Kites - Loughborough University

flexible

structures

Eddie Norman Jay Cubitt

Flexible structures –Kites

Philip Allan Publishers Limited

Market Place

Deddington

Oxfordshire OX15 0SE

First published 1999

ISBN 0 86003 229 9

© 1999 Philip Allan Publishers Limited

All rights reserved

Artwork and design by Juha Sorsa

Printed by Lindsay Ross, Abingdon

COPYRIGHT NOTICE

Any educational institution that has purchased one copy of this publicationmay make duplicate copies for use exclusively within that institution.Permission does not extend to reproduction, storage in a retrieval system, ortransmittal, in any form or means, electronic, mechanical, photocopying,recording or otherwise, of duplicate copies for loaning, renting or selling to anyother institution without the prior consent in writing of the publisher.

The butterfly image on p.18 is reproduced by kind permission of Breck P. Kent /Oxford Scientific Films.

The greetings card kites pictured on p. 28 are available from:Kite Corner, 657 Watford Way, London NW7

The ‘Incredible Pocket Kite’ pictured on p. 28 can be obtained from:Lagoon Games, PO Box 311, Kingston KT2 5QW

The image of the Flexifoil power kites on p. 51 is reproduced by kind permission of Flexifoil International.

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KEY STAGE 3 DESIGN AND TECHNOLOGY RESOURCE PACK

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esContents

Introduction .............................................................................................................. 1

Information Sheet (IS)1:Construction of a ‘paper and artstraw’ original kite ............................................. 11

Section 1: Building a kite – a focused practical task

Teacher’s notes (TN)1 ............................................................................................. 12

Focused practical task (FPT)1–12 .......................................................................... 16

Information sheet (IS)2: Some interesting kite designs ....................................... 28

Section 2: Kite design – a design and make assignment


Design and make assignment (DMA)1–17 ........................................................... 34

Information sheet (IS)3: Kites and materials ......................................................... 51

Section 3: IDEAs and extension tasks


Materials and components (MC)1–5 ................................................................... 56

Structures (S)1–3 ..................................................................................................... 61

Science (Sc)1–4 ....................................................................................................... 65

Mathematics (M)1–2 .............................................................................................. 69

Information and communication technology (ICT)1–2 ...................................... 71


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IntroductionAuthors

Eddie Norman is a senior lecturer in the Department of Designand Technology at Loughborough University and has beenappointed co-director of IDATER (the International Conference onDesign and Technology Educational Research and CurriculumDevelopment). He was a co-author of the textbook Advanced Designand Technology (Longman) and of a video series aimed at Key Stage 3design and technology. Most recently, he was chief editor of the GCSEmagazine New Designer. He is also a guitar enthusiast.

Jay Cubitt is a part-time lecturer in the Department of Design andTechnology at Loughborough University. She was a co-author ofAdvanced Design and Technology and is at present researching andproducing flexible learning materials in design and technology. Jay has also spent the last 10 years pursuing research into the humanenergy system. She is the founder member of Spectrum Healing,which she practises and teaches in the UK and abroad. She alsoenjoys music and Appalachian Dance.

About this packThis resource pack has two essential aims:

u to provide the opportunity to meet National Curriculum (NC) requirementsthrough a broadly based, innovative approach;

u to facilitate designing through the visual representation of technology, wherepossible.

The pack has a number of key objectives:

u to support the teaching and learning of design and technology at Key Stage 3 (KS3);u to facilitate teaching and learning in relation to structures and materials and

components;u to support cross-curricular links to art and design, information and communication

technology (ICT), humanities, mathematics and science;u to support differentiation by providing extension tasks for the more able students and

revisiting opportunities for the less able ones.

The resource pack is targeted at the teaching of structures at KS3, but is flexibly organisedto allow the depth in many other areas to be varied depending on the available time andthe students’ capabilities, e.g. designing skills, making skills, materials and components,quality and planning. It has been designed to fit into any one of Years 7, 8 or 9, whichallows teachers flexibility in fitting work in this area into their existing programmes. It hasbeen envisaged that the project would be one of approximately nine completed duringthis Key Stage (see the SCAA model on page 2). A particular innovative feature of this packis the teaching of structures, which is traditionally regarded as ‘hard’ technology, throughwork including ‘soft’ materials such as paper and textiles. Such ‘soft’ materials are notalways fully accepted as suitable for work in technology, and this resource pack seeks tosupport the technological aspects of their use.

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The National Curriculum requirements concerning structures at KS3 could be metin a variety of ways, but kites offer a particularly rich context. Kites have been madein schools for decades for the very good reason that they offer pupils an excitingopportunity to explore designing and making. They have been the focus of work insubject areas such as science and art and design, and there are well-known oppor-tunities for many other cross-curricular links, e.g. to the humanities, ICT andmathematics. This pack has been designed to develop these strengths, in supportingthe teaching and learning of KS3 design and technology. There are other flexiblestructures that could be similarly addressed (e.g. carrier bags, shelters, umbrellas andfurniture), but kites have been selected as they seem to offer the richer opportunities.

A selection of briefs is provided on one of the photocopiable sheets (DMA4). The majorpotential difficulty is the possibility of inclement weather conditions, and homeworkprobably provides the best means of overcoming this problem. Students can then test theirkites in their own time when the conditions are right.

There are many kite enthusiasts, and the potential interaction associated with kitedesigning and making offers the opportunity to build useful links between the school andthe community.

The initial focused practical task – making and evaluating a kite constructed mainly fromrecycled materials – is also a familiar theme, but this is one which echoes current designmovements. The Recycling exhibition, organised by the Crafts Council, toured the UK recently.This and the Re(f)use exhibition in the USA have celebrated the work of many designers usingrecycled materials. The International Design Resource Awards (IDRA) competition involvesdesigning with recycled materials and is organised from Seattle in the USA. It can be enteredby both professional and student designers, including school pupils. The World WideWeb site is http://www.worldinc.com/idra/ – further information can be found there.

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1 Provisional titles are chosen

for nine units of work which will provide opportunities for activities

in a range of contexts.

2 Each unit reflects the main requirements of the Programme of Study. Once each unit has been organised on an individual basis, the units are compared to check for overall coverage and progression across the key stage.

Source: SCAA (1995) Key Stage 3 Design and Technology – The New Requirements.

U N I T 5 : M A N U F A C T U R I N G

u Range of activities

u Designing

u Making

u Knowledge and understanding

– Materials – Systems and control – Structures – Products and applications

– Quality – Health and safety

Y7

Y8

Y9

UNIT 1 Play

UNIT 2 Community UNIT 3

Retail world

UNIT 6 Transport

UNIT 5 Manufacturing

UNIT 4 Communications

UNIT 7 Safety and security

SCAA model for Key Stage 3 design and technology

Howard Gardner, in considering human rationality as part of his authoritativeaccount of the development of cognitive science, made the followingcomments:

We can better understand the logical reasoning of humans not by imputing tothem any formal logical calculus but by attending instead to two factors. Thefirst has to do with content: the greater the familiarity and the richer the rele-vant schemata which are available, the more readily can one solve a problem. Thesecond attribute has to do with form: one succeeds on problems to the extent thatone can construct mental models that represent the relevant information in anappropriate fashion and use these mental models flexibly. Just how one learns to con-struct such mental models, to integrate them with ‘real world’ knowledge, and todeploy them appropriately in the proper circumstances are fertile questions for devel-opmental and educational psychology.

Source: H. Gardner (1985) The Mind’s New Science: A History of the Cognitive Revolution, Basic Books Inc., pp. 369–70.

The connection between Gardner’s analysis and this resource pack concerning kitedesign might not be immediately apparent, but it is real enough. Foundation studies –focused practical tasks (FPTs) – improve familiarity of a particular technology andcontext and help the construction of relevant schemata. The FPT presented hereprovides the opportunity for lessons on drawing skills, materials recycling, forces,structural members, understanding solutions evolved from nature, centre of gravity,stability and safety issues, the making skills associated with kite building, the basics of kite flying and the undertaking of systematic tests in order to troubleshootdifficulties.

Teachers could spend a considerable amount of time on such topics, and couldstart the design and make assignment (DMA) in parallel if they wish (choosing abrief, developing a specification, etc.) DMAs seek to develop the ability to constructappropriate mental models and use them flexibly. The pupils are encouraged hereto be as free-thinking and experimental as they can. The DMA is a learningexperience and they need to be adventurous and take risks in order to get the mostfrom it. One or two experimental kites might ultimately not fly too well, but theymay have other qualities that make their builders equally proud of their efforts.

The other issue that Gardner raises concerns the richness of the relevant schemata. Indeveloping foundation studies and the associated designing activities, the opportunityshould be provided for students to make the greatest number of possible connectionsto design whilst building up their capability in a particular area of technology. Kitesprovide a particularly rich opportunity because of their history, cultural significance andthe nature of the associated technology – as well, of course, as the excitement andenjoyment of getting them to fly. The following examples demonstrate some of theirpotential.

Kite technologyThe traditional approach to getting kites to fly has been to follow an established pattern.Essentially, kite making has been a craft activity. Our understanding has now increased,however, and this means other approaches are possible. Two scientists – Toshio Ito andHirotsugu Komura – studied kites and sought to explain why they fly (see their book Kites: the Science and the Wonder, Japan Publications Inc., 1983). Thus it is possible tolook more closely at the scientific aspects of the technological knowledge that enablesworking kites to be designed, rather than simply repeating previous successes.

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Kite materialsIt is essential to achieve good ratios of strength and stiffness to weight, if thekites are to fly. Kite materials have therefore been selected from those availableat particular times and places to fulfil the required roles. Silk, paper, bamboo,cloth, leaves, wood and modern synthetic materials have all been used.Identifying why and finding modern available equivalents can lead to consider-able understanding of the nature of materials. The focused practical task suggeststhe use of newspaper and artstraws in order to construct a kite, but the use of recycledmaterials is also a posssibility. Experimenting with such materials helps to developtechnological values like practicality, ingenuity, empathy and a concern for ‘appropri-ateness’.

Kite designDesigning and making a kite requires the synthesis of issues from a range of areas –cultural, historical, visual and technological. Such synthesis will require a variety ofmodelling techniques, including 2-D drawings, both decorative and functional, 3-Dprototypes to test performance, and cognitive modelling in order to imagine a design.As the design moves into the areas of structural analysis and materials selection, thepedagogical difficulties associated with integrating design and science need to beaddressed. Designers tend to talk in terms of various kinds of modelling, whereasscientists refer to various kinds of notation. Finding representations of scientificprinciples that facilitate design modelling is not always straightforward, but visualrepresentations (graphs and diagrams) would be expected to help.

Visual explanationsOne way of addressing the issue of visual representation, particularly bearing inmind the age range of the pupils, is to make maximum use of clear diagrams toexplain technical ideas. Technology has been captured visually for generations,probably since it was first captured.

Three A4 posters have been included in this pack. These could be enlarged and puton a wall, in order to be directly available to the pupils. Visual explanations oftechnology are one way of helping pupils bring design and science together.

Cross-curricular linksCross-curricular links to the humanities and art and design have been built into theFPT and DMA. Links to science, mathematics and ICT have been treated separately inorder to give teachers specific control of these areas. They may be suitable for somepupils and not for others. Such cross-curricular links are one way in which teachers canapproach differentiation.

DifferentiationDifferentiation has also been facilitated through the inclusion of tasks relating to investi-gating, disassembling and evaluating familiar products and applications (IDEAs). Theserelate to two areas of the design and technology programmes of study – materials, andcomponents and structures. These can be used flexibly both to support those havingdifficulty with particular areas and to challenge pupils to look at new areas.

Teachers need to spend as much time as possible on more challenging tasks such as dif-ferentiation. It is hoped that this pack will promote and support an independentlearning approach, which is a key aspect of design and technology.

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Structure of this packThe pack consists of:

u this general introduction;u teacher’s notes (TN) before each of the three sections (FPT; DMA; IDEAs and

extension tasks);u 45 photocopiable student worksheets;u three A4 colour information sheets (IS), which could be enlarged to make posters

if required.

Student worksheets

Section 1 (Building a kite – a focused practical task)

12 WORKSHEETS (FPT1–12) Context: recyclingFocuses: making skills

evaluating structures

Section 2 (Kite design – a design and make assignment)

17 WORKSHEETS (DMA1–17) Briefs: ‘kite’ briefs for different contexts Focuses: designing skills (links to art and design)

making skillsmaterials and componentsqualityplanning

Section 3 (IDEAs and extension tasks)

16 WORKSHEETS

MC1–5: materials Activities aimed at Years 7, 8 and 9. They are suitableand components for either initial teaching or extension activities.

S1–3: structures Activities aimed at Years 7, 8 and 9. Again, they are suitable for either initial teaching or extension activities.

Cross-curricular links:

Sc1–4: science Understanding the atmosphere, measuring forces, under-standing gravity, lift and drag forces.

M1–2: mathematics Measuring distances, angles and heights, scaling lengths and enlargements.

ICT1–2: information and Use of the Internet (kites, recycling, etc.), graphics packages,communication technology CAD/CAM (stick-on plastic images, embroidery).

Information sheetsThese sheets divide the text, but it is also possible to enlarge them so they serve as wallcharts/posters. The first of these posters tries to indicate the general strategy forconstructing the original kite shown in the FPT, so that pupils can be given an overview of the kite-making process. The second poster shows some interesting modern designswhich relate to the design briefs given in the pack. It might be used to provide inspirationif necessary. The third poster relates particularly to materials for kite making in differenttimes and cultures. It also indicates the key features of kite forms and how they haveevolved.

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Programmes of studyIt is anticipated that teachers will use the pack flexibly and place appropriateemphases in order to provide the required balance in the school’s Key Stage 3curriculum. The table below, however, indicates those aspects of the KS3programmes of study that could potentially be addressed through this resourcepack, along with relevant worksheets. The time available for the project will be themajor factor in determining which aspects are covered.

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DMAs: resistant materialscompliant materials and/or food

FPTsIDEAs

work independently/in teamsapply programmes of study of other subjects

Identify sourcesUse design briefsDevelop specificationConsider needs and valuesGenerate and modify proposalsConsider aesthetics, functionTake account of properties of materialsPrioritise and reconcile decisionsTake account of restrictionsModel ideasDevelop plan and alternativesEvaluate design ideas

Use forming processesSelect tools/process materialsUse appropriate methods of shapingJoin/combine materials and componentsUse construction kitsInterconnect a variety of componentsApply finishing techniquesMake products in quantityDevelop strategies for makingEvaluate/test productsImplement identified improvements

Properties of materialsClassification of materialsCombining, processing, finishing materialsHeat treatment and combining materialsPressing/casting materials

DMA1–17DMA 1–17

FPT1–10MC1–5, S1–3

DMA16Sc1–4, M1–2,ICT1–2

ICT1, DMA9DMA4DMA5DMA1, DMA4DMA6–7DMA6–7DMA2–3DMA13DMA12–13DMA6, DMA12DMA15DMA13

DMA12DMA12DMA12DMA11

DMA11DMA10DMA16DMA14–15FPT8–11, DMA17FPT12, DMA12

MC2–3DMA9DMA10–11, MC4

Opportunities for capability through:

Opportunities to:

Designing skills

Making skills

Materials andcomponents

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Covered RelevantAspects of programmes of study in pack? worksheets

The SCAA document Key Stage 3 Design and Technology — The New Requirements makesthe following suggestions concerning how teachers can support pupils in theirdesigning. They should:

u ask appropriate questions;u encourage pupils to discuss and explore their ideas;u encourage pupils to reflect on their work at various points in the process;u help pupils draw on skills and knowledge drawn from other subjects, particularly art;u display aspects of designing as a process, as well as finished products;u provide pupils with the opportunity to find out about designing in other contexts,

e.g. through developing links with local industry and designers.(p. 11)

It is clear that this resource pack provides the necessary opportunities to achieve the firstfive of these objectives. The last objective would require further organisation, but isimaginable within the context of a kites project.

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Design, use, interconnectMechanisms and movementUse switches to control devicesUse sensorsSystems have inputs, process, outputsFeedbackAnalyse performance of systems

Recognise and use structuresFailure of structuresTest for excessive loadsReinforcement methodsUnderstand forces and their effects

Intended purposeChoice of materials/componentsProcesses usedScientific principles

Views of users and manufacturersAlternative products

Meets needFitness for purposeUse of resourcesImpact beyond purpose

Recognise hazardsInformation to assess risksAction to control risks

MC5

S1–2DMA12S3MC1Sc2–4

DMA1FPT2, DMA2–3DMA3DMA1, FPT1,Sc2–4

DMA13, DMA17DMA13–17DMA1–3

FPT9FPT9FPT9

Systems and control

Structures

Products and applications

Quality

Health and safety

×√×××××

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××

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Covered RelevantAspects of programmes of study in pack? worksheets

In relation to making skills, the SCAA document suggests that teachersshould help pupils to consider:

u the physical and chemical properties of materials, and relate theseproperties to the ways in which materials are worked and used;

u that materials can be classified according to their properties and behaviourand to the major classifications with the material categories they are using,e.g. thermoplastics and thermosets;

u that materials can be combined, processed and finished in order to create moreuseful properties and desired effects, e.g. combining different ingredients tocreate products with different sensory characteristics;

u how knowledge and skills drawn from art, mathematics and science can be appliedto making;

u how to relate previous experiences to new problems so that pupils develop theirability to draw on their repertoire of skills and understanding.

(p. 15)

Of course other projects, such as the use of food and polymers, are the intendedroute for meeting some of these objectives, but the potential of a project thatinvolves designing and making kites is evident.

MaterialsThe following is a list of possible sources of reclaimed materials that could beused to make the kites.

Artstraws, dowelling and ‘structa sticks’ can be purchased cheaply and are veryeffective materials for struts.

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Material Purpose

bin bags coverbuilders’ plastic sheeting cover

cotton handkerchiefs covercarrier bags coverold cagoules/waterproofs cover

polystyrene tiles coverstiff foam covertorn sails coverwrapping paper coverwallpaper covernewspaper coverhole reinforcers reinforcerbiro cases tail attacherbeads connectorsfermenting tubes (from home-brew kits) connectors

fish tank air tubing connectorsplastic coated electrical wire connectors

Material Purposeribbon connectors/tailpaper cups tail decorationplastic cartons tail decorationplastic bottles tail decorationdrinking straws struts/springs/

tail attacherbamboo strutscoat hangers strutskebab or barbecue sticks struts

garden sticks for potted plants struts

plastic tubes (rigid) strutsplastic knitting needles strutstwigs (willow is best) strutsreeds strutsfishing reel line line/bridlesewing thread line/connectorscotton reels reeldrinks cans reelfood trays (polystyrene) reel

Tools and equipmentThe following items are typical of those that need to be available:

u sellotape u pairs of compassesu coping saws u cutting knivesu cutting mats u felt tipsu glue u hand drillsu hot glue gun u masking tapeu paint u scissorsu spray mount u vices

Contacts and other resources

The InternetThe Internet is a very powerful resource for use with this project, both for pupils andteachers. The Kite Society of Great Britain Web site (http://ourworld.compuserve.com/homepages/kite_society/) provides an up-to-date list of shops, wholesalers, retailers,festival traders, manufacturers and mail order companies, as well as indicating whetherbooks, magazines, kite-making materials, etc. are stocked. These are shown by area andit would be the best way to locate useful contacts near to you. The first page of this Website has been reproduced on ICT1 (p.70); the postal address of the Kite Society ofGreat Britain is shown overleaf in case you do not have access to the Internet.

There are other sites containing a wealth of information concerning the art, history,science, technology and practice of building and flying kites, as well as details oforganisations, publications and events. Some sites contain details of music relatingto kites, stories and safety rules for flying. It is well worth making the effort to finda way of obtaining Internet access. The best Web sites relating to kites are asfollows:

u The American Kitefliers Association: http://www.aka.kite.org/u The Australian Kiteflyers Society: http://www.aks.org.au/u The Drachen Foundation: http://www.drachen.org/u Exeter Kite Central: http://info.ex.ac.uk/~jastaple/kites/htmlu Kite Fliers Site: http://www.kfs.org/kites/u The Kite Society of Great Britain (see above)u Kites.Org: http://www.kites.org/u The Midlands Kite Fliers of Great Britain:

http://www.canleo.demon.co.uk/mkf/welcome.htmu Peter’s Kite Site: http://www.win.tue.nl/cs/fm/pp/kites/index.html

BooksBridgewater, A. and G. (1985) Easy to Make Decorative Kites, Dover Publications Inc.Eden, M. (1989) Kiteworks: Explorations in Kite Building and Flying, Sterling Publishing

Company Inc.Hart, C. (1982) Kites: An Historical Survey, Paul P. Appel.Ito, T. and Komura, H. (1983) Kites: the Science and the Wonder, Japan Publications Inc.Kent, S. (1997) The Creative Book of Kites, CLB International.Moulton, R. (1978) Kites, Pelham Books.Pelham, D. (1976) The Penguin Book of Kites, Penguin.Streeter, T. (1980) The Art of the Japanese Kite, Weatherhill.

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MagazinesFor an extensive, up-to-date list of books and magazines, see the Peter’s KiteSite Web pages (address above).

AcknowledgementsWe would like to thank Dr Howard Denton (Programme Leader for the IndustrialDesign and Technology degree at Loughborough University) and Georgina Royle(Head of Design and Technology at St Paul’s RC Comprehensive School, Leicester)for their helpful comments and criticisms concerning early drafts.

Thanks also to Nicola Heyes for her work as a Research Assistant on this resourcepack, the preparation of which was substantially funded by the Department of Designand Technology at Loughborough University.

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American KiteP O Box 699Cedar RidgeCA 95924USATel.: 916-273-3855Fax: 916-273-3319

Kites17 Crowborough RoadSaltdeanEast SussexBN2 8EATel./fax: 01273-308787

Kite PassionP O Box 152WokingGU21 1FSTel.: 01795-414849

The Kiteflier (newsletter of the Kite Society of Great Britain)P O Box 2274Gt HorkesleyColchesterEssex CO6 4AYTel./fax: 01206-271489

Kite LinesP O Box 466RandallstownMD 21133-9987USATel.: 410-922-1212Fax: 410-922-4262e-mail: [email protected]

Construction of a ‘paperand artstraw’ original kite

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Key Stage 3 Design and Technology Resource Pack©

Spring

Main stiffeners Smaller ribs

Stiffened area

Building a kite – a focused practical task

he general aim of this focused practical task (FPT) is to motivate the pupilsby putting them in the position of the early kite builders and taking themthrough a first kite-building experience in a controlled way. Clearly it is to be

hoped that the kites fly well, but there are a great many minor objectives to be metprior to the ‘flight tests’. For example, developing an understanding of:

u the requisite shape of kites (FPT1);u kite materials and their required properties (FPT2);u natural forms by looking at nature for inspiration (FPT3);u the role of stiffeners (FPT4);u compression forces (struts) and a feel for the forces involved in kite flying (FPT5);u the concept of centre of gravity (FPT6);u tension forces (ties) (FPT7);u stability (FPT8 and FPT10);u safety issues relating to kite flying (FPT9);u how to fly a kite (FPT11);u how to analyse and improve a design (FPT12).

Pupils may be more or less aware of these concepts from previous studies and,consequently, the time allocated and the balance of the activities must bedetermined by the teacher to suit their circumstances. The following notes relate tothe possibilities afforded by each worksheet; the relevance in a particular school’scurriculum cannot be predetermined. The notes are intended to help teachers tomake the most of the opportunities.

The analysis presented here is a very simplified version of that developed by twoscientists, Drs Toshio Ito and Hirotsugu Komura. They experimented for 4 yearswith over 1,000 model kites and presented their findings in a book, Kites: the Scienceand the Wonder (Japan Publications Inc., 1983). The book is too complex for KS3pupils, but would nevertheless make a useful addition to the school library for teachersand older pupils. It is hoped that this FPT will provide a richer educational experiencethan the ‘paperfold’ kites, which can be found in David Pelham’s The Penguin Book ofKites, and the ‘trash-bag sled’, which can be found in Sara Kent’s The Creative Book of Kites.However, both of these would be quicker for the pupils to make and get them into kiteflying more rapidly.

Notes on worksheets FPT1–12

FPT1 The shape of a kiteKites come in a vast range of shapes and sizes, which is part of their fascination. Theworksheet should help pupils to realise that there are two key features that can beidentified on all kites: (a) a ‘wind-receiving plane’; and (b) some surface area perpendic-ular to the wind-receiving plane.

A wind-receiving plane does exactly that – it receives the wind and provides the lift.However, a kite consisting solely of a flat surface would be unstable, so it is necessary tohave some surface area perpendicular to it in order to provide lateral stability. A keel is oneway of arranging this, but there are other possibilities. A curved surface has some vertical

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Key Stage 3 Design and Technology Resource Pack 12©

height (it is not flat if looked at from the side) and can have an equivalenteffect. This is the reason for the curved shape of the classic ‘bowed eddy’ kite.

It is possible to look at all kinds of kite shapes and identify these two keyfeatures.

FPT2 Choosing materials for your kiteHow much the pupils know about different materials and their properties willvary, but the worksheet provides an opportunity to discuss this subject. It would beadvisable either to have collected materials in advance and ask pupils to choosethose that are suitable for different parts of the kite – or to set them the task ofbringing some in to discuss. It is also an opportunity to discuss the making of kitesfrom materials reclaimed from the immediate environment (e.g. dustbin liners, fishingline, newspapers/magazines, etc.) This is an informal way of developing children’sunderstanding of material properties and the requirements for different situations. (Thisconcept can be developed more formally through the IDEAs worksheets on materialsand structures.) The extension task on the worksheet continues the development of anunderstanding of kite shapes by analogy with yachts and catamarans. Lateral stabilitycan be achieved by a pair of hulls as well as a keel.

FPT3 Making the kite bodyThe first kite builders looked towards birds and other flying creatures in order to helpthem understand how things fly; this is therefore a natural step to ask children totake. This particular worksheet asks them to look at butterflies and provides theopportunity for pupils to be given a lesson on observing nature and drawing whatthey see. Examples could be drawn from the work of numerous artists, butLeonardo da Vinci is a good artist to study. All the pupils need is rough paper, someold Sunday supplement magazines, newspapers or plastic carrier bags, and scissorsto cut out their butterfly shapes. Some books or slides showing pictures of variousbutterflies would be a useful addition in the classroom.

FPT4 Stiffening the wingsThis worksheet continues the theme of observing nature. The veins in a butterfly’swing stiffen the wing when pumped full of blood, and this give the wings thestrength that enables the butterfly to fly. The illustrations show the principlesdeveloped by Ito and Komura for stiffening a wing made of flat material. Aninexpensive way for the pupils to experience the process of stiffening is for them tostick double and single artstraws onto a paper shape (from FPT3). As the straws arestuck on, the stiffening effect is remarkable; this forms a valuable lesson for the pupils.

Of course, many kite designs use fabric or flexible materials in tension rather than stiffwing sections, but one of the significant attractions of starting with the above approachis the experience the pupils will have in glueing on the stiffeners. It is better to use anadhesive that dries reasonably quickly, so that the pupils can create their design quickly,and in easy stages. The effect is thus more obvious than if they have to wait until nextlesson for the adhesive to have dried fully on all the stiffeners.

FPT5 Springing the wingsFrom the point of view of its use in the classroom, this is probably both the greateststrength and the greatest weakness of the kite design approach developed by Ito andKomura. Some craft skill is required to glue the spring in position but the great benefitsare that you can fly the kite with ordinary cotton (because the kite collapses when thewind force gets too high) and the pupils can thereby get a feel for the force created bythe wind. They will know that quite a high force is required to compress the spring but

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they will see the kite folding when it flies and the wind gusts. Ito and Komurarecommended using piano wire for the spring, but the ends can be rathersharp. A plastic drinking straw (the small-diameter type used in cartons) seemsto work just as well as piano wire and the pupils can be asked to bring someto the class. The straws can be joined by pushing them together and, ifnecessary, secured with a glue gun.

The spring is a member in compression – a strut – and this is a good introductionto the behaviour of struts when they are subjected to loads sufficient to make thembuckle. If pupils get into difficulties fitting the spring, a solid (wooden) strut couldbe fitted instead – although the wings will not then, of course, flap when the kite isflown. (The dihedral angle should be set at 5–10° – see worksheet FPT10.) The forcegenerated by a high gust of wind may also break an ordinary cotton line if the strut istoo solid.

This spring is performing a similar function to the cross-member in a delta kite (seeDMA3) – although the delta kite is the other way up. It would be useful to demonstratethis if one happens to be available (one of the pupils might own one). More able pupilsmight be encouraged to research and explain the operation of the Indian fighting kite,which has a bamboo spring.

FPT6 How to balance the kiteThe towing line must be attached so that when pulled it acts above the centre ofgravity if the kite is to fly. (This is illustrated in the science extension worksheetsSc2–4.) The FPT6 worksheet introduces students to the concept of the centre ofgravity and how to find it. Once they have grasped the idea of balance around thecentre of gravity they will have begun to understand stability. In discussing theconcept of stability it may be useful to draw attention to work done in sciencelessons on human balance and the workings of the inner ear in detecting yaw, rolland pitch.

FPT7 Attaching the lineAttaching the line to the kite is the first preparation for flying. This worksheetillustrates simple ways of creating a bridle point, which is easily adjusted using aRED connection (named after Red Braswell, a kite designer). It also shows how a reelcan be made from an old drinks can.

FPT8 Preparing to test your kiteThere is a need for pupils to record in detail their first attempts at flying their kite, andthen to try to analyse any problems that occurred. This worksheet prepares the way forthis process and should be used in conjunction with FPT9–11. The pupils should decideon any modifications to the design that may be needed, retest the kites and record theeventual results. They might be asked to carry out the tests and complete FPT8 forhomework after suitable preparations have been made in class (using FPT9 and 10).

FPT9 SafetyClearly, before any flying takes place it will be necessary to consider safety issues.Lightning, cliffs, trees, electricity pylons and airports all present their own hazards. It willbe useful to have a general discussion concerning safety hazards when flying kites andthen to bring to the pupils’ attention any known local issues. Kites can interfere with radarsignals, which is why they should not be flown within 5 kilometres of an airport. Legallykites must also fly below 200 feet (c.60 metres).

Large kites can generate correspondingly large forces, therefore there is a risk of stringburns, etc., when manipulating the line. Large kites require careful attention to be paid

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to the design of suitable line-winding mechanisms. The kites being made in theFPT are small, and cotton rather than nylon is being used for the flying line.Such risks are therefore minimal.

FPT10 Improving stability – stopping the wobbleWithout a tail or fin, the kite is likely to fly in a very unstable way. The pupilsshould try this to see what happens, but at some point in the flight trials it willprove necessary to add either a tail fin or a tail. This worksheet explains how. Thepupils could be asked to test the kites for homework and to add a tail fin and, ifnecessary, a tail. They could then report back on their successes and failures in flyingthe paper kites.

FPT11 First flightsWorksheet FPT10 should give enough information for the students to troubleshoot earlyflying difficulties. If the first flights are taking place on the school field, it will be usefulif they are organised. It is helpful to establish the wind direction and spread the studentsout – perhaps in four or five groups – parallel to the wind. They should be able to taketurns in flying their kites without tangling the lines. The students watching will gainuseful information for their evaluations from taking notes on what happens to theirfriends’ kites.

The paper kites are likely to be damaged during these trials, but should last longenough for the students to gain some flying experience. Artstraws tend to fold whentoo high a load is applied, which allows the wing to fold. The kite will then not flyproperly. Such damage provides a very useful starting point for discussions onstructures: what is good about artstraws? What stronger material could replacethem? Bamboo is commonly used for struts and it would be useful at this stage todiscuss its properties. Very thin bamboo could be used with paper kites, but thinsections of wood (or veneer) are equally possible. What shape should these be? Itis useful to have scissors and sellotape available when the paper kites are beingflown, in order to make initial running repairs.

FPT12 Final evaluationThis worksheet is provided to enable pupils to record their analysis of the problems,the changes they made and whether or not these changes led to an improvement intheir kite’s performance. With a little time spent in the classroom it should bepossible for the damage from the first flights to be repaired and the kites returned toa good enough condition to allow them to be retested. Repairs with sellotape and/orstrips of paper and glue should be strong enough.

The extension task, concerning the investigation of the effects of changing the (fixed)dihedral angle on the kites’ stability, has been included to stretch the most able. Thespring will need to be removed and replaced by fixed struts of increasing length. The testscould be carried out with and without a tail fin and with and without a tail.

Leading towards the DMAThe experience of making and testing a kite made from paper and artstraws should havehelped the pupils start to get to grips with structural and kite technology. It is not intendedto be an end in itself, but to provide a rich learning experience at low cost. If the primaryrequirement, however, is to cover the ‘structures’ element of the National Curriculum, itcould provide sufficiently for this. There are elements of designing involved, and itprovides enough opportunities with appropriate materials and structures extension tasksto cover the NC requirements. It is, however, the DMA that should provide the realdesign experience.

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Control line

Bow string

Spar

View of the frame

SpineBridle

Tail

Key Stage 3 Design and Technology Resource Pack

The shape of a kiteThese diagrams show the two classic kite shapes. They show us the importantfeatures that determine how a kite flies. Kites need to have:

u a large area that catches the wind. This is called the ‘body’, ‘cover’ or ‘wind-receiving plane’;

u an area that helps to control it when riding the wind. The kite will then keepits position rather than sliding away with the wind.

The area that helps the kite to ride the wind can be formed in either of twoways:

u by making a keel, like a keel on a boat. This forms a piece at right angles tothe main kite area;

u by giving the kite a flexible body so that it curves with the wind and is three-dimensional (3-D).

SECTION 1 focused practical task

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TTTTAAAASSSSKKKK 1111(a) Identify the wind-receiving plane on both of the kites shown.(b) Identify the keel on one of these kites.(c) Find the kite that has no keel and identify the area that helps it to keep

its position in the wind.

Bowed Eddy

Delta

16©


Choosing materials for your kiteKites have a number of key parts, some of which you have seen on FPT1. These are:

u the line;u the wind-receiving plane, body or cover;u the keel;u stiffening ribs to keep the right shape;u connectors to join all the parts.

Traditionally, many different people have made kites; the style and materials thatthey used reflected their country and culture. You can make use of reclaimedmaterials that you might find at home or at school to make your kite. Beforeyou start you need to have a clear idea of the structure of your kite. Then thinkabout the materials that might be suitable for each part of the structure. A goodway of doing this is to brainstorm the problem and put the ideas that you comeup with onto a diagram:

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CONNECTORS

Plastic tubing

BODY

Dustbin liners

STIFFENING RIBS

Plant canes

LINE

Fishing line

Extension taskThe kite that we have sketched is abox kite. Itsstability comesfrom being like acatamaran. Findpictures of a yachtand a catamaranand compare theirshapes. Can youwork out why theyare stable? (This isquite a difficultquestion!)

TTTTAAAASSSSKKKK 2222We have started to brainstorm a kite design and record ourideas on the diagram above. Look at any posters in your class-room showing different kinds of kites. You may also havebooks or computer-based resources to help you.

(a) Choose a kite design and draw a sketch of it in a big box inthe centre of a new page.

(b) Identify the parts that you would need for your chosen kitedesign and draw them in spaces around the central sketchin a similar way to the one shown above.

(c) Decide which materials you could either buy cheaply orrecycle for each part of your design.

(d) Now match up a suitable material with each part of yourkite design. Show them clearly on your diagram, perhapsby colouring in the ones that you have chosen.

Box kite

Key Stage 3 Design and Technology Resource Pack 18


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Making the kite bodyKites have been made in many differentcountries for thousands of years and havefascinated a great number of people. Let’s build

one of our own and try it out. Some insects –such as the butterfly – have fixed wings, so they

make an ideal form for our kite design. We shall build a kite based on the butterfly, with two fixed wings.

These wings are able to flapgently in the wind.

A kite design based on Kites: the Science and the Wonder by Toshio Ito and Hirotsugu Komura.

TTTTAAAASSSSKKKK 3333(a) Practise drawing a butterfly shape on rough paper until you are happy with the

shape.(b) Your kite fabric will be paper. Open out a double sheet of paper from a news-

paper or magazine. These are about the right size for you to draw your butterfly.The area of your kite should be between 1,000 and 2,000 cm2.

(c) Fold your paper down the middle. Mark a point 7 cm from the top of the rectangle and another point 25 cm below this. These two pointsrepresent the length of the centrespine. (See ll1 on the diagramopposite.)

(d) Draw a small arc to represent thebutterfly’s head, near the top marked point. ll2

(e) Draw a large forward arc for theleading edge. ll3

(f) Draw a shallower curve to about twothirds of the height. ll4

(g) Draw a lower curve to intersect withthe previous one. This forms thebottom part of the wing. ll5

2 3

7 cm

25 cm

1 3

1

Fold

Leading edge2 3

4

5

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Stiffening the wingsBefore we can fly the kite the wings need to be made rigid. Just as the veins onthe butterfly’s wings give them rigidity, we need to attach stiffening ribs. Thereare three areas of stiffening:

u The forward edge of the kite is also called the leading edge. This must hold itsshape in the wind, no matter how strong the wind is, so it needs to bestiffened with several small ribs.

u The back edge is also known as the trailing edge. This does not need to be sostiff, as the wind flows over it more easily. A smaller number of light ribs willdo here.

u The main area of the kite needs to be very stiff; this is done with stronger ribs.

The diagram opposite shows you how to stiffen your kite wing.

u The solid lines represent heavyribs, which create the wind-receiving plane (shown shaded).

u The dotted lines representthinner stiffening ribs, whichcan be used to keep the weightdown.



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TTTTAAAASSSSKKKK 4444(a) Choose a strong, light material for the

heavy ribs and stick them to the butter-fly shape you have cut out, as shown.You will need to join the ribs wherethey cross. The photographs show you how this can be done.

(b) Find materials you think will besuitable for the small ribs and stickthem to the edges of the butterfly wing, to stiffen it.

Leading edge

Trailing edge

Heavy ribs Lighter ribs Wind- receiving plane

Figure 1

Figure 2

Figure 3

Figures 1–3 show the principle of stiffeningthe wings, in this case, using single and doubleartstraws for the heavy and lighter ribs.

©


Springing the wingsBy now you should have two stiffened wings that flap. In order for the kite to fly, however, you must make sure that the wings cannot close. This is done witha strut, which acts like a spring (see the photos below). The strut is held betweentwo holders. It is a little bit shorter than the distance between the holders and ispushed against the ribs to stop the wings closing together. The wings should beset at a small angle of between 5° and 10°. If the wind blows too strongly thestrut will collapse; this stops your line breaking.

The ends of the strut can be held in cut paper artstraws, which need to be gluedto the thick ribs. The spring can be glued in directly or else wrapped in paper, inorder to provide a more secure fit.

TTTTAAAASSSSKKKK 5555Attach a length of stiff, springy plastic tubingor wire (e.g. piano wire of about 1 mm dia-meter) to hold the two wings in a flying position. Two plastic drinking straws fixedtogether will also work well, as shown here.

Extension taskIf you think that you may want to fold your kite to carry it, design a safe fixingthat you can release to fold it flat.

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or wrap in paper first 1–2 cm

Cut the paper artstraw


How to balance the kiteEvery object has a point of balance where all of its weight appears to act. Thispoint is called the centre of gravity. Can you guess where the centre of gravity ofsome objects – like a ruler or a pair of scissors or a book – might be? We canfind where the centre of gravity is for any object.

(a) Finding the centre of gravity of a rulerPlace your hand under the mid-point of a ruler sothat it balances on one finger. You are supportingall the ruler’s weight at this point and your fingeris directly under the centre of gravity.

(b) Finding the centre of gravity of a different shapeu Cut a triangle or other shape out of card. Now that we

have a 2-D shape it is harder to find its centre of gravity.

u Pin the shape to a board with a drawing pin closeto one corner.

u Hang a heavy weight by a string so that it hangsfreely from the drawing pin. (This is known as aplumb line.)

u Mark where the string crosses the bottom edge of the shape. Then draw a line to join this point to the top corner.

u Now hang the shape up by another corner and mark a new vertical line.

u Where the two lines cross is the centre of gravity. If you marked a third vertical line it would go through the same point.

(c) Finding the centre of gravity of your butterfly wingsThe centre of gravity of the butterfly wings will bedown the centre fold because the butterfly is asymmetrical shape. Hang it up by a wing tip and markwhere the vertical line crosses the centre fold. This is thepoint at which the weight of the butterfly appears to act.

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A

A B

C

C

B

Line previously

drawn

Where the lines cross is the centre of gravity

Centre of gravity

TTTTAAAASSSSKKKK 6666


Attaching the lineThe kite is expected to fly with the spine at an angle of 10–15° to the horizontal.This can only be achieved if the control line is attached to a point on the bridle,so that when pulled it acts in front of the centre of gravity (i.e. between theleading edge of your kite and the centre of gravity). We must now attach the linein the right place on the central spine so that it is supported at this angle.

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Centre of gravity

Control line ‘pulled’ in flight Bridle

3 cm

3 cm

10–15°

Control line acts in front of the centre of gravity

RED connection loop (named after Red Braswell, a kite designer), also known as a larkshead hitch Put the ring through the loop to make a connection that is easily adjusted along the bridle

Bridle line

Washer

TTTTAAAASSSSKKKK 7777(a) Choose a material for your kite line. (Cotton should be strong enough for a

sprung kite.)(b) Tie the bridle line to the kite’s main frame about 3 cm from each end of the

main spine. (c) Make a RED connection

using a small washer, asshown in the diagram.

(d) Tie the control line to thewasher.

(e) Wrap the other end of theline around an old drinkscan and secure the otherend to the ring pull.

(f) Adjust your kite so that ithangs at about 10–15°.

Your kite is now nearly ready to fly.


Preparing to testyour kiteWhen you first try to fly your kite many different things can go wrong. If youkeep a careful record of what happens it will help you to understand anyproblems that may arise. Then you can discuss with your teacher things youmight do to improve the kite. It is also better to change only one thing at a time, as you will probably already have learnt in your science lessons! Thisworksheet is for you to record what happens when you test your original kiteand then when you add a tail fin and a tail. Before you test your kite, however,you must think about safety (worksheet FPT9) and learn how to make tail finsand tails (worksheet FPT10).

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Test Sketch Flight report Comments

No tail

With tail fin

With tail fin and tail


SafetyFlying kites might not seem dangerous, but there are a number of ways accidents can happen.



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TTTTAAAASSSSKKKK 9999(a) Look at the diagrams on

this worksheet, and thinkabout possible dangerswhen you fly a kite.

(b) List some accidents thatcould happen when youfly a kite.

(c) Decide how you are goingto make sure that you willbe a safe kite pilot.

©

Improving stability –stopping the wobbleWithout a tail fin or tail your kite islikely to rotate, wobble and dive aswell as slide down to the ground.This means that it is unstable andthere are many different ways thatyour kite can crash! Attaching theline as we did, in front of the centreof gravity, will help to make it morestable. The kite already has its wingsat a small angle (known as a dihedralangle), which gives some stability.

If we add an area of verticalmaterial it will help to improvethe stability of your kite. This isknown as a vertical tail fin.

Under some conditions youmight also need to add a tail with bows made from cotton,ribbons or paper tape to stabiliseit further, so be prepared whenyou test your kite.

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Dihedral angle (5–10°)

TTTTAAAASSSSKKKK 11110000(a) Think of a shape for your kite tail fin and cut out two

identical pieces. (A circle with a radius of 6 cm or a square with 5cm sides will be about the right size.)

(b) Use light kebab sticks or connect plastic drinking straws together ifnecessary, to make a length of about 20 cm and cut another to be thesame height as your tail fin.

(c) Glue these as shown between the pieces that you have cut for the tail fin. Thelonger stick will be attached to the main central spar of the butterfly and theshorter one will be at right angles to it. (Thin, stiff wire can be used as a goodalternative material for the fin stiffeners, but be careful of the sharp ends.)

(d) Make a tail which you can attach to your kite.

The force of the wind on the tail stops the kite

rotating forwards

Key Stage 3 Design and Technology R esource Pack©

Fly your kite on a short line with no tail, with a tail fin and with a tail and record yourresults on worksheet FPT8. Then study the information given below and see if you canwork out the solution to any difficulties you have found.

TroubleshootingThe most likely difficulty that you will have (apart from the wind) is the position of the bridle (or towing) point where the line attaches to the kite.

u If the kite spins and crashes forward, move the bridle point towards the centre. If this point is too low, however, the kite will not fly.

u In a light breeze you should move the bridle point forward. This makes the kite fly more easily and also higher, but you may need a vertical tail fin if you have not already got one.

u In a heavy wind the bridle should be moved back.u If the kite is still unstable, check that the wind-receiving plane is flat, that the frame

is not bent and that there are no wrinkles in the paper.u If the kite flies with one wing higher than the other, attach a piece of tape

(or something similar) to the higher side. u If the kite flies forward and then dives, check that the leading edge is flat and

undamaged or make the ribs on the trailing edge lighter.u If you still have problems, add a tail. This should stop the kite diving.


First flightsIt is now time to have a goat flying your kite.

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1111

‘Crashing’forward

Poor lift


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Final evaluation

This worksheet should help you to evaluate the kite you have made.

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Results of the first flight tests

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Problems encountered

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Changes made

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Results of the next flight tests

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Suggested reasons for problems

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Extension taskIf you have finished everything else then there is one final set of tests you cando. The spring can be replaced with a solid spar so that it does not buckle. Ofcourse the cotton may now break, but it is possible to investigate the effect ofchanging the dihedral angle (see worksheet FPT10). You will need to start with along spar and measure the dihedral angle. Fly the kite to see what happens andthen try shortening the spar, so that the dihedral angle increases. How does thebehaviour of the kite change?

©Key Stage 3 Design and Technology Resource Pack

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es Some interesting kite designs

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es Kite design – a design and makeassignment

he 17 worksheets in this section provide a loose framework for the managementof the design and make assignment (DMA). Designing should be as open anexperience as possible, drawing on any available resources in any way that helps.

The Internet, local kite clubs and shops, visiting enthusiasts, books and magazines mayall have major roles to play. In the end, the fact that appropriate activities are beingcarried out by the students is more important than the order in which things get done.All teachers will, no doubt, have their own preferred way of monitoring the progress oftheir pupils as their design directions diverge, but the photocopiable chart on p. 33 hasbeen included as one possibility.

Notes on worksheets DMA1–17

DMA1–3 Different designs and materialsThese three worksheets are intended to open the pupils’ minds to the wide range ofways in which kites have been used and the different materials from which theyhave been made through the ages. The materials used are related to the localenvironment, time period and culture, and studying the purposes for which thekites have been designed and the associated materials provides potential links withthe humanities curriculum.

The key aim of these worksheets, however, is to ensure that the pupils do not thinkthat there is only one way forward (if they have completed a paper kite as a focusedpractical task). It is important to emphasise that they can and should take anyappropriate route. Worksheets DMA2 and 3 show the more recent materials to havebeen used and the associated design developments. Many of the designs depend onthe ability of textile and polymer materials to carry large wind loads without tearing.It would be possible to draw parallels with the development of sails, parachutes, tentsand similar items. Teachers may at this point want to use worksheet MC1, concerningbag and tent construction, as either a homework or an extension task.

DMA4–5 Design briefs and specificationsSome possible design briefs are shown on DMA4. Clearly there are many other possibil-ities, but these briefs will provide a starting point. Writing a detailed specification of allthe things that the kite must be able to do is a difficult task, and worksheet DMA5contains some suggestions and various matters that need to be taken into account. Thepupils will probably just want to start designing, but it is important that they establish adirection in which to head. Setting this clear target helps provide a basis for thejudgements they will have to make when carrying out their design.

DMA6 Designing a shapeThe pupils may well have a clear idea of the shape that they would like their kite to be.Helping them to realise this objective, rather than having them make a kite that isknown to fly well from previous experience, is one of the key principles behind thisresource pack. This is one element of the activity that delineates it as ‘designing’.

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Alternatively, kite making could be approached entirely legitimately, andpossibly more successfully (in terms of flying prowess), as a ‘craft’ activity. Itwould be possible to take the pupils through the stages required to make a kitewhose design has been well established. There are numerous books with step-by-step instructions. The pupils could even be encouraged to pursue such atask as well as flying commercial designs. The class might be asked to bring inas many kites as they can and time could be spent analysing their constructionand flying performance. Utilising craft-based knowledge is just as valuable asusing knowledge derived from science, but it is to be hoped that the endpoint ofsuch activities would be that the pupils are inspired to be adventurous rather thanconformist.

It is possible that some students will want to begin their project by looking to nature(as encouraged in worksheets FPT3 and 4). They may find a small diagram of a bird,insect or other animal that they wish to enlarge. Worksheet M1 has been included tohelp with such tasks. Having established a direction, some of the first judgements haveto be made. The shape must be symmetrical in order to be stable; if the pupil wishes to pursue a very difficult shape from this point of view, perhaps they can make a ‘pair’(e.g. a pair of trainers).

The materials from which the kite is made have to be chosen in relation to its size. Very small kites have to be made from light materials such as balsa wood andclingfilm. It is also important that the towing line is attached in front of the centre ofgravity (see the science extension worksheets Sc2–4), so we must consider how andto what it is to be attached.

The pupils need to look at a range of kite designs and make their own judgements.Evaluation of their first models will soon tell them how accurate their decisionswere, and they can always change them for Mark II! The students might need to beencouraged to overcome their fear of being wrong and simply to set out along apath to find out.

DMA7–8 Original kitesThese two worksheets show a very brief version of the method recommended by Itoand Komura for making kites of different shapes fly (see the FPT worksheets). Thismight be an appropriate way forward for some of the kites the pupils wish to make.

The main stiffeners define the wind-receiving plane, but it is in the area beyond thisthat there may be difficulties. The trailing edges can be shaped by the wind, but theymust not be so weak that they fold. It is important that the leading edge is stiff. Pupilsshould be encouraged to experiment, using cheap or reclaimed materials. Artstraws arerecommended for the paper kite in the FPT, but more resistant materials might now bemore appropriate. Pupils pursuing this approach might well make use of worksheet S3(testing cantilever beams) in order to reach a decision concerning a suitable material andsection. This might be an appropriate stage at which to teach them how to plane somewood to produce a thin section. The pupils may need to be referred back to some of theFPT worksheets.

DMA9 Investigating kite materialsOne of the requirements of NC design and technology at KS3 is that pupils should be ableto classify materials. This worksheet is intended to provide the basis for an investigation(possibly as homework), which can be followed by a more formal discussion. Classifyingmaterials is not a straightforward task. The students may already have looked at the classification of metals and non-metals in science, and care needs to be taken to buildon such work.

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Materials in design and technology tend to be classified according to theirworking properties at room temperature (resistant, compliant, etc.), butmolten metals or mercury, for example, are clearly not resistant. Classifyingmercury as a metal requires a deeper understanding than simply looking at itsmechanical properties. The teacher must decide the appropriate sophisticationof the definitions of the categories of materials.

As learning outcomes the pupils might be expected to be able give examples of ametal, a polymer, a composite, etc. and to give some examples of ways in whichthey can be distinguished. From the DMA point of view the key matter is that theygive some detailed consideration to choosing the materials they are going to use fortheir kite, and that they can explain why they chose them. Part of their projectevaluation is to reflect and learn from such judgements. Worksheets MC2 and 3indicate suitable approaches to testing line and cover materials, which might beappropriate extension activities at this stage.

DMA10 Kite decorationOne of the reasons for undertaking a kites project in schools is to give pupils the chanceto decorate them. This is a clear opportunity to link to work they may have done in artand design and, perhaps, to set up a joint project. This worksheet sets out the issues andaims to encourage the pupils to experiment.

There is also a potential opportunity to exploit any graphics packages that may be onthe school’s computers. Again, it is possible that a joint project could be establishedwith ICT in order to draw the shapes and investigate different patterns, lettering andcolours. Worksheet ICT2 might be useful in indicating some of the possibilities.

DMA11 Methods of joiningThe wind produces very strong forces and, if the pupils have done the FPT first, theymay well already have discovered that the joints can break under the load. This isone of the virtues of kite projects: they provide ample opportunities for pupils todevise ways of reinforcing joints!

The students might do some of the experimenting beforehand (for example,ensuring that the jointed member is at least as strong as an equivalent memberwithout a joint), but they could equally well find ways of improving joints that failin flight tests. It might be necessary, for instance, either to add extra stiffeners or tomake hollow members solid. Worksheet MC4 provides some additional tasks andadvice that might be appropriate at this stage.

DMA12 3-D modellingThere are a lot of things that have to be got right in a kite design, so testing out ideas earlyon is important. This worksheet is intended to encourage pupils to try out their ideas, andshows a range of kite designs made from reclaimed materials. The pupils may need to bereferred to worksheets FPT7–10 in order to cover some of the basic matters relating to kiteflying.

DMA13–15 Preparations for making the kiteEvaluating the design, detailing the dimensions and planning for manufacture are all keyaspects of preparing to make the kite. It is good modern design practice to get as much aspossible right first time. The pupils are, of course, on a learning curve and they probablywill not get everything right immediately. They might perhaps be encouraged if they aretold to imagine being a test pilot for a new aeroplane design. In that position they wouldhope that the designer had tried to think of everything they possibly could, conductedevery useful test they could imagine and double-checked everything before they were

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asked to test the first real prototype. Design modelling is all about this processof thoroughly exploring all aspects of a design, although this might be a hardconcept for pupils to grasp. Their specification, drawings, ‘lash-ups’, tests, etc.are all aspects of design modelling, which should lead to a successful flight testof the first prototype – although most people are likely to overlook something!

The questions on DMA13 are intended to get students to start evaluating theirdesign. The diagrams of alternative line-winding mechanisms are part of areminder to them to review all aspects of their design. Worksheet MC5 providesfurther guidance and tasks concerning the design of line-winding mechanisms,which might be appropriate as an extension task for more able pupils.

DMA16 Group manufacturingSome design briefs for kites might well provide the opportunity for team rather thanindividual manufacturing. There are a variety of reasons why teachers might want to optfor this strategy. For example:

u Some of the experimental designs might not have performed well in flight trials. Thepupils will have learnt a great deal from the activity, although their kite does not flyas well as others.

u The National Curriculum requires pupils to work in teams as well as individually,and this might be the best available opportunity.

u There might be a requirement for a small batch to be made up as gifts for schoolvisitors or to sell as part of a business studies project.

Whatever the reason, the opportunity for the pupils to select a design(s) to develop,to work on it as a team and to take part in a group manufacturing experience wouldbe invaluable. Perhaps local engineers or industrialists could help at this point. The method and prompts in DMA16 should set the pupils off on such a taskconstructively and get them into an appropriate frame of mind.

Teachers might choose to tell them at the beginning of the project that after a setnumber of weeks, the most promising design(s) will be chosen for development,and that they will then collaborate on making a batch of the developed design.There are considerable potential advantages of this strategy from a classroommanagement point of view. The FPT is easily managed, but divergent design activitycan be more challenging. A cut-off point for the individual design activities sets up asituation in which the pupils can engage in open-ended design activity at low risk. Ifit all goes wrong, they can enjoy joining in the development of someone else’s design.It also gives the teacher clear control of the final manufacturing stages and hence theopportunity to ensure high standards. It is a strategy well worth considering.

DMA17 Evaluating the design and manufactureThis worksheet gives the opportunity for a final check on the design before the manufac-turing starts. Most importantly the quality checklist should help the pupils to establishtargets so that they achieve the highest standard of which they are capable in the makingstage. It also sets up the final evaluation of the work once the manufacturing is over. Of course, from the point of view of the kite project it is too late at that stage, which is why the emphasis in these worksheets is on reviewing the design and manufacture whileyou still have time to do something about it.


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esDM A Kites from differentplaces and differenttimesKites have been made for thousands of years all over the world. They have been used as part of religious festivals, for scientific investigation, for militaryoperations, for helping find and rescuepeople and for leisure. Worksheets DMA2and 3 show how the design of kites hasdeveloped through the ages.

First kites – 400 bc

11TTTTAAAASSSSKKKK 1111aaaa

Find out about anotherunusual way in whichkites have been used indifferent cultures. Beprepared to explain to thegroup how it would work.

Bamboo

Banana leaves

Silk

Paper

Flat kite

Bird kite

TTTTAAAASSSSKKKK 1111bbbbEarly kites used materials such asbamboo, banana leaves, silk andpaper.

(a) Explain why these materialswere used.

(b) Suggest modern equivalents to these materials.


Hardwood

Cotton cambric


Developments in kite design

Alexander Graham Bell developed the box kite further when he was trying tocreate a flying machine. (He was also the inventor of the telephone andpresident of the National Geographic Society.) In about 1900 Bell worked outthat a triangular box kite would be lighter and stronger and found out that theyfly just as well. He continued to develop this idea and made compound versions with more cells.

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Box kite – 1893Bowed Eddy – 1891

TTTTAAAASSSSKKKK 2222These kites used cotton for thecover material.

(a) Explain why cotton was used.(b) Where else would this kind of

technology have been used?

This was further developed by LouisBlériot, who added wings to the mainbody of the triangular section. (LouisBlériot was later to become the firstperson to fly across the EnglishChannel.) This shape has been found tobe extremely stable over a wide range ofwind speeds and it was also adopted inthe US, where it became known as theConyne kite.

Alexander Bell triangular

cell kite

Alexander Bell compound triangular kite

Blériot or Conyne kite


Later kites

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TTTTAAAASSSSKKKK 3333These modern kite designs usepolymers. Look at them carefullyand discuss whether they couldhave been made with the sorts of materials that were used forearlier kites, like banana leavesand cotton.

Sled kite – 1950

Parafoil – 1964

Heavygaugemylar

Ripstopnylon

Deltawing – 1950s

Aluminiumtubing

Fibreglass (or GRP)

Circoflex – 1996


Design briefsNow you need to decide exactly what you want your kite to do. Is it to bedecorative or do you want it to perform a particular function? Is it for you orsomeone else? The answers to these questions will form the design brief.

The design brief might be set by:

u your teacher;u your friends or family;u yourself, because you have a clear idea of exactly what you want to do.

Here are some other ideas for situations where kites may be useful.

As a bird scarerFarmers need to keep birds away from their crops and newly planted seeds. Fish farmers also need to deter herons from eating all of their stock. Housesfrequently have a large plate-glass window; birds often do not see these and flyinto them, injuring themselves, sometimes severely. Could a kite be usedeffectively to scare the birds away in such situations?

As a display for an eventIt is possible to make kites so small and light that they can be flown by walking indoors. In Japan, mini kites of 10 cm by 5 cm are manufactured,and in the USA they have been made from microfilm and balsa wood. Smallkites could be designed to provide an exciting flying display at an indoor event.

As a search and rescue beaconHill walkers and people sailing in small boats need to attract the attention ofrescue teams if they are in distress. Traditionally they have used flares, which canbe bulky and have to be replaced every year or two. A small, bright kite could bemade to fly above the person to attract help.

As a souvenirIf your town has been twinned with one overseas, consider how you couldconvey to the visitors from your twin town the essential character and features of yours. Several kites could be made and flown together to make a vibrantdisplay. They could then be given to your visitors afterwards as a souvenir.

Here is another interesting design, made from wood veneer and tissue paper:

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TTTTAAAASSSSKKKK 4444Write a design brief for your kite.


Towards a specificationAs you are designing your kite you will need to make all sorts of decisions. Itwill help you to make the right decisions if you have developed a specificationfor your design. You will need a list of factors that will make your design a goodone. Some examples of points to consider are given below.

TTTTAAAASSSSKKKK 5555(a) For your chosen design brief, list everything you can think of that

should be part of the specification and that will make your design agood one.

(b) Create the design specification for your kite.

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Things to do

A bird scarerSee if you can arrange to visit a farm,fish farm or a building with a largeplate-glass window. Find out whatwould be the most suitable type ofkite to use as a bird scarer: what sizeof kite? and what design would scarebirds away?

A display for an eventCan you work out suitable displays for the event you have in mind? Can you find very light materials to use?

A search and rescue beaconExamine the type of situation where akite might be used. Consider thepossible weather conditions andfitness of the person using it.

A souvenirResearch your town’s coat of arms,logo, motto, key landmarks and otherdistinguishing features so that yourkite can truly be representative of the town.

Possible considerations

If it is to be a good design it must:

u be a design that .............................. ;u be strong enough

to withstand ................................... ;u not need hands to

fly it, so that ................................... .


u be light enough to .......................... ;u be visible from ................................ ;u have surfaces that ........................... .


u be bright enough to ........................ ;u be light and small enough to ........ ; u be easy to fly because .................... .


u show the character of ..................... ;u be symbolic of ................................ ;u be easy to make because ................ .


Designing a shape

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Kites come in many different shapes and sizes. Some shapes arebased on insects, birds and othercreatures (whether or not theynormally manage to fly!) However,cartoon characters, rockets, aircraftand other shapes can be equallyinspiring. Some examples areshown below. When you chooseyour shape, remember that your kite needs to be symmetrical.

Teddy bear

Racing car

Ladybird

Concorde

Fish

TTTTAAAASSSSKKKK 6666Sketch shapes that seemsuitable for your design brief.Then consider each of themcarefully, until you find a shape that you think would beappropriate for you to make.


Original kitesSome of the kites that you have looked at already may have given you ideas foryour own design. You may want to base it on a traditional design, on some ofthe later developments or on one of the more recent innovations. If you wish todesign an original-shaped kite that is yours alone you will need extra help tomake it stable and strong. The following approach to original kite design wasdeveloped in the USA, and might be useful.

Decide whether your chosen shape is short and wide or long and narrow. Thesketches below then show you how to design your kite.

Stiffening the kiteYour kite will need to be stiffened. The main stiffening will only be added to aforward, central area of the kite because if it were added to the whole area itwould make it too heavy to fly. This main area of stronger bracing creates thewind-receiving plane. The basic shape of the stiffening frame is the samewhatever the shape of your kite surface.

A second stiffening structure, to strengthen the edges of the kite, ismade from thinner, less rigid materials such as artstraws. This

area of small ribs should overlap the main stiffened area alittle, and has two functions:

u to stiffen the leading edge;u to prevent excessive flapping of

the trailing edge.

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Dotted lines show lighter ribs

Areas stiffened by the thicker ribs

Penguin –long andnarrow

Butterfly – short and wide

TTTTAAAASSSSKKKK 7777Sketch your kitedesign and show thepattern of the mainstiffening frame andthe position of thethin stiffening ribs.


Stabilising original kitesIf we tried to fly a kite with a flat stiffened surface but without any extra parts itwould twist and slide in the air and be unstable in flight.

Short and wide kitesShort and wide kites require anextra tail fin. This can be made bycutting a suitable length of thinwire, plastic tubing or wood and sticking it between two discs(or other shape of your choice) offabric or paper (see photographopposite). This makes a flatsurface at right angles to the mainarea of the kite and so stabilises itin the other direction.

Long and narrow kitesLong and narrow kites can be stabilised bymaking a vertical area from the fabric of thekite. This can be done by allowing extramaterial on the centre line and then folding it to make a pleat. This is called a vertical fin(see photograph opposite).

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Thin frame

.1 cm

Fold in and seal

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Vertical tail fin Original outline

TTTTAAAASSSSKKKK 8888aaaaIf your kite is short and wide, design and make a stabiliser to attach to it. A typical area of a stabiliser for a small kite would be 20–30 cm2.

TTTTAAAASSSSKKKK 8888bbbbIf your kite is long and narrow, a vertical finshould give sufficient stability. Practise withscrap paper to see if it will work and todetermine what shape of material you willneed to cut out so that the finished designlooks right after you have made the fold.


Investigating kitematerialsKites from Asian countries have been made traditionally from paper andbamboo. In the UK, commercial kites nowadays are likely to be made frompolymers, metals and composites. Of course kites are made of the best materialsavailable at the time. What you can find out about these materials depends onthe resources you have available, but books in your library and the World WideWeb (WWW) are obvious possibilities.

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Wrapped ‘solid’ paper

Hollow paper tube

TTTTAAAASSSSKKKK 9999(a) Carry out research to answer as many of the following questions as you can.

u How is paper made?u Why is handmade Japanese paper the most suitable paper for kites?u What is bamboo and where does it come from?u What are polymers?u What makes polymer sheets particularly suitable for kites?u What are metals?u Where might you use metal on a kite?u Which properties make metal particularly useful for this purpose?u What are composites?u Why might composite tubes be better for kites than bamboo or metal tubes?

(b) Decide on the main components that you will need for your kite. Choose asuitable material for each one and complete the table below. (Some suggestions

have already beenprovided.)Kite part Type of material

Wind-receiving plane Plastic sheet

Stiff bracing Structa sticks

Thin ribs Artstraws

Structasticks

Artstraws


Kite decorationMany kites aredecorated with fabulouscolours and patterns.They can be interestingto look at and exciting,but sometimes they canconvey a particularmeaning. Some of thematerials that you havechosen for your kite, for instance paper, willbe easy to decorate.

Others, like polythene, will present more of a challenge.You could try watercolours, felt-tip pens and other kindsof paint. Oil-based paints will work well on some polymermaterials, although watercolours will not. You will need to explore different ways of decorating polymers until you find something that works the way you want it to.

Explore patterns and colours to give adifferent feel to your design and toconvey a special meaning. For instance,tartan could represent Scotland; yellow,Norwich Football Club. Nature has manywonderful patterns and forms – take thebee and the hive, for example. Animalsand nature may provide you with someinspiration.

Painting paper often means getting it wet.You may already have learnt how to keepthe paper flat when it dries. Some typesof paper may wrinkle when they dry. You may find that wetting the papercompletely first and then stretching it canstop the wrinkles. When watercolours dry

they often cause thepaper to curl towardsthe coloured side. This not only spoils thelook of the kite, but if the leading edge isnot flat it can cause problems in flight.

The photographs show a commerciallymade paper Chinese butterfly kite and aplastic snake kite. The butterfly kite is beautifully decoratedand also shows the principle of the stiff leading edge. Thesnake kite also has a stiff leading edge as well as a very longtail, which is an extension of the main body of the kite.

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TTTTAAAASSSSKKKK 11110000Investigate ways ofdecorating the kitematerial you havechosen until you have found a way with which you aresatisfied.


Methods of joining When acting on kites, the wind produces very strong forces. The kite may faileither under the normal wind load or when it lands. It can fail in one of twoways: either the wing may pull away from the framework or the framework itselfmay break. There are clearly very large ‘dynamic’ (or ‘impact’) loads when thekite crash-lands. If you have time, investigate the strength of the joints beforeyou try to fly your first model. The diagrams below show some typical joints andsome simple tests to ensure that they are strong enough.

You might need this kind of joint to stiffen the wing. You could practise makingit and try adapting it to make it stronger.

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Does creating a flat surface help?

What if you bind the stiffeners together?

Does the length of the overlap matter?

Does the glue you use matter?

Weights can test the strength of the joint

Does the shape here matter?

These photo-graphs show theassembly of acommerciallymade paper kite. It folds in a veryingenious way to fit in its box.

TTTTAAAASSSSKKKK 11111111(a) Identify all the joints you need to make.(b) Decide whether you need to do any

testing or redesigning to improve them.(c) Identify which type of glue will work

best.(d) Decide whether you wish to design a

kite that folds to make it easier to carry.


3-D modellingAt this stage you will:

u have a good graphic design for your kite;u have a clear design specification;u know what materials you are going to use for

each part of your design;u know how you are going to join the parts together.

Now you have to check that your kite will fly!Obviously you don’t want to risk crashing andwrecking your finished design before you have gotit working properly so you might build a fast,cheap model from scrap materials that will help to get the details right for the final kite design. The photographs showsketch modelsof kites madeup fromreclaimedmaterials suchas plastic, paperand fabric.

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TTTTAAAASSSSKKKK 11112222(a) Build a 3-D model of your kite

and test it to find out more abouthow the real design will perform.

(b) Move the towing line until you arehappy with its position.

(c) Decide whether the kite will bestrong enough and make suitableadjustments. If you need tostrengthen the fabric or spars, your teacher has extra worksheetsthat will help you.

Testing a model of your design in this way gives you the chanceto adjust its performance beforeyou build a prototype. This is thetime to investigate the effect of:

u moving the point at which the towing line is attached.This will change the angle atwhich the kite flies andtherefore its height;

u different patterns of thestiffening ribs, which may alter the way the kite flies.


Evaluating thequalityof thedesign

Before detailing your design andplanning the manufacture youshould check whether the modelmeets the requirements. This meanscomparing it with your specification.

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Plastic from carrierbags andartstraws –not stiffenough

Card and bamboo – too heavy, and only flies well in a high wind

Paper and art-straws – the wayforward?

TTTTAAAASSSSKKKK 11113333Evaluate the performance of your kite model against thespecification by asking yourselfthe following questions andmaking any changes youconsider necessary.

(a) Which aspects of yourdesign work well?

(b) Which aspects of yourdesign need improvement?

(c) Have you considered theviews of all the expectedusers?

(d) Have you checked that thekite flies properly?

(e) Does the kite do all that wasexpected?

(f) Does the kite look asattractive as you had hoped?

If everything is all rightyou might like toinvestigate replacing thesoft drinks can as thewinding mechanism.Here are somesuggestions:


Detailing the designIt is very important to have a clear idea of exactly what you want to do beforeyou start to make the actual kite. So far you will have used various kinds ofmodelling to help you develop your design. These will have included both 3-D and 2-D models. The 2-D models are most likely to have been sketchesrather than exact drawings.

One of the best ways to examine the detail of a design is to produce a moreaccurate drawing. These are generally known as engineering or working drawings. Ifit is possible, this kind of drawing is best produced full-size (scale 1:1). Thismeans there is less chance of your eye being deceived. Obviously if things arevery big – like the buildings designed by architects – then the drawings andmodels must be drawn to scale, but the architect must take great care in workingout what a person’s-eye view would be like.

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TTTTAAAASSSSKKKK 11114444(a) Produce a working drawing, like the one shown, which helps with your kite

design.(b) Sketch the main joints to make sure you know exactly how you are going

to join the different parts (components) of your kite.

Planning the position of theart straw stiffeners for the‘Butterfly original kite’


Planning for manufactureIt is nearly time to make your kite. A little bit of extra planning, however, will help you to make it more quickly and effectively. You may not want tospend any more time planning your design, but it could save you making time-consuming and expensive mistakes. This means it will speed things up –not slow them down!

You need to think about all the things you have to do and the best order inwhich to do them. For example:

Answering such questions should help you to make the best use of theworkshop time available.

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A cutting list (helps you to organise the manufacture ofthe components)

u How many parts are there to make?u What materials are you going to use?u How are you going to make each

part?u How are you going to join each part

together?

u What is the best order in which tojoin the parts?

u Should you paint or decorate any ofthe parts before they are assembled?

u Do you need to test any of the partsbefore they are assembled?

TTTTAAAASSSSKKKK 11115555(a) Gather together the materials that

you may want to use and prepare a cutting list (see opposite).

(b) Identify any parts that can be madetogether – for example if they wereto be made of wood and all neededa plane or saw to make them.

(c) Test the joints, before they areassembled and difficult to replace, tocheck that they are strong enough.

(d) Plan a timetable for the constructionof your kite using one of themethods described on this sheet.

Start

Investigate WWW

Test possible materials

Choose materials

Visit library

Terminal

Process

Decision

Any stage at which the project starts or stops is delayed or interrupted

Anything that needs to be done

The stage at which a decision needs to be made

M T W T F

WEEK 1

M T W T F

WEEK 2

M T W T F

WEEK 3

M T W T F

WEEK 4

M T W T F

WEEK 5

Investigate

Complete design

Choose and obtain materials

Analyse and improve design

Make first prototypeTest

A Gantt chart (overlapping tasks can be done on the same day/week so that you never waste time)

A flow chart (a well recognised way of present-ing a plan)

Part Number Material Material size (mm)required Length Width Thickness

Ribs 5 Softwood 200 3 3

Joint overlaps 2 Softwood 40 30 2

Wings 1 Polythene 400 500 —


Group manufacturingYour teacher might let you undertake the manufacturing as a team. You couldeven form a small company! If you are forming a manufacturing group, thenyour first task is to decide which design to pursue. This can be difficult if youdon’t want to upset anyone.

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TTTTAAAASSSSKKKK 11116666(a) Mark the outline of a table (see the example provided below) on a large

piece of paper and sketch each team member’s design in the top row.(b) If you are all working on the same design brief, look at your specifications

and decide which factors are the most important.(c) Fill in these factors in the left-hand column of the table.(d) Choose any of your kites to be the one that you compare all the others to.

This is your datum design. (Design number 3 was chosen as our datum andthis is shown in the table below.)

(e) For each factor put a plus sign in the box if the design does better than thedatum or a minus sign if it does worse.

(f) Discuss and try to improve each item marked with a minus sign. Thisshould help you choose a group design.

(g) If you wish, you can develop this design as a team so that you are all happywith it.

Flying + — D — —

Making + + A + —

Excitement — + T — +

Cost U

M

1 2 3 4 5


Evaluating the designand manufactureMaking sure that products are of the highest possible quality is one of the tasksregularly faced by manufacturers. This means that they have to check both thequality of the design and the quality of the manufacturing. One way of testingthe quality of the design is by building a prototype to see how well it meets thedesign specification. At various stages during the design process you will haveheld discussions with your teacher, who will probably have asked you questionssuch as:

u Are you sure the kite will work?u Are you sure everyone will like this colour?

These kinds of questions will contribute to theongoing evaluation which is an essential part ofdesigning; you may have been doing this all theway through the design process anyway. Now itis time to double-check.

So now the design is as good as you can get it,you must build the highest possible quality into the manufacturing. Quality checklists (seeopposite) are a good way of focusing attentionon areas where you need to improve and toevaluate how well you did when you havecompleted your project.

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Quality checklistDo you aim for error-free work?

q all of the timeq most of the timeq just some of the timeq only when I feel like itq never

Do you check the quality of your work against the standards expected?


Does your work meet the expected standard of quality?


Are you proud of your work?


Are you a positive influence on your friends and others in your group?


Source: Jim Sage, New Designer Vol.2, No.1, September 1996.

TTTTAAAASSSSKKKK 11117777aaaa(a) Swap your design work with that of a friend.(b) Ask sufficient questions (like those above)

about your friend’s design.(c) See if you can spot any improvements that

your friend could make to his/her kite.

TTTTAAAASSSSKKKK 11117777bbbb(a) Fill in a quality checklist like the one

opposite.(b) Discuss your answers with a group of

friends in order to identify one or two goalsthat will improve the quality of themanufacture of your kite.

(c) Record these goals and use them to reviewhow well you did after you have completedyour project.

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he investigating, disassembling and evaluating familiar products and appli-cations (IDEAs) and extension tasks are organised into five areas:

(a) Materials and components (worksheets MC1–5 in this pack)(b) Structures (S1–3)(c) Science in design and technology (Sc1–4)(d) Mathematics in design and technology (M1–2)(e) ICT in design and technology (ICT1–2)

The first two areas are designed to give opportunities to cover aspects of NC design andtechnology, which may not be completely covered by other projects that the pupils havecompleted at KS3. They also serve as extension tasks at appropriate points in the DMA(see TN2). The final three areas provide opportunities to develop links with science,mathematics and ICT. Links to art and design and the humanities are included withinthe DMA. It is not that links to science, mathematics and ICT are any less appropriate,but it was felt in designing this resource pack that these areas should be clearly withinthe teacher’s control.

Notes on worksheets

MC1–5 Materials and components extension tasksWorksheet MC1 gives an opportunity to explore the strengthening techniques usedin the construction of bags and tents. It allows the pupils to examine otherproducts related to kites and see to what extent the techniques employed can betransferred to their design activities. Investigating the design and manufacture ofproducts is a key aspect of NC design and technology, and a range of tents and bagsshould be readily available.

Worksheets MC2–3 suggest ways in which the line (MC2) and cover (MC3) materialscan be tested. This is a good opportunity to discuss what is meant by a fair test, whichis what underpins an understanding of the concepts of stress and strain (i.e. force perunit area and extension per unit length). For a kite line it is really the force for a givenweight of line that is significant and, more exactly, the force for a particular length andweight. It would be possible either to fix one variable, for example to take a standardlength of each line material (say 1 m) and then look at the force per unit weight, or totake the approach indicated in the table on MC2. Whichever route is chosen, some pupilsmay need considerable help in getting to grips with completing the table. The more ablepupils would, however, benefit from thinking through the issues. There is a safety concernif strong line materials are being tested. The floor should be padded to protect against thefall of large masses, and eye protection should be worn. Testing lower-strength materialslike cotton is obviously safer.

Testing cover materials presents similar difficulties, but more so. There is no standard wayof testing cover materials, so the pupils will have to invent one. In essence, because thematerials will fail as a result of the propagation of cracks, the pupils must find a way ofproducing standard cracks. Ito and Komura record their conclusions in their book, butthey do not state the procedure by which they were reached. They provide an interestingcomparison for the results of the pupils’ study. This task should challenge even the

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most able students. The context of MC3 might provide a good opportunity forthe examination of a sample of ripstop nylon, as used in modern kites. Tornsails have little further use and any keen sailors amongst the parents might beable to reclaim enough for test samples, if not for making whole kites. (Theripstop nylon used for sails may well be a heavier gauge than that normallyused for kite making.)

MC4 provides an opportunity for pupils to explore the kind of joints neededwhen fabrics and textiles are attached to a framework. Many kite designs requiresuch joints (e.g. delta kites), although the FPT included in this pack deals withconstruction methods using paper and artstraws. This approach was chosen becauseit provides significant teaching and learning opportunities, not because it necessarilyresults in the best flying kites. It is quite likely that the pupils’ designs will require moreeffort to make, for example the manufacture of a suitable framework from wood andfinding ways of joining it to cover materials. Details of useful knots are also provided onthis worksheet, because they may well be less familiar to pupils than they once were.

The line-winding mechanism is not the most important part of the design, and theempty drinks cans used in the FPT will be found to work perfectly adequately. WorksheetMC5 does, however, provide a couple of suggestions for pupils who have completedother aspects of their designs. Designing a line-winding mechanism would be a usefulextension task for the more able pupils. Both the designs shown in worksheet MC5could be constructed using dowelling.

S1–3 Structures extension tasksKites are structures, and the key NC requirements should be covered through thedesigning and making of a kite. These three worksheets introduce some moredifficult areas, but areas that it is necessary for some pupils to cover.

Many kite designs (e.g the parafoil and the flexifoil wing) require fabrics to makethem into 3-D forms. In this case a pattern needs to be made, which can then beused to cut out the repeating shapes. This is a difficult task and pupils pursuing thisroute should be aware that it will require persistence and experimentation. Thereare, however, numerous successful kite designs of this kind. The reference to thework of Ray Merry and Andrew Wilf Jones when they were students is intended toinspire the pupils into action!

Classifying structural members is a useful exercise in developing analytical skills, justas it is in other areas like biology and chemistry. If you only have three types ofstructural member to think about you can organise your thoughts into these groupings.There are two other types of structural member that are not mentioned here – torsionand shear members – but it is a good beginning if the pupils can get the three indicatedon S2 clear in their minds. Structural analysis tends to be done by identifying the type ofstructural member (is this a tie? strut? beam? etc.), and then applying the accumulatedexpertise in relation to the type identified. Clearly, KS3 pupils’ expertise will be justbeginning to form, but learning to classify structural members correctly will provide asecure basis for further learning.

For many designs the kite framework is crucial to its success, and the stiffness of theindividual members is the key issue. Artstraws are stiff because they have a comparativelylarge hollow section. In considering alternative materials, pupils need to look at thestiffness-to-weight ratio of the frame materials; worksheet S3 shows how this can be done.Measuring the gradient is the most elegant way of analysing the results, but if the conceptof a gradient is too advanced then it may be easier to fix the length of the cantilever andcompare the deflection to the weight of the section.

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Sc1–4 Science extension tasksThere is an element of mystery surrounding kite flying and, whilst some of itmight be appropriate, kite flying is certainly not completely beyond explana-tion. Understanding is one of the things that lies behind innovation, becauseit leads to a sense of purpose and direction. Without understanding pupils areoften afraid to change anything in case it leads to insurmountable problems.Whilst by no means providing a full explanation, these four worksheets areintended to encourage the more technologically imaginative pupils to innovate.

Sc1 discusses the atmosphere. It is air movements that generate the lift on the kite,which enables it to fly. Innovative designs are less likely to perform well first time, inwhich case it will be vital to undertake careful tests to distinguish between instabilityproblems resulting from air movement and instabilities that are inherent in the kitedesign. These investigations could take the form of some interesting homeworkexercises based on microkites. Very light kites can be flown indoors by simply pulling ona short line, and would respond to thermal currents.

Worksheets Sc2–4 cover different aspects of the reasons why kites fly. Sc2 enables pupilsto demonstrate lift and drag forces for themselves. This is a valuable exercise by itself,but if they can go one stage further and learn to add these forces together, it will providethe basis for the fuller explanation of kite flying provided on Sc4. The addition ofvectors using the triangle or parallelogram forces is now missed out of manymathematics and science courses, but it is worth the trouble of teaching it here. Elasticbands are a classic teaching aid for the purpose.

Sc3 is most obviously concerned with measuring the force acting on the kite line,but it has the hidden agenda of introducing the concept of equilibrium. The forceon the line and the pressure drag (the resultant of the addition of the lift and dragforces) are equal and opposite. This model of why a kite flies is appropriate instrong winds, where the pressure drag is very much greater than the weight of thekite.

Worksheet Sc4 provides an explanation more appropriate to normal flying. Theforce from the line and the pressure drag do not act at the same point, and theconsequential rotating ‘couple’ is opposed by the weight of the kite. The visualexplanation provided should be accessible to the more able pupils. In reality, thepoint at which the pressure drag acts (the centre of pressure) moves in different windconditions; this is one of the key reasons why some designs are more appropriate thanothers for particular wind conditions. The structural strength of the kite is, of course,another key issue.

M1–2 Mathematics extension tasksOne of the major contributions that design and technology can make to the wholeschool curriculum is the way in which it can make some subjects come to life. These twoworksheets take two areas of mathematics and show how the skills acquired can beapplied. It is important to check with the mathematics department to find out exactlywhen these areas are taught within KS3.

M1 concerns enlargements. Pupils may find a drawing or photograph of a shape that theywould like for their kite, but which is too small. Enlarging the shape by drawing linesthrough key points from a central pole is a skill that the pupils have probably mastered,and this is a chance to use it. The very able pupils may know how to calculate thenecessary ratio from the given kite area; however, making the shape fit onto a largeSunday supplement magazine should be within the scope of them all.

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M2 concerns trigonometry. Pupils may already have learnt to measure theheight of trees in science or mathematics classes, and it is a natural extensionto measure the height at which their kite is flying. Making a simple clinometerand undertaking such a measurement is a useful extension task for pupilswhose kites fly easily, while other pupils finish their test flights.

ICT1–2 ICT extension tasksMaking use of ICT obviously depends on having access to suitable equipment.These worksheets do little more than note some of the possibilities if they happento be available. They are by no means crucial to the success of the project, but canadd further richness to the experience.

ICT1 concerns gathering information. The Internet is an amazing resource and there isa wealth of information available about kites. As more and more pupils gain access tothe Internet at home or at computer clubs, there is the possibility of setting homeworkthat can be carried out using this technology. Some design and technology departmentsnow have access to the WWW, and a class demonstration of the use of the Web as adesign tool may be beneficial. It would be advisable to have found suitable addresses, aswell as trying out search engines, before embarking on the demonstration. A list ofsuitable addresses is provided on p. 9 of this pack.

ICT2 concerns computer-aided design and manufacture (CAD and CAM). More andmore schools are getting access to various kinds of CAD/CAM equipment, and mosttypes can find application in a kite design project. CAD can be used to produceaccurate working drawings. These can be plotted (photocopied and enlarged ifnecessary), cut out and used as patterns. It is also possible to get logos or patternscut out of sticky-backed plastic, which could be used to decorate the kite. Someschools now have computer-aided embroidery equipment that could be similarlyused.

The possibility of using a spreadsheet/database to see the effect of changes in thedesign on cost should also be noted as a good way of incorporating ICT in designand technology. This would be particularly appropriate if a group of pupils wereundertaking the manufacture of a small batch, where small changes in the cost of asingle kite can still have a significant impact on the total cost.

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Bag and tent constructionLarge forces act on sheet materials in a number of different situations – not just for kites.Shopping bags carry very great loads when theyare full. Tentshave to withstandlarge wind forcesas well as keepingpeople dry.

Tents are strengthenedin particular places inorder to ensure thatthey do not rip apartin the wind.

Shopping bags are designed to have a high strength-to-weight ratio. This meansthat they are as light as possible, but arestrong enough to carry a full load ofshopping.

TTTTAAAASSSSKKKK 1111(a) Examine different types of shopping bag – plastic, paper and fabric – to see how they

are made to be strong and light. Are there any ideas here that you can use in your kiteconstruction?

(b) Examine a tent that you or a friend own, or look at one in a shop, and see how it hasbeen made sufficiently strong. Are there any helpful ideas here that you can use?

(c) The photographs above show some faults that occurred in model kites. Can youidentify similar weaknesses in your kite(s)? Can you think of ways of strengtheningyour design to avoid such faults?


SECTION 3 IDEAs and extension tasks

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Torn sheet

Bent rib

Detached rib

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Testing samples ofmaterials – linesFrame materials, and joints in them, have been investi-gated in DMA11, but we have not yet considered thematerial for the body and the line. The line materialsare easy to test, so these will be discussed first. Theforce on the line can be measured using a Newtonmeter (see Sc3). We need to measure the force thata line can take before it breaks. The diagramopposite shows how we can test this.

The kite must be able to lift its own weight as well as the weight of the line, so we mustweigh a length of the line. Finding the weight ofa short length of line may be difficult to measureaccurately, so it may be better to weigh a longlength and calculate it (see below).

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Long length of line

TTTTAAAASSSSKKKK 2222(a) Choose three or four possible line materials, including a sample of kite line

if it is available and can be tested safely.(b) Test the strength of each one and record the force needed to break it in

Newtons (N).(c) Measure its weight in Newtons and its length in centimetres (cm).(d) Fill these values in a table like the one shown below.(e) Calculate the weight per unit length and put the answer in the W—L column.

Then calculate the force per weight per unit length and place this in thefinal column.

(f) Decide from these last two columns which of the tested materials might bethe best for your line.

MaterialForce to Weight, W Length, L

Fbreak, F (N) (N) (cm)W–L /W–

L

Cotton

Foam pad


Testing samples ofsheet materialsSheet materials will tend to tear when the wind gusts. Also, some materials willstretch in the wind. A material tears when small ‘nicks’ spread through it when itis under pressure. You could test samples ofmaterial by making the same size nick ineach one and seeing which will carry thelargest weight before it tears. Be careful toload it gently!

To measure ‘stretchiness’ you need to leavethe weight on for a long time. Perhaps youcan set up your material in one lesson andsee how much it has stretched by the nextlesson. You may need to test each materialin several directions if it is more stretchy inone direction than another.

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Scientists have found sheet materials need certain qualities to make it good for making kites. For akite whose area is 0.1 m2 to 0.3 m2:

(a) The mass for every square metre should be less than 100 g.(b) The material should stretch similar amounts in all the directions that you test it.(c) If you take a sample of material 1 cm wide and 4 cm long and hang a 1 kg mass carefully on it

as shown, it should return to the same size when the mass is removed. Materials with a low yieldpoint will stretch permanently under this load.

(d) If you keep loading from the yield point, where it starts stretching permanently, it should stretchmore than 1 cm before it breaks.

Source: Adapted from T. Ito and H. Komura (1983) Kites: the Science and the Wonder, Japan Publications Inc., p. 85.

TTTTAAAASSSSKKKK 3333(a) Test a number of samples

of possible cover materials,recording:

u the mass at whichstretching starts;

u the amount it stretchesbefore the material breaks;

u the mass of a square metre,if possible.

(b) Decide from this datawhich might be the bestmaterial to use for the coverof your kite.

Standard ‘nick’

4 cm

1 cm

The scientists found that polyester non-woven cloth and handmade Japanesepaper, as well as polyethylene film, metthese conditions. There is also a specialmaterial – ripstop nylon – that wasoriginally developed for sails, but is also agood kite material. You can probablyguess why it is called ‘ripstop’. It hadthreads in a square pattern which stopsany tears propagating.

Another point to consider is how easy it isto decorate the material used for the kitebody. Test the possible materials withwater colours, marker pens, crayons, paintor whatever else you would like todecorate it with, and see if they work.


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(i) Does the width of this overlap make a difference?

(ii) Does it matter what adhesive you use?

(iii) Does the stitch type and spacing matter?

(iv) Does the number of rows of stitching matter?

TTTTAAAASSSSKKKK 4444(a)

(b) You also need to attach the line.Which sorts of knot are best?Again, you might do some tests, or carry out research intodifferent kinds of knots and when and where they have been used.(i)Practise tying a reef knot,

a clove hitch and any othersthat you can find out about.

(ii) Test the strength and otherimportant features of eachknot, then try to decide which type of knot is best for attaching the line.

Reef knot – for joining lines of equalthickness

Clove hitch – forjoining lines to strutsand attaching the tail

59Key Stage 3 Design and Technology Resource Pack

Testing differentapproaches to joiningHaving investigated the frame, cover and line materials, all you need to knownow is how best to join them together. Many designs require the cover to bejoined to the frame and you might like to investigate this more carefully.

A hot glue gun is a useful tool for joining plastic material, and your teacher maysuggest that you try other adhesives. If you are stitching your material, whateffect does the spacing and length of the stitches have, the stitch type and thenumber of rows?

Your teacher may be able to give you some hints, or else might ask you to devisesuitable tests to find out. (See the task on worksheet MC3.)

A

BC

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Line-winding mechanismsSo far we have not paid too much attention to the way the line is controlled. A wide range of line winders is available, however. You will have tried using adrinks can already and perhaps replaced it with an improved design, as shownon worksheet DMA13. You might now like to give this component some moreattention and design something special.

One of the tasks that the line winder has to perform is enabling the line to bewound back neatly, but it is also necessary to allow it to release quickly andeasily. The Korean el-lai reel is hand-held and has rotating spokes. The line cantherefore be fed out carefully, be pulled from the reel or slip off sideways, givingthe kite flyer many options. The Japanese itomaki bobbin-type reel gives similaroptions. These two designs are shown in the diagrams below.

TTTTAAAASSSSKKKK 5555(a) Look carefully at the Korean el-lai reel and the Japanese itomaki bobbin-type reel.

Decide what are the best features of each design.

(b) Design a line-winding mechanism that you feel would be suitable for your kite.



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Japanese itomaki bobbin-type reel– used for kite flying and fishingKorean el-lai reel

©


3-Dstructuresfrom2-D piecesOne of the fascinating aspects of working with sheet materials such as textiles,plastics and paper is the way in which three-dimensional forms can be createdfrom two-dimensional, flat materials. It depends, of course, on cutting out theright kind of pattern or template from which the three-dimensional shape canbe created. Most kites can be made from two-dimensional materials. Apart fromremembering to leave on a little extra fabric for the tabs and joins, they are fairlystraightforward to cut out. If you like a challenge, however, you might try doingsome research on Jalbert’s parafoil kite, which is made only of fabric, or aflexifoil wing kite, which has a stiff spar atthe leading edge.

The flexifoil wing kite was developed in1971 by two students, Ray Merry andAndrew Wilf Jones, as part of a classassignment when they were industrialdesign students at Newcastle-upon-Tyne Polytechnic. Getting it to fly took a lot of experimenting; this isreported in Maxwell Eden’s bookKiteworks:

Source: M. Eden (1989) Kiteworks:Explorations in Kite Building and Flying, Sterling PublishingCompany Inc., p. 79.

Many technologicaldiscoveries are made by accident, so don’t be afraid to experimentwith your design. If you are creative andpersistent, hopefully youshould be just as successful.

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The flexifoil wing is inflated by the wind Flexible spar at the

leading edge (bends in flight)

Jalbert’sparafoil kite

Flexifoilwing kite

TTTTAAAASSSSKKKK 1111Can you work out what shape would need to be cut out to make one sectionof the parafoil kite or the flexifoil wing?

One day...everything fell into place. Afterflipping over on its back, the wing tookoff and adopted an improved high angleof flight. This was a purely accidental discovery.


Identifying and comparing structural membersThe three main types ofstructural member found onkites are tension members,compression members andbeams.

u Tension members haveforces acting on them whichstretch them, and they areknown as ties.

u Compression members haveforces acting on them whichsquash them, and they canbe called struts.

u Beams have forces actingat right angles to themember. They can havepoint loads (e.g. wherethe line is attached to thekite) and distributedloads (e.g. the force fromthe wind).

These three types of structuralmember are shown in thediagrams opposite.

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Point load

FAILUREFAILUREFAILUREFAILUREFAILUREFAILUREFAILUREFAILURE

Distributed load

Cantilever

Tearing from the tension side

FAILUREFAILUREFAILUREFAILURE

Tension member (tie)

Beams

Compression member (strut)

TTTTAAAASSSSKKKK 2222In the diagrams onp. 63, draw linesbetween thestructural memberson the left-hand side and the kites onthe right, to showwhere each type ofstructural membercan be found.


Identifying and comparing structural members

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Box

Delta

Original

Bowed Eddy

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Testing cantilever beamsThe lift force on the kite keeps it up in the air and is dependent on the strengthof the wind. With a high wind speed there is a large lift force. If the winds arelight and the kite is heavy it will not fly. The framework is the heaviest part ofthe kite, so you will need to find the lightest framework to stiffen the wings.These stiffeners are known as beams (see worksheet S2) and their resistance tobending is related to both their shape and the material from which they aremade. Therefore a ‘stiff shape’ and a ‘stiff material’ will need to be found.

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0

5

10

15

5 10 15 20

20 mm

15N

Deflection (mm)

Slope (k) = = 0.75 N/mm

Load

(N

)Deflection

Load

Standard length cantilever beam

15 20

TTTTAAAASSSSKKKK 3333One way to find such a framework is to test the available materials, as shown below.

(a) Cut different materials and clamp them to form cantilever beams of the samelength. Then do the following:(i) Place a suitable load on the end of the beam and measure its deflection.

By dividing the value of load in Newtons (N) by the deflection inmillimetres you can find the stiffness of the beam (k) in N/mm. Thesevalues can be placed in column 2 of the table below.

(ii) By repeating step (i) five or six times and drawing a graph for each beam, as shown in the diagram above, you can find a more accurate value of thestiffness (k), bycalculating theslope (gradient) of the graph.

(b) Weigh each beam andwrite its weight (w) incolumn 3. Thendivide the answer fork by the weight of thebeam and put theanswer in the lastcolumn. The highestvalue of k/w is thestiffest, lightest beam.

Beam Stiffness, k Weight, W (N) k—WN/mm

Woodendowel

Artstraw

Aluminiumtube

©


The atmosphereHave you ever stopped to watch birds gliding and soaring, leaves falling inautumn, felt the breezes near the coast and sheltered from strong winds. How well kites fly depends entirely on the wind and how it behaves. We cananticipate some of these effects and we can learn about others by observingcarefully what happens to the kite when we fly it.

Thermal currents will affect the way your kite flies. Some areas of the ground areheated by the sun more than others, which causes the air to rise, i.e. as a thermalcurrent. These thermals are used by gliders to gain height. There are othersources of thermal currents, such as fires and heated buildings. If you made amicrokite (out of balsa wood and plastic film perhaps) you might be able to flyit on the thermal currents in a room.

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Winds

Winds

TTTTAAAASSSSKKKK 1111bbbbIf possible, fly yourkite – safely – close to a building or agroup of trees, and see if it becomesunstable.

TTTTAAAASSSSKKKK 1111aaaaIf possible, fly yourkite in a flat, openarea and comparethe way it flieshere with how itflies near to a hill.

Near a hill therewill be anupdraught.

Trees and buildings will create turbulentareas behind them.


Why do kites fly?It is quite difficult to understand why kites fly. It can be made simpler by firsttrying to understand the forces at work. The lift force acts perpendicular to thewind direction and the drag force acts in the wind direction. It is these kinds oflift forces that keep aircraft, gliders and kites up in the sky. In order to under-stand these forces better, try out the following experiment.

These diagrams show the lift and drag forcesthat cause such move-ments. They also showhow the two forces areadded together using a‘parallelogram of forces’to give a single force rep-resenting their combinedeffect. This is known asthe pressure drag.

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TTTTAAAASSSSKKKK 2222(a) Cut a piece of paper 12 cm by 5 cm and bend it round to make a loop

with a curved edge and a flat edge where the sellotape joins it together.This is an aerofoil shape, which is like the wing of an aeroplane or glider.

(b) Place a pencil in the loop and you will find that the sellotaped edgedrops down.

(c) Now blow over the top of the pencil so that the air that you blow hits thetop of the loop. You should notice that the trailing edge lifts up as youblow, without anything lifting it up directly. This demonstrates the liftforces generated by the wind.

(d) You should also have noticed that the loop moves backwards. Thisdemonstrates the drag force acting on the aerofoil section. This is a kindof friction force between the air and the surface of the paper.

Lift force, L P

Drag force, D

P is the pressure drag and the result of adding L and D. This will be in the direction in which the paper aerofoil moves

P

L

D

The paper will move in the direction indicated by P

Which way does the pellet go?

Combined force

Elastic bands can help you tounderstand why forces are addedin this way. When the band isstretched its length represents theforce acting – when it is stretchedfurther the force gets larger. So ifa band is held between yourthumb and your first finger andpulled, you can imagine a paral-lelogram of forces. The combinedforce acts along the diagonal ofthe parallelogram.

Drag force

Lift force

Wind


Measuring the forceacting on the lineMass is a measure of the quantity of material in an object. It is measured inkilograms (kg). When gravity acts on a mass it creates weight. Your mass wouldbe the same on the earth and the moon, but your weight would be different.You would actually weigh much less on the moon, because the moon is smallerand has a much lower gravitational effect. (Have you seen pictures of people inspace suits jumping high on the surface of the moon with apparently littleeffort?) Weight is actually a measure of the gravitational force, and is measuredin Newtons (N). On the earth’s surface the effect of gravity (g) causes a force of9.81 N on a mass of 1 kg, which is why people sometimes say you shouldmultiply the mass in kilograms by 10 in order to calculate the weight inNewtons.

Mass × g = weight

Apples give us another way of thinking about Newtons and kilograms. An appleweighs about 1 N and has a mass of 0.1kg. Ten apples have a mass of 1 kg. It iseasy to remember that an apple weighs 1 Newton because of the story of IsaacNewton: an apple is said to have fallen onhis head when he first discovered gravity.

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Weight ≈ 1 N

1 kg of apples weighs approximately 10 N

Mass 0.1 kg

T

Newton meter Drag force

Weight of the line

The line will be curved in reality because of the combined effect of its weight and the drag force

TTTTAAAASSSSKKKK 3333Try flying your kite (either the oneyou have made or a commercialdesign) with a Newton meter orspring balance attached to the line.The Newton meter will show theforce acting on the line.

It is gravity that pulls your kitedownwards, and you can measurethe ‘lift force’ that is keeping itflying with a Newton meter.Knowing this force would help you to choose an appropriatematerial for the line, butmeasuring it can also help yougain a further understanding of the forces acting.


The forces actingon a kiteThe model shown below will describe adequately the forces acting on a kite in a strong wind, i.e. where they are very large. The pressure drag, P, which actsperpendicular to the surface, is equal and opposite to the force in the line, T.

You might think that the value of the liftforce would be quite near to the weightof the kite, but you have to rememberthat it has to lift the line as well. Evenif you take this into account, youmight still find that there is anerror. This is because the forcesacting on a kite are a little morecomplicated than the simple ‘strong winds’ model.

It is hard to calculate the values, but thecause of the error is the friction drag, F,which acts along the surface of the kite. Youshould, however, be able to see why one ofthe golden rules of kite flying is to attach the line so that when pulled it actsabove the kite’s centre of gravity. The combined action of T and P tends to turnthe kite anticlockwise, and it is the effect of the weight that stops this happening.

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P

T

L

D

P

Measure T with a Newton meter

T = P

Triangle of forces

or

D

L

P

TTTTAAAASSSSKKKK 4444Measure the force on the line (T) with a Newton meter. This value can now beused for the pressure drag (P), as they are equal.

Calculate or estimate the angle at which your kite was flying (see worksheet M2,or you can assume 15°) and now, on graph paper, draw to scale a line repre-senting P at this angle (75° to the horizontal). By either drawing the rectangleor triangle of forces as shown, you can now find the lift and drag forces actingon the kite. The vertical measurement represents L (the lift) and the horizontalrepresents D (the drag).

P

F

Mg

Wind

T

P = the pressure drag

F = the friction drag

T = the tension or pull in the line

Mg = the weight of the line


Enlargements

You need to make kites with different areas in order to get them to fly well when they are made from different materials. Very small kites would need to bemade from light materials such as balsa wood and clingfilm. Large kites couldbe made from cotton and bamboo. You should find that paper and artstrawswork well for kites with an area about the same as a weekend magazine.

The kind of original kites described in this pack have a typical area of1,000–2,000 cm2. This is about the same size as a double sheet from a largeSunday supplement magazine. However, you might find either a photograph ora drawing of a shape that you would like to use for your kite, but which is thewrong size. It might be a shape from nature – a bird, perhaps, or an animal – or a cartoon character. The shape can be enlarged as shown below.

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TTTTAAAASSSSKKKK 1111Find a small picture of a shape you wouldlike for your kite andenlarge it as shown inthe diagram.

Car Ladybird Concorde

Lines through the pole and key points

Pole in the centre of

enlargement for the

butterfly

Measure line, e, from the centre of the enlargement. Multiply this length by the scale factor (shown here as 2). Mark out this length, E, from the centre of the enlargement to the new point. Repeat for all the key points of your chosen shape. If the scale factor is 2, the area is 2 2, or 4 times the original area. Calculate how much bigger in area your new kite is.

1 2 3 4 5

e

E


Measurement of heightWhen you have got your kite to fly in the way that you want it to, you can try tomeasure the height at which it flies. It is easier to measure the height of your kitewhen it is flying steadily, so you must hope that the day you pick has calmwinds. You will need the help of at least one of your friends in order to carry outall the measurements.

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TTTTAAAASSSSKKKK 2222(a) First you must find a protractor in

order to measure angles, and a smalltube of about 20 mm diameter.They will not be damaged, but if you cannot find them easily, roll up some thin card to make the tubeand mark a few angles on a piece of card. Join them together withtape and then attach a plumb line,as shown in the diagram on theright.

(b) The device you have made is called a clinometer, and is used to measureangles. Make sure your friend is standing directly under the kite and thenlook at your kite through the tube. Mark the angle that the plumb linemakes with vertical. (This is where you might need the help of anotherfriend, but you can probably hold the plumb line in position!) Theperson standing under the kite must walk back to where you arestanding and count the number of paces they take. If you measurethe length of one pace, then you will be able to calculate thedistance they walked. Once you know this distance and the angle,you can calculate the height of the kite. There is a reminder below if you have forgotten your trigonometry.

Narrow tube – approximately 20 mm in diameter

Plumb lineProtractor or marked card

y (altitude)

BA

C

x (Horizontal distance from you to the kite)

tan =

y = x.tan

y x

(opposite) (adjacent)

Remember to add your height!

Altitude

Clinometer


Gathering informationand the Internet

You might already know what theInternet is and you may have alreadyused it, but have you thought of using itto help with your projects in design andtechnology? If you don’t already knowwhat the Internet is, then try to imaginehundreds of thousands of computers allaround the globe, all connected together.People use the Internet to send electronicmail (e-mail) messages to one another,and this is becoming quite a popular wayof communicating. It is, however, thegrowth of the World Wide Web (WWW)that really captures people’s imagina-tions. The WWW is like a gigantic ency-clopaedia or CD-ROM with informationon every conceivable topic.

You can use a computer that is connected to the Internet to browse, or ‘surf ’, aroundthousands of sites. You mightbe able to find useful informa-tion for your kite design fromall over the world – looking at,and sometimes downloading,pictures and text.

The Internet and the WWW do not have to be just one-way traffic. User groups, withmembers in differentcountries, form to discusstopics of interest. You couldask questions, look at otherpeople’s designs and evenshow other pupils your work.You could be comparingnotes on kite designs withpupils not only in thiscountry, but anywhere – theUnited States, Japan, etc.

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TTTTAAAASSSSKKKK 1111If you have access to the WWW, see if you canfind useful information concerning kite design.Can you use the Internet to make contactwith other pupils interested in kite design? Try visiting http://www.designit.org/

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Computer-aided designand manufacture(CAD and CAM)Computer software and equipment is now available which can help you with yourdesigning and making. This worksheet suggests a few possibilities that you cantry out if you have the opportunity.

Working drawings often need to be altered when some new infor-mation becomes available. There are a number of computer-aideddesign programs available. Theytake a little bit of time to learn, but once you have drawn your kiteusing such software it is very easyto alter. You can also print out thedrawing to give you a pattern if asuitable plotter is available.

The effects of changing colours andpatterns are sometimes hard to imagine. If you have drawn your kite with software,which includes options to colour indifferent areas in various colours, then youcan see what happens before you try it out.It is still a good idea, however, to try it outwith materials you are not too concernedabout before you make the real kite.

A logo can add something specialto your design. If you draw a shapeusing computer software and yourschool has the right equipment,then you might be able to get thelogo cut out of sticky-backedplastic and even embroidered onto a textile material.

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TTTTAAAASSSSKKKK 2222Find out if your school has any CAD/CAM equipment and try to think of ways that you can use it in your kite project.

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Kites - Loughborough University