the glider. Therefore two rolls of tape will be sufficient. Almost any
kind of tape will stick to DEPRON® well.
4
Glider
Glider
Chall
CHallenge
Teams
Two students per team is ideal. Even with a small group
of students individual building is not recommended. Not
only would the positive effect of team work be lost but the
students would not have to reason with a teammate. Three
members per team are also not recommended because the
assignment will not occupy all three students effectively.
Sometimes a group of three is unavoidable. In this case every team member has only two launch attempts during the
challenge.
Challenge
It is strongly recommended to host the challenge indoors in
an environment free of wind. Close all doors and windows
as they can all greatly effect the gliders’ flight. Nothing is
more frustrating to the students than unpredictable wind
conditions, which will make the competition unfair. In most
cases a large classroom free of chairs and tables or a hallway
will be sufficient. The flight distance can reach up to 12 m so
keep that in mind.
Since the glider challenge is the main motivation to most
students they are likely to take this competition seriously.
For this reason the instructor must sometimes act as a
referee besides marking down the distances.
We recommend keeping the score sheet in a visible place,
this adds more fun to the challenge. Mark down only full
meters and strictly round down.
The launch attempts are carried out one at a time team
after team. This will keep all teams involved until the last
round is completed. Every team member must take three
attempts, so both team members are equally involved.
5
Glider
Chall
Crazy
GLIDER
Crazy
glider
Glider
CHallenge
Teachers’ troubleshooting
Managing the unforeseen is part of every instructors daily
routine. This project has been tested many times in a variety
of classroom settings so we will gladly share with you the
occasional trouble we experienced.
Try out the glider challenge by yourself in advance. This will
take 90 minutes at the most and is the best preparation by
far.
Falling behind schedule
This happens almost every time, because students are so
busy working that they loose track of time. The instructors
don’t want to interrupt so deadline after deadline is being
sacrificed. Even if this is an annoying job you need to call out
the remaining time for each segment on a regular basis. If
you find teams stuck on a problem remind them to keep it
simple and urge them to move on. This is especially important during the planing segment of phase 2.
Do not allow students to work through the break. Phase 2
is more extensive than phase 1 so all students should start
fresh into the task.
One way to make up time can be a modified challenge with
only 4 attempts instead of six.
The gliders won’t fly
Students do not like to read the students’ guide, which
results in avoidable problems. During phase 1 we included a
segment for instructions. Right after they have been training with their Crazy Glider for the first 10 minutes bring the
group back together and demonstrate how the glider should
be launched. Many of the students will have launched the
glider with too much force and blame the glider. If you want
to impress the class you can ask for an exceptionally bad
flying glider as a demonstration object. This information is
included in the students guide but often ties neglected.
6
Glider
Glider
Chall
CHallenge
The typical flight of a Crazy Glider that has been launched
too strong will follow this pattern:
Right after launch it enters a steep climb.
Fighting gravity it looses speed resulting in reduced lift.
At the highest point the glider stands still. No air can pass
over the wing anymore to create lift. The glider stalls.
As the glider drops to the ground nose first it picks up speed
again and therefore lift increases.
The glider enters into a climb again and the process starts
over.
Tell the students to visualize a slight slope, which the glider
must gently glide down on.
The challenge is too much to handle by yourself
During the challenge your primary task is to follow each
glider. Position yourself parallel to the 6 meter mark. This is
where most gliders land so you have a good view. Designate
a student to write down the distances you are calling out.
This will safe time during the challenge.
The DEPRON® won’t cut right
Make sure the box cutters have a sharp blade and the angle
of the blade to the DEPRON® is small.
Not enough room for the challenge
Only very few gliders will reach a distances of 12 meters. If
your room ends after 10 meters you can award a bonus if a
team reaches the end.
A narrow room forces the teams to throw very accurately
because a contact with any obstacle ends the flight. Make
sure the conditions remain the same and chairs are removed
during the competition.
7
Glider
Glider
Chall
CHallenge
Not enough DEPRON®
35x50cm is generously calculated. You can decrease the material and still build two planes. The shortest side should not
be less than 35cm because that is the wingspan of the Crazy
Glider.
Permanent markers are not allowed
You can also use regular ball point pens instead of permanent markers to trace the templates. However, coloring the
plane will work best with permanents markers.
Students want to build bigger gliders
Building bigger glider is no problem and the same rules must
be applied.
I am not a math or physics teacher
Everything you need to know can be found in the students’
and teachers’ guide as well as the supporting material online. This project has already been very successfully conducted at birthday parties by parents without a professional
background in teaching.
8
Glider
Glider
Chall
CHallenge
Going beyond the classroom
The glider challenge can easily be extended beyond the
classroom. Challenging another class within your school to
build better flying custom gliders can take this project to
another level. Of course a challenge between schools or even
regions can be arranged without much effort. Tell a friend,
tell a colleague and soon you will find yourself in a glider
building community eager to exchange tips and tricks on
how to improve a custom glider.
Closing remarks
The glider challenge is only a small part of a wide variety of
information material provided through the Fly High project.
All of our information is constantly being reviewed and improve in order to maintain the highest quality standards. We
encourage you to provide us with comments, questions, and
observations about the offered information material. Only
by doing so we are able improve the provided information
material to meet the expectations of schools throughout
Europe.
10
Glider
Glider
Chall
CHallenge
Fly High at a glance
The aim of Fly High is the provision of a creative and interactive curriculum for secondary schools (lower and upper
level) including the guidelines for teachers and the corresponding demonstration objects and teaching means.
The curriculum will be a strong motivation factor for students – girls and boys equally – to deal with physics, mathematics and engineering sciences.
The material can be used for the initial training and the continuous professional development of teachers in the field
of physics and mathematics and related transversal key competences to make strongly theory based learning contents more attractive and accessible to students.
Fly High intends to satisfy the need for appropriate and practically relevant teaching material and methodology for
natural sciences (especially physics and mathematics)
fostering a problem solving, more self-guided and practically
relevant learning approach for students in natural sciences.
The approach is developed in full compliance with the general priorities, the sustainable cooperation between the
worlds of education (at secondary and third level), training
and work.
10
This project has been funded with
support from the European Commission. This publication reflects
the views only of the author, and
the Commission cannot be held
responsible for any use which
may be made of the information
contained therein.
Imprint
Hochschule Bremen, University of Applied Sciences
In cooperation with:
FH Joanneum Graz
Inholland University of Applied Sciences
Universidad Politecnica de Madrid
Crazy Glider
Students‘
Guide
Crazy
Crazy
Glider
Glider
Welcome to the world of flight!
You are about to enter the exciting world flight. The fascination of traveling through air like a fish through water is
shared around the globe. However, only a few people really
know why birds, aircraft, and paper gliders fly. Just turn the
page and find out everything you need to know to design
your own custom glider.
2
The
The
prinzipl
principles of fliGHT
The four forces
To understand why an aircraft can fly we need to understand
the four forces that act upon it. They push an aircraft up,
down, forward, or slow it down.four forces that act upon it.
They push a plane up, down, forward, or slow it down.
Thrust is the force that
moves an aircraft in the
direction of motion. It is usually generated by
a propeller or jet engine.
A glider has no propulsion
system, so it relies on a
winch or a tow plane to
reach altitude from where
it will slowly return to the
ground, gliding through
the air like a wagon rolling
down a hill.
Drag is the force acting
opposite to the direction
of motion and slows an aircraft down. Drag is caused
by friction and differences
in air pressure. An example is putting
your hand out of a moving
car window and feeling it
pull back.
Weight is the force caused
by gravity. Aircraft are built from
very light materials so it
will fly better.
Lift is the force that holds
an airplane in the air. Lift can only be generated
when air is passing over
the wing.
All four forces act on an aircraft and determine its path of
flight. Every force has an opposing force working against it.
Lift and weight work opposite to each other as well as thrust
and drag. An aircraft will move forward if thrust is greater
than drag. An aircraft will climb if lift is greater than its
weight.
3
The
The
prinziple
principles of fliGHT
The secret of lift
Lift is created when air passes
over the wing surface of an
aircraft. Take a close look at
the wing of the Crazy Glider
and you will notice that it is
slightly angled. This is called
angle of attack. The angle
of attack determines how
strong the air that has passed
over the surface of the wing
is deflected downwards. The
deflected air is called downwash. The greater the angle
of attack is towards the upcoming air, the greater is the
downwash, and the greater
is the resulting lift. In simple
terms we can say, that the
air is bending over the wing.
The air is forced downward
pushing the wing in the opposite direction.
You can make this effect
visible by running a small
stream of water from a
faucet. Hold a water glass
horizontally and move it
towards the stream until it
just touches. You will see
how the stream of water is
bent around the glass just
like the air is bent around
the wing.
The velocity of the air passing over the wing is directly related to the amount of lift that is
generated:
High Airspeed = Strong Downwash = High Lift
Low Airspeed = Weak Downwash = Low Lift
No Airspeed = No Downwash = No Lift
4
CONSTRU
Construction
Crazy Glider Construction
The following steps will guide you through the building
process of the Crazy Glider. After you have completed the
construction you will be able to improve your piloting skills
by training with this ready to fly design. Finally you and your
friends will enter the Glider Challenge to find out, who the
best pilot is. Follow this step by step guide carefully to keep
your chances of winning the challenge high.
Material:
3 mm DEPRON® board
Tape
Permanent marker
One-cent coin
Scissors
Box cutter
Crazy Glider template
5
The
The
prinziple
principles of fliGHT
The right balance
The point in which an object
is perfectly balanced is called
center of gravity. Take book
or a pen and try to balance it on your finger to find
the center of gravity. The position of the center
of gravity of an aircraft is
very important. If the center
of gravity is not in the right
position, the aircraft will
not fly well. Every aircraft
is carefully balanced in two
directions before it takes off.
It must be balanced down
the center so it will not
tilt to the left or the right.
Even more important is the
balance from front to back.
Here the center of gravity
must be located in the front
part of the wing. The Crazy
Glider carries a one-cent
coin on its nose. This brings
the center of gravity to the
right position.
Lay a pencil on an even surface and balance the
glider across it to find the
center of gravity.
Two types of stabilizers
You can find them on almost every type of aircraft. Stabilizers are typically found on the tail of an aircraft and
ensure straight and level flight:
1
2
1.1
The vertical stabilizer provides directional stability.
It keeps the aircraft aligned
in the direction of flight.
2
The horizontal stabilizer provides longitudinal stability.
It prevents the nose of the aircraft from pitching up or down.
To learn more about the principles of flight visit our website
or
experience the principles of flight by playing the FlyHigh!
game. The App is available for free at the iTunes App Store.
-------- ---
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1
€
en
t
------ ----
Crazy
GLID
Crazy glider
tio
no
f
ec
Dir
ht
Fl
ig
Di
re
io
n
ct
of
Fl
igh
t
Crazy
GLIDER
Crazy
glider
Caution!
a. Cut out all three templates
for the construction of the
Crazy Glider as shown.
Box cutters are very
sharp. Retract the blade after each use to prevent injuries.
b. Place the templates on
the DEPRON® board and
trace the contour with a
permanent marker.
Do not forget to
transfer the slots for the
wing and the horizontal
stabilizer to the fuselage.
c. Now place the DEPRON®
board on a cutting surface
and cut along the inner edge
of your marks with the box
cutter. Both slots for the
wing and the vertical stabilizer have to be cut along the
outer edge of your mark.
Hint!
DEPRON® can be cut
very easily by guiding
the sharp blade at a
low angle without
force. Tight turns
can be realized
by making several
straight cuts along
the outline of the
curve.
Crazy
GLIDER
Crazy
glider
d. Carefully remove the cut out pieces
and slide the wing and the vertical stabilizer into the designated slots on
the fuselage.
Notice, the correct mounting direction
of the wing and the vertical stabilizer
are marked by an arrow on the template.
e. Finally the one-cent coin
must be taped to the nose
of the Crazy Glider.
The exact spot is
market on the template.
f. If you have worked accurately
and the wing and vertical stabilizer are centered your
Crazy Glider should glide
straight when gently launched by hand.
Hint!
To color your glider use
permanent markers.
9
PILOT
PILOT
TR
TRAINING
Pilot Training
The following steps will guide you through the building
process of the Crazy Glider. After you have completed the
construction you will be able to improve your piloting skills
by training with this ready to fly design. Finally you and your
friends will enter the Glider Challenge to find out, who the
best pilot is. Follow this step by step guide carefully to keep
your chances of winning the challenge high.
Launching the Crazy Glider
properly is important for a
smooth flight:
a. Hold the Glider just below
the front edge of the wing.
b. Release the glider in a very
gentle forward motion of
your arm with its nose pointing slightly downwards.
Trouble shooting:
The glider enters a steep
climb immediately after
release:
b. The nose of the glider
was directed upwards at
the moment of release. Remember what we learned
about the angle of attack.
The glider turns towards the
left or the right:
a. The glider was not launched
in a straight direction.
b. The wing are not centered.
Shift the wing left or right to
correct the turning behavior.
a. Too much force was applied
when launching. Remember
what we learned about the
relationship of airspeed to
lift.
10
Glider
Glider
Chall
CHallenge
Glider Challenge
The Glider Challenge is your chance to test your piloting
skills. The competition should be held indoors. Make sure
no gliders entering the competition have been modified
from the original design. Clear the room of chairs, tables and
other objects and mark off a launch point. From this point
the gliders are launched. Mark of 12 meters in a straight
line from the launch point by placing a strip of tape on the
ground for every meter.
Every team has six attempts to launch the glider. Try to cover
the longest distance from the launch point to the first point
of contact with the ground, wall, ceiling, or any other object.
The best three out of all six flight distances are added to find
the total flight distance. The following table is an example
for a score sheet:
Attempt Team 1Team
Team 2 Team
3 Team 4 Team
5 Team 6 C
Team
7 Team 8D
Team
9 Team 10
Attempt
A Team
B Team
Team
Team
E
1
1
2
2
3
3
4
4
5
5
6
6
Total
Total
(only best 3)
(only best 3)
Place
Place
11
CUSTOM
gLID
Custom Glider
Designing a custom glider
25% D
25% D
D
D
D = Depth of the wing area
CG =
=Center of Gravity
Congratulations, you have built a Crazy Glider and successfully completed the Glider Challenge. Now it is time for you to design a custom glider.
A few important additional steps must be considered
in the construction of your own design. Finally you will enter
the Glider Challenge with your custom glider.
a. Planing your
glider is easiest on a
sheet of paper. Keep
in mind that your glider will
have to perform well in the
glider challenge, so “keeping
it simple” may be the key
to success. Read the following steps b. and c. carefully
before planing your glider,
because they must
be considered for the
design.
b. The Crazy Glider
was predesigned and
the center of gravity was in
the right position. Now you
will need to trim your glider
on your own. The center of
gravity must be exactly located at 25% of the depth (D)
of the wing area.
This “25% Rule” in crucial
and applies to a bird just the
same as it does to a jumbo jet.
Use the tape to place small
weights in form of coins or
paper clips at the nose of
your glider. This will shift the
glider’s center of gravity forward.
Example: The Depth of your
wing is 4cm (D = 4cm).
After you have assembled your
glider completely the center
of gravity must be at 1cm from
the front of the wing
(25% of 4cm = 1cm).
Notice: D = wing AREA.
Choosing a rectangular shape
for the wing makes it easy to
find 25% of D. If you decide on
a delta shape or even a curved
wing it is significantly harder
to calculate 25% of the area of
the wing.
12
CUSTOM
gLID
Custom Glider
Designing a custom glider
Hint!
Find the center of gravity
by balancing the glider on
a round pen or a straight
edge.
+5°
c. A close look at the Crazy
glider’s flight characteristics
before you start making adGlider reveals that the wing
justments. Make small adjustis slightly angled up towards
ments, one at a time so you
the front and the horizontal
can observe how they impact
stabilizer is slightly angled
your glider’s flight.
downwards. Without this
positive angle of attack the
Your glider dives to the ground
wing of your glider will not
nose first:
create lift. The negative
a. the center of gravity is proangle of attack on the horibably too much forward.
zontal stabilizer will stabilize
Remove some weight from the
your glider during flight.
nose of your glider.
Construct your glider with
an angle of attack of +5° for b. Your launch speed was too
low.
the wing and a negative
angle of attack for the
Your glider will not pick up
horizontal stabilizer of -5°
speed or follow a wavy up and
as shown in the drawing.
down path of flight:
a. The center of gravity is too far
back. Add some weight to the
-5°
nose of your glider.
b. Your launch speed too low.
Troubleshooting:
Most gliders will not fly well
right from the start. Be patient and take some
time to get to know your
= Center
of Gravity
25%
25%
25%
Sometimes it is necessary to
redesign parts of your glider.
For example if your wings are
not large enough to support
the weight of your glider or
the horizontal stabilizer is too
small. Use the common proportions of an aircraft as
a guide.
13
Glider
Glider
Chal
Challenge
Glider Challenge
Finally all participants enter the second glider challenge
with their custom built gliders. The same rules from the
Crazy Glider Challenge apply.
Good Luck!
Conclusion
We hope you enjoyed this project and recommend you take
a look at the following website to gain access to more
information:
www.flyhigh-321.eu
14
This project has been funded with
support from the European Commission. This publication reflects
the views only of the author, and
the Commission cannot be held
responsible for any use which
may be made of the information
contained therein.
Imprint
Hochschule Bremen, University of Applied Sciences
In cooperation with:
FH Joanneum Graz
Inholland University of Applied Sciences
Universidad Politecnica de Madrid
Construction Manual
IHU - Windtunnel
Authors:
Umayer Hussain, Daphne Bantjes, Katja Jongen
1
Fly High – The Principles of Aviation as an Opportunity to Make Physical Theory Accessible
This project has been funded with support of the European commission. It reflects the views only of the
author, and the Commission cannot be held responsible for any use which may be made of the
information contained therein.
Project Number: 518156-LLP-1-2011-1-AT-COMENIUS-CMP
Grant Agreement: 2011 – 3562 / 001 – 001
Sub-programme or KA: Comenius
Web Site: www.flyhigh-321.eu
© July 2013, InHolland University of Applied Sciences
Editor-in-Chief: B. Wiesler
2
Table of Contents
1 2 Introduction ...................................................................................................................................... 4 Required items .................................................................................................................................. 5 2.1 The wooden kit ......................................................................................................................... 5 2.2 Aluminium diffuser................................................................................................................... 5 2.3 Fan ............................................................................................................................................ 5 2.4 Electronics ................................................................................................................................ 6 2.5 Price overview .......................................................................................................................... 6 3 List of Materials................................................................................................................................ 7 4 Construction of the Inlet ................................................................................................................ 10 4.1 Assembling the boards ............................................................................................................ 11 4.2 Assembling the front and back frames ................................................................................... 12 5 Construction of the test and measurement section ..................................................................... 14 5.1 Construction of the measurement section ............................................................................... 15 5.2 Construction of the test section ............................................................................................... 16 5.3 Assemble the top and the bottom of the test section............................................................... 19 6 Assembling the Measuring Equipment ........................................................................................ 20 6.1 Assemble the bottom plate and connectors............................................................................. 21 6.2 Connect Electronics to Bottom plate ...................................................................................... 21 6.3 Pitot tube connection .............................................................................................................. 24 7 Construction of the fan support .................................................................................................... 26 8 Assembly ....................................................................................................................................... 27 Appendix 1: 2D Drawing Diffuser.......................................................................................................... 28 Appendix 2: 2D Drawing Bottom plate.................................................................................................. 29 Appendix 3: 2D Drawing of Load cell to bottom plate connector. ...................................................... 30 Appendix 4: 2D Drawing of Load cell to model connector .................................................................. 31 Appendix 5: 2D Drawing of Load cell to load cell connector .............................................................. 32 3
1
Introduction
Fly High intends to satisfy the need for appropriate and practically relevant teaching material and
methodology for natural sciences (especially physics and mathematics) fostering a problem
solving, more self-guided and practically relevant learning approach for pupils in natural sciences.
The approach is developed in full compliance with the general priorities, the sustainable
cooperation between the worlds of education (at secondary and third level), training and work.
To show the principles of aviation a curriculum is written around three teaching materials, the so
called Demonstration Objects. The first object is a small affordable wind tunnel. The main focus
will be on easy to use and readily available materials. This manual shows how to order and build
this wind tunnel yourself. Everything can be adjusted to your own preference. This is only an
indication on how to build it.
For further information and all original drawings, please contact your Fly High partner in your
country (see www.flyhigh-321.eu/partner )
4
2
Required items
The tunnel consists of four parts:
1.
2.
3.
4.
2.1
Wooden kit
Aluminium diffuser
Fan
Electronics
The wooden kit
Order at a CNC wood cutting company using Autocad drawings (please contact your Fly High
partner in your country, see www.flyhigh-321.eu/partner)
The wooden kit consists of the test section, the inlet and the wind tunnel support frame. You can
use the CATIA drawings and send them to a CNC wood cutting company.
This wooden package excludes the following:
- Windows (three times)
- Manometer for analogue wind speed calculation
The costs of cutting the wood at a CNC company should be between €400,- and €450,-.
2.2
Aluminium diffuser
Order at an air duct manufacturer using CATIA drawings (Appendix 1).
The Aluminium diffuser is also drawn in CATIA. With the 2D drawings any air duct company
should be able to make this diffusor. Make sure to tell them not to make it air tight (=they will put
sticky material on the inside and it should be non-sticky material on the outside).
Make it air tight with silicone kit on the outside
Costs should be between €70,- and €110,-.
2.3
Fan
Order from the internet.
The fan is an: AXIAL 2-250M 45 impulsion (ᴓ250mm) with a capacity of 3010m3/hr.
Impulsion means a pull fan instead of a blow fan. The outside diameter of this fan is fitted to the
inside diameter of the ᴓ270mm 'diffuser'. The wind speed of the fan is not adjustable; you will
need an additional regulator. An alternative option is the QC312M (airflow from impellor to
motor). Code Fan: 1QC3203. This fan is ᴓ300mm, which means you have to adjust the diffuser
drawings and the wooden support frame for the fan. This fan has a similar or slightly higher
capacity.
Costs of a fan should be between €300,-. and €400,-.
Costs for the regulator €60,5
2.4
Electronics
Order from the internet.
The electronics can be ordered by a company in your own country that sells Phidgets. Table 2.1
states the prices of a Dutch company. These prices are indications.
In the document Fly High Electronics Wind tunnel is explained how to install and use the
programme on the laptop in combination with the wind tunnel.
Table 2.1.
Phidget
Serial nr.
3132
Load cell 0-780 g
1046
Phiget bridge 4-input 1046
3801
Acrylic enclosure for the 1046
1018
Phidget interface kit 8/8/8
3804
Acrylic enclosure for the 1018
1115
Barometric Pressure sensor
1124
Precision temperature sensor
1136
Differential gas pressure sensor 2 KPa
Cable 60 cm
M-3x10 and M-3x20 Bolts and Nuts
2.5
pcs
2
1
1
1
1
1
1
1
2
20
Price
€ 8,26
€ 77,35
€ 7,74
€ 71,40
€ 8,33
€ 46,41
€ 12,20
€ 34,31
€ 2,81
n/a
Price overview
Part
Wooden Kit
Aluminium Diffuser
Fan
Electronics
Total
Average Costs
425,95,410,280,1210,-
These prices are exclusive all material needed to mount the parts together.
6
Total
€ 16,52
€ 77,35
€ 7,74
€ 71,40
€ 8,33
€ 46,41
€ 12,20
€ 34,31
€ 5,62
n/a
----------€ 279,88
3
List of Materials
This chapter lists all the parts that are needed for the construction of the complete wind tunnel.
Wooden parts
Part A (4x)
Flexible inlet
Part B (6x)
Curvature Inlet
Part D (1x)
Curvature inlet Support 2
Part E (1x)
Front Inlet
Part G (1x)
Roof Test Section
Part H (1x)
Bottom Test Section
Part I (4x)
Sides Test Section
Part J (1x)
Support test Section 1
Part K (1x)
Support test Section 2
Part L (1x)
Support test Section 3
Part M (2x)
Front and Back Test Section
Part N (1x)
Fan Support
Part O (2x)
Fan Support Feet
7
Part C (1x)
Curvature inlet Support 1
Part F (1x)
End Inlet
Part list for the measurement equipment
3132 Load cell 0-780g (2x)
1046 Phidget bridge 4-input
3801 Acrylic enclosure for the 1046
1018 Phidget interface kit
3804 Acrylic enclosure for
the 1018
1115 Pressure sensor
1124 Precision temperature 1136 Differential gas pressure sensor
2Kpa
sensor
Bottom plate (use drawings Appendix 2)
Connection Cable
Rubber Tube M4
Load cell to model
Load cell to bottom plate
Load cell to load cell connector
connector
connector
All connectors have to be made using the drawings (Appendix 3,4,5).
8
Drills
Bolts
Nuts
Rings
Screw Eye
Screws
Extension piece
Wing nuts
Steal pipes
Required tools
Type
Number
M3, M5, M8
M5 x 60
M5
M2 x 20
M4 x 40
M5
M3, M4, wall
thickness 1mm
Hand drill
Hacksaw
Epoxy Adhesive
Woodworking adhesive
Pencil
Polyester filler
Polyurethane kit
Ring spanner
Sandpaper
Screwdriver
Spatula
Wrench
9
4
Construction of the Inlet
The following items are required to construct the inlet:
Wooden Parts
Part A (4x)
Flexible inlet
Part B (6x)
Curvature Inlet
Part C (1x)
Curvature inlet Support 1
Part D (1x)
Curvature inlet Support 2
Part E (1x)
Front Inlet
Part F (1x)
End Inlet
Required tools
Screws
Hand drill
Woodworking adhesive
Polyester filler
Polyurethane kit
Sandpaper
Spatula
Type
M4 x 40
Number
72
Part A (4x)
Part B (6x)
Part F (1x)
Part E (1x)
Part C (1x)
Part D (1x)
10
1.
4.1
Assembling the boards
The first step is to draw marks on Part A. These marks are used to screw on Parts B and C. For
each board 7 screws are needed. Meaning that 14 holes will need to be drilled in Part A. Step by
step an explanation is given how and where the parts need to be screwed on.
Step 1) Required materials: Part A (4x)
Part B (1x)
Pencil
First we need to know were the holes have to be drilled. Take Part B and place it on the reverse
side of Part A , the hollow side (figure 1.1). Make sure Part B is parallel with part A. Draw a line
across part A (figure 1.2). Now we know were the holes can be drilled. Repeat the same action
for every board.
Part B
Part A
Figure 1.1:
Through the curves of Part B it will
in part A without any cracks.
Figure 1.2:
The red lines will show where the line has to be drawn. fit
If everything is correct, you will have some space at
the rear and the front, were part E and F can be assembled.
Step 2) Required materials: Part A (4x)
Pencil
Draw 7 marks between the lines. Divide the marks equally, so you eventually end up having 14
marks on each board.
Step 3) Required materials: Part A (4x)
Hand drill (diameter: M3)
Drill the holes on the marks using the hand drill.
Step 4) Required materials: Part A (4x)
Part B (6x)
Part C (1x)
Part D (1x)
Screws M4 x 40 (56x)
Part B, C and D can be screwed on now the holes have been drilled. Make sure the boards are
put in a right-angle.
11
4.2
Assembling the front and back frames
In this step parts A, E and F are assembled. The result is an unfinished inlet. You first assemble
the front of the inlet and afterwards you assemble the back.
Step 1) Required materials:
Part A (1x)
Part E (1x)
Pencil
A total of eight holes have to be drilled in Part E. To know exactly where the holes have to be
drilled, a line is drawn on the flat side of Part E, using the same method as step 1 in 3.2. Put the
front of Part A in the rear of Part E. Draw a line following the profile of the already assembled
Part B. Make sure you repeat this action for all four sides of Part E.
Step 2) Required materials:
Part A (1x)
Part F (1x)
Pencil
A total of twelve holes have to be drilled in part F. Eight holes are used to connect Part F with
Part A and four holes are used to connect Part F to the test section. At the back of Part A a space
is left in which you can fit Part F. Put Part F in Part A and draw a line following the profile of the
already assembled Part B. Repeat this action for every side of Part F. Place a mark in the middle
of this line on each side of Part F.
Step 3) Required materials:
Part E (1x)
Part F (1x)
Pencil
Draw a mark on Part E and F within the lines.
Step 4) Required materials: Part E (1x)
Hand drill (diameter: M3)
Drill the holes in Part E.
Step 6) Required materials:
Part A (4x)
Part E (1x)
Part F (1x)
Screws M4 x 40 (16x)
Woodworking adhesive
Hand drill
Sandpaper
12
The next step is to glue and screw the
parts together. Firstly we place Part E
on the floor with the flat side up. Use
some woodworking adhesive between
the drawn lines. Secondly you will slide
Part A onto each side of Part E. Part A
will rest on Part E, because of the
already screwed on Parts B, C and D.
The ends of Part A will come together,
so you can place Part F within. Use
woodworking adhesive between the
drawn lines on Part F and place it
within Parts A. Screw on Part F.
Carefully turn over the unfinished inlet,
so Part F will be on the floor. You can
now screw on Part E.
As a result you will have an unfinished
inlet. You can now fill up the tapped holes with Polyurethane kit and use Polyester filler to fill
up the gaps. Finish it off using sandpaper.
13
5
Construction of the test and measurement section
The following items are required to construct the test and measurement section:
Wooden Parts
Part G (1x)
Roof Test Section
Part H (1x)
Bottom Test Section
Part I (4x)
Sides Test Section
Part J (1x)
Support Test Section 1
Part K (1x)
Support Test Section 2
Part L (1x)
Support Test Section 3
Part M (2x)
Front and Back Test Section
Part M
(2x)
Part G (1x)
Required tools
Screws
Hand drill
Woodworking adhesive
Polyester filler
Polyurethane kit
Sandpaper
Spatula
Type
M4 x 40
Number
38
Part I (4x)
Part H (1x)
Part K (1x)
Part J (1x)
14
Part L (1x)
5.1
Construction of the measurement section
The test section is supported by two vertical boards. In
between these two vertical boards a horizontal board is
screwed. The electronics will be placed on this middle
board.
Step 1) Required materials: Part J
Part K
Pencil
Hand drill
(diameter: M3)
Draw three marks on Part K. These marks have to be
placed as high as possible on the board, but below the
main hole on Part K. Put Part K on Part J and drill the
three holes (figure 2.1).
Step 2) Required materials:
Figure 2.1
Part L (1x)
Pencil
Hand drill (diameter: M5)
Two holes have to be drilled in Part L. The holes are meant to fix a steal plate on with the
electronics will be placed. Draw two marks on Part L and drill the holes (figure 2.2).
Figure 2.2
Step 3) Required materials: Part J (1x)
Part K (1x)
Part L (1x)
Screws M4 x 40 (6x)
Hand drill
Screw on Part J and K on Part L (figure 2.3).
Figure 2.3
The measurement section is now complete. The next paragraph will explain how the test section
has to be constructed.
15
5.2
Construction of the test section
This section will explain how the test section is constructed. This is the part which is used for the
model. Subsequently the measurement section and the test section can be assembled together.
Step 1) Required materials: Part H
Pencil
Hand drill (diameter: M8, M3)
A total of three holes have to be drilled in Part H (figure 2.4). One hole has to be placed in the
middle for the model. The two other holes are placed at the side. These holes are used to connect
two tubes that will be used to measure the pressure difference.
Draw a mark in the middle of part H and drill a hole using a hand drill with a diameter of 8mm.
Draw two marks at the site and drill two holes using a hand drill with a diameter of 3mm.
Figure 2.4
Step 2) Required materials: Part H (1x)
Part I (4x)
Pencil
Part I has to be screwed onto part H in each corner.
Place Part I in the corner of Part H. Make sure the
parts are level and draw around Part I onto part H.
Repeat this action for each corner.
Draw two marks between the lines (figure 2.5)
Figure 2.5
Step 3) Required materials: Part G (1x)
Part H (1x)
Hand drill (diameter: M3)
The holes in Part G need to be at the same spot as Part H. Put Part H on Part G and drill the
holes in Part H and G simultaneously.
16
Step 4) Required materials: Part G (1x)
Part H (1x)
Part I (4x)
Hand drill
Screws M4 x 40 (16x)
Screw Part I onto Parts H and G (figure 2.6).
Figure 2.6
Step 5) Required materials: Part M (2x)
Part F (1x)
The diffuser
Pencil
Hand drill (diameter: M5)
Four holes need to be drilled in part M and part F (precisely on the same spot) to be able to
connect the test section with the inlet. You use a hand drill with a diameter of 3mm (see figure
2.7).
Do the same for the other part M and the diffuser to be able to connect the test section to the
aluminium diffuser.
Figure 2.7
Figure 2.8
Step 6) Required materials: Part M (2x)
Pencil
Hand drill (diameter: M3)
Draw two marks on each side of Part M, so Part M has eight marks in total on the sides (see the
orange marks in figure 2.8). Drill the holes. These holes are used to assemble Part M to the top
of the test section. The holes need to have some space between them.
17
Step 7) Required materials Top of the test section
Part M (2x)
Woodworking adhesive
Screws M4 x 40 (16x)
Hand drill
Use Part M (2x) and the unfinished test section. Put some woodworking adhesive on the inside
of Part M. Place the test section with the holes down within Part M (figure 2.9). Screw
everything together.
Figure 2.9
18
5.3
Assemble the top and the bottom of the test section
The final step is to assemble the top and the bottom of the test section. You can do this using
only woodworking adhesive. As soon as the adhesive has hardened, the test section can be
assemble to the inlet.
Step 1) Required materials Top of test section
Bottom of test section
Woodworking adhesive
Sandpaper
Put woodworking adhesive on the edges of the bottom of the test section. Place the top section
on the bottom part. Figure 2.10 will show you the final result.
Figure 2.10
An unfinished test section is the final result. You can use a filler to fill out the tapped holes.
The cracks at the inside of the test section can be filled out with Polyurethane kit. Finish it off
using sandpaper.
19
6
Assembling the Measuring Equipment
Part list for the measurement equipment
3132 Load cell 0-780g (2x)
1046 Phidget bridge 4-input
1018 Phidget interface kit
3804 Acrylic enclosure for the
1018
1124
Precision temperature sensor
1136 Differential gas pressure
sensor 2Kpa
Bottom plate (us the drawings Appendix 2)
3801 Acrylic enclosure for the
1046
1115 Pressure sensor
Connection Cable
Rubber Tube M4
Load cell to model
Load cell to bottom plate
Load cell to load cell connector
connector
connector
All connectors have to be made using the drawings (Appendix 3,4,5).
20
6.1
Assemble the bottom plate and connectors
To make the bottom plate and the three load cell connectors see attachment 2 to 5 for the detailed
drawings.
6.2
Connect Electronics to Bottom plate
Step 1) Required Materials: Load cell (2x)
Load cell to bottom plate connector
Load cell to load cell connector
Load cell to model connector
Figure 3.3
Figure 3.1
Figure 3.2
The arrows on the load cells indicate in which direction the load cell will measure the force. The
first load cell (measures the lift) is connected to the bottom plate by using the load cell to bottom
plate connector (see figure 3.1). The second load cell (measures the drag) is connected to the lift
load cell by using the load cell to load cell connector (see figure 3.2). A model can be connected
to the load cell combination by using the load cell to model connector (see figure 3.3).
21
Step 2) Required Materials 1046 Phidget bridge 4-input
3801 Acrylic enclosure for the 1046
1018 Phidget interface kit
3804 Acrylic enclosure for the 1018
Build the Acrylic enclosures around the 1046 and the 3804 (see figure 3.4, 3.5, 3.6 and 3.7).
Figure 3.5
Figure 3.4
Figure 3.7
Figure 3.6
22
Step 3) Required materials All parts
Connect all parts to the bottom plate as in figure 3.8. Connect all electronics together as in the
schematic overview in figure 3.9. The two USB cables can be connected directly to a laptop
using Excel visual Basic.
Pressure
sensor
Temperature
sensor
Differential
pressure
sensor
1046 +
Acrylic
enclosure
1018+Acrylic
enclosure
Drag Load
Cell
Figure 3.8
Lift Load
Cell
Figure 3.9
Figure 3.8
Figure 3.9
23
6.3
Pitot tube connection
Whilst building the test section 2 holes have been drilled in Part H. These holes are intended to
connect a Pitot tube. A Pitot tube is a pressure measurement instrument. Two connections are
made. One of the tubes will be bent through 90 degrees and the second tube will be parallel to
the wall of the test section. These tubes will be glued to the test section and a rubber tube is used
to connect to the pressure sensor.
Step by step the assembly of the connection will be explained.
Step 1) Required materials Steal tube M3, wall thickness: 1 mm
The first step is to bend the 3mm tube through 90 degrees. You need a cylinder shaped figure to
do this. It can’t be done by hand. You place the tube on the side of the cylinder and bend
alongside the cylinder shaped figure. The angled of the tube will have a circular shape (see
figure 3.10).
Figure 3.10
Step 2) Required materials: Curved tube M3, wall thickness 1 mm (1x)
Hack saw
The curved tube has to be sawed. Figure 3.11 will show you the measurements of the tube.
30 mm
Figure 3.11
24
50 mm
Step 3) Required materials: Steal tube M3, wall thickness 1 mm
Hack saw
Saw off a length of 50mm of this tube.
Step 4) Required materials: Steal tube M4, wall thickness 1 mm
Hack saw
Saw off a length of 40mm of this tube. Repeat this action.
Step 5) Required materials: Rubber tube M4
Cut off a part of this tube. Repeat the action.
Step 6) Required materials: Curved tube M3, wall thickness 1 mm (1x)
Steal tube M3, wall thickness 1 mm (1x)
Steal tube M4, wall thickness 1 mm (2x)
Epoxy adhesive
All the tubes have the right measurements now. They have to be glued
inside the test section with Epoxy adhesive. The tube with a wall thickness
of 4 mm can be slit onto the smaller tubes. First put Epoxy adhesive on
the M3 tubes and slide the M4 tube in. Place the test section on the floor
on its side and glue the tube in one of the holes at the front. The curved
tube can be glued in the same way. Make sure the curved tube is in the
direction of the inlet. Figure 3.12 and 3.13 show how the pitot tube can be
glued in the bottom of the tunnel. Figure 3.14 will show the final result as
an example in two different wind tunnels.
Test section (Part H)
Pitot tube
Figure 3.12
Tube M4
Figure 3.13
Figure 3.14
Step 7) Required materials: Test section
Rubberen tube M4 (2x)
Epoxy adhesive
Put some Epoxy adhesive on the 4 mm tubes and slide them into the rubber tubes.
The adhesive will be hardened after approximately a day. The differential pressure sensor can be
connected to the other ends of the tubes.
25
7
Construction of the fan support
The following items are required to construct the fan support:
Part N (1x)
Fan Support
Part O (2x)
Fan Support Feet
Step 1) Required materials Part N (1x)
Part O (2x)
Please connect the support and the feet together like in figure 4.1 and 4.2.
Figure 4.1
Figure 4.2
26
8
Assembly
The inlet and the test section have been constructed and the
measuring equipment has been set up. In this chapter it is explained
how all these elements will be connected to make the windtunnel
ready to use.
Step 1) Required materials: Inlet
Test section
Bolds M5 x 60 (4x)
Wing nuts M5 (4x)
Rings M5 (8x)
Connect the inlet to the test section using the bolds and wing nuts
(figure 5.1).
Step 2) Required materials: Test section
Diffuser
Bolds M5 x 60 (4x)
Wing nuts M5 (4x)
Rings M5 (8x)
Figure 5.1
Connect the test section to the diffuser using the bolds and wing nuts.
Step 3) Required materials: Diffuser
Fan
Step 4) Required materials:
Measurement Section
Electronics
On the other side of the diffuser the fan will be connected. The wind tunnel is now ready to use.
See figure 5.2 for the final result.
Figure 5.2
27
Appendix 1: 2D Drawing Diffuser
Please note the drawing is scaled down to fit this document; scale indicated on drawing is not representative.
28
Appendix 2: 2D Drawing Bottom plate
Please note the drawing is scaled down to fit this document; scale indicated on drawing is not representative.
29
Appendix 3: 2D Drawing of Load cell to bottom plate connector.
Please note the drawing is scaled down to fit this document; scale indicated on drawing is not
representative.
30
Appendix 4: 2D Drawing of Load cell to model connector
Please note drawing is scaled down to fit this document; scale indicated on drawing is not
representative.
31
Appendix 5: 2D Drawing of Load cell to load cell connector
Please note the drawing is scaled down to fit this document; scale indicated on drawing is not
representative.
32
The J-Plane
Authors:
Bruno Wiesler, Mario Gruber
-1-
Fly High – The Principles of Aviation as an Opportunity to Make Physical Theory Accessible
This project has been funded with support of the European commission. It reflects the views only
of the author, and the Commission cannot be held responsible for any use which may be made of
the information contained therein.
Project Number: 518156-LLP-1-2011-1-AT-COMENIUS-CMP
Grant Agreement: 2011 – 3562 / 001 – 001
Sub-programme or KA: Comenius
Web Site: www.flyhigh-321.eu
© July 2013, FH JOANNEUM GmbH
Editor-in-Chief: B. Wiesler
-2-
Contents
1 2 3 4 Introduction .........................................................................................................................4 J-Plane design ......................................................................................................................4 J-Plane launcher...................................................................................................................7 Water propulsion .................................................................................................................9 4.1 The bottles ....................................................................................................................9 4.2 Launching velocity and pressure ................................................................................12 5 Flight test results................................................................................................................13 Literature References ................................................................................................................16 Picture References ....................................................................................................................16 -3-
1
Introduction
J-Planes (Water Jet-Planes or JOANNEUM-Planes) are gliders with water jet propulsion at an
initial phase. The propulsion system is a bottle, partially filled with water and pressurized air.
Design your own glider for fun or to participate in the Fly High: Challenge according to the Fly
High: Body of Rules.
For your support, a document, Fly High: The Basic Principles of Flying, is provided as well as a
calculation sheet. The calculations are based on Fly High: The Golden Rules of Glider Design.
2 J-Plane design
An example of a J-Plane design is given in Figure 1. The J-Plane was built according to the
calculations (Figure 2). The results of the flight tests proofed the correctness of the used formulas.
J‐Plane
Input
Result Summary
Wing (W)
bW
ArW
Wing span
Aspect ratio
Angle of attack (tail)
Lift coefficient at 5 deg angle of attack (2D)
cl5W
Location of aerodynamic center, AC, of each wing (at c/4) xacW
Drag coefficient of bottle
Common
cDB
Diameter of bottle
Drag correction factor
Launching velocity
Launching height
Ambient temperature
Ambient pressure
dB
DCF
v
h
T
p
1,12
5,6
0,5
0
Tail (T)
bT
ArT
AlphatT
cl5T
xacT
0,15
4
‐2
0,5
0,7
Units
m
‐
deg
‐
m
Weight
AoA W
Chord W
Stability
Gliding angle
Distance
Orientation angle
Wing setting T
0,566 kg
7,174 deg
0,200 m
10,069 %
5,050 deg
20,369 m
2,124 deg
‐9,174 deg
0,50
0,07
1,35
8,89
1,8
298,15
1,00E+05
m
m/s
m
K
Pa
Final Geometry
Wing span W
Chord W
Wing span T
Chord T
Distance W TE ‐ T LE
Wing setting T
Center of gravity
1,120 m
0,200 m
0,150 m
0,038 m
0,541 m
‐9,174 deg
‐0,004 m
Figure 1: Example of a J-Plane design
Remarks:
Aspect ratio: should be as high as possible, higher values reduce drag, sailplanes have values of
higher than 20 or even higher than 30.
Location of AC of each wing: the distance from c/4 line of the wing to the c/4 line of the tail
(horizontal stabilizer).
AoA: angle of attack
Stability: The value indicates the glider’s stability in respect to gusts. A value of 10% or more is
recommended
Distance W TE – T LE: Distance for the wing’s trailing edge to the tail’s leading edge.
-4-
Figure 2: The J-Plane built according to figures given in the example
In addition to the calculation sheet, a graphical user interface made in MATLAB is provided for the
glider design. If MATLAB is not available, a stand-alone version can be used together with a freely
available
MATLAB
Compiler
Runtime
(http://www.mathworks.com/products/
compiler/mcr/index.html). Figure 3 shows the input mask of the program and Figure 4 the
corresponding results of a design. The software is also capable of handling predefined wing
profiles.
Figure 3: Glider design software, inputs
-5-
Figure 4: Glider design software, results
Whereas the J-Plane in Figure 2 has the bottle on-board, Figure 5 and Figure 6 show different
configurations using the water propulsion only during the initial phase on the launcher. These two
designs use an aspect ratio of 8 for the wing and an aspect ratio of 4 for the tail. The “Shark” in
Figure 5 has a wing-span of 83 cm and a weight of 109 g. The “Dragon” in Figure 6 weighs 240 g
and has a span width of 100 cm. Note that such variations of design and look are intended when
building the plane with pupils.
Figure 5: J-Plane design “Shark”
-6-
Figure 6: J-Plane design “Dragon”
3 J-Plane launcher
Examples of plane launchers and J-Planes are displayed in
Figure 7 and Figure 8.
-7-
Figure 7: Examples of plane launchers and J-Planes with the bottle on board
Figure 8: Examples of plane launchers and J-Planes with the bottle on the launcher
Figure 9 shows a sketch of a simple J-Plane launcher using a rain pipe for the guidance of the
bottle, two metal rails for holding the plane and a wooden frame construction.
Figure 9: Sketch of a simple J-Plane launcher
-8-
4
Water propulsion
4.1
The bottles
We have considered three designs of 0.5 l PET bottles (Figure 10):
•
Juice bottle for drinks without gas (no carbon acid), light design,
bottleneck: 35 mm
•
Juice bottle for drinks with gas, light design,
bottleneck: 22 mm
•
Juice bottle for drinks with gas, heavy design,
bottleneck: 22 mm
Upon request, a bottle manufacturer stated:
•
PET bottles are tested according to the specifications of the drink providers, e.g. bottles for
drinks with gas (heavy design) with reinforced bottom: pressure: 4.5 bar, duration: 10 h,
max. pressure: 12 bar, duration: unknown
F
Juice bottle for
drinks without gas,
light design (iced tea),
bottleneck: 34mm
Bottle for drinks with
gas, light design
(mineral water),
no reinforced bottom,
bottleneck: 22mm
Figure 10: Three different bottle designs
-9-
Bottle for drinks with gas, heavy
design (Almdudler, Coca Cola),
reinforced bottom,
bottleneck: 22mm
We just used the third design for the propulsion of J-planes. Anyway, we cannot take any guarantee
these bottles can withstand any pressure. You use it on your own responsibility and risk.
The bottle was prepared (Figure 11):
• Bottom drilling:13mm
• Standard valve of a car tire
• Tire filling device used
Figure 11: Preparation of the bottle
We built a test bench for pneumatic pressure test for PET bottles (Figure 12):
Tire filling device on one side of an aircraft door, bottle on the opposite side, ear protection.
An excess pressure up to 9.5 bar is available in our labs.
Figure 12: Test bench for pneumatic test for PET bottles
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These are the results of the tests (Figure 13):

Bottle, iced tea without gas, max excess pressure 8 bar, breakage of screw cap, strong
bulge of the entire bottle;

Bottle, mineral water with gas, max. excess pressure: 8.5 bar, breakage at the drilling for
the valve because of a strong bulge of the bottom;

Bottle, Almdudler and Coca Cola with gas, max. excess pressure 9.5 bar, no significant
deformation, no breakage.
Figure 13: Bottles after the pressure test series
Further, we have tested two different systems for the release mechanism: a connector of a garden
hose and a cork (Figure 14). Both worked well. They can be used for the selection of the release
opening. Obviously, with the cork the full bottleneck area with a diameter of 22 mm is used. Using
the connector, the opening is reduced to a diameter of 9 mm.
Figure 14: Release mechanisms
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4.2
Launching velocity and pressure
Using the water propulsion from the previous chapter, appropriate launching velocities can be
achieved according to the weight of the plane. An approximation derived from experiments is
given in Table 1. The values may change for different launchers due to friction. In this evaluation
the launching angle was 0 degrees and the 500 ml bottle was filled with 250 ml of cold tap water.
Excess pressure in bar Weight in g (without bottle and water) 100 110 120 130 140 150 160 170 180 190 200 5,5 59,7 59,5 59,1 58,6 58,0 57,2 56,3 55,2 54,0 52,6 51,1 5 54,7 54,5 54,1 53,6 53,0 52,2 51,2 50,2 49,0 47,6 46,1 4,5 49,7 49,5 49,1 48,6 48,0 47,2 46,2 45,2 43,9 42,6 41,1 4 44,7 44,5 44,1 43,6 43,0 42,2 41,2 40,2 39,0 37,6 36,1 3,5 39,8 39,5 39,2 38,6 38,0 37,2 36,3 35,2 34,0 32,6 31,1 3 34,8 34,6 34,2 33,7 33,0 32,3 31,3 30,3 29,0 27,7 26,2 2,5 29,9 29,6 29,3 28,8 28,1 27,3 26,4 25,3 24,1 22,8 21,3 2 24,9 24,7 24,4 23,8 23,2 22,4 21,5 20,4 19,2 17,8 16,3 1,5 20,1 19,8 19,5 18,9 18,3 17,5 16,6 15,5 14,3 12,9 11,4 1 15,2 14,9 14,6 14,1 13,4 12,6 11,7 10,6 9,4 8,1 6,6 0,5 10,3 10,1 9,7 9,2 8,6 7,8 6,8 5,8 4,5 3,2 1,7 Excess pressure in bar Weight in g (without bottle and water) 200 210 220 230 240 250 260 270 280 290 300 5,5 51,1 49,5 47,7 45,8 43,7 41,5 39,2 36,7 34,1 31,4 28,5 5 46,1 44,5 42,7 40,8 38,7 36,5 34,2 31,7 29,1 26,3 23,4 4,5 41,1 39,5 37,7 35,8 33,7 31,5 29,2 26,7 24,1 21,3 18,4 4 36,1 34,5 32,7 30,8 28,7 26,5 24,2 21,7 19,1 16,3 13,4 3,5 31,1 29,5 27,7 25,8 23,8 21,6 19,2 16,8 14,1 11,4 8,5 3 26,2 24,6 22,8 20,9 18,8 16,6 14,3 11,8 9,2 6,4 3,5 2,5 21,3 19,6 17,9 15,9 13,9 11,7 9,3 6,9 4,2 1,5 2 16,3 14,7 12,9 11,0 9,0 6,8 4,4 1,9 1,5 11,4 9,8 8,0 6,1 4,1 1,9 1 6,6 4,9 3,2 1,2 0,5 1,7 0,1 Table 1: Approximation of launching velocities in km/h (0.5 l PET bottle, 50 % Water)
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5
Flight test results
According to [1], lift differs quite much from theory for Reynolds numbers below 105 at any angle
of attack, because there is flow separation for most areas of the profile. Advanced investigations in
[2] lead to an estimate for a maximum lift-to-drag ratio of about 6 for the examined design. This
can only be an approximate value, since a flat plate with a Reynolds number of 2·104 is subject of
the literature. It has to be considered that we are not treating a profile only, but an entire plane
including an airframe and a tail, which would even reduce the maximum lift. On the other hand, the
Reynolds number of the design “Shark” was determined to be around 4·104, which would improve
the lift-to-drag ratio.
In fact, the performance of the J-Plane designs proofed to be slightly better than expected, not
accounting for additional measurement errors. Table 2 shows a summary of different designs
tested. Measurements are highlighted in red. All other values are derived from these measurements,
except those which are marked as estimation (based on [2]) or calculation (see chapter 2 for
details). All flight tests were performed with a launching angle of 0 degrees and a launching height
of 1.80 m.
Note that only proper gliding flights with constant velocity are considered for this comparison.
Much longer distances can be achieved with higher launching velocities allowing phugoids.
However, such flights are not matter of the calculation sheets, harder to quantify and require
advanced knowledge of physics to be characterised accurately.
In any case, the measurements already exceed the initial estimation of a lift-to-drag ratio of about
6. Table 2 shows that L/D ratios between 6 and 9 are possible, giving flight distances of up to 17
metres with the presented designs without the bottle on board. Again with the limitation for proper
gliding flights, longer distances can easily be achieved allowing phugoids for challenges.
For using the glider calculation sheet presented in Figure 1, this means a drag correction factor
(DCF) of about 2.8 should give realistic results, especially for wooden structures with similar
dimensions. Figure 15 is a visual summary of the measurements, showing the pressure in the bottle,
the launching velocity, as well as the weight and the achieved flight distance for the different
designs investigated.
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Description Lift L [N] Drag D [N] L/D [‐] Gliding
angle [deg] Estimation Re < 10 (Max.) 6 9,5 10,80 5
Weight Excess Launching Distance [kg] pressure velocity
[m] [bar] [km/h] h = 1,8 m DCF [‐] J‐Plane design "Shark" (Wing span = 83 cm) Calculation sheets 1,064 0,149 7,1 8,0 0,108 2,0 22,0 12,85 2,8 Measurements with Balsa wood designs Standard Configuration 1,059 0,149 7,11 8,0 0,109 2,0 23,6 12,8 2,82 Standard Configuration 1,058 0,155 6,83 8,3 0,109 2,0 23,6 12,3 2,93 Standard Configuration 1,058 0,157 6,72 8,5 0,109 2,0 23,6 12,1 2,98 Standard Configuration 1,059 0,147 7,22 7,9 0,109 2,0 24,7 13,0 2,77 Additional end plates 1,352 0,243 5,56 10,2 0,140 2,3 25,9 10,0 3,73 Additional end plates 1,360 0,188 7,22 7,9 0,140 2,5 28,8 13,0 2,87 2,992 0,490 6,11 9,3 0,309 6,5 37,0 11,0 3,8 Aluminium tube body Measurements with design entirely made of glass fibre sheets Standard Configuration 2,130 0,349 6,11 9,3 0,220 4,0 32,0 11,0 3,62 Standard Configuration 2,138 0,296 7,22 7,9 0,220 4,5 37,0 13,0 3,06 Standard Configuration 2,146 0,227 9,44 6,0 0,220 5,0 43,2 17,0 2,34 J‐Plane Design "Dragon" (Wing span = 1 m) Calculation sheets 2,358 0,295 8,0 7,1 0,240 4,0 28,8 14,39 2,8 Measurements with Balsa wood designs Standard Configuration 2,340 0,263 8,89 6,4 0,240 4,0 32,4 16,0 2,88 Standard Configuration 2,335 0,300 7,78 7,3 0,240 4,0 28,8 14,0 2,52 Table 2: J-Plane designs and results of flight tests
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Figure 15: J-Plane designs and results of flight tests
- 15 -
Literature References
[1]
H. Schlichting, E. Truckenbrodt, Aerodynamik des Flugzeuges, Erster Band, Grundlagen aus
der Strömungstechnik: Aerodynamik des Tragflügels (Teil I), 3. Auflage, Springer-Verlag,
2001
[2]
John McArthur, Aerodynamics of Wings at Low Reynolds Numbers: Boundary Layer
Separation and Reattachment, Dissertation, University of Southern California, 2008
Picture References
Bruno Wiesler
Mario Gruber
Richard Wagner
Figures 1-2, 7
Figures 3-4, 8, 15
Figures 5-6, 9-14
Fly High Partners:
FH JOANNEUM – University of Applied Sciences Graz – AT
Styrian Association for Education and Economics Graz – AT
BG und BRG Seebachergasse Graz – AT
Hochschule Bremen – DE
InHolland University of Applied Sciences Delft – NL
Christelijk Lyceum Delft – NL
Universidad Politecnica de Madrid – ES
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