Launch of the Rings
Transcription
Launch of the Rings
Launch of the Rings B3: Group Design Projects. The Oxford Roller Coaster. Engineering Department. University of Oxford. Authors Arthur Coates William Hancock Charlie Hill Max Jackson Edward Jamie McDonald St. Johns’ College St. Johns’ College Worcester College Pembroke College Lincoln College Supervisors Dr. S. J. Payne Dr. M. Chappell Keble College St. Johns’ College FINAL HONOUR SCHOOL OF ENG / EEM (delete as appropriate) DECLARATION OF AUTHORSHIP You should complete this certificate. It should be bound into your third year project report, immediately after the title page. Three copies of the report should be submitted to the Chairman of Examiners for the Honour School of Engineering Science, c/o Clerk of the Schools, Examination Schools, High Street, Oxford. Name (in capitals): ARTHUR COATES College (in capitals): Supervisor: ST. JOHNS’ COLLEGE DR. S. J. PAYNE Title of project (in capitals): B3: GROUP DESIGN PROJECT. THE OXFORD ROLLER COASTER. Page count __30__ Please tick to confirm the following: I have read and understood the University’s disciplinary regulations concerning conduct in examinations and, in particular, the regulations on plagiarism (Essential Information for Students. The Proctors’ and Assessor’s Memorandum, Section 9.6; also available at www.admin.ox.ac.uk/proctors/info/pam/section9.shtml). I have read and understood the Education Committee’s information and guidance on academic good practice and plagiarism at www.admin.ox.ac.uk/edc/goodpractice. The project report I am submitting is entirely my own work except where otherwise indicated. It has not been submitted, either partially or in full, for another Honour School or qualification of this University (except where the Special Regulations for the subject permit this), or for a qualification at any other institution. I have clearly indicated the presence of all material I have quoted from other sources, including any diagrams, charts, tables or graphs. I have clearly indicated the presence of all paraphrased material with appropriate references. I have acknowledged appropriately any assistance I have received in addition to that provided by my supervisor. I have not copied from the work of any other candidate. I have not used the services of any agency providing specimen, model or ghostwritten work in the preparation of this thesis/dissertation/extended essay/assignment/project/other submitted work. (See also section 2.4 of Statute XI on University Discipline under which members of the University are prohibited from providing material of this nature for candidates in examinations at this University or elsewhere: http://www.admin.ox.ac.uk/statutes/352-051a.shtml#_Toc28142348.) The project report does not exceed 30 pages (including all diagrams, photographs, references and appendices). I agree to retain an electronic copy of this work until the publication of my final examination result, except where submission in hand-written format is permitted. I agree to make any such electronic copy available to the examiners should it be necessary to confirm my word count or to check for plagiarism. Candidate’s signature: ………………………………………………… Date: ..……………….. FINAL HONOUR SCHOOL OF ENG / EEM (delete as appropriate) DECLARATION OF AUTHORSHIP You should complete this certificate. It should be bound into your third year project report, immediately after the title page. Three copies of the report should be submitted to the Chairman of Examiners for the Honour School of Engineering Science, c/o Clerk of the Schools, Examination Schools, High Street, Oxford. Name (in capitals): WILLIAM HANCOCK College (in capitals): Supervisor: ST. JOHNS’ COLLEGE DR. S. J. PAYNE Title of project (in capitals): B3: GROUP DESIGN PROJECT. THE OXFORD ROLLER COASTER. Page count __30__ Please tick to confirm the following: I have read and understood the University’s disciplinary regulations concerning conduct in examinations and, in particular, the regulations on plagiarism (Essential Information for Students. The Proctors’ and Assessor’s Memorandum, Section 9.6; also available at www.admin.ox.ac.uk/proctors/info/pam/section9.shtml). I have read and understood the Education Committee’s information and guidance on academic good practice and plagiarism at www.admin.ox.ac.uk/edc/goodpractice. The project report I am submitting is entirely my own work except where otherwise indicated. It has not been submitted, either partially or in full, for another Honour School or qualification of this University (except where the Special Regulations for the subject permit this), or for a qualification at any other institution. I have clearly indicated the presence of all material I have quoted from other sources, including any diagrams, charts, tables or graphs. I have clearly indicated the presence of all paraphrased material with appropriate references. I have acknowledged appropriately any assistance I have received in addition to that provided by my supervisor. I have not copied from the work of any other candidate. I have not used the services of any agency providing specimen, model or ghostwritten work in the preparation of this thesis/dissertation/extended essay/assignment/project/other submitted work. (See also section 2.4 of Statute XI on University Discipline under which members of the University are prohibited from providing material of this nature for candidates in examinations at this University or elsewhere: http://www.admin.ox.ac.uk/statutes/352-051a.shtml#_Toc28142348.) The project report does not exceed 30 pages (including all diagrams, photographs, references and appendices). I agree to retain an electronic copy of this work until the publication of my final examination result, except where submission in hand-written format is permitted. I agree to make any such electronic copy available to the examiners should it be necessary to confirm my word count or to check for plagiarism. Candidate’s signature: ………………………………………………… Date: ..……………….. FINAL HONOUR SCHOOL OF ENG / EEM (delete as appropriate) DECLARATION OF AUTHORSHIP You should complete this certificate. It should be bound into your third year project report, immediately after the title page. Three copies of the report should be submitted to the Chairman of Examiners for the Honour School of Engineering Science, c/o Clerk of the Schools, Examination Schools, High Street, Oxford. Name (in capitals): CHARLIE HILL College (in capitals): Supervisor: WORCESTER COLLEGE Title of project (in capitals): DR. S. J. PAYNE B3: GROUP DESIGN PROJECT. THE OXFORD ROLLER COASTER. Page count __29__ Please tick to confirm the following: I have read and understood the University’s disciplinary regulations concerning conduct in examinations and, in particular, the regulations on plagiarism (Essential Information for Students. The Proctors’ and Assessor’s Memorandum, Section 9.6; also available at www.admin.ox.ac.uk/proctors/info/pam/section9.shtml). I have read and understood the Education Committee’s information and guidance on academic good practice and plagiarism at www.admin.ox.ac.uk/edc/goodpractice. The project report I am submitting is entirely my own work except where otherwise indicated. It has not been submitted, either partially or in full, for another Honour School or qualification of this University (except where the Special Regulations for the subject permit this), or for a qualification at any other institution. I have clearly indicated the presence of all material I have quoted from other sources, including any diagrams, charts, tables or graphs. I have clearly indicated the presence of all paraphrased material with appropriate references. I have acknowledged appropriately any assistance I have received in addition to that provided by my supervisor. I have not copied from the work of any other candidate. I have not used the services of any agency providing specimen, model or ghostwritten work in the preparation of this thesis/dissertation/extended essay/assignment/project/other submitted work. (See also section 2.4 of Statute XI on University Discipline under which members of the University are prohibited from providing material of this nature for candidates in examinations at this University or elsewhere: http://www.admin.ox.ac.uk/statutes/352-051a.shtml#_Toc28142348.) The project report does not exceed 30 pages (including all diagrams, photographs, references and appendices). I agree to retain an electronic copy of this work until the publication of my final examination result, except where submission in hand-written format is permitted. I agree to make any such electronic copy available to the examiners should it be necessary to confirm my word count or to check for plagiarism. Candidate’s signature: ………………………………………………… Date: ..……………….. FINAL HONOUR SCHOOL OF ENG / EEM (delete as appropriate) DECLARATION OF AUTHORSHIP You should complete this certificate. It should be bound into your third year project report, immediately after the title page. Three copies of the report should be submitted to the Chairman of Examiners for the Honour School of Engineering Science, c/o Clerk of the Schools, Examination Schools, High Street, Oxford. Name (in capitals): MAX JACKSON College (in capitals): Supervisor: PEMBROKE COLLEGE DR. S. J. PAYNE Title of project (in capitals): B3: GROUP DESIGN PROJECT. THE OXFORD ROLLER COASTER. Page count __30__ Please tick to confirm the following: I have read and understood the University’s disciplinary regulations concerning conduct in examinations and, in particular, the regulations on plagiarism (Essential Information for Students. The Proctors’ and Assessor’s Memorandum, Section 9.6; also available at www.admin.ox.ac.uk/proctors/info/pam/section9.shtml). I have read and understood the Education Committee’s information and guidance on academic good practice and plagiarism at www.admin.ox.ac.uk/edc/goodpractice. The project report I am submitting is entirely my own work except where otherwise indicated. It has not been submitted, either partially or in full, for another Honour School or qualification of this University (except where the Special Regulations for the subject permit this), or for a qualification at any other institution. I have clearly indicated the presence of all material I have quoted from other sources, including any diagrams, charts, tables or graphs. I have clearly indicated the presence of all paraphrased material with appropriate references. I have acknowledged appropriately any assistance I have received in addition to that provided by my supervisor. I have not copied from the work of any other candidate. I have not used the services of any agency providing specimen, model or ghostwritten work in the preparation of this thesis/dissertation/extended essay/assignment/project/other submitted work. (See also section 2.4 of Statute XI on University Discipline under which members of the University are prohibited from providing material of this nature for candidates in examinations at this University or elsewhere: http://www.admin.ox.ac.uk/statutes/352-051a.shtml#_Toc28142348.) The project report does not exceed 30 pages (including all diagrams, photographs, references and appendices). I agree to retain an electronic copy of this work until the publication of my final examination result, except where submission in hand-written format is permitted. I agree to make any such electronic copy available to the examiners should it be necessary to confirm my word count or to check for plagiarism. Candidate’s signature: ………………………………………………… Date: ..……………….. FINAL HONOUR SCHOOL OF ENG / EEM (delete as appropriate) DECLARATION OF AUTHORSHIP You should complete this certificate. It should be bound into your third year project report, immediately after the title page. Three copies of the report should be submitted to the Chairman of Examiners for the Honour School of Engineering Science, c/o Clerk of the Schools, Examination Schools, High Street, Oxford. Name (in capitals): EDWARD JAMIE MCDONALD College (in capitals): Supervisor: LINCOLN COLLEGE DR. S. J. PAYNE Title of project (in capitals): B3: GROUP DESIGN PROJECT. THE OXFORD ROLLER COASTER. Page count __30__ Please tick to confirm the following: I have read and understood the University’s disciplinary regulations concerning conduct in examinations and, in particular, the regulations on plagiarism (Essential Information for Students. The Proctors’ and Assessor’s Memorandum, Section 9.6; also available at www.admin.ox.ac.uk/proctors/info/pam/section9.shtml). I have read and understood the Education Committee’s information and guidance on academic good practice and plagiarism at www.admin.ox.ac.uk/edc/goodpractice. The project report I am submitting is entirely my own work except where otherwise indicated. It has not been submitted, either partially or in full, for another Honour School or qualification of this University (except where the Special Regulations for the subject permit this), or for a qualification at any other institution. I have clearly indicated the presence of all material I have quoted from other sources, including any diagrams, charts, tables or graphs. I have clearly indicated the presence of all paraphrased material with appropriate references. I have acknowledged appropriately any assistance I have received in addition to that provided by my supervisor. I have not copied from the work of any other candidate. I have not used the services of any agency providing specimen, model or ghostwritten work in the preparation of this thesis/dissertation/extended essay/assignment/project/other submitted work. (See also section 2.4 of Statute XI on University Discipline under which members of the University are prohibited from providing material of this nature for candidates in examinations at this University or elsewhere: http://www.admin.ox.ac.uk/statutes/352-051a.shtml#_Toc28142348.) The project report does not exceed 30 pages (including all diagrams, photographs, references and appendices). I agree to retain an electronic copy of this work until the publication of my final examination result, except where submission in hand-written format is permitted. I agree to make any such electronic copy available to the examiners should it be necessary to confirm my word count or to check for plagiarism. Candidate’s signature: ………………………………………………… Date: ..……………….. William Hancock Page 1 EXECUTIVE SUMMARY The Oxford Area action plan was adopted in 2008 and states that ‘a high quality and mixed-use development, as befits its location and role, will be created.’ In accordance with this plan, the construction of ‘Launch of the Rings’ has been proposed on Oxpens Meadow. ‘Launch of the Rings’ is a roller coaster that will compete with the best rides in the world whilst maintaining superb standards of safety. The ride not only complements the historic nature of Oxford City but also has carefully been designed with high standards of environmental responsibility. The economic viability of the roller-coaster will ensure a life time profit of £24 million, while the ride itself will create a vibrant landmark for the city. 0: CONTENTS PAGE 1. Introduction 3 1.1 Introduction to the project 5 1.2 Site Description 2. The Roller Coaster 7 2.1 Final Design 8 2.2 Elements 11 2.3 Design Iteration 16 2.4 Layouts 18 2.5 Competition 3. Ride Characteristics 21 3.1 Flying Coaster 22 3.2 Patents 24 3.3 Loading Method 25 3.4 Cart Design 26 3.5 Throughput 29 3.6 Cart Details 33 3.7 Launch 39 3.8 Braking 42 3.9 Control System 47 3.10 Wheels 4. Foundations and Framework 49 4.1 Geology 52 4.2 Foundations 58 4.3 Construction Companies 59 4.4 Structural Analysis 59 4.5 Dynamics and Force Analysis 66 4.6 Fatigue Analysis 69 4.7 Stress Analysis 73 4.8 Further Structural Considerations Author EM WH MJ MJ MJ MJ MJ MJ MJ MJ MJ EM EM EM EM CH WH WH WH WH AC AC AC AC AC William Hancock Page 2 5. Construction 76 5.1 Construction Methods 81 5.2 Manufacturing Process 82 5.3 Time and Cost 85 5.4 Materials 6. Environment and Area Considerations 88 6.1 Sustainability Intro 89 6.2 Renewable Energy 94 6.3 Environmental Sustainability 97 6.4 Social Sustainability 99 6.5 Economic Sustainability 101 6.6 Council Planning Policies 103 6.7 Flood Risk 107 6.8 Noise Pollution 111 6.9 Bomb Risk 112 6.10 Transport 7. Safety 117 7.1 Risk Assessment 121 7.2 Maintenance 122 7.3 Legislation 8. Theme 124 8.1 Commercial 125 8.2 Implementation 127 8.3 Ring Location 128 8.4 Building Design 9. Commercial 131 9.1 View Analysis 132 9.2 USPs 133 9.3 Economics Model 133 9.4 Ticket Prices 139 9.5 Commercial Throughput 140 9.6 Costs 142 9.7 Spreadsheet 145 9.8 Long Term Business Plan 147 9.9 Conclusions 10. Appendix 149 10.1 Appendix to 6.8: Noise Pollution AC: Arthur Coates. WH: Will Hancock. CH: Charlie Hill. MJ: Max Jackson. EM: Edward Jamie McDonald. Report edited and collated by: Charlie Hill EM MJ MJ MJ AC AC AC AC AC WH WH WH WH CH EM EM EM CH WH MJ MJ CH CH CH CH CH CH CH CH CH WH Edward Jamie McDonald Page 3 1: INTRODUCTION 1.1: Introduction to the project This report outlines plans to bring an exciting new tourist attraction to the centre of Oxford. Oxpens Meadow will be transformed by ‘Launch of the Rings’, a thrilling roller coaster able to measure up to any of the many world-class rides already present in the UK. It will have a truly unique edge, being by far the largest roller coaster in the country to exist outside a theme park and is within a mile of a city centre. This top thrill-seekers’ destination will make extensive use of Oxford’s wealth of history, leaning heavily on Tolkien’s connections to the University through Pembroke College to create an accessible and yet immersive Lord of the Rings theme which will form a heavy part of the riders’ experiences. There is also of course Oxford’s historic connection to thrill rides through the ever popular St Giles’ fair, which still draws thousands of visitors in its third century of existence1. The roller coaster itself is the world’s first flying launched coaster, combining two popular styles for the first time. Anticipation will build for the riders as they move slowly through a heavily themed indoor section of the ride, before being launched at speeds of up to Figure 1.1.1: Launch of the Rings roller coaster fifty miles per hour to plunge around four full inversions and other exciting track elements. The total ride time is around sixty five seconds with G-forces edging close to the maximum possible comfortable levels. This is a truly unique ride, blending together the extreme thrill of a high acceleration launch with the out of this world flight experience that can only come from swooping around corners in a flying coaster. Of course, there is more to a project of this magnitude than simply designing an exciting roller coaster. Such a costly enterprise needs to be able to prove that it can be a commercial success as well as just enjoyed by its users. Over a forty year lifetime this roller coaster is anticipated to generate returns of twenty four million pounds or more with an annual turnover of two million pounds per annum once it is up and running. It is expected that almost seven hundred 1 www.headington.org.uk/oxon/stgiles/fair/ - Accessed April 2012 Edward Jamie McDonald Page 4 thousand thrill seekers will ride the roller coaster each year. In the context of this high profitability, the initial costs of construction should be easily raised through loans from both banks and other organisations. The benefits of the roller coaster will also be spread far more widely than just to the riders and owners. The ride could easily become the cornerstone of the redevelopment of Oxford’s West End, fitting ideally with the West End Area Action Plan, Oxford City Council’s development proposals for this area of the city. There will be major benefits to the area from the extra visitors the ride will draw, particularly given the huge effort which has been invested in ensuring that any negative consequences of the development are as minimal as possible. The proposals comply fully with the ‘triple bottom line’ theory of sustainability, meaning that social, economic and environmental sustainability have all been carefully considered and acted upon during the process of producing the best possible roller coaster option. Furthermore, much work has focussed on ensuring the construction of Launch of the Rings results in as unnoticeable a level of disruption as possible. In this report we present our exciting vision for the roller coaster development. Our final design is showcased with thorough analysis of the various elements included and explanation of why riders will love them. Next, some further detail on specific aspects of the ride, from the flying aspect to the revolutionary magnetic braking technology to the optimised control and wheels. There is a detailed analysis showing how the roller coaster will stand up and make it round the track covering every technical aspect from foundations to loop design. This is followed by information on the important construction phase, with explanations of how disruption will be minimised as well as the methods to be used. Environmental, sustainability and area considerations are also discussed in detail demonstrating how we have truly engaged with the specifics of where our coaster fits into the Oxford landscape. Safety is of course of utmost importance, and we have taken the time to show how we will ensure that the ride remains free of any major accidents throughout its lifetime. The report then details how the Lord of the Rings theme is developed into not just into the ride itself but all around the area it is set. Finally, there is a section of commercial analysis confirming the customer numbers and profits previously set out. William Hancock Page 5 1.2: Site Description Area of site: 18,900m2 Perimeter of site2: 750m Figure 1.2.1: Maps of site from Google maps and digimap.com On 15th October a preliminary research visit was conducted to look at and to analyse the site of the proposed rollercoaster. This was important as it allowed potential problems and constraints of the site to be highlighted. At the time of the visit Oxpen’s meadow was being used as a recreational area by people playing Frisbee and other sports. Most obviously there was a hot air balloon being launched from the meadow3. Walking along Dale Close, which is in the residential area that can be seen in figure 1.2.1; it was easy to see that many of the houses had invested in flood defences. One example is a removable watertight gate (figure 1.2.3) which fits in between the wall so protecting the house. This gives a reason to expect a high flood risk to the area as residents have invested in protection. This suggests that this is likely to be a significant issue. Figure 1.2.2 map to the left was created to show the contours of the site. This is particularly important as it illustrates which part of the site is the lowest lying hence most likely to flood. Data points were taken across the site of the height in metres above ordinance datum. Using the data, contour lines were drawn linking parts of the site of similar height. Figure 1.2.2: Height contours of site 2 3 Averaged from two sources; freemaptools.com and mapdevelopers.com – Accessed 12-2011 Virgin Hot Air Balloon Rides launch from Oxpen’s Meadow virginballoonflights.co.uk William Hancock Page 6 There was also a small line of trees between the houses and the meadow. This would have been planted to give privacy to the houses and to reduce any noise from activities on the meadow disturbing the residents. There was at least one house that had invested in mounting photo-voltaic cells on its roof. This suggests the potential for energy production from solar PV cells. Figure 1.2.3: 1) Hot air balloon 2) Solar PV Panels 3) Flood defence One of the most notable businesses in the area is the ice rink. This is the only ice rink in the entire Oxford area, and is adjacent to our site. This holds regular events, such as a late night disco skate, and is a constant tourist attraction. Not far along Oxpens road, less than 100m away, there is The Coven which is currently a night club attracting many students on nights out. There has been an application for a sexual entertainment licence and for it to be re-opened as a ‘lap dancing bar.4’ This could be another possible source of custom but it raises the issue of reputational risk if the roller coaster became associated with such activities. There will be a wide range of customers visiting the rollercoaster and it is likely some would take offence and oppose the proposed activities at the ‘The Coven.’ The close proximity of the residential area could potentially produce problems. If the welfare and privacy of the residents is not taken into consideration they could prove to be strong opposition to the rollercoaster. An action group has already been set up to preserve Oxpens meadow and to try to prohibit any development of the meadow. Throughout the planning proposal stage there will be plenty of communication with local residents and committee of ‘Friends of Oxpens Meadow5’ to try and reduce the possible tensions that could be created. The design will try to incorporate the viewpoint of all effected groups to produce the solution which will be the best for everyone. 4 5 Research taken from quote from OxfordStudent newspaper Accessed 4-2012 Friends of Oxpens meadow website Accessed 12-2011 Max Jackson Page 7 2: THE ROLLER COASTER This section discusses the final design of the ‘Launch of the Rings’ roller coaster, as well as the design process and decisions made that led to it. 2.1: Final Design Figure 2.1.1: The Final Design The ‘Launch of the Rings’ roller coaster is shown above in Figure 2.1.2 and the first thing of note is that is be split into two distinct parts: the indoor section (Figure 2.1.2) and the outdoor section (Figure 2.1.3). The riders begin indoors, as they follow a slow section of track inside the building. They do this facing upwards with their backs lying parallel to the track, as a Vekoma style loading method will be employed. This section is strongly Lord of the Ring themed, and is used to build anticipation for the launch. At the end of the indoor segment of track, the riders are flipped 180° into the flying position and brought to a complete stop, before being launched rapidly up to their maximum speed of 46mph, this can be seen in Figure 2.1.2. Almost immediately after this, they complete a classic loop and cobra roll in quick succession which, especially in the flying position, will produce a completely unique sensation in the roller coaster world. After this, a 540° Figure 2.1.2: The Indoor Section Figure 2.1.3: The Outdoor Section Max Jackson Page 8 helix turn is used, followed directly by a tight, overbanked turn in the opposite direction. The riders are then subjected to a small drop leading into a corkscrew to produce one final thrill before the ride comes to an end, as can be seen in figure 2.1.3. The roller coaster lasts a total of 64 seconds, with both the indoor and outdoor sections taking roughly the same amount of time to complete, which is useful in regards to the control of the system. The maximum G-force experienced by the riders is 4.17G in the positive vertical direction, which is both comfortable and safe, despite being thrilling for the riders. The maximum G-forces in the negative vertical and lateral direction are 0.7G and 1.7G respectively, which again are well with the comfortable region. The ride is a flying coaster, which means that the riders are in the prone position for the entirety of the ride, in order to simulate the experience of flight. It relies on a launched mechanism to start it, which when combined with the flying style, makes it the only roller coaster of its type in existence, which will be a real selling point. 2.2: Elements In the final design of the roller coaster, four different roller coaster elements have been utilised. These are the traditional loop, the cobra roll, the helix and finally the corkscrew, in that order. It is now important to look in more detail at each of these, and the reasons for selecting these four in particular out of the many available options. 2.2.1 Loop The first element in our ride is the loop, which is the most widely used element in steel, inverted coasters. It is essentially a section of continuously upwards sloping track which continues until a full 360° turn has been completed. Figure 2.2.1: The Clothoid loop However, most of these loops are not circular in Max Jackson Page 9 shape, but instead are in the form of a tear drop, as visible in Figure 2.2.1 . The names of loops 1 this shape are clothoid loops, and they are used to reduce the G-forces acting upon the rider2. Although this could be seen to be counterintuitive given normal roller coaster design, it allows more speed to be carried into, and thus out of, the loop, without danger to the passenger. A more detailed analysis of this shape can be found in Section 4.5. Here the train decelerates to its slowest point at the top of the loop, before it begins to accelerate under gravity for the second half of the loop. The reason the loop was selected was for its simplicity and traditional, iconic looks. It is a well-revered element in many successful roller coasters, and when combined with the flying position of the riders and its close proximity to the initial launch, the feeling of flight given by this section will be extremely exhilarating. 2.2.2 Cobra Roll The next element in our roller coaster is the cobra roll. This gets its name from the fact that the shape of the element resembles closely the head of a hooded cobra. This element can be broken up into four distinct parts. Firstly, the passengers begin with a continuously upwards sloping track, as with the loop. This continues until the riders have been fully inverted (or half a loop has been completed). They then perform half a corkscrew in order to leave them back in the upright direction but travelling perpendicular to the direction in which they approached the cobra roll. Next, follows another half corkscrew, but this time in the opposite direction, inverting the riders for a second time. Finally, the passengers traverse another half loop to leave them at ground level, travelling parallel to the way in which they approached the cobra roll, but in the opposite direction3. One reason for choosing the cobra roll to be used in the design is that it is an extremely exciting element, and due to the double inversion also has the capacity to disorientate the riders. Furthermore, it has a very impressive presence and will be visible from afar, allowing it to draw in customers to the ride. 1 Image from www.dmcinfo.com accessed 4/2012 www.physicsclassroom.com accessed 4/2012 3 www.snowboardcoaster.2ofc.com accessed 4/2012 2 Max Jackson Page 10 2.2.3 Helix The next element used is the helix turn. These are closely related to banked turns, where the riders are tilted through an angle of up to 90° during corners, in order to convert the lateral Gforces which would result from an unbanked turn into a positive-vertical G-force. This is important as the human body’s comfort and pain thresholds for force in the positive-vertical direction are much greater than in both the lateral and negative-vertical directions. The result of this is that turns can be taken at much greater speeds without discomfort to the riders. A helix turn is simply a banked turn which forms a radius of 360° or more. It is a spiral section and can either be upwards or downwards sloping, so that after a full rotation the passengers will either be some distance above, or some distance below where they began the turn4. A turn of 540° has been selected for use in our design; this is because the nature of the helix means that the result is very compact, providing lots of excitement and thrill in a relatively small area. This is extremely important given the small plot of land with which we are dealing and the necessity to make a ride that competes with the best rides in the world in all aspects, including the total duration. 2.2.4 Corkscrew The final element selected for the design is the corkscrew, which gets its name from its close resemblance to a kitchen corkscrew. The corkscrew very much resembles a small loop which has been stretched perpendicular to the direction of the loop. The result of this is that the start and finish of the element are no longer very close to one another, as with a loop, and the inverted section of the element is no longer parallel to the direction of travel. Instead, the inverted section is perpendicular to the direction of the entrance to the element. Corkscrews are usually found in pairs, either directly one after the other or interlocking from two distinct sections of track, however due to the size restrictions on our roller coaster, it was not possible to feature this in our design. A benefit of the corkscrew design is that they can be very small in size, and as a result of this possess the ability to invert the riders without needing a lot of speed. For this reason, as in our design, they are often found towards the end of rides. 4 www.themeparks.about.com accessed 4/2012 Max Jackson Page 11 The corkscrew was selected for its high thrill to size ratio and the fact that it does not require a great deal of speed to be completed, allowing it to be placed at the end of our ride to provide a final burst of excitement. 2.3: Design Iteration Initially, in order to get a better grasp of roller coaster design, the relatively basic NoLimits editor was used to create ten initial designs. However due to the limitations of the program, in particular the inability to save and the lack of useful information given, it has been decided that Roller Coaster Tycoon 3 will be used in the analysis of the designs instead. Although it is a game, rather than a specific simulator, the roller coaster design features and useful information that can be gathered from it are very impressive. For any given design, RCT3 allows the user to view the maximum and average speeds, the total ride time and length, the G-forces felt by riders in the positive vertical, negative vertical and lateral directions, as well as more option based values such as the excitement, intensity and nausea rating, in order to give an idea of how popular the ride will be with the passengers. These values allowed each of the designs made to be compared to the best roller coasters in the world, in order to ensure they will be able to compete and even surpass them. The design process, as with most roller coasters across the world, is an iterative one, with each new design addressing problems with the last. In order to begin the process, three very different initial designs were created. Then looking at the problems that had arisen from these three rides, a fourth design was created, and again this was modified to correct any problems, leading to a fifth design. Eventually a final design was reached, which addressed every issue with the previous designs and was felt to be the best roller coaster that could be built on the plot of land specified, in terms of not only excitement and its ability to draw in riders, but also its environmental and social impact. 2.3.1 Initial design 1 This design features a launched start, Figure 2.3 1 Initial Design 1 Max Jackson Page 12 accelerating the riders up to 44mph, which immediately leads into a small camelback hill. This is then followed by two consecutive corkscrews and two consecutive overbanked turns. Next there is an unbanked turn, followed by a single roll. The remainder of the track is made up of small unbanked turns. This design has the benefit of leaving lots of open space to be enjoyed as a park, by the public. This is especially useful given the fact that it is an SR.5 Protected open space. This ride is relatively small in size, especially when compared to some of the best rides, with which we are trying to compete. At just 25 seconds long, and 1119ft it length it falls short of any of the rides in the top five, and could leave the passengers feeling dissatisfied with the amount of ride time they received for their money. Furthermore all the flat turns produce very high lateral G-forces (2.7G) on the passengers, which are well outside the comfortable region for the human body. On the other hand. the positive and negative vertical G-forces are within acceptable limits at 4.3G and 1.0G respectively. 2.3.2 Initial design 2 This design features the same 44mph launch and immediately after being launched the passengers perform a roll, around the axis of the track. They then complete one and a half corkscrews before a half roll is used to return the passengers to the upright position, although at a Figure 2.3.3: Initial Design 2 higher elevation than before. The riders then complete a 90° unbanked turn before a small drop and corkscrew in quick succession. The remainder of the track is made up of small unbanked turns, as in Initial Design 1. It has further similarities with Initial Design 1, for example the large open space in the centre of the ride is an environmental and social positive. It, too, is a very short roller coaster, even shorter than the previous design, at just 740ft in length and taking a total of 17 seconds to complete. This is far too short to compete with the best roller coasters and in the final design steps must be taken to ensure the ride is of suitable time, despite the relatively small plot of land on which it is to be built. The Max Jackson Page 13 lateral G-forces are again much too high, at 2.3G, due to the fast, unbanked turns that are present in the design and both the vertical G-forces are in the comfortable region. 2.3.3 Initial design 3 The third design launches the passengers at a slightly higher speed of 54mph, in order to give the carts enough speed to complete the course. It begins with a cobra roll, which has the effect of disorientating the riders from the start, and is directly followed by a classic loop. This loop then leads into a corkscrew and finally a Figure 2.3.4: Initial Design 3 large, overbanked turn to really give the feeling of flight to the passengers. As with the previous two designs the ride is then completed by several unbanked turns. Due to the combination of the slightly faster launch speed and cobra roll, the positive vertical G-forces reach a maximum value of 5.24G which is not only uncomfortable, but also unsafe. Again, as with previous designs, the lateral G-forces are also too large, at 2.72G. The length of the ride is again an issue in this design, taking just 19 seconds to complete, which is far too short. The final and most important problem with the design is the Carfax Height limit of 18.2m, which is spoken about in more detail in section 6.6, is broken. The large, overbanked turn reaches a maximum height of 20.42m and this means that it would not be possible to construct this design within 1.2km of Oxford city centre. From the three initial designs, it is clear to see that there are some common problems arising. Firstly, although all three of the designs fit comfortably within the specified boundaries, as set out by the plot of land itself, they do not make effective use of the space, leading to very short rides. All three of the designs roughly follow the shape of an oval, leaving green space in the centre to be enjoyed by the public. While this has several positive outcomes, it also means that the ride is far too short to be taken seriously as a contender for one of the best rides in the world. The ride should be made to conform more to the irregular shape of the plot, and to be more convoluted in design. Max Jackson Page 14 Furthermore all of the design received high ratings for both intensity (7.0-7.5) and nausea (5.5-6), and this is something that has to be addressed in future designs. These rating are calculated by the simulation, in order to predict how enjoyable the ride will be for the passengers. Despite the fact that these high ratings could draw in roller coaster enthusiasts from around the world, to experience what would be one of the world’s most thrilling rides, this would be far outweighed by the number of potential customers that would be put off by them. 2.3.4 Design 4 This design features a 46mph launch, which leads into the classic loop, then immediately the cobra roll. This combination is very effective in creating an exciting ride and disorientating riders. Next, two 180° banked turns are used to make more effective use of the area of land. A cobra roll followed by several Figure 2.3.5: Design 4 sweeping, banked turns complete the ride. This design tackles several issues that were observed in the initial designs. For example, through drawing the perimeter and working with it to create the design, a more suitable shape for the ride was found, that made use of the irregular shape of the boundaries. This brought the ride time up to 33 seconds, which, although still fairly short, represents a big improvement on the initial designs. Furthermore the intensity and nausea ratings were reduced to 6.5 and 5.3 respectively, which means many more people would be inclined to ride it. Another positive is that the G-forces in all three directions now fit within the acceptable range for comfort, as discussed in section 7. There are, however, several problems with the design that need to be eliminated in the next iteration. Firstly the launch, loop and cobra roll are all currently located along the riverbank at the closest possible points to the houses opposite. These three elements are likely to create a great deal of noise and so, if possible, should be placed as far away from the houses as possible, in order to avoid any complaints. Secondly the location of the station needs to be adjusted, both for ease of access and in order to avoid the flood plane on which it currently sits. Finally, the second Max Jackson Page 15 half of the ride, which is currently mundane and unexciting needs to be modified, to ensure the riders are not allowed to feel bored whilst on the ride itself. This will have the added benefit of increasing the length of the ride further, bringing it closer to the standard set by many of the world’s best rides. 2.3.5 Design 5 This design is different to any of the previous designs in that there is now an indoor section to the track. This indoor section runs along the river bank and has several positive consequences. Firstly, it keeps the Figure 2.3.6: Design 5 noise levels to a minimum close to the houses opposite, which will prevent any animosity between the ride owners and residents nearby. Furthermore the slow indoor section will build anticipation for the big launch, making it even more exciting than in previous designs. It will also give the opportunity to use props to really enhance the Lord of the Rings theme and to tell a story to the riders, allowing them to be transported to the scene of the film before experiencing the thrill of the ride itself. The riders will be launched from the dark indoor section, instantaneously into a large loop. This, combined with the fact that the riders are in the flying position, will produce a sensation that will be unmatched in the roller coaster world. The ride itself is very similar to Design 4, with the only difference being the indoor section. Therefore, as expected, the G-forces in the three directions are all well within comfortable limits, and the nausea and intensity rating are of an acceptable level. The main difference is in the time taken for the ride to be completed. It now takes a total of 1.04 minutes, which is much more alike the times of the leading roller coasters. The one issue remaining is that it is unfeasible to have an indoor section of nearly 150m in length due to the flooding problems associated with the site. A building that large on a flood plain would mean the water has nowhere to go and this could cause severe flooding in other areas. Max Jackson Page 16 Furthermore, having the launch located where it is, at the place most susceptible to flooding, could lead to serious problems. For this reason it has been decided that in the final design, which is discussed in Section 2.1, a smaller building will be used, and the whole of the outdoor section of track will be mirrored in its design to keep the launch as far away as possible from the flood zone. 2.4: Layouts There are several different types of roller coaster, which can be categorised by the layout of their track. Several different options were considered before a final decision was reached that a simple circuit roller coaster would be the most appropriate for the Oxford site. First the ‘Wildmouse’ style roller coaster was explored. These are rides in which the carts seat a small number of people, generally four or fewer, and the track is made up of tight, flat turns which are taken at relatively high speeds to create very high lateral G-forces5. These rides induce fear through giving the impression of danger. They achieve this using random banking of the track, using cars that are wider than the track itself and in some cases even using spinning cars. Despite the fact that they are cheap and do not take up much room, this style would be inappropriate for use in our case due to the relatively low throughput and the large number of accidents in recent years6. The next option considered was the Duelling Roller Coaster. This type of roller coaster consists of two or more sections of track which in some way or another interact and can be split into three separate categories. Firstly, there is the traditional Duelling Roller Coaster. This is where two or more separate, but similar rides are built close to one another, intertwining and navigating near misses in order to heighten the sense of fear and danger for the riders. Next, there is the Racing Coaster, for which riders follow very similar tracks close to one another (often as close as a few feet, allowing riders to reach out and touch riders on the other track), this simulates the adrenaline filled thrill of a race. Finally, there are the Mobius Loop Roller Coasters. These can have the design of either a duelling or racing ride, but with the unique feature that there is only one, continuous loop of track, allowing passengers to experience both halves of the duelling ride. The 5 6 www.thecoastercritic.com accessed 4/2012 Examples of accidents from www.news.bbc.co.uk, www.foxnews.com and www.orlandosentinel.com Max Jackson Page 17 manner in which they do this is relatively straightforward and identical to the method used in Scalextrix with a crossover section of track7. Due to the size constraints on our plot, and the reasonably low throughput needed for our ride to operate at maximum capacity, it would be both unfeasible and unnecessary to try and introduce a ride of this nature to Oxford. The next layout to be considered was the Dive Roller Coaster, in which riders are transported up a lift hill before completing a slow, near horizontal section of track, and finally executing a vertical or near vertical drop8. The carriages involved in the style of ride are generally two or three rows deep, with each row seating between six and ten people. In order to ensure that all the riders have the chance to take in the views around them and get an understanding of the magnitude of the drop, stadium seating is often employed (where the rear seats are raised above the front ones). Due to the height constraint of 18.2m and the inability to dig underground because of the flood risks, it would be impossible to create an effective dive roller coaster in our plot. Terrain Roller Coasters were also investigated. These are rides which take advantage of either the natural undulations of the land on which they are built, or manmade hills, remaining close to the ground at all times and using conforming to the shape of the land9. This reduces the costs involved in building the ride as much smaller support structures are needed. However, as our plot is far too flat to be used in this type of ride, and the floodplain on which it sits inhibits any major landscape changes, this ride too would be unfeasible. Out and back roller coasters were also considered. These are rides where the cart climbs a large lift hill before racing in a near straight line to the far end of track, navigating several camelback hills, before performing a 180° turn and returning in another straight line, this time with several smaller hills10. This style of ride is very easy to design and construct, and as a consequence of this is very cheap, relative to other layouts. However, due to the long narrow area of land and tall hills needed, it would not be possible to design a track with this layout. Shuttle roller coasters are rides where the track does not form a complete circuit, but rather completes a section of track before reversing at a given point, and traversing the same section of 7 www.rcdb.com accessed 4/2012 www.bolliger-mabillard.com accessed 4/2012 9 www.thecoastercritic.com accessed 4/2012 10 www.theultimaterollercoaster.com accessed 4/2012 8 Max Jackson Page 18 track in the reverse direction . While these rides can be extremely small and compact, due to the 11 fact that the cart uses each part of the track twice per run, they also have some drawbacks. For example, due to the fact that this type of ride relies on gravity, both to slow the carts to a stop and then to reverse their direction, a large upwards sloping section of track is needed. Another tall, sloping piece of track is needed at the start of the ride. However, because of the 18.2m height limit in place neither of these would be possible on our site. Having exhausted all the other possibilities for an appropriate track layout, for one reason or another, the only remaining option is the simple circuit roller coaster. This is by far the most common layout for roller coasters and that, it appears, lies in its adaptability. This style of roller coaster can come in a great range of sizes and shapes, from the small fairground rides aimed at younger children all the way up to the giant Hulk ride at Universal Studios. There are many different styles of roller coaster with this layout, but ultimately all share the same simple premise; they follow a single track, and finish at near enough the same point that they began. Using this layout will enable the most efficient use of our small area of land, thanks to the ability to create tight convoluted shapes. Furthermore, it will allow us to use a launched start rather than a lift-hill, in order to ensure we remain below the 18.2m height limit at all times. Finally, the possibility of having several cars on the track at the same time means that there will be no issues in terms of throughput at peak times throughout the year. 2.5: Competition The aim of the Oxford roller coaster is to be able to compete with the best rides in the UK, and even the world. In order to do this it is useful to compare our ride to the top-ranked rides currently in the UK for a number of properties. Below is a table of statistics12 for what are often agreed to be the top five rides13. First, it is worth noting that all the rides in the top five are inverting, steel roller coasters. This highlights the importance of our decision with regards to what material should be used and the 11 www.en.wikipedia.org accessed 4/2012 All statistics from www.rcdb.com accessed 4/2012 13 According to The Ride Guide Forum Poll 12 Max Jackson Page 19 Name Nemesis Stealth Oblivion Shockwave Swarm Cost £10,000,000 £17,000,000 £12,000,000 £4,000,000 £20,000,000 Time to Build 3 years 6 months 14 months 2 years 1 year Mechanism Chain lift Launched Chain lift Chain lift Chain lift Length 2,349ft 1,312ft 1,223ft 1,640ft 2,543ft Height 180ft 203ft 197ft 80ft 128ft Max Speed 50mph 80mph 70mph 53mph 57mph Duration 1min20s 0min28s 2min40s 1min36s 1min21 G-force 4G 4,5G 4.5G 4G 4.7G Table 2.5.1: Statistics for Top Five Rides in the UK superiority of steel in this respect. Furthermore, it is also important to note that each of these rides has a feature that makes them completely unique. Nemesis was the first inverted coaster in the world, Stealth the fastest ride in Europe, Oblivion had the world’s first vertical drop, Shockwave was the world’s first stand-up coaster and Swarm is Europe’s only winged roller coaster. In light of this, the decision to make our ride the world’s first launched, flying coaster appears to have been a very positive one. When comparing our ride with the top five UK rides, several other positives come to light. For example, with a total cost of £6.82 million our ride is towards the lower end of the spectrum, and some way below the average cost of £12.6million. This is both an expected and pleasing result. Due to the fact that the ride will not be built to be part of a large park, but instead as an individual attraction, the budget for the ride will of course be less. This is due to the higher risk involved in creating a single ride, arising from the fact that if the ride is not popular, the owner does not have other rides to continue making an income. The lower cost means a greater profit is possible, which is the aim of building the ride in the first place. In terms of time taken to build, our ride is expected to take roughly one year, but this is very susceptible to change, given the uncertainties involved with every aspect of the design and construction process. This falls roughly in the middle of the competition, and as the average amount of time is 1.5 years, this too is a positive result. Next it is important to look at the length and duration of our ride, as they are key to ensuring the riders feel satisfied with the amount of enjoyment they received for their payment. Our ride is a Max Jackson Page 20 total of 2258ft, which is some way above the mean of 1813ft, despite being almost the central value. This is another positive result, especially given the relatively small plot of land on which it is to be built. This is due to the use of the long, 540° Helix turn and other compact elements. In terms of duration, at 1min4s, our ride sits slightly lower in relation to the competition, but is close to the average of 1min19s. The reason for the discrepancy between length and duration comes from the fact that our ride does not employ a slow chain lift hill, but rather a launch mechanism. When compared with Stealth, the other Launched Roller Coaster in the top five, our ride lasts almost double the amount of time and so will be more than satisfactory for the customers. Another positive consequence of using the launched start in our design is in the vastly reduced height of the roller coaster. Our ride reaches a maximum height of 18m (20cm shy of the Carfax Height limit of 18.2m), whereas the average height of the other five is more than double that value, at 157.6ft. The reason for stealth being so tall, despite it being a launched roller coaster, is that it relies on its height to scare the passengers, whereas we utilise a more exciting, inverting design to achieve the same. The maximum speed of our design is 46mph, which is the slowest out of all the rides in the top five, and far below the 62mph average. While this could be seen as the first real negative result for our ride, several measures have been taken to ensure that our ride doesn’t feel slow in comparison to the competition. The rides are launched up to their maximum speed very quickly, having just completed a slow dark section with the aim of building anticipation for the launch. This sudden acceleration, especially when juxtaposed with the slow indoor section will give a real sense of speed, heightened further by the use of the 5 rings surrounding the track at the launch. Finally, in terms of the G-forces experienced by the rider, our value of 4.17G sits roughly in the middle, which is high enough to be very thrilling, but not too high so that it becomes uncomfortable. SECTION CONCLUSION The roller coaster has been designed to compete with the very best rides currently operating in the world, whilst complying with all the constraints set out both by nature and the law, for example height limits, flooding risk, and noise restrictions. Max Jackson Page 21 3: RIDE CHARACTERISTICS This section provides a much more in depth look into the ‘Launch of the Rings’ ride, covering all technical aspects, in order to ensure that it is a safe, exciting and well functioning ride. 3.1: Flying Coaster After discussing the many different styles of roller coaster that could be built in Oxford, the decision was narrowed down to two options: 4D or flying. These two were chosen because in order to compete with the best roller coasters in the world, given the size constraints present, the ride would need to be extremely unique and exciting in order to draw in customers. With just 4 flying coasters in Europe and 6 4D coasters in the world 1, these two styles would do just that. A 4th Dimension roller coaster is one where the passengers are free to rotate on a horizontal axis, perpendicular to the track. This gives an added sense of uncertainty and heightens adrenaline for the riders. There are two types of 4D roller coasters, the Arrow Dynamics and Intamin designs. The main difference between the two is that the Intamin design relies on an uncontrolled rotation of the carts, which leads to a completely unique ride each time 2. The Arrow Dynamics design, on the other hand, uses an intelligent, fourrail system in order to control the rotation of the cart. Two of the rails are used, as in any roller coaster, for the carriages to travel along, and the other two, known as ‘X-Rails’ to control the spin of the carts, using a rack and pinion gear mechanism3. 4D roller coasters are almost always designed with no lateral movements at all, i.e the track is built in a 2D plane, which leads to very tall structures, as can be seen in Figure 3.1.14. This is a big problem due to the 18.2m Figure 3.1.1: Example of a 4D ride: Kimu Carfax height limit, and so this style of roller coaster, although unique, would not be suitable for our plot. 1 Roller Coaster Database Census (www.rcdb.com ) accessed 4/2012 www.itaminworldwide.com accessed 4/2012 3 www.engineeringexcitement.com 4 Image from www.itaminworldwide.com accessed 4/2012 2 Max Jackson Page 22 Instead, it has been decided that a flying roller coaster will be designed. Clearly, a flying roller coaster is a ride built to simulate the sensation of flight. It does this through keeping riders in the prone position, with their backs to the track for its entirety. While there are currently 4 rides of this style in Europe, when combined with the ‘launched start’, rather than, for example, a ‘chain lift hill’ it becomes the only ride of its kind in the world 5. This uniqueness would be a huge selling point for our ride, drawing in enthusiasts from all over to experience this one of a kind ride. As with the 4D roller coaster, there are two main, and very different, styles of flying coaster. These will be explored in more detail in the next section. 3.2: Patents For the flying roller coaster, there are currently several patents in existence which concern: how the passengers are loaded, how the carts are attached to the track, the loading mechanism, the restraint mechanism and any unique features6. In this section, the two main styles of flying coaster, Vekoma and Bollinger & Mabillard (B+M), will be investigated (ignoring the much smaller and lesser known Zamperta style). Vekoma are responsible for the most iconic and well known flying roller coaster, called the Flying Dutchman, as well as a smaller ride, called the Firehawk. B+M, on the other hand are known for creating several identical Superman rides for use Figure 3.2.1: B+M Loading Method by Six Flags, Tatsu ( the tallest, longest and fastest flying coaster in the world), Air ( the only UK flying coaster) and several others. By far the most important difference between the two styles is the loading mechanism, which will be the basis for our decision. For B+M flying coasters, generally, the riders sit in the carriage in the same way Figure 3.2.2: B+M Loading Method II 5 Roller Coaster Database Census (www.rcdb.com ) accessed 4/2012 All images and reference to patents in this section can be found on the United States patent and Trademark Office (www.patft.uspto.gov) accessed 4/2012 6 Max Jackson Page 23 they would any inverted roller coaster (where the carriage sits below the track) as shown in Figure 3.2.1. Each row is then hydraulically lifted, pivoting about the point where the top of the seats meets the track, in order to position the riders with their backs parallel to the track, in the flying position. The carriages are then released from the station to begin the ride. B+M also have a second loading method under patent and although it has not been used on a roller coaster to date, we feel it could be a possibility to use this method in our design. Here the carriage performs a 90° turn around the axis of track, before entering the station, so Figure 3.2.3: Vekoma 180° Rotation that it is on its side, ready to be loaded. The seats are then rotated 90° into an upright position as shown in Figure 3.2 2 and the passengers are allowed to load. The seats then rotate 90° in the opposite direction in order to line up the passengers back with the track, and the cart is allowed to leave the station. This loading method is very complex, and relies on an electric motor and rotating ring design. The Vekoma loading mechanism is far simpler than the two B+M designs, and as a consequence, cheaper too. Here the passengers load the train in an upright seated position, as they would any traditional roller coaster, however they will be facing the rear of the carriage. The riders are then lowered backwards until their backs are parallel with the track, as in Figure 3.2.4. Generally with Vekoma rides, the passengers are kept in this position whilst they climb the lift hill, then, soon after they reach the top, they are rotated 180° around the track into the flying position to complete the entire circuit. Just before the riders reach the braking section of the track, in order to enter the station, they are flipped a second time to be facing upwards. This allows them to be unloaded in a similar manner to how they were loaded. Due simplicity design, to the of the the lower costs involved and the Figure 3.2.4: Vekoma Loading Method benefit of having the Max Jackson Page 24 passengers facing upwards for the initial section of track, as discussed in more detail in the next section, it has been decided that a Vekoma loading style will be used. Instead of simply adapting their design to fit our needs, the design of the carts loading mechanism will be outsourced to Vekoma themselves, as this will reduce costs and benefit from their many years of experience. Finally, it is worth noting that a 3-restraint harness will be employed for safety purposes. Here the riders will be clamped at their shoulders, hips and ankles, as is common with flying roller coasters, due to the higher negative-vertical G-forces experienced during this type of ride. 3.3: Loading Method A Vekoma method of launching has been selected for use on the ride. As seen in the previous section, this is where the passengers load facing the back of the cart. The harnesses are then lowered and the riders are rotated backwards, until their backs lie parallel to the track. The cart then generally traverses a small section of track or climbs the lift hill in this position before it is rotated 180° around the track to place the riders in the flying position. This method, however, is being modified in order to benefit the ride. In our ride the passengers start the loading process as normal, entering facing the rear of the cart and being lowered onto their backs. They will then complete a dark, strongly themed indoor Figure 3.3.1: Indoor Section of Track to Show Location of 180° Rotation section of track. Here they will experience some of the Lord of the Rings journey first hand and learn more about the journey of Bilbo Baggins. This section will transport riders to a parallel world and build anticipation for the big launch out of the darkness, of the indoor section. This initial section of track will rely solely on gravity, rather than any chain or pulley systems, for the cart to traverse it. The entire section will be at a slight decline, and for this Figure 3.3.2: Indoor Section of Track to Show Incline of Track Max Jackson Page 25 reason the loading station will have to be relatively tall (this has the bonus of creating a smaller, denser queue, leaving more open greenery to be enjoyed by the public). The kicker wheel used to roll the cart into the station, and stop it in position, will also be used to start the cart on this section. As the riders are on their backs, facing upwards for this initial section, there will be lots of space above the track to design an effective attraction which is both aesthetically pleasing and exciting in nature. 3.4: Cart Design 3.4.1 Colours The two colours selected for use on the roller coaster cart are black and gold. These colours are not only an aesthetically pleasing pair, which complement each other well, but also link in well with the Lord of the Rings theme. The carts will be gold and the track painted black. The carts will be used to symbolise the gold ring from the film, and track to symbolise the dark, dangerous path to Mordor. The dark track also provides the added benefit of not drawing attention away from the fantastic Oxford skyline. The ride is intended to harmonise with the beauty of Oxford, and a garish, bright roller coaster (as so many are) would simply not fit in and could actually detract from the allure of the ride. 3.2.1 Layout As section 3.5, it has been found that only four riders are needed on each carriage in order to fulfil the maximum required throughput, at the peak of summer, of 250 people per hour. In light of this our carts have been designed to seat the minimum of four, as anymore would be uneconomical. Instead of the conventional 2x2 layout employed in almost all 4 seat carts, it has been decided to sit the four passengers in a single row. This will allow all the passengers to experience the highly desirable ‘front row ride’. Everyone will have the best seat available and be able to enjoy the thrills and views of Oxford that accompany it. 3.4.3 Theme As well as employing the Lord of the Rings colours in the design, the single row layout has allowed us to stamp the acronym L.O.T.R across the four seats. This will ensure that the theme is not lost on the rider and further enhance the experience. Figure 3.4 1 Final Cart Design Edward Jamie McDonald Page 26 3.5: Throughput The commercial model predicts that at peak times a maximum of 240 people per hour will ride our roller coaster. This is a throughput of significantly less than most existing roller coasters, for example the eleven roller coasters at Thorpe Park and Alton Towers all have throughputs of between 1000 and 2000 passengers per hour78. This enables smaller individual carts to be used rather than full trains, a technique that has been used before on a launched roller coaster by the manufacturer Gerstlauer on Lynet, a roller coaster at Fårup Sommerland in Denmark 9. The smaller vehicles are able to be accelerated over a lesser distance, a huge advantage on such a constrained site. The proposal is to have one row of four seats in each cart, allowing all riders to get the most sought after ‘front seat’ experience. With four people per cart, to achieve the predicted maximum throughput of 240 people per hour one cart will have to be dispatched every minute. The track can be broken down into three sections, the indoor section, outdoor section and station. A cart takes seventy seconds to complete an entire lap of the circuit, with the indoor and outdoor sections taking around thirty five seconds each. It is perfectly safe to have one train running in the indoor section and one in the outdoor section simultaneously, as the ride will be programmed to prevent launch out of the indoor section until the previous train has cleared the outdoor section. It is also perfectly acceptable to have multiple cars in the brake run and station area, as cars here are individually controlled by kicker wheels. These are wheels in the track touching the base of the cars, moving them slowly forwards as they turn. Also, the cars will be travelling at such low speeds here that any collision that did occur would have no consequence beyond a small jolt for the riders. 7 Figure 3.3.1: Indoor, outdoor and station sections www.thorpepark.com/downloads/press/THORPE-PARK-Press-Pack-2012.pdf - Accessed March 2012 www.rcdb.com – Accessed March 2012 9 http://www.gerstlauer-rides.de – Accessed January 2012 8 Edward Jamie McDonald Page 27 Throughput can be fulfilled using only two carts if they can consistently be unloaded, loaded and dispatched in 50 seconds. This is shown in Table 3.3.2. Time Station 0s – 10s Indoor Section Outdoor Section X1 X2 10s – 35s X2 X1 35s – 60s X2 X1 X1 X2 X1 60s – 70s Table 3.3.2: Two cart system. Each ‘X’ represents a cart, underlining represents loading. An alternative method of achieving the throughput using three cars allows more loading time per car and is shown in Table 3.3.3. This system still launches a car every 60 seconds but also allows 60 seconds unloading, loading and dispatching time. The downside is that passengers are required to sit waiting in the cart in the station for up to 50 seconds after the ride. There are also extra costs associated with running an additional cart, but these are minimal. Time Indoor Section Outdoor Section X1 X2 X3 10s – 35s X3 X1 X2 35s – 60s X3 X1 X1 X2 60s – 70s X3 X1 X2 0s – 10s Station Table 3.3.3: Three cart system. Each ‘X’ represents a cart, underlining represents loading. If even this system does not provide enough loading time, a final option exists which involves four carts, two of them loading at a time. This allows a loading time of up to 120 seconds and is shown in Table 3.3.4. The maximum waiting time after the ride is maintained at fifty seconds. Extra costs are those associated with a fourth car, as well as a bigger station area to allow the loading of two carts at once. Edward Jamie McDonald Page 28 Time Station Indoor Section 0s – 35s X1 X2 X3 X4 35s – 70s X1 X2 X3 70s – 105s 105s – 120s 120s – 155s X4 X1 X2 Outdoor Section X4 X3 X3 X4 X1 X2 X3 X4 X1 X2 Table 3.3.4: Four cart system. Each ‘X’ represents a cart, underlining represents loading. At Thorpe Park at peak times staff working on the two roller coasters Colossus and Nemesis Inferno have a target to launch the coaster within forty seconds of stopping it after the previous ride. This is considered an ambitious target and is not consistently met. Launch of the Rings has the advantage over these two that only four or eight riders need to be changed over as opposed to the twenty eight of Colossus or Nemesis Inferno10. On the other hand, there may be extra time costs associated with the more complicated restraint system of a flying roller coaster. For example on Air at Alton Towers restraints very often need to be locked a second time or do not unlock successfully without attention from a member of ride staff. The Vekoma flying roller coaster design does have the loading time advantage of performing the change to prone position after leaving the station whilst the ride is in operation as opposed to some other designs such as B&M’s 11. It seems likely that fifty seconds will not be long enough to be able to consistently unload, load and dispatch. Sixty seconds is significantly more feasible, and the full hundred and twenty seconds of the four cart system will definitely be possible. It is therefore necessary to ensure there are sufficient vehicles to be able to run this system, potentially also allowing expected maximum throughput to be exceeded. Which system is used will depend on experience gained ‘on the ground’ of how quickly the trains can realistically be loaded. The aim will be to use as few cars as possible given throughput. Clearly for the majority of time for which the ride is running it will not be at maximum capacity and so the two car system can be used with greater loading times. 10 11 www.thorpepark.com/downloads/press/THORPE-PARK-Press-Pack-2012.pdf - Accessed March 2012 www.vekoma.com/index.php?option=com_content&task=view&id=26&Itemid=19 - Accessed March 2012 Edward Jamie McDonald Page 29 3.6: Cart Details As explained in section 3.2 Vekoma has been chosen as our cart manufacturer, enabling their patented loading mechanism to be used. All previous Vekoma flying coasters have used full trains rather than the shorter four person single carts to be used on Launch of the Rings. The intention is to use a similar design to these longer trains but simply curtailed after the first passenger car. The green box in figure 3.4.212 shows the part in question of an existing Vekoma train. Figure 3.4.2: Firehawk at King’s Island Figure 3.4.3: Batwing at Six Flags America The small ‘lead car’ and associated wheels which immediately precedes the first passenger car will be retained. As shown in Figure 3.4.1 this would be used to house the magnets required for the launch and braking mechanisms. The lead car will be themed to the Lord of the Rings theme along with the rest of the ride. The carts will be made primarily from fibreglass, as is typical on modern roller coasters to reduce weight13. One of the most important aspects of the cart is the restraint system due to its safety implications. This roller coaster will use the design favoured by Vekoma on a number of previous rides consisting of an over-the-shoulder harness with additional waist and ankle restraints mounted on a pillar hinged into the base of the car. This can be seen in detail in Figure 3.4.3 14. The overall mass of the cart is important to bear in mind during design to ensure the train successfully travels the whole way round the track at a sensible velocity, as well as to calibrate the launching and braking sections correctly. Since this design is so similar to that of a typical flying 12 13 Image shown courtesy of kiextreme.com/gallery/albums/userpics/10001/may074-firehawk7.jpg www.madehow.com/Volume-6/Roller-Coaster.html - Accessed March 2012. 14 Image shown courtesy of www.themeparkreview.com/forum/files/batwing_p1040804_524.jpg Edward Jamie McDonald Page 30 roller coaster, we can just assume our mass will be a proportion of the mass of a full train, plus some additional mass to account for the heavy magnets we are using in our launch system. It can also be safely assumed that the front ‘lead car’ is half the mass of the other cars as in practice it will be significantly less than that. The typical flying roller coaster Manta at Seaworld Orlando has an empty mass of 15000kg and is eight four person carts long 15. The shorter carts used here will therefore have a mass of around 3000kg each. The approximate cost of roller coaster cars varies from around $20k - $100k per cart. Since flying roller coasters are amongst the most complicated of trains due to their extra restraints and hydraulic mechanisms our cars will cost towards the top end of this range. Accounting for the additional cost of the ‘lead car’ this will equate to around £65k per full cart. In section 3.5 it was decided that five carts are needed amounting to a total cost of £400k.16 This cost has been included in the estimate of initial construction costs. However it has also been factored in to running costs over the forty years for which the roller coaster is estimated to be in operation, as carts only have a lifetime of around eight years and so will need to be replaced several times.17 There will be an indoor depot for maintenance and storage of the carts when not in use. This will be in the indoor section of the ride to avoid further impinging on the green space of the meadow. Trains will be moved into and out of the depot through a changeable track layout and kicker wheels as shown in Figure 3.4.4. Station Depot Figure 3.4.4: Changeable track layout. 15 www.seaworld.com/sitepage.aspx?PageID=800 – Accessed March 2012 www.alibaba.com/showroom/roller-coaster-car.html - Accessed March 2012 17 Ibid. 16 Edward Jamie McDonald Page 31 3.4.1: Stress Analysis Figure 3.4.5: Side on view. Red indicates track, yellow is the braking fin, green the electromagnet for launch, black the restraints and hydraulic mechanism and brown the cart body. Most of the metal on a roller coaster car is manufactured from aluminium or steel 18. The two parts of the cart that will be suffering the most stress that this will particularly apply to are the base of the wheel casings, which take the whole weight of the cart, and the bar which holds the rear part to the lead car. The maximum positive G-force the rollercoaster experiences is 4G and the maximum negative 1.5G. One G is equivalent to 10ms -2 of acceleration. Using we therefore find that the maximum tensile force on wheel casing connection is 45kN, split between the lead car and the trailing car. The maximum compressive force is 120kN again split between the two cars. Stress, σ, is defined as where A is the cross-sectional area of the section. This connection has been designed with a cross-section of 50mm x 50mm giving 2500mm 2. The maximum tension in the section will therefore be below 18MPa and the maximum compression below 48MPa. Equally the maximum forwards acceleration suffered by the car is 6.05ms -1 and the maximum deceleration 15ms-1. Due to the position of the electromagnet in the lead car, and the braking fin attached to the connecting bar, both of these will cause tension, which will therefore have a 18 Scott Rutherford, The American Rollercoaster, 2nd edition, 2004, Motorbooks International, St Paul, Minn. Edward Jamie McDonald Page 32 maximum of 45kN. This equates to a maximum stress of 50MPa for the bar used which is 30mm x 30mm in dimension. Due to its lighter weight than steel, it would be preferable to use aluminium for these parts. Pure aluminium has a low yield strength, however the most commonly used aluminium alloy, 6061 has the higher yield strengths shown in Figure 3.4.6. for different tempering. It consists of between 95% and 99% aluminium alloyed with various other metals including silicon, iron, magnesium and chromium19. Aluminium 6061-T4 can be seen to have a yield strength σy of 110MPa which is greater than the stresses these elements of the cart will undergo. It is also highly weldable, an important consideration for ease and cost of construction. The wheel casings and connector between the carts will therefore be made from this alloy. The cost of Aluminium 6061-T4 is around £2000 per metre cubed which is well within our budget for the carts 20. The joint between each of the wheel casings and the connecting bar holding the two carts together will be a pin type joint. This will enable each set of wheels to follow the track independently. Aluminium 6061-O 55MPa Aluminium 6061-T4 110MPa Aluminium 6061-T6 241MPa Table 3.4.6: σy for Aluminium 6061 19 20 www.alcoa.com/adip/catalog/pdf/Extruded_Alloy_6061.pdf - Accessed April 2012 www.metalsdepot.com/products/alum2.phtml?page=square – Accessed April 2012 Edward Jamie McDonald Page 33 3.7: Launch Due to the eighteen metre height restriction it was quickly decided that a launch coaster was the only way to achieve the required speeds that would make the roller coaster sufficiently thrilling and exciting to compete with other rides on a national and global scale. The other primary alternative, a traditional lift hill, would not be able to generate sufficient speed from such a small height. There are four main possible methods of powering a launched roller coaster – linear induction motors, linear synchronous motors, hydraulic or pneumatic launch 21. Linear synchronous motors or LSM were opted for. It was decided against linear induction motors as rides powered by this method typically have slower acceleration, two good examples being California Screamin’ and Mr Freeze. Most manufacturers have moved away from induction motors and towards synchronous motors in recent years due to improved performance and cost. Fast acceleration is particularly important here due to the small size of land available and slower acceleration meaning more space is required for the launch to reach the same top speed. A pneumatic launch works by compressed air. This is a fairly new technology that has only been applied to three roller coasters before22. Its main advantage is high acceleration to the very fastest speeds, for example the pneumatically powered Ring˚Racer under construction at the Nürburgring reaches a top speed of 134.8mph. The downside is that costs are quite high and since the technology has not been used on many roller coasters there is little information on likely reliability. As our Launch of the Rings only needs to reach a top speed of around 50mph there would be no advantage in using this launch method and the high cost and reliability uncertainties caused it to be decided against. Hydraulic launch roller coasters use hydraulic fluid to compress nitrogen which, when released, powers a turbine connected to a winch which pulls the car. This system is already well used in the UK, with Stealth at Thorpe Park and Rita: Queen of Speed at Alton Towers both using a hydraulic launch23. The biggest problem with this method is that it is unreliable with high maintenance 21 22 23 http://www.buzzle.com/articles/physics-of-roller-coasters.html - Accessed March 2012 www.rcdb.com – Accessed January 2012 www.popsci.com/technology/article/2011-03/how-it-works-worlds-fastest-rollercoaster – Accessed April 2012 Edward Jamie McDonald Page 34 requirements and lots of down time. Additionally synchronous motors produce faster acceleration to speeds below around 60mph and so are a better option for this roller coaster with its top speed of only around 50mph. 3.7.1: LSM Launch An LSM roller coaster is accelerated through magnetic interaction. There is a powerful electromagnet mounted in the train and permanent magnets located to each side of the track. The electromagnet is powered by a battery in the lead car which charges while the car is stopped in the station. As shown in Figure 3.4.1 the magnets are arranged such that the North Pole of the electromagnet in the train experiences a repulsive force in the direction of acceleration from the North permanent magnet behind it and an attractive force from the South permanent magnet ahead. As the train moves along the track the current powering the electromagnet is reversed causing its poles to swap. If performed at appropriate timing intervals this will ensure that the train is always accelerated in the correct direction24. This is a very reliable launch method with lower maintenance requirements than other systems as there are few parts and no friction, physical contact or moving parts. Figure 3.4.1: Diagram of an LSM launch system. Note the permanent magnets shown below the track rather than their usual place to the side. The electromagnets have quite a large power requirement. Other LSM roller coasters that accelerate to 50mph require a constant power input of around 120kW and a storage system. While the roller coaster is running power is drawn at a constant 120kW and stored before being used in a burst each time a launch takes place25. 24 25 www.unc.edu/~bhuang/lsmcoasters.htm - Accessed March 2012 www.gerstlauer-rides.de – Accessed November 2011 Edward Jamie McDonald Page 35 3.7.2: Acceleration and Launch Length The launch part of the track is forty metres long. Carts will stop at the start of this section to build anticipation and so that launch can be delayed if the previous cart has not yet cleared the next track section. This means that the launch will be required to accelerate the cart from 0 - 22ms1 . Therefore in the acceleration, velocity and displacement curves shown in Figure 3.4.2 V1 22ms 1 X 1 40m . We know that a dv d 2 x and dt dt 2 v x0 at t 0 therefore 2 AT V1 A1T1 22 and X 1 1 1 40 which solve to give A1 6.05ms 2 . 2 This acceleration is equivalent to 0.6G, well within the comfortable limit for positive G forces of 4G. Furthermore, Figure 3.4.2: Acceleration, velocity and displacement curves against time acceleration is this easily possible using a standard LSM launch arrangement as demonstrated below. 3.7.3: LSM Launch Acceleration The extremely powerful neodymium type of magnet will be used for the permanent magnets. This is the most powerful kind of permanent magnet known and has four to five times the power of a similar ceramic magnet26. They are made of NdFeB, neodymium-iron-boron. For the purposes of the calculation it has been assumed that grade N38 magnets will be used with dimensions of 50mm x 25.4mm x 12mm. The poles are separated by the full 50mm27. A typical LSM launch system uses about two hundred magnets. Over a forty metre section of launch track this is equivalent to one every 200mm. The electromagnet in the cart has length exactly equal to the gap between two poles and so will also have length of 200mm. An 26 27 www.wondermagnet.com/magfaq.html - Accessed March 2012 Magnet data from www.ndfeb-info.com/ndfeb_rectangular_magnets.aspx - Accessed March 2012 Edward Jamie McDonald Page 36 electromagnet of the strength required will have similar diameter to length and so 100mm has been used as the value for radius in the calculation. In the calculation subscript f indicates the fixed, permanent magnets and t the electromagnet on the train. Figure 3.4.3 shows the key magnets providing propulsion to the cart at any one time. The magnets will be mounted in such a way as to minimise the out of line distance, the vertical distance in the diagram, and so this can be approximated to zero. Finally, the forwards direction of the cart is considered positive. Figure 3.4.3: Magnet Arrangement Using the Gilbert model28, each pole can be treated as a magnetic monopole. The total force on each monopole can then be found from the superposition of the forces on that monopole by each other monopole29. Each of these forces can be calculated using the equation F q f qt 4r 2 where μ = permittivity of air30, q = charge of monopole and r = distance. Repulsive forces will be in the opposite direction. The total force on the roller coaster cart is equal to the force on the electromagnet’s North monopole plus the force on the electromagnet’s South monopole. Neglecting the effects of all but the closest two other monopoles on each monopole, and considering that the effects of the electromagnet’s North monopole on its South monopole will be equal and opposite and thus negated by the effects of the South monopole on the North monopole, the total horizontal force on the cart is: 28 A L Davalos, Fundamentals of electromagnetism: vacuum electrodynamics, media and relativity, Springer, Berlin, 1999, Section 6 Magnetic Field 29 http://geophysics.ou.edu/solid_earth/notes/mag_basic/mag_basic.html- accessed March 2012 30 Value taken from A M Howatson et al, Engineering Tables and Data, 2009. Edward Jamie McDonald F 2 0 q f q t 4 Page 37 ( 1 1 ) 2 x Lt x 2 Again from Gilbert’s model31 q for each monopole can be approximated to: q where B0 = magnetic flux density at r=0, A = Cross sectional pole area, 2 B0 A L2 R 2 0 L L = length of magnet and R = radius of magnet (or approximation in the case of a cuboid magnet). The N38 magnets chosen for the fixed magnets have the following properties 32: B0 f 0.554T , A f 6 10 4 m 2 , L f 0.0254m 2 , R f 15 10 3 m , b 0.006m The electromagnet has the dimensions calculated above, and the mass of the cart has been calculated in section 3.6: Cart Details: Lt 0.2m , Rt 0.1m , At 0.0314m 2 , mass of cart m 3000kg . Therefore, F 6.93B0t ( 1 1 1 ) . Average force = 2 2 Lt x 0.2 x Lt b b Fdx 5620 B0t N . 2 From F ma , the acceleration of the cart will be 1.9 B0t ms . There is one more important factor not considered. The force on the overall cart will actually be double what is calculated here as there are two sets of magnets, one each side of the cart. Therefore to achieve the required acceleration of 6.25ms-2 the electromagnet needs to have a value of B0 of 1.6T. There are a number of assumptions in this calculation which will have varying effects on the final figure for B0. Since it is impossible in practice to have a single monopole, the permanent magnets will have another pole which causes deceleration, as shown in Figure 3.4.3. Due to the out of line, vertical on the figure, distance between these poles and the electromagnet they will cause a lesser force than the magnets considered. In this calculation, the deceleration force will be less than the acceleration force by a factor of cos(tan 1 ( 0.0254 )) which approximates to total x acceleration around two thirds of what we have calculated. Potentially the value for B 0 could 31 32 http://instruct.tri-c.edu/fgram/web/Mdipole.htm - accessed March 2012 Magnet data from www.ndfeb-info.com/ndfeb_rectangular_magnets.aspx - Accessed March 2012 Edward Jamie McDonald Page 38 therefore need to be around 50% greater than the calculated value. Fortunately this is in part negated by the other major assumption which is that the magnets on one side of the car will have no effect on the electromagnet on the other side. In practice there will be interaction between these increasing the acceleration. Other assumptions which will have a negligible impact on the value are the small out of line distance of the main poles discussed above, and the effects of poles further in front and behind the car, which will for the most part cancel out. Fortunately electromagnets do exist with B 0 values around this level. The maximum possible magnetic flux density of an electromagnet is determined by the saturation induction of the metal used for the core. Whilst iron has a fairly high saturation induction it is not great enough for this purpose. Instead, we will need to use permendur, a cobalt iron alloy. This has a very high saturation induction of 2.35T33. This is roughly the value required. Once the effects of the additional poles described in the assumptions above is taken into account it may prove slightly too low in practice. This should not be of concern however as we have used a very conservative estimate of the value of B0 of our permanent magnets. By simply using a higher grade of permanent magnet the required acceleration will be easily achieved. There is potentially a problem with the additional mass of the electromagnet causing slower acceleration of the train. The total volume of the two electromagnets is 6.28x10-3 metres cubed and the density of permendur is 8200kgm-3 resulting in a total additional mass of 52kg 34. This is well within the margin of error of the mass of the train anyway so this should not cause any difficulties. Finally, the cost of the electromagnets is in the region of £1,500 each35. There are five trains, with two magnets each giving a total cost of £15,000. The permanent magnets at a higher grade cost about £50 each and four hundred are required making a total cost of £20,000 again. Therefore the total cost of all the magnets will be around £35,00036. This is well within the project’s budget. 33 www.coilws.com/index.php?main_page=page&id=104 – Accessed March 2012 www.hightempmetals.com/techdata/hitempPermendurdata.php - Accessed March 2012 35 http://www.goodfellow.com/E/Permendur-49-Rod.html - Accessed March 2012 36 http://e-magnetsuk.com/magnet_products/neodymium_magnets/rectangular_magnets.aspx - Accessed March 2012. 34 Edward Jamie McDonald Page 39 3.8 Braking The roller coaster will make use of a modern magnetic braking system. This has much lower running and maintenance costs than traditional fin brakes as there is no wear or tear caused by friction between parts. Unfortunately magnetic brakes are unable to bring a train to a complete stop as deceleration is proportional to velocity. It is therefore necessary to have some frictional braking component, in many cases this comprises fin brakes after the magnetic brakes. Launch of the Rings, however relies to a greater extent on magnetic braking and uses kicker wheels to bring the cart to a complete stop when it bumps over and against them. These kicker wheels will then be used to control the movement of the car into and out of the station. The magnetic brakes work by having a fin which passes through a strong magnetic field. The field induces eddy currents in the fin as shown in Figure 3.4.4. These produce a conflicting magnetic field which works to provide a force against the movement of the cart. There are two possible arrangements; either the fin can be mounted to the cart with strong permanent magnets in the track to generate the magnetic field or alternatively many launched roller coasters have fins mounted to the track and magnets in the carts. This latter has the advantage that emergency brakes that rise out of the track can be located in the launch section, stopping the cart in case of a roll-back or timing error in the launch. It is impossible to place permanent magnets in the carts as these would interfere with the magnetic launch process. Therefore if a fin were to be attached to the track it would be necessary to use the electromagnets already in the cart for launch Figure 3.4.4: Magnetic Braking to generate the magnetic field. Edward Jamie McDonald Page 40 Unfortunately this is not a feasible option as this would not create a failsafe system as the magnets would become demagnetised in the event of a loss of power. The alternative system of a fin attached to the cart and permanent magnets in the track will therefore be used. To overcome the potential safety implications of a roll-back or problem in launch an extra emergency brake run will be included just before the launch section which the car can safely move back into and be stopped. The fin on the cart will lift up when it is traversing this section forwards so that the car is not stopped then. 3.8.1: Magnetic Braking Calculation For the purposes of this calculation the fin will be treated as a disc with the eddy currents flowing in concentric circles of width dr. The eddy current produced in one of these circles should be calculated using the principles of electromagnetism. where E = emf generated, B = magnetic flux density l = length of loop and u = fin velocity. The next step is to use in which ρ = the resistivity of the fin, to find J, the current density. This enables the current di in one loop to be calculated from when A is the cross sectional area of the loop and t the thickness of the fin. Combining these equations gives and by rearrangement: Next , the equation for the motor effect, to calculate the opposing force from this loop: This can then be integrated to find the total decelerating force on the cart using boundaries of zero and r0: ∫ Using the same N38 class of magnet as for the launch situated very close to the fin B = 1.1T.can be achieved. Based on the size of the magnet the maximum effective radius of the fin is Edward Jamie McDonald Page 41 r0 = 25mm. As is common for this braking method the fin will be made from copper as it has a very low resistivity of ρ = 16nΩm at ambient temperature37 and will have thickness 6mm. By substituting these figures into the equation above a total force of 214u N on the cart is achieved where u is its velocity and therefore the fin velocity. The cart has a total mass of 3000kg therefore using this is equivalent to a deceleration of 0.0713u ms-2. The deceleration can be further increased by having a larger fin allowing multiple eddy currents at a time. If n is the number of eddy currents therefore deceleration = 0.0713nu ms-2.38 The maximum deceleration that can be allowed is 15ms-2 as this is equivalent to a negative Gforce of 1.5G which is the maximum deemed permissible. In order to stop the cart in as short a space as possible, it is desirable to be as close as possible to this upper limit. The maximum velocity of the car will be just as it enters the brake run when it is travelling at a velocity of approximately 20ms-1. Therefore we set n=10 as this produces a maximum deceleration of 1.43ms 2 . There is plenty of space for this on the car as from the dimensions of the magnet each eddy current is 100mm long meaning that with 100mm spacing the total fin length will be only 2m, less than the length of the cart. As it enters the brake run the car is travelling at a velocity of approximately 20ms -1 and needs to be slowed to a maximum speed of 2ms-1 to be safely and comfortably stopped by kicker wheels alone. Denoting velocity by v, acceleration by a and displacement by x, ∫ At ∫ ∫ therefore To determine the total length of magnetic brakes required it is necessary to substitute in and solve for x which gives the solution 25.2m. The true answer will however be up to 2m greater than this due to the fact that the entire fin needs to be within the brake run to generate maximum deceleration. In this design there is thirty metres allowed for the brake run which is therefore sufficient. 37 David R. Lide, CRC Handbook of Chemistry and Physics, 84th Edition. CRC Press. Boca Raton, Florida, 2003; Section 12, Properties of Solids; Electrical Resistivity of Pure Metals 38 Edward Hughes, Electrical and Electronic Technology, 10th edition, Pearson Education, Harlow, pages 136-142 Charlie Hill Page 42 3.9: Control System In considering the control system for a roller coaster, safety must be the upmost priority. A roller coaster inherently involves high speeds, large amounts of acceleration, and also presents an interface between man and machine. As such, a control system needs to minimise the possibility of human error. The Launch of the Rings circuit can be broken up into three constituent components: The station, the indoor section, and the outdoor section, as shown in Figure 3.9.1. The outdoor section is the main body of the roller coaster, and is free flowing and fast. There are no braking Figure 3.9.1: Sections of the track. Outdoor: Green. Indoor: Orange. Station: Red or acceleration sections outside, and as such, the operators have no control over the roller coaster. All the operators can do is feel comfortable knowing that as the roller coaster left the station, all of the appropriate safety constraints, i.e. harnesses, were correct. The indoor section is relatively slow moving. The track contains kicker wheels, at up to 1m intervals, that ensure the cart is going the appropriate speed. By running a succession of wheels at the desired speed, the cart is either accelerated or decelerated to this speed. The control for this system is simple. The wheels need to run at a predetermined velocity. The current velocity of the kicker wheels is determined from an electromagnetic sensor measuring the speed of rotation of the shaft connected to the wheels. The algorithm running the control system is: loop if end if if end if wait do loop Charlie Hill is the power delivered to the electric motor driving the kicker wheels, and wheel velocity and desired wheel velocity respectively, level, and Page 43 are the actual is a predetermined change in power is the time taken for the change in power to lead to a steady state change in velocity. If the velocity is lower than desired, the power to the motor is increased - leading to an increase in the velocity of the kicker wheel. The opposite is true should the velocity be lower than desired. The system then waits for the change to settle down, before checking again. The kicker wheel implementation also provides a failsafe solution. Should power to the ride suddenly fail, the wheels will stop turning. The frictional resistance of the motors would also provide a stopping force on the carts. Due to the low speed of the carts in this section, this braking force would not be sufficiently great to cause harsh deceleration to the carts or the riders. The only fail risky scenario would be a failure in the control system, leading to the power to the motors being constantly increased, and thus constantly increasing wheel velocity, i.e. a loop in the line. This could be due to a software fault, or a hardware fault in the power supply, or the velocity sensor of the wheel. Although the risk is small, a failure plan still needs to be considered. To mitigate against this risk, we will consider the nominal, expected power required to drive the wheels at the desired velocity, . A power supply system would be purchased that was not able to produce a large amount of power more than . Thus, the power supply would be limited to: being the amount of extra power required to accelerate the wheels at a satisfactory rate. Typical values for may lie between 1.6 - 2.5. A third application of control mechanisms on the kicker wheels involves power saving. Rather than having the wheels permanently running, it is recommended that each block of kicker wheels be preceded by a switch that signals a passing cart, and starts that block of wheels. A second switch would then follow the kicker wheels, and power them off. As such, the wheels would only run periodically, rather than continuously, reducing electricity usage. The “off switch” block could be placed immediately after the kicker wheels. As soon as the cart has cleared the section, the power saving Figure 3.9.2: Arrangement of switches on wheel sections Charlie Hill Page 44 could be realised. The “on switch” block position is determined by the need for the wheels to be turning at the correct velocity before the cart reaches them. Taking the length, , as the distance between the start block, and the beginning of the kicker wheels, as shown in figure 3.9.2, then this distance must be: Where speed, and is the expected speed of the cart, usually the same speed as the kicker wheels target is the time for the wheels to stabilise at their desired speed, than this value, allowing for error. Typically, . must be greater might be 2 times greater than the calculated value, to ensure the kicker wheels are running at the appropriate speed before the cart arrives. The station provides the most control over the cart. Here, the carts will run permanently on kicker wheels, as described above. The kicker wheels will run at variable speed, allowing for the cart to stop, and then resume. The control system for this section will run off a number of signals. Figure 3.9.3 details the station, and shows the origin of these signals. The signals are binary, and are thus either on or off. The “Master” switch is a complete override switch located with the ride manager: on signifying the track is clear for operation; off signifying that some event has occurred and all movement on the track should stop. This would stop all of our kicker wheel sections, and thus bring any carts in the inside and station sections to a quick stop. Should communications with this switch fail, the control system would interpret the failure as the master switch being off: failure in the system, leads to the safest outcome - the carts are stopped until the fault can Figure 3.9.3: The signals within the station be rectified. Other signals include the entry signal, E, which sends a positive pulse to the control system as a cart passes over it, the waiting signal, W, which indicates to the launch system that a cart is waiting for the track to clear, otherwise it is ready for launch, and the station signals, S. These are Charlie Hill Page 45 a bank of signals, which prepare the cart to be ready to leave the station. Highlighted here, these include Ss - the station stop - there is a cart stopped in the station; Sh - the station harness indicating that the carts locking device has successfully secured its occupants; and Sm - the station master - which takes input from the ride operator, that the ride is ready to depart. The ride operator is presented with a switch that allows him to launch the ride, yet, if the station harness, or station stop switches are not ready, the ride will not launch. A cart will only leave the station when all S signals are set to 1: The following steps summarise the process as a cart passes into the station, through until the cart is launched onto the track. 1. A cart enters the station, triggering the E switch as it passes. 2. The cart stops at the station, triggering the Ss switch. 3. Passengers exit the cart. New passengers enter the cart. 4. The harness drops into place, securely locking, and triggering the S h switch. 5. The ride operator gives the all clear, triggering S m and permitting the cart to continue. 6. As the above equation, S is now triggered, the cart moves into the slow section. 7. The cart reaches the end of the slow section, and triggers the waiting switch. 8. A second cart enters the station, triggering the E switch as it passes, restarting this loop at step 1, but for the second cart. 9. The track is now known to be clear, and the first cart is launched around the track. The system can easily be modified to allow for three carts - two carts having passed the E switch means the track is clear. The launch conditions, into the outdoor section, can be summarised as: Where z is set by the following expressions: %safe cart counter %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% if E = 1 then safe = safe + 1 if launch then safe = safe - 1 if safe = n then z = 1 % n is number of carts in total Charlie Hill Page 46 The second expression is relatively straightforward. It states that if all signals give clearance to launch around the track, then launch should be initiated. Station signals are not incorporated into this consideration. Instead, the station variables are only used to move the cart from the station into the indoors section. That is to say, when S is triggered, the cart can immediately move into the indoors section. Three variables are considered when determining whether to launch the cart. W signals that there is a cart waiting and ready to be launched. M signals that the track is clear to run according the master switch, and z signals that there are no other carts on the outdoor section of the track. The first part of the expression is slightly more complicated. The aim is to count the number of “safe carts” - that is to say carts that are either in the station, or on the inside section, with frequent kicker wheels, providing lots of control - and then returning a signal if all of the carts are safe. Alternatively, a signal that there are no carts on the track, and any waiting cart can be launched. As such, any pulse, E generated by a cart entering the station leads to an extra cart being added to the safe count - the cart has become safe, because it has entered the station. A launch leads to a cart being made “not safe” - it is in the outdoor section, and we have no control over it. The overall number of safe carts is constantly evaluated, and, if all carts are considered safe, then the next cart is cleared to launch, i.e. the z signal is set to 1. This signal stays positive until the cart is launched, that is that the w and m signals are also set. This system guarantees that there is only one cart on the free-flowing part of the track at any one time, and guarantees that in event of emergency or failure, all carts cease movement as quickly as possible. Strain gauges incorporated into the track and structure would have access to set the master switch. Strain gauge analysis over time would lead to a record of expected strain values. A sudden change in reading from any strain gauge, or linear drifting of values might indicate a failure of the track. The strain gauges would then be able to de-select the master switch, stopping all of the carts until the track was checked by maintenance, repaired if necessary, and the ride manager had cleared the fault. William Hancock Page 47 3.10: Wheels Two important considerations in designing a rollercoaster are safety and speed. These are reflected in all aspects of the design and manufacture. The main limiting factors for the speed of a roller coaster are the design and the materials used for the wheels. The four aims during the design of the wheels are; low rolling resistance, high load endurance, smooth ride performance, and high durability which leads to low maintenance cost. To maximise the energy efficiency the rolling resistance caused by deformation at contact has to be minimised. The coefficient is typically 0.007-0.01839, but is increased by a lower pressure on the wheels or a higher exerted force. Using other existing designs, a novel Solidworks model was created for the initial design. 3.10.1: Design of wheel connection Nylon Wheels Polyurethane wheels Load bearing wheels Folded edge Filleted corner Side friction wheels Cart connection Up stop wheels Figure 3.7.2: Side view of wheel attachment Figure 3.7.1: Initial wheel design There are three main types of wheels used in the roller coaster. Firstly road wheels, these bear the load or the weight of the car. Secondly are the side friction wheels which are mounted perpendicular to road wheels and prevent any lateral movement of the cart. Lastly, there are upstop wheels which are placed under the rails to prevent the cart from coming off the track. The cart will attach to the centre connection. It was deemed necessary to add a folded lip, shown in figure 3.7.1, to the outer edge to add strength and protect against the axle shearing up through the metal. A lighter cart requires less energy to launch; therefore the connection should also be lightweight. The thickness of the metal should be as thin as safely possible. To withstand the high forces every corner has been filleted to reduce the stress concentrations. There is a mixture of two materials used for the wheels, firstly, there is an aluminium hub surrounded by polyurethane. This is a softer material which reduces vibration providing smoother 39 Value taken from coaster101.com Accessed 1-2012 William Hancock Page 48 ride but does increase friction giving a slower ride. Secondly there is solid nylon which is hard so has high vibrations and puts more wear into the track but does provide a faster ride. The combination between these types creates a smooth yet fast ride. It is both hard and expensive to make a track with no imperfections; therefore the wheels must absorb the small defects. 3.10.2: Calculation of wheel speed The cart can travel up to a speed of approximately 45 mph, 72.42km/h, as it passes along the track. The load bearing wheels are 150mm diameter and circumference of 0.5027m. ( ) 3.10.3: Wheel fatigue It is important to have a prediction for the lifetime of the wheels under the stress load. Routine maintenance checks should highlight any wheels which are damaged. To analyse the properties of the wheels a finite element model can be created. In a biaxial stress state two equations are solved: ( ) ( ) , ( ) For any fatigue analysis the loading condition has to be known. In this case the input stress is cyclic whilst the ride is in operation as shown in figure 3.7.3. Figure 3.7.440 shows the relationship between the alternating stress amplitude and the number of cycles to failure of a material. Figure 3.7.3: Loading on wheel Figure 3.7.4: S-N Curve stress amplitude vs. number of cycles to failure SECTION CONCLUSION The decisions made during the design of the Launch of the Rings will ensure that it is unique and will compete with the best rides in the world. The ride has many novel features and has overcome numerous technical engineering challenges through attention to details and intricate design procedures. 40 Graph researched from docstoc.com – accessed 04/12 William Hancock Page 49 4: FOUNDATIONS AND FRAMEWORK A detailed analysis into the support structure and foundations was undertaken. This is to ensure that the ride will be safe and not fail in any way for the duration of its operational lifetime. 4.1: Geology For any major construction the foundations are an integral part of the design and build process. To be able to effectively and efficiently carry out this task an extensive evaluation of the site has to be undertaken. A significant part of this is the local geology. The British geological survey carries out soil analysis from many boreholes. On the site that is being studied there are five relevant boreholes1 as shown in figure 4.1.1. As an overview the site is superficially, Alluvium, clay and silt overlying sand and gravel. At bedrock level it is Oxford Clay formation and West Walton formation which is an undifferentiated mudstone. Details of borehole SP50NW59, marked A on figure 4.1.1, are shown A in figure 4.1.2. The borehole is 30m deep but only the first 14m, are relevant as the foundations will not be this deep. Figure 4.1.1: Borehole data Comparing data from across the site and neighbouring samples showed that although there were slight variations of depth and types of soils, these were all in the top soil region Figure 4.1.2: Borehole A <0.5m depth. The soil below this depth showed great similarity. An initial survey called ‘Geosure2’ will be carried out by geological specialists. This happens before any work occurs and looks to see if any existing water pipes or drains under the surface of the site would be damaged by the planned buildings. The extra weight and forces from the foundations could cause problems if placed on saturated ground or if in presence of surface water. The water table at the time of sample was 18.29m below the surface. Nevertheless research has demonstrated that the site is prone to flooding. This will have to be a consideration during design. 1 2 British Geological survey www.bgs.ac.uk - Accessed 1-2012 Geosure survey service www.bgs.ac.uk/geosure - Accessed 1-2012 William Hancock Page 50 A simple soil sample structure was constructed for use in calculations, figure 4.1.3. Thickness Soft brown sandy clays 2m 3m Medium Gravel 13m Oxford Clay (becoming harder with depth) Soil Type Sandy soft clays Medium gravel Oxford clay Coefficient of compressibility (u) m2/MN 0.07 Dry weight, kN/m3 15.7 Critical failure angle, 30 Shear strength kPa 25 0.0052-0.01 18.8 38 15 0.046-0.12 19.9 23-25 17-76 Figure 4.1.4: Table of soil physical properties Data from ‘Engineering properties of soil and rocks’ F.G Bell Figure 4.1.3: Soil Structure There are many potential problems that can arise from different soil types. A detailed survey would be carried out to find the exact values of the properties shown in figure 4.1.4 above. The frost depth would be found along with additional soil properties such as; bearing capacity, compaction of soil, lateral strength and permeability. One problem that can become significant in foundations is uplift pressure which causes heaving. This mainly occurs in fine grained clays which are present on site but overlain by well draining gravel. Any potential problem should therefore be minimised. The fact that the medium gravel is well draining also reduces the potential effect of frost action, which causes different soils to expand at different rates. In general gravel and gravelly silts have good load bearing capacity and undergo little consolidation under load. An important calculation to consider is the one dimensional compression and consolidation relationship using Terzaghi’s equation3. A general rule4 for large structures is that soil compaction should be strictly less than ⁄ ” (approx 0.0127m). It can be assumed that consolidation only occurs in the sandy soft clays and medium gravel, as the hardness and strength of Oxford Clay increases with depth. 3 4 Terzaghi’s equation from ‘Theoretical Soil Mechanics’ Terzaghi K 1943 Recommended by BGS bgs.ac.uk - Accessed 2-2012 William Hancock Page 51 Using an approximate design of a foundation based on a concrete cylinder 3m diameter and 3m deep. The weight can be estimated to be around 0.5MN. From structural analysis in section 4.5 the live forces from the roller coaster are predicted to be around 0.1MN. The stress is equal to the combination of loads divided by the surface area of the foundation. ( ) ( ) The answer given for maximum consolidation is slightly greater than the target value. This can be then used to find the time till consolidation using chart 4.1.5 5. Degree of consolidation: This value of Uv = 0.121 corresponds to a time factor of 0.13 from chart. The time required for consolidation can be Figure 4.1.5: Solutions to consolidation equation calculated using the following equation: Rearranging this equation and substituting consolidation coefficient6 as approximately 1.5m2/year gives the time for any further consolidation to be less than 0.0127m as 0.54 years. This approximate calculation shows that in the building process the foundations need to be cast and placed in the ground then left for a period of 6 months; this gives time for the ground to consolidate before the track is built on top of it. In many cases this time delay cannot be afforded and so there have been many techniques developed to reduce the amount of consolidation of soils, for example dredging out a certain depth of clay from under foundation sites and filling with more suitable material. Alternatively, where coarse-grain soil (sand) is present compaction can be achieved by using smooth rollers, or utilising dynamic impact or rapid impact compactors or vibroflotation.7 5 ‘Solutions to consolidation equation in terms of degree of consolidation’ Barnes 1995 ‘Value of consolidation of average soil sample’ environment.uwe.ac.uk - Accessed 3-2012 7 ‘Compaction and consolidation techniques’ iadc-dredging.com - Accessed 3-2012 6 William Hancock Page 52 4.2: Foundations Once the geology of the site has been fully analysed it is important to produce detailed designs of the structure of the foundations. The functions of the foundations are to transfer the loads from the building to the ground, anchor the building against live loads, such as wind, and to isolate the building from heaving and expansive soils. The loads acting from a roller coaster are much more variable in size and range then in normal buildings which emphasises the importance of the foundations for safe operation. The forces acting upon the foundation are compressive and tensile forces, in both the vertical and horizontal direction. The uplift force, for example, is caused by the cart passing through the cobra roll which creates a centripetal force on the cars and hence a reactive centrifugal force is applied to the track by the cars. As the cart leaves the cobra roll it travels down the hill and provides a downwards force on the track which is transferred through to the foundations. A shear force from horizontal forces of the track must be accommodated by the foundations. Finally a moment is created about the base of the support from forces being applied at the top of the supports. The initial foundation structure was designed using Solidworks and is shown in figures 4.2.1 and 4.2.2. The type of soil present and the forces that were predicted to be acting on the foundation were taken into consideration when creating the most appropriate foundation type. The dimensions of the foundations are approximately a cylinder of 3m depth and a diameter of 3m. A depth of 3m was chosen as it allows the foundation to utilise the strength of the medium gravel 2m below the surface. The edges of the outside concrete in practice will not be a smooth side as shown in the diagram but in fact 3m depth much more uneven and lumpy. This increases the surface area in contact with the soil and so 3m diameter Figure 4.2.1: Solidworks design of foundation increases the shear strength performance of the foundation. and overall William Hancock Page 53 1. Supporting column of roller coaster 2. Column base plate Close contact between steel and grout 3. Anchor bolts 4. Shear connector Close contact between grout and concrete Close contact between grout and soil 5. 2nd Stage high strength grout 6. 1st Stage concrete Figure 4.2.2: Section cut through foundation The main bulk of the foundation is made from concrete which has very high compressive strength, 40MPa8, but is however weak in tension, 3MPa9. To give the foundation strength against any uplifting tensile force steel anchor bolts are added, which have a high tensile strength, 2,000MPa. The compressive forces produced by the dead weight of the rollercoaster and any additional loads are transmitted effectively through the 2 nd stage grout. If the entire structure was made from concrete the stresses produced by the support would be greater than the shear capacity of the concrete and so likely to cause damage. A high strength grout is used for the section nearest the base of the support. At the contact between the concrete and grout, the increase in surface area means that the forces are dispersed. This reduces the stresses which can then be transmitted through the concrete. If the grout wasn’t ‘non-shrink’ it would be likely that cracks would form in the concrete parallel to major stress planes, because concrete is a brittle material. Any cracks that form would dramatically reduce the strength of the foundation. The shear forces are effectively transmitted through the shear pin to the grout and also to a lesser extent through the anchor bolts to the grout. This ensures that the support will not shear and snap off at its base. The shear force of the concrete against the soil provides a resistive moment to act against the possible overturning moment that is predicted. An analysis is shown below of the performance of the foundations under different failure mechanisms. 8 Material physical properties from Engineering tables and data Howatson Lund and Todd 2009 William Hancock Page 54 To analyse how the foundation will perform, calculations were undertaken which evaluate the forces that will be applied to the foundation. A support structure is shown in figures 4.2.3 and 4.2.4; this is the design which will be typical for many of the roller coaster supports. Figure 4.2.3: Solidworks model of support structure 9 Figure 4.2.4: Vekoma flying coaster ‘Stealth’ This model can be simplified and analysed as a pin jointed frame with rigid fixed joints at the foundation bases, figure 4.2.5. The loading case during the clothoid loop is considered to be one of the most extreme. Taking the maximum values from the Matlab simulation of the loop and creating the maximum moment by taking the height of the support to be the maximum, 18.2m. Fy D2 = 3m Maximum values from Matlab simulation: C Fx 60 kN Fx Fy -40 kN Mz D1 = 18.2m Mz 130 kNm Resolving forces of the structure gives two equations: A 60˚ V1 M1 B V2 M2 H1 H2 Figure 4.2.5: Diagram of support for analysis 9 Photo taken from CoasterGallery Joel Rogers ⁄ William Hancock Page 55 A similar analysis is used around joint C, which can be assumed to be a single rigid body in equilibrium. Fy Mz V1 V2 H1 H2 M1 M2 Fx M1 R1 M2 R2 -64 kN +104 kN 0 kN -60 kN -70 kNm -60 kNm Figure 4.2.7: Table of results from analysis Figure 4.2.6: Diagram of joint C These calculations can give us a prediction of the order of scale of forces that the foundations will have to withstand. There are three major types of failure for the foundation. 1 2 Soil Soil 3 Soil Soil Figure 4.2.8: Showing three methods of failure of the foundation 1. The first method of failure is when the uplift forces are greater than the foundation weight and shear forces acting on it so the entire foundation is lifted out of the ground. Even a small displacement would have extreme consequences on the support and track it is attached to. ( ) This proves that the value of the weight of the concrete10 used is significantly greater than the uplift force of 104kN so ensuring that with a large margin the foundation should not fail this way. 2. The second failure is when the structure is moved in a horizontal direction due to large forces. Soil pressure and weight provides a resistive force against movement which would have to be overcome. Soil can only provide compressive strength and so has no tension force ‘pulling’ the foundation. This is because it is well above the water table and so can be assumed to be dry without any pore pressure from water content. 10 Density concrete from Engineering tables and data HLT Howatson Lund and Todd William Hancock Page 56 Table of stresses in soil: A Position Vertical Stress kPa Horizontal Stress kPa A 0 0 B 31.4 94.2 C 50.2 210 Sand 2m B Gravel 1m C Figure 4.2.9: Diagram of soil pressure distribution Figure 4.2.10: Table of stresses in soil compared with depth The equations used are from Rankine’s passive soil state theory: , The stresses can be summed up and averaged over the height. This average stress when taking only the components working against the horizontal force can be assumed to act on an area of 9m2. This gives a resistive force of 739 kN, which is significantly greater than the maximum force applied of 64kN so it will not fail by horizontal displacement. 3. The third is where the moment force will overturn the entire concrete base. The resistive forces are provided by the soil displacement similar to above and also the shear forces around the perimeter between the soil and concrete. During the calculations the centre of rotation (C.O.R) is assumed to be about the centre of the foundation. Using equations above a similar analysis can be carried out C.O.R except multiplying by distance to C.O.R to create a moment. This gives a moment from passive failure of ~300kNm. The total shear force can be calculated using: Figure 4.2.11: Diagram of moment forces This gives a moment caused by the shear force of 919 kNm. This again is significantly greater than the maximum moment applied of 70 kNm. William Hancock Page 57 In conclusion the values of all three failure methods are significantly larger than the forces applied. A safety factor of almost 10 times has been scaled in to ensure minimal risk of any failure that would lead to catastrophic consequences. This method of analysis makes many assumptions and is simplified to quite an extent, a more accurate analysis using finite element programs will be carried out for the exact foundations. In undertaking this project it is important to evaluate the cost of foundations and site preparations. 1. Site Clearance: Clearing site and taking off topsoil. Using an area footprint of the building and supports of 3,500m2 and borehole data recommending removing 0.5m of topsoil this part of the project will cost £2,000.11 Additionally the change in height of the ground across the site will require more material to be removed so levelling the gradient out, this produces a similar cost of around £2,000. 2. Setting out: Set foundation trench outlines. This is a skilled job involving the application of surveying skills. Every load bearing wall and support has to have a marked out foundation beneath it and has to be aligned with other parts of the structure. A simple site is around £200 cost 12, due to the complex nature of our roller coaster this has been increased to £2,000. 3. Trench excavations: The deeper excavation for foundations will require the use of hired heavy machinery. For buildings it is likely to be 60-70% of the footprint13 which leads to an estimate of £17,500. Assuming there are approximately 50 support structures each requiring a 3m diameter hole of depth 3m gives a cost of £15,700. 4. Concrete: The main construction material of the foundation. An estimate of ready mix concrete is assumed to be £60 per m3. As footings are required the amount of concrete is slightly less than the spoils removed. Assuming 2,000m3 concrete is needed the cost is £120,000. Using comparative data13 an estimate of the cost of labour for concrete setting will be around £25,000. 5. Footings: The addition of brickwork or damp proofing between concrete and the building. The cost can vary depending on technique. For the building which has 1,750m of foundation trenches the cost is approximately £9,000. 11 12 Using cost of £15 per m3 removed from homebuilding.co.uk - Accessed 3-2012 Estimate values from homebuilding.co.uk - Accessed 3-2012 William Hancock Page 58 Process Site Clearance Setting out Trench excavations Concrete Building Supports Material Labour Footings Total Cost Cost £ 4,000 2,000 17,500 15,700 120,000 25,000 9,000 £193,200 Figure 4.2.12: Table of costs of foundations 4.3: Construction Companies To ensure competitive pricing the raw materials needed to build the roller coaster have to be sourced from a wide range of companies. As an example, the concrete that is being used to build the foundations will be supplied by Smiths Concrete Ltd. This company was chosen in particular for several reasons. Firstly the concrete plant is based near Witney which is only 10 miles away or 30 minutes by lorry from our site. This not only reduces costs, but also reduces the environmental impact from transportation. Secondly the company has many policies that are in accordance with the environmental outlook of our rollercoaster: “Smiths strive to protect and enhance the environment around their sites. They seek to use secondary and recycled materials whenever feasible. ”13 Our aim is to use as many locally sourced materials with environmental awareness. The track and roller coaster carts are both being outsourced and built by Vekoma TM . Both the design of our track and carts are based upon Vekoma designs and the entire loading procedure is identical to the Flying Dutchman flying roller coaster. Vekoma have manufacturing factories globally, from China across to Poland, Czech Republic and Netherlands. 14 All of these facilities are fully equipped to build the intricate design of our track. We will choose to have the rollercoaster built at one of the factories near the UK. From research into marine transportation (freight liners) it is ‘the most carbon efficient mode of transportation.’ 15 The aim would be to use train transportation to the coast and then shipping to UK. Either the factories in Poland or Netherlands would be most suitable for the production and transportation of the track. 13 Smiths concrete environmental policy smithsconcrete.oc.uk/environment Research from vekoma.com 15 Quote from Liner shipping industry and carbons emission policy apl.com/environment - Accessed 4-2012 14 Arthur Coates Page 59 4.4: Structural Analysis The typical loads that the roller coaster structure needs to be designed to counteract are; Vertical loads - Dead load of the track, cart and the passengers - Accelerations Horizontal loads - Accelerations, especially at the launch - Braking forces towards the end of the ride - Dynamic wind loads - Friction forces Other considerations include - Fatigue analysis - Thermal expansion and contraction - Bracing for the highest parts The model structure of the roller coaster will have a central spine onto which solid symmetric ribs will be placed, onto which the circular track section will form. The main structure i.e the columns, will then be welded onto the central spine structure so that the loads can be transferred to the foundations and therefore the soil beneath. Roller coaster design companies such as Bollinger and Mabillard use a square box section as the central spine, however this can be very complex to design for due to the twists, rolls and banked turns which occur in the roller coaster. Hence a circular spine section would be more efficient in use, as it is easier to design for because of its symmetry, uses less material and therefore easier to manufacture. 4.5 Dynamics and Force Analysis Since the highest forces will occur where there is the greatest acceleration, , it is assumed that the greatest forces will take place at the beginning of the ride in the loop when the velocity is Arthur Coates Page 60 greatest. Hence the focus of the structural analysis will cover the initial loop structure due to the highly curved nature of the track at this point. It is intended that the structural analysis of the rest of the ride will follow from these results. The loop must form a special geometric shape called a clothoid because if the loop was circular, in order to complete a full loop the acceleration experienced by the riders would equal 6Gs16. This is well above the allowable health limit. The clothoid emerges as part of an Euler Spiral defined with its curvature, , being proportional to its arc length, . The equation of a clothoid loop is: Equation 4.5.1 Where: Where and are the radius and arc length at the end of the clothoid section respectively. Hence whereas the circle has a constant high curvature leading to a high centripetal acceleration, the curvature and hence acceleration in the clothoid increases with arc length from a low constant value, ultimately leading to a reduction in the maximum G force (centripetal acceleration). In terms of energy, the decreasing radius leads to a slower rate of increase in potential energy which leads to a faster rate of decrease in kinetic energy which helps maintain lower accelerations. The typical coefficient of friction is approximately 0.01 for the material used and energy losses due to friction forces acting in the loop can be neglected through this analysis. The constant defines the shape of the clothoid section: √ If the curvature , then integrating the clothoid equation 4.5.1leads to: ( ) A clothoid loop is typically defined parametrically through the Fresnel Integrals: 16 ‘Amusement Park Physics: A Teacher’s Guide’, Nathan A. Unterman 2001 Arthur Coates Page 61 Where and ∫ ( ) ∫ ( ) . The loop for the roller coaster consists of a circular section for the bottom run-up section up to . The clothoid section is defined as an intermediate section varying from Finally there is another circular section at the top as indicated below: 18 16 14 Y Position 12 65° 10 8 θ 6 4 30° 2 0 0 2 4 6 8 X Position 10 12 Figure 4.5.1: Matlab formulation of track position and angles Parametrically, the run-up circular section for For the top circular section for is: ) ( ) : For the clothoid section: ∫ θ ( ∫ 14 . Arthur Coates Page 62 Hence after solving simultaneously: ( ) The aim of conducting design work on the loop is to produce a force-time/track position plot onto which dimensions for the structural supports can be determined. From this a stress-time/track position plot can be generated using bending stresses through treating the analysis independently, firstly as a beam and then as a column. First of all, the loop needs to be determined in order to obtain a vector position of every part of the loop: ̂ ̂ From this, the Frenet-Serret relationships17 are used to determine the dynamics of the loop including velocity and centripetal acceleration: ̂ Where κ is the curvature, ̂ , ̂ is the unit tangent vector and ̂ is the unit normal vector √ where: ̂ ̂ Hence ̂ ⁄ ̂ | | , where v, the velocity, can be determined from energy conservation, neglecting the effects of dynamic and aerodynamic friction losses: √ Where u is the initial velocity going into the loop. The method for constructing the shape of the loop is described below including code on Matlab. 1. Construct the bottom circle % Bottom circle definition dt = 0.001 ; t=0:dt:(pi/6) ; xcirc = Rb*sin(t); ycirc = Rb*(1-cos(t)); 17 See http://galileo.math.siu.edu/~msulliva/Courses/251/S11/torsion.pdf Arthur Coates Page 63 2. Construct the intermediate clothoid % Clothoid definition ds = 0.001; s = (a*2*pi):ds:(a*(17/3)*pi); xcloth = (1/a)*cumtrapz(cos(s.^2))*ds; ycloth = (1/a)*cumtrapz(sin(s.^2))*ds; 3. Find the angle, , of the tangent to the track to the horizontal line at the end of the bottom circle, and rotate the clothoid by this amount and then subtract the existing angle the clothoid makes with the horizontal axis: ( ) This is enacted using the rotation matrix: ( ) ( )( ) % Angle which clothoid must be rotated by to fit with bottom circle n = length(t); iniangle = atan((ycloth(2)-ycloth(1))/(xcloth(2)-xcloth(1))); ang = atan((ycirc(n) - ycirc(n-1))/(xcirc(n) - xcirc(n-1))) - iniangle; % Rotation matrix, rotated clothoid xyang = [cos(ang), -sin(ang); sin(ang), cos(ang)]*[xcloth; ycloth]; 4. Translate the clothoid section by the x/y coordinates of the end of the bottom loop in order to fit them together, % Translation nxyang = length(xyang); % End circle point plus x/y coordinates of clothoid xang = xcirc(n)*ones(1,nxyang) + xyang(1,:); yang = ycirc(n)*ones(1,nxyang) + xyang(2,:); % Addition of bottom circle and intermediate clothoid x1 = horzcat(xcirc,xang); y1 = horzcat(ycirc,yang); Arthur Coates Page 64 5. Next construct the top circle using the same parametric equations used for the bottom circle using , and translate so that it fits onto the end of the clothoid. % Angle of end of clothoid to the horizontal axis nbot = length(x1); angtop = atan((y1(nbot) - y1(nbot-1))/(x1(nbot) - x1(nbot1))); % Definition of top circle Rt = 6; dt = 0.001 ; t = (pi-abs(angtop)):dt:pi; xcirctop = Rt*sin(t); ycirctop = Rt*(1-cos(t)); % Translation xt = xcirctop + (x1(end) - xcirctop(1))*ones(1,length(t)); yt = ycirctop + (y1(end) - ycirctop(1))*ones(1,length(t)); % x/y coordinates of half loop x = horzcat(x1,xt); y = horzcat(y1,yt); % Whole loop loopx = [x, (-fliplr(x)+(2*x(end)*ones(1,length(x))))]; loopy = [y, fliplr(y)]; 6. The Frenet-Serret relationships are then implemented on Matlab using ‘for’ loops as shown: for i = 1:p-2; % N = dUnitT/ds N(:,i) = (UnitT(:,i+1)-UnitT(:,i))./hypot((rmid(1,i+1)rmid(1,i)),(rmid(2,i+1)-rmid(2,i))); % UnitN = N/mod(N) UnitN(:,i) = N(:,i)./hypot(N(1,i),N(2,i)); % Curvature = mod(N) curv(i) = hypot(N(1,i),N(2,i)); % Radial acceleration acc(i) = curv(i)*((v(i))')^2; end Arthur Coates Page 65 The velocity and radial acceleration plots are shown below for the whole loop: 35 20 18 Radial Acceleration of Loop/m/s2 30 Velocity/m/s 16 14 12 25 20 15 10 8 0 0.5 1 1.5 2 Time/s 2.5 3 3.5 4 10 0 10 20 30 Length of Track/m 40 50 60 Figure 4.5.3: Plot of radial acceleration against time for half the loop Figure 4.5.2: Plot of velocity against time for half the loop Hence this gives a maximum G force of 3.3Gs which is well below the allowable health limit for humans. From the dynamic analysis of the cart as it passes along the loop in the track, analysis into the forces which act on the supports can be completed using a discrete method using the vector of position. The main supports which will take the dynamic forces due to the accelerations of the carts on the track are placed at the end of the clothoid section at the 65° points on either side. Ry Rx Mz 65° Figure 4.5.4: Diagram showing the layout of the supports for the loop The resultant reaction force acting on the cart is equal to: Arthur Coates Page 66 Which was calculated using the Frenet-Serret formulae. Hence the global forces and moment acting on the supports, need to be found in a track position plot as the cart passes through the loop. Resolving horizontally and vertically, and treating the loop as two dimensional, the global forces and moment about the z-axis acting on the supports are, ( ( ) ) ( ( ) ) Moment about Support/kNm Y Force on Support/kN X Force on Support/kN Plots of the forces against the length of track for half the loop are shown below: 80 60 40 20 0 0 5 10 15 Length of Track/m 20 25 30 0 5 10 15 Length of Track/m 20 25 30 0 5 10 15 Length of Track/m 20 25 30 60 40 20 0 200 0 -200 -400 -600 Figure 4.5.5: Plot of the horizontal, vertical and moment force acting on the support of the half loop respectively. The horizontal and vertical force plots show that as the horizontal force reaches a maximum, the vertical force becomes a minimum, when no vertical force is applied to the support. The moment acting on the support begins with a negative moment of 548KNm, but steadily becomes positive over the course of the loop. These values will now be used in the derivation of support dimensions and stress calculations. 4.6 Fatigue Analysis Analysis into the lifetime of the loop can determine which section properties for the supports to decide upon. Fatigue fracture analysis under fluctuating stresses is utilised. The structural Arthur Coates Page 67 members of the roller coaster must be designed to last for the 40 year lifespan as no structural element has been designed to be replaced during this period. It takes 3.8s for the cart to complete the whole loop. Assuming once the cart has left the loop, no forces will act on the loop supports. This implies that the self-weight of the steel supports are negligible compared to the dynamic loads due to the cart’s acceleration whilst completing the loop. For the 40 year lifespan, the number of cycles to failure, = (9 hrs/day x 303 days/year x 40 years)/(time for overall ride in hours) Hence cycles. This is the minimum the track should be designed for. This signifies that high cycle fatigue will take place. Therefore the supports are designed so that no yielding takes place. Assuming that the probability of plastic deformation can be neglected, and the deflections are purely elastic, Basquin’s equation can be used to determine the allowable stress range, given zero mean stress in a cycle, having determined the design lifetime of the structure. It is found that the S-N curve which plots stress range, against the number of cycles to failure, when transposed onto a double logarithmic scale produces a linear relationship, therefore indicating a power law equation: Where and are empirical constants. In order to maintain at least safety factor of F, the stress range must be not exceed a design value of strength for this number of cycles is 18. Figure 4.6.1: Plot of the Basquin Equation 18 Lecture 3, Mechanics of Materials, C. P. Buckley 2010 cycles of stress with a where the fatigue Arthur Coates 19 A typical S-N graph Page 68 for high-yield structural steel which will be used in the construction of the supports for the track is evidenced below. Steel exhibits a fatigue limit at roughly half the ultimate tensile stress at around cycles. Figure 4.6.2: S-N curve of high-yield structural steel So having obtained two empirical points determined from experimental data of the fatigue strength of high-yield structural steel after a certain number of cycles, the constants for the characteristic Basquin equation for this steel can be obtained. From this, the design stress range for the number of cycles for the 40 year lifespan of the roller coaster can be gathered. 20 Solving the two equations simultaneously leads to the Basquin equation that defines high cycle fatigue in high-yield structural steel, Hence after cycles, the maximum allowable stress range before plastic deformation occurs is 314MPa. 19 20 http://www.efunda.com/formulae/solid_mechanics/fatigue/fatigue_highcycle.cfm http://www.efunda.com/formulae/solid_mechanics/fatigue/fatigue_highcycle.cfm Arthur Coates Page 69 However the Basquin equation is formed on the assumption of zero mean stress, whereas the loop has a high variable stress for the first 4s of the ride, and is then assumed to be zero. So Goodman’s rule is used which estimates a linear interpolation between the stress range, will give a lifetime, , in the presence of a non-zero mean stress, , that 21 . Stress, 314MPa Loop Rest of Track 64 4 Length of Ride in Time in Seconds 4 Figure 4.6.3: Plot of effective stress range against time for the ride 600MPa Figure 4.6.4: Plot of Goodman’s Rule for high-yield structural steel Solving this equation leads to an effective stress range under zero-mean stress, where of 304MPa . Therefore with a safety factor, F = 1.5, the design stress range, This design value for the maximum allowable stress will be used for the calculation of support dimensions. 4.7 Stress Analysis Having determined the maximum allowable stress range, i.e the modulus of the maximum allowable stress, an iterative process can now be utilised that calculates the stress in the supports through changing the structural geometric properties of the supports resulting from the force analysis conducted earlier in section 4.5. 21 Lecture 3, Mechanics of Materials, C. P. Buckley 2010 Arthur Coates Page 70 There will be three ways in which the right support dimensions can be obtained; firstly considering the maximum bending stresses, secondly determining the axial stress and then considering the minimum buckling load of the support. Ry Rx Mz Figure 4.7.1: Diagram of the bending stress The bending stress is calculated as: Where the maximum bending stress is taken on the surface of the beam support by using the maximum value of which is a geometric property along with , whereas is a product of the shape and dynamics of the loop from the Frenet-Serret relationships (see section 4.5). Hence using an iterative process of varying the dimensions according to the British Standards of circular hollow sections22 and using the Matlab values calculated from the moment and force analysis before, % Moment stress variation % Using max stress on surface StressXX = ((D/2)/I)*ones(length(Mz),1).*Mz; The dimensions are minimised in order to give the maximum bending moment up to the stress range limit of 202MPa. The graph below shows a variation of the maximum bending stress with time for half the loop with the dimensions of . The modulus of the stress range gives 22 Engineering Tables and Data, Howatson, Lund and Todd 2009 . Arthur Coates 100 Page 71 Maximum Bending Stress/MPa 50 0 -50 -100 -150 -200 0 0.2 0.4 0.6 0.8 1 Time/s 1.2 1.4 1.6 1.8 2 Figure 4.7.2: Plot of maximum bending stress against time for half the loop Relating the global forces obtained earlier to the global displacements using the global stiffness matrix: Then: ( Where is the transformation matrix with ) for the orientation of the support from figure 4.5.4, ( ) And the local displacements are given by: The end of the support anchored to the ground through the foundations has no degrees of freedom and is treated as a rigid joint, and the overall member is treated as a one-dimensional beam in order to analyse failure by axial and bending stresses through the support. 1 2 Figure 4.7.3: Diagram of the local degrees of freedom of a one-dimensional structural member Arthur Coates Page 72 The degrees of freedom are . Hence the local stiffness matrix is given by: ( ) Considering axial stress in Cartesian coordinates by treating the support as a structural member as from Hooke’s law for a linear, isotropic material: before in plane stress Where the axial strain is given by the local displacement 1.5 divided by the length in that 1 axial direction. To the right is 0.5 time for half the loop, which records a maximum compressive axial stress of only 1.7MPa and Axial Stress/MPa a plot of axial stress against 0 -0.5 -1 tensile -1.5 stress of 1.1MPa, compared to the yield stress of 400MPa. -2 0 0.2 0.4 0.6 0.8 1 Time/s 1.2 1.4 1.6 1.8 2 Figure 4.7.4: Plot of axial stress against time for half the loop Having considered failure by bending and axial stresses through treating the support as a beam, the dimensions are further checked by considering the buckling load. The support effectively acts as a cantilever column, in fact this gives the most conservative outcome, and so the Euler critical load is given by: ( ) Arthur Coates Which for the support’s geometric properties discussed earlier gives greatest local longitudinal axial force acting along the support is Page 73 , whereas the , well below the limit. In conclusion the support has been designed against failure by bending and axial stress by considering it as a beam, and also collapse through buckling by analysing the support as a vertical member. Moreover the support has been designed to outlive the 40 year lifespan of the roller coaster through fatigue fracture analysis with a conservative safety factor. This complex analysis has been completed on the support which is assumed will take the highest forces and stresses in the track, and it is believed that further structural analysis will follow from the analysis provided by considering the loop. 4.8 Further Structural Considerations Further analysis that is essential to the technical structural analysis of the track must firstly consider the dynamic wind loads, and then consider the thermoelasticity of the structure and how the structure reacts to thermal changes. 4.8.1: Dynamic Wind Loads The following guidance on wind loading for structural elements is taken from the British Standards; Code of Practice for wind loads. The wind load will be calculated, again just for the track of the loop including its structural supports. The ‘standard method’ is used which provides values of effective wind speed through inputs of geographical and topographical considerations along with the standard pressure coefficient determined by the shape and geometry of the structure, to determine orthogonal load cases. This is the simplest analysis available, but includes important and sufficient conservative coefficients which provide allowance for high loading cases. For free-standing structural elements; Where is the dynamic pressure, is the net pressure coefficient for the element and size effect factor for external pressures. The value of the dynamic pressure Where is the effective wind speed. is given by, is the Arthur Coates Page 74 For the site on Oxpens Field, the effective wind speed takes into account the basic wind speed and altitude, directional, seasonal and probability factors including also a terrain and building factor, overall producing . Hence . Moreover, when deriving the overall forces on the structure of the loop, the contribution of the frictional forces must be taken into account. These act in the direction of the wind, and are added to the normal wind pressure forces using vectorial summation assuming the wind is normal to the plane of the loop (a probability factor based on directionality is taken into account in the effective wind speed). Hence the overall loading P with values of ( Where = 0.8 and ) is the frictional drag coefficient and equal to 0.04 and and is equal to = 0.91; . Therefore the overall wind load is the area swept by the wind . When compared to the dynamic forces due to the accelerations in the loop through its motion, see figure 4.5.5, the values are entirely negligible. Hence after analysing the potential effects of wind loading it is decided that the wind loads can be ignored purely due to the area swept being extremely small and because of such low wind speeds for the site. Hence the pressure does not equate to high enough stresses to be significant. 4.8.2: Thermoelasticity Another consideration that requires analysis are thermal strains caused by changes in temperature. The effect of temperature on strain is dilatational i.e all shear strains = 0, so for highyield structural steel which is assumed to be homogenous and isotropic, Hence the axial stress of the main structural supports is given by: ( However since ) , in order to produce values of stress that could significantly affect the structure the changes in temperature, , must exceed 120° including a safety factor of 1.5. Thermal changes caused by the weather are not going to cause these kinds of stresses. The typical coefficient of friction is equal to 0.01 as mentioned in section 4.2, so typical energy losses Arthur Coates Page 75 are not sufficient to cause such a rise in temperature as well. Hence like the dynamic wind forces, strains as a consequence of thermal changes can be ignored. Section Conclusion In conclusion, through firstly conducting soil and other geotechnical analysis, resulting in the design of foundations, and then considering the structural aspects of the roller coaster, a thorough and comprehensive framework has been established for the ‘Launch of the Rings’ ride. Edward Jamie McDonald Page 76 5: CONSTRUCTION The construction of a major structure such as a roller coaster is often very disruptive. In this section is explanation of the various mitigation measures in place to minimise this disruption as well as a detailed description of the construction process and the main materials to be used. 5.1: Construction Methods Much analysis was focussed on ensuring that the finished roller coaster follows environmental and sustainable principles and causes as little disruption as possible to local businesses and residents around the site. It is easy to overlook however that a great many such problems can occur during the construction of the project. This area of the report focuses on the potential disruption caused by construction and the mitigation measures being put in place to negate this. 5.1.1: Considerate Constructors Scheme The Considerate Constructors Scheme (CCS) is a construction industry initiative intended to reduce the disruption caused to residents and by construction sites generally. Construction companies operating within the United Kingdom can sign up to the scheme indicating that they agree to maintain certain minimum standards on their sites. Additionally, individual construction sites can be registered. Adherence to the scheme is measured through regular inspections by a monitor working for the CCS1. Measures will be taken to ensure that only contractors accredited with the CCS will be permitted to work on the site. Additionally, the site itself will be registered with the CCS before construction starts. All contractors will be made aware of the CCS requirements and there will be internal inspections to ensure that the correct standards are being upheld. The main requirements of the CCS are in respect of safety, responsibility, accountability, appearance, considerateness, environmental awareness and appearance. These are all areas which are important for our site. It is important to note that the standards of the CSS are not the standards the site is aiming to achieve but absolute minimum standards. In many areas performance will go much further than the scheme demands as set out below. 1 www.ccscheme.org.uk/ - Accessed March 2012 Edward Jamie McDonald Page 77 5.1.2: Noise Noise is a major concern for neighbours of construction sites. Inevitably, building work is a noisy process, with plant and power tools creating high volumes. It is an aim to reduce noise as far as possible, as well as scheduling it carefully to minimise disruption. The primary way in which noise will be minimised is by constructing as much as possible of the roller coaster off site. Large parts will be transported by road to the site where they will be assembled. Unfortunately there is very little that can be done to minimise the noise of the ground works and assembly, however steps can be taken to minimise the impact that this noise will cause. Firstly, in the noise abatement strategy for the finished roller coaster there are plans to import and plant a belt of trees along the East boundary of the site. Steps will be taken to ensure this is the first work to take place on the site, so that the trees will help reduce the noise of the further construction work which takes place. A belt of trees such as this can reduce noise behind it by up to 10dB and since the closest houses to the site are in this direction this will have a significant effect23. Equally, there are plans to install double glazing for the closest residents to the roller coaster and this will also be completed before construction begins to minimise noise. Good quality double glazing can reduce the A-weighting of noise, a measure of noise to reflect volume heard by the human range, by over 30dB45. The average A-weighting level of noise from a construction site is 86dB and this should be reduced to below 65dB for residents during the day 6. The effect of the trees and double glazing should therefore minimise noise to below acceptable levels even negating for the effect of the distance of the houses from the site. Finally, a moratorium will be imposed on noisy construction work at night. The only exception to this is that it may be necessary to perform some road work at night in order to minimise traffic disruption. As far as possible attempts will also be made to schedule noisy work between Monday and Friday in order to minimise disruption for the ice rink which is busiest at weekends. 2 http://140.128.71.160/wrIIncut/course/20120116013749376.pdf - Accessed March 2012 www.medway.gov.uk/environmentandplanning/conservation/treemanagement/treeguides/treesandnoisecontr ol.aspx - Accessed March 2012 4 www.1st-4-secondary-double-glazing.co.uk/sound_noise.html - Accessed March 2012 5 www.slimliteglass.co.uk/sound-reduction-and-u-values.html - Accessed March 2012 6 www.lhsfna.org/files/bpguide.pdf - Accessed March 2012. 3 Edward Jamie McDonald Page 78 5.1.3: Traffic The other most significant impact of construction sites on local residents is traffic disruption. This takes two forms, disruption caused by road works with associated contra flows and other traffic management methods as well as the additional construction traffic itself, which typically consists of large lorries which may be unsuitable for some roads. Whilst it is inevitable that some works will need to take place in the road, efforts will be made to try to minimise the effect of these as far as possible by using appropriate traffic management measures to reduce disruption to road users. Site management will work with the local council under the provisions of the Traffic Management Act 2004 and will try and perform road works only at off-peak times when traffic levels are significantly lower. To reduce the effects of construction traffic, all deliveries and site traffic will follow a designated route into Oxford and to the construction site shown in Figure 5.1.1. This will be via the Ring Road and the Botley Road. This route has been chosen as it avoids the historic city centre which traffic entering along Iffley Road, Cowley Road, Headington Road, Banbury Road or Woodstock Road would have to pass through. Abingdon Road was not chosen as it is narrower where it passes over the river. In case of problems Abingdon Road will be the backup route. Construction traffic will be instructed to avoid travelling at peak times as Botley Road becomes heavily congested then and additional construction traffic would worsen these problems. Figure 5.1.1: Route for construction traffic. Edward Jamie McDonald Page 79 5.1.4: Access to Oxpens Meadow Another potential area of disruption involves access to Oxpens Meadow. This is a protected open space and is widely used for recreational activities. Access and as much green space as possible will be maintained during the construction work as well as afterwards by working on only small sections of the meadow at a time. These can then be opened for public use once completed and work can move onto another area. Figure 5.1.27 shows an example of how work might be split up. The work on the trees is undertaken first so that the houses on the East side of the site are protected from as much noise as possible. The indoor part of the ride is constructed last as this is the one area which cannot be reopened to the public as a green space once construction has finished. Whilst this area is under construction access to the Southern part of the field will still be possible by following the path along Castle Mill stream in front of the houses to the East of the site. This route will be clearly signed. Figure 5.1.2: Possible Construction Phases 5.1.5: Keeping People Informed A key element of minimising the problems caused by the construction works will be ensuring that people are aware of possible disruption well in advance. There will be a road show held on the park explaining what is going to be happening in advance of construction. Residents will receive a fortnightly newsletter throughout the works advising of any disruption well before it happens. This will include traffic works, night work, noisy activities, restricted access to Oxpens Meadow and so on. The same information will be shown on a notice board at the entrance to the Meadow for others to see. 7 Map courtesy of www.google.com/maps Edward Jamie McDonald Page 80 5.1.6: Environment and Sustainability As required by the West End Area Action Plan sustainability is at the heart of the roller coaster design. We intend to continue this diligence through to the construction process. To do this steps will be taken to ensure during the tendering process that any potential contractor must prove their environment and sustainable credentials. The winning contractor will be required to draw up a plan to minimise any damage to the environment during the construction work. The design intentionally avoids the tree line in front of Castle Mill Stream and the main river as these are the places of most importance environmentally with the trees providing cover for bats and over fifty species of bird 8. Construction methods will follow on from this with fencing being erected so as to ensure that the construction plant does not encroach too closely to these and to any other areas identified as environmentally important and so prevent damage. 5.1.7: Deliveries and Site Office The southern-most half of the coach park will be used for deliveries and the site office. There is sufficient space in this area for adequate welfare and office space for workers as well as additional room for large lorries to be able to deliver. Using this space for deliveries will prevent the need for construction traffic to stop on the main road which would severely hinder traffic. As there is space in the coach park for the trucks to turn around this will also enable them to arrive and to depart from the site via Botley Road without causing more delays turning in the road. An access for the plant will be introduced from the southernmost tip of the coach Figure 5.1.3: Site office and entrance park into the meadow. This will enable the plant to be kept as far away from both the main road and the residential area to the East of the meadow reducing noise and traffic problems. 8 http://www.oxpensmeadow.org/environment.html - Accessed March 2012 Max Jackson Page 81 5.2: Manufacturing Process There are several ways to go about erecting a roller coaster, depending, for example, on the size and the materials used. Below is a common method9, and the proposed one to be employed in the manufacturing and construction of our ride. 1. The site is completely cleared and a small section of the park will be closed to the public at a time. This will take place in the off season in order to reduce the disruption caused. 2. Any existing obstacles, for example old structures, are removed from the site. 3. The ground is then moulded into the desired shape, through either filling or excavating. 4. Next, suitable holes for the foundations are dug or drilled, and the foundations themselves are either poured or piled into these holes. The next section of the park is then closed and steps 1-4 are repeated. 5. The main track supports are manufactured in two parts, to be bolted together. Initially, a crane is used to bolt the bottom half of the supports to connector plates on the foundations. 6. The lower supports are then braced, allowing the top sections of the supports to be bolted to them, again using the crane. 7. The track is manufactured off-site (a benefit of designing a steel roller coaster) and then transported to the site to be erected. It is connected to the upper supports piece by piece as it arrives from the factory. 8. The walkways and handrails, to be used for maintenance or in the case of an emergency evacuation from the ride, are then fitted. 9. Next the starting mechanism and braking mechanism (in our case the launch and magnetic braking) are transported to site and set up in the appropriate positions. 10. The roller coaster carts are also produced off-site and delivered by truck. 11. The building surrounding the indoor section of track and the boarding station for the ride are then constructed. 12. Finally all the electrical wiring is connected, the roller coaster itself is painted black and lots of Lord of the Rings props are delivered to aid with enhancing the theme. 9 www.madehow.com accessed 4/2012 Max Jackson Page 82 5.3: Cost and Time 5.3.1 Time The creation of a new roller coaster can be split into two main parts: the planning and the construction of the ride itself. The time taken for each are related, insofar as a well-planned rollercoaster with good, easy to follow engineering drawings would be very quick to erect, whereas a disorganised or inaccurate planning section could cause large delays in the construction of the ride. 5.3.1.1 Planning The planning of a roller coaster usually comes in three parts, each concerning a different person, or group of people. Firstly the theme park owner usually decides that his park is in need of a new ride, either in order to replace a ride that is shutting down or simply to keep his park up to date and ahead of the competition. Then, through working with the local council and investigating any other constraints set out by law or the landscape of the park, decides on a suitable size and shape for the boundaries of the ride and a rough idea of what type of ride is required. This stage doesn’t take very long; it is usually less than one month from start to finish 10. This information is then passed onto the designers. The designers’ job is to design the ride to the best of their ability, whilst adhering to the constraints set out by the park owner. They try to make the ride as interesting and exciting as possible, so that the ride, when it comes to fruition, attracts as many people as possible to the park. This process, which is often an iterative one, can lead so several different designs of possible rides and can last anywhere from one month to a whole year11. In the final stage of the planning, the designers work with engineers in order to combine the initial ride designs into a single final design. The engineers’ job is to ensure that the ride is safe, through investigating the forces experienced by the passengers, the track, the cart and the supports at suitable points in the track, for example on tight bends or big loops. Once a final design is reached, which can take several months, the planning stage is over. 10 11 www.ultimaterollercoaster.com/forum accessed 4/2012 www.ultimaterollercoaster.com/forum accessed 4/2012 Max Jackson Page 83 5.3.1.2 Construction As the manufacturing process has already been looked at in some detail in Section 5.2 it will not be discussed in great detail here. However, it is of note that after the construction of the ride, which can take from 6 months to a year on average, there is a period of testing or inspection, in order to ensure there are no problems with the roller coaster. 5.3.2 Cost The cost of designing and building a roller coaster can be very high indeed, for example Mission: Space in Disneyland Paris is rumoured to have cost roughly £200 million 12, with the sponsor, HP, and the park itself splitting the cost equally. Moreover, several rides currently in operation have cost more than £100 million in total13; these include the vast majority of Disneys’ ‘Eticket Rides’ which are said to be the best rides in the park, along with some of the largest rides at other parks, such as Universal Studio’s Hulk Ride. However, for the roller coaster being designed in Oxford, it has been agreed that we wish to keep the total cost below £20 million. As with the time taken to build a roller coaster, the cost too can be split up into several distinct parts. Firstly, there is the cost of research and development. This varies a great deal depending on the size of the park in question. Large parks have a dedicated team of designers, whose sole job is to create many designs and proposals each year, of which very few ever come to fruition. Smaller parks tend to have one design and stick with it from beginning to end, driving down the costs involved with design. It is difficult to put a cost on this aspect of creating a rollercoaster as it is often ignored when discussing the financial side of particular roller coasters. Next there is the cost of manufacturing the ride itself. This usually makes up the largest proportion of the total costs, and generally the fabrication of the ride is outsourced to a specialist company. Some parks are able to reduce the cost of this process by fabricating their own rides (for example Disneyland), but if the proposed design is complex and convoluted even the largest amusement parks in the world are unable to manufacture them in house. Generally the ride alone can cost anywhere from £1-25million 14. 12 www.thecoastercritic.com accessed 4/2012 Roller Coaster Database ( www.rcdb.com accessed 4/2012) 14 www.themeparkinsider.com accessed 4/2012 13 Max Jackson Page 84 The next cost comes in the form of making the ride adhere to the desired theme. This usually consists of using props and mannequins, both around the track and queuing areas, to recreate desired scenes, painting the ride and ensuring any buildings fit in well with the theme. As with the previous two sections, this cost can vary a great deal between parks. Some choose not to spend a lot of money on the theme, instead hoping that the ride experience alone would be enough to keep the passengers coming back time and time again, whereas others spend a great deal of money, ensuring every detail is correct, in order to transport riders to a different world before they experience the thrill of the roller coaster. This cost can be millions of pounds, and in some instances, if the application of the theme is particularly intricate, can be as expensive as the ride itself. The final costs are associated with the maintenance and operation of the attraction itself. These values are difficult to determine an exact figure for, as, for the most part, parks have a maintenance and operation budget for the entire park, rather than for a single attraction. However, it is accepted that each attraction can have maintenance costs of up to £100,000 a year15. 5.3.1.1 Cost of Track The track can be split into three distinct parts. It consists of a large tube (which will be the backbone of the ride), two smaller tubes (along which the carts travel) and the connecting beams. To work out the cost of the materials, first we must calculate the amount of material needed. The large tube will be 500mm in diameter and have a thickness of 14.2mm, while the two smaller tubes will be 140mm in diameter and have a thickness of 10mm. These values give a cross sectional area of 220cm 2 and 35cm2 respectively. As the connecting beams have a CSA of approximately 400cm 2, but as they are not continuous along the length of the track and instead only appear every 100cm, for 10cm, a value of 1/10 of their cross sectional area is taken. Combining these three values gives a cross sectional area of 300cm 2 or 0.03m2. The total length of the track is 688m, and therefore: 15 www.coasterforce.com accessed 4/2012 Max Jackson Page 85 As structural steel costs between £1500 and £2000 per tonne, the maximum cost of the materials for the track alone is £326,112. 5.4: Materials Roller coasters can be built from either wood or steel, and selecting the more suitable of the two materials is fundamental for the ride to be a success. There also exist rides of a hybrid nature, where both wood and steel are used, but these are often complex and expensive and will not be considered further in this report. 5.4.1 Wood These are considered the original roller coaster, dating back as far as the 19 th century. Roller coasters of this nature generally rely on ‘trestle-style’ structures to support the track and usually Douglas Fir or Sothern Yellow Pine is used in construction16, which is then painted or treated in order to give the desired effect. Steel is also used in this type of roller coaster both to reinforce any important joints and in flattened strips, which are attached to the wooden track to allow the carts ride on them. As wood is unable to endure the same magnitude of forces acting on it as steel, it is impractical to include steep drops, sharp turns or high speeds in the design of the ride, and due to the nature of the support structure, inversions too are unfeasible. In terms of cost, while wooden roller coasters are initially much cheaper than their steel counterparts, the cost of maintaining the ride is often far greater. This is due to the fact that they require regular track lubrication and support maintenance, as well as occasional replacement of all the flattened steel used for the track, as this deforms over time and can lead to a rough, uncomfortable ride. A further drawback of rides of this nature is that they are very difficult to sell in advertisement, as due to the limits of wood, words like biggest, fastest and tallest are reserved for steel roller coasters. Unfortunately, it is words like this that bring in crowds from a far, as riders want to experience firsthand these superlatives. One positive of wooden roller coasters, which has become possible in recent years, is the ability for them to be pre-fabricated in factory, and then shipped to the site, as with steel roller 16 http://forthofer.hubpages.com accessed 4/2012 Max Jackson Page 86 coasters. This greatly reduces both construction time and the disruption to the park during construction. It has the added benefit of ensuring less maintenance is needed as these prefabricated sections of track remain smooth much longer, reducing the need for regular re-tracking. The ride experience provided by wooden roller coasters is greatly dissimilar from that produced from steel rides. Although they cannot compete with steel in terms of speed and the gforces felt by the passengers, they create fear in a very different manner. They use a more psychological approach to frightening the riders, for example through the rough, unpredictable movement of the carts or the deformation of the track itself. Here, the track is allowed to deform up to a few feet, in extreme cases, as the carriages round steep bends. This gives an impression that the ride is unsafe and could collapse at any minute, despite the fact that it is of course not dangerous at all and remains well within the safe, elastic region of deformation. 5.4.2 Steel In recent years, the steel roller coaster has become immensely popular, far surpassing the wooden roller coaster. In fact, in 2012, of the 2822 known roller coasters in existence, 2649 are made from steel and a mere 173 from wood17. This reflects both the public and the park owners affection for steel rides. They use tubular steel track for the carts to ride on, which can be easily manufactured off-site and transported to the site for construction. This allows fast construction, little disruption to the park and the ability to create very accurate sections of track, which when combined with polyurethane wheels produces an extremely smooth ride for the passengers. A further positive of steel rides is their ability to disregard the ‘trestle- style supports’ of wooden coasters, for much fewer steel supports. These large, steel tubes appear much more elegant in design ( although a few die-hard wooden roller coaster fans may disagree) and have the added benefit of permitting several exciting elements to be employed in their design. These include loops, barrel rolls and, in fact, any type of inversion. It is possible to see just how much using wood limits the design of roller coasters by comparing the records held by rides of each material 18. 17 18 Roller Coaster Database (www.rcdb.com accessed 4/2012) Roller Coaster Database (www.rcdb.com accessed 4/2012) Max Jackson Tallest Longest Fastest Most inversions Steel 456ft (Kingda Ka) 8133ft (Steel Dragon 2000) 149.1mph (Formula Rossa) 10 (Colossus) Wood Page 87 218ft (Son of Beast) 7359ft (Beast) 70mph (El torro) 0 Table 5.4 1 Table of Records Held by Steel and Wooden Roller Coasters From this table is it is clear that steel rides have the capability to be built twice as high and to travel twice as fast as their wooden equivalent, however the length of the ride is not dependent on the material selected. It has been decided that steel will be used in our design for several reasons. Firstly, the relatively small plot of land on which the ride is to be built means that there is no room for the long sweeping turns utilized in wooden coasters. The convoluted shapes possible with steel also mean that we could create a longer ride, which is able to compete with the world’s best, despite the small space available. Furthermore the height limit of 18.2m means that it would not be possible to use the wooden coaster’s most exciting element – the large camelback hill. The more subtle support system is another benefit of using steel to build our ride. It is important for the ride to complement the feel of Oxford, in an unobtrusive manner, which would be near impossible using wood, given the large, support structure that is needed. A further benefit of using steel in our design would be its ability to draw people in from across the world. The exciting designs possible with steel are much more appealing to the public and easy to advertise than wooden designs. The final property of steel rides that appeal are the low maintenance costs. After the reasonably high initial costs, there is very little money that needs to be spent on the upkeep of the ride, which, given the long design life of our roller coaster, would be a great benefit. SECTION CONCLUSION Several techniques will be employed in the manufacturing and construction of the ride, in order to minimise disruption and risk to the public. Furthermore, an idea of the time and cost involved in building a ride was reached, and a suitable material selected. Arthur Coates Page 88 6: ENVIRONMENT AND AREA CONSIDERATIONS The environmental and other area specific considerations of the site will now be considered including restrictions and constraints posed by Oxford City Council policy. 6.1: Sustainability Introduction The roller coaster development will aim to address many of Oxford’s existing sustainability issues that affect the community in the West Area of Oxford. A key statement from the Area Action Plan declares: ‘The renaissance of the West End will look to the future; developments will be economically and socially sustainable and have environmental sustainability at their heart’.1 Therefore the ambition for the roller coaster project is to adhere to all environmental conservation codes, to reduce the use of natural resources, to construct in a sustainable manner and to utilise innovative technology that promotes sustainability. Overall the aim is to place equal importance on social, economic and environmental sustainability issues in Oxford through the Oxpens Field development as promoted by the ‘triple-bottom line’2 theory of sustainability. The most widely recognised definition of sustainable development: ‘Development which meets the needs of the present without compromising the ability of future generations to meet their own needs’. The roller coaster aims to tackle the challenges presented by the UK Sustainable Development Strategy3 which places strong emphasis on climate change, natural resource protection and the creation of sustainable communities. On a more local scale, the Oxford Sustainability Appraisal4 lists certain objectives that the development will be able to combat and will be continually referred to. 1 - To create and sustain vibrant communities - To make opportunities for culture, leisure and recreation readily available Area Action Plan, Oxford City Council See for example, http://www.economist.com/node/14301663 3 ‘Securing the Future - UK Sustainable Development Strategy’, March 2005, http://www.sustainabledevelopment. gov.uk/documents/publications/strategy/SecFut_complete.pdf 4 Table 7, Sustainability Appraisal, Oxford City Council 2 Arthur Coates - Page 89 To address the causes of climate change through reducing emissions of greenhouse gases, and ensure Oxford is prepared for associated impacts - To conserve and enhance Oxford’s biodiversity - To increase energy efficiency and the proportion of energy generated from renewable sources in Oxford - To develop and maintain a skilled workforce to support long-term competitiveness of the region - To ensure high and stable levels of employment so everyone can benefit from the economic growth of Oxford - To develop a dynamic, diverse and knowledge-based economy that excels in innovation with higher value, lower impact activities - To encourage the development of a buoyant, sustainable tourism sector 6.2: Renewable Energy The Government is seeking to encourage the development of renewable energy production through a range of legislative and commercial ambitions introduced through the Climate Change Act of 2008; - Target of reducing CO2 emissions by 80% by 2050 (compared to 1990 levels) - Target of generating 20% of UK electricity by renewable by 2020 A key document from the Local Plan 2001-2016 introduced by Oxford City Council from which the Area Action Plan was developed states: ‘The City Council will in particular encourage the use of solar panels, photovoltaics and, where appropriate, wind generators on all developments (both new and existing), and on residential and non-residential buildings.’ 5 Therefore it is highly favourable for the roller coaster development to include and design for one, or a possible fusion of multiple forms of renewable energy to power a high percentage of the ride and surrounding attractions. 5 Section 2.0, Core Policies, The Oxford Local Plan 2001-2016, Oxford City Council Arthur Coates Page 90 The two principal types of renewable energy that the development will consider for powering the roller coaster are wind and solar power. The following data are for the consideration, practically and financially, of wind power and show the average wind speeds for Oxford. Average wind speed at 10m (m/s) Annual Lat 51 Lon -2 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec average 10 year average 6.62 6.11 6.26 5.34 4.88 4.61 4.55 4.57 5.23 5.74 6.22 6.47 5.54 Figure 6.2.1: Average wind speeds for the Oxpens Field Site 6 According to the Energy Saving Trust, average wind speeds of below 5m/s are not a cost-effective way of providing electricity using current technology7. However, the data provided are more importantly for ‘terrain similar to airports’, and unfortunately the site at Oxpens Field is enclosed by relatively tall housing, tall trees and the ice rink on one side which have the combined effect of lowering the wind speed as well as heightening its unpredictability. Hence it was concluded that the construction of micro-scale wind turbines on location was not financially viable because of the lack of potential power output. Therefore the decision of focusing the renewable power generation on solar power was reached. Solar PV technology already exists in the neighbouring streets such as in Dale Close and Trinity Street8 as displayed below. This demonstrates that solar panels can be used in this area of Oxford, so long as a suitable location is found on the site. Clearly there are numerous challenges involved in the implementation of a solar panel array. The area in which the panels are placed must have as little shading as possible either by tall trees and the ice rink. The array must 6 Figure 6.2.2: Photo of existing solar panels on nearby housing Natural Resource Impact Analysis, Oxford City Council http://www.energysavingtrust.org.uk/Generate-your-own-energy/Wind-turbines/How-to-measure-wind-speed 8 See the Oxford Solar Initiative, http://oxfordsolar.energyprojects.net/ 7 Arthur Coates Page 91 have as much direct contact with solar radiation as possible to maximise the output power. Moreover, the PV array must be higher than the height of a typical flood. Hence the solar panels will be placed on top of the indoor section of the roller coaster which has a potential area of 3750m2. From the Energy Saving Trust, the solar data for the Oxpens Field site were recorded9 and the amount of power that can potentially be extracted using a PV crystalline silicon array of the typical 1, 2 or 4 KWp systems is calculated for the area. Solar PV Array Data System 1KWp Power (KWh) 851 2 Area (m ) 10 Cost (£) 7500 2KWp 1707 16 12000 4KWp 3414 28 16000 Power needed for launch = 150kW So running for 9 hours/day, 303 days/year Power needed = 409050KWh/year Figure 6.2.3: Table of Solar panel characteristics for 1,2 and 4 KWp systems From this information about the three different types of solar panel systems, and based upon the power required to run the roller coaster, a linear optimisation program in Matlab is constructed. This calculates the numbers of each system that maximises the potential output power, given the three constraints of power and area required, and initial capital cost. Since the area is insufficient in providing 100% of the power of the roller coaster through solar, the cost of powering the necessary shortfall is taken into account. This will be supplied by the electricity grid from the Osney substation. Furthermore to produce a more realistic model, two extra factors are considered; the degradation in the output efficiency of the PV panels over time and electricity inflation over the 40 year lifetime of the ride. Ultimately this is used to prove that it costs less to power the roller coaster through the utilisation of solar panels compared to powering through the general grid. 6.2.1: Cost of powering through the grid Assuming 5% constant inflation for the next 40 years (standard goods inflation at 3% plus energy inflation at 2%) Present cost of 1KWh through grid = 12.5p 9 http://www.energysavingtrust.org.uk/Generate-your-own-energy/Solar-panels-PV/Solar-Energy-Calculator Arthur Coates Page 92 Cost in first year, a = 409050 x 0.125 = £51,000 Hence over n = 40 year lifetime of the roller coaster using a geometric series with r = 1.05, = ( − 1) −1 The total cost of powering the roller coaster purely through the grid will cost £6.18m. 6.2.2: Cost of utilising solar power Analysis into the cost of powering the ride using solar arrays firstly uses linear optimisation. This uses a linear function to be maximised which in this case is the power, max ≤ , ≥ 0 Where is the objective power maximisation function and ≤ are the linear constraint matrices of power, area and cost as shown below with numbers from figure 6.2.3: 851 = − 1707& 3414 ) 409050 851 1707 3414 10 16 28 & * & = & 7500 12000 16000 + Where ) ,* and + are the number of 1,2 and 4 KWp systems to be used in the array. If one-third of the area on top of the indoor section of the roller coaster is required for maintenance of the solar panels then that leaves a 50m x 50m section available. Given an initial capital investment of £1.8m for the acquisition of solar panels, the following code produces results shown below: % Set up matrices f=-[851; 1707; 3414]; A=[851 1707 3414; 10 16 28; 7500 12000 16000]; b=[409050; Area; Cost]; lb = zeros(3,1); % Power maximisation % Solve x = linprog(f,A,b,[],[],lb); y=floor(x) % Power, Area and Cost calculation P = [851 1707 3414]*y % KWh A = [10 16 28]*y % m^2 C = 1000*[7.5 12 16]*y % £ Arthur Coates Page 93 Hence this produces 303846KWh/year using 2492m2 of area and costs £1.424m using the optimal combination of solar systems, 1, 2 or 4 KWp. Since there is a shortfall in the amount of power produced to the amount required, it is now the objective to calculate how much more power will be needed and the cost of it. A degradation equation which models the decrease in output efficiency over time of the crystalline silicon solar panels is introduced. From research10, the most favourable equation which exactly models the decrease is a logarithmic function of the type, () = − ln( + ) + Where a, b and c are constants. To find these constants, three typical boundary conditions are used with, 1. () = 1 = 0 2. () = 0.9 = 12 3. () = 0.8 = 25 (10% ↓ 34125) (20% ↓ 34255) Hence solving the simultaneous equations produces, () = 7.21 − 1.25ln( + 144) 0 ≤ ≤ 405 Furthermore a basic inflation model is constructed in continuous time which is used to calculate the cost of drawing the necessary extra power from the grid for the 40 year lifespan. The following code produces a column vector of average values of inflation per year in order to directly calculate the yearly costs of powering the roller coaster. syms t i = 1.05^t; 40yrs ezplot(i,[0,40]) % 5% constant inflation over % Inflation function plot I = int(i,0,1); for k=2:40 I = [I; int(i,k-1,k)]; % Average inflation per year end F = vpa(I) 10 % Inflation values per year % as a multiple of the first year See for example http://www1.eere.energy.gov/solar/pdfs/pvmrw2011_p71_csi_chou.pdf Arthur Coates Page 94 The yearly cost of powering through solar power for the roller coaster is then calculated through: 65 = 7409050 − (8 × ): × 0.125 × ; Where P is the power produced each year, which is constant, e is the fractional yearly degradation values and F is the yearly inflation values. Therefore the total cost comes out as, = <= 65> + ?@44?@3A@ In conclusion the total cost reaches a value of £4.02m for the 40 year lifespan and therefore the introduction of solar panels for powering the roller coaster leads to approximately a 35% reduction in costs in the longevity of the ride. Moreover from the Energy Saving Trust11 this assembly of solar panels will save 145 tonnes of CO2 a year which goes a huge way in cutting Oxford’s greenhouse gas emissions. 6.3: Environmental Sustainability In terms of environmental sustainability, the roller coaster aims in three parts to conserve wildlife, maintain green space and enhance the natural biodiversity as specified in Oxford’s sustainability objectives from the Sustainability Appraisal. Oxpens Field is bordered by two rivers; the river Thames and Castle Mill Stream which runs along the Eastern edge. From the Area Action Plan, numerous ambitions were established for the Oxpens Field development to preserve the river environment, but also to accentuate the natural features of the site to make it a more welcoming place to visit. First of all, according to the Oxford City Council, the Thames ‘represents one of Oxford’s most important natural assets’. The Thames forms value in terms of natural Figure 6.3.1: Photo of existing Thames path on Oxpens Field 11 http://www.energysavingtrust.org.uk/Generate-your-own-energy/Solar-panels-PV/Solar-Energy-Calculator Arthur Coates Page 95 beauty, recreation and the enrichment of Oxford’s landscape. Development on Oxpens Field will provide an ‘opportunity to improve access to the Thames’ and an ‘attractive frontage to the river will be created’12. The aim is therefore to fashion a green, tree-lined frontage to the Thames by planting more trees which will also encourage wildlife. Furthermore an upgrade of the network of cycle and walking routes along the Thames will take place which will improve access for locals and boost tourism through the Thames national trail13. A new footbridge will also be constructed between Oxpens Field and Grandpont nature park on the opposite side of the river again improving access and linking two great tourism features of Oxford in the future. Again from the Area Action Plan, Castle Mill Stream offers ‘significant opportunities in terms of amenity, recreational and biodiversity’ value. Not only does it hold an opportunity to create an ‘attractive streamside park’ but also an exciting ‘wildlife corridor’. The aim in redeveloping Castle Mill Stream is two-fold; from a biodiversity enhancement and an access point of view. More native aquatic vegetation will be planted in the stream, along with consolidation of the natural banks which will take place during the construction of the roller coaster. This will encourage new species of plants and animals to colonise the area, therefore heightening the biodiversity of Oxpens Field. Moreover a pedestrian path will be built that runs along Castle Mill Stream from the River Thames towards the city centre of Oxford, therefore encouraging visitors to the amusement park. Plant more trees along waterfront Attractive streamside walkway Consolidate natural banks Plant more aquatic vegetation 12 13 Area Action Plan, Oxford City Council See http://www.nationaltrail.co.uk/ThamesPath/ Figure 6.3.2: Photo showing proposed plans to redevelop Castle Mill Stream Arthur Coates Page 96 There are currently no protected trees in Oxpens field covered by council planning policy, yet there are some mature and beautiful blue cedar trees along Castle Mill Stream and adjacent to the ice rink. It is the aim of the construction process to minimise the risk of losing trees whilst the roller coaster is being built. Any trees lost during the construction aspect will be replaced according to the council’s planning policy14. POLICY NE.15 - LOSS OF TREES AND HEDGEROWS Planning permission will not be granted for development proposals which include the removal of trees, hedgerows and other valuable landscape features that form part of a development site, where this would have a significant adverse impact upon public amenity or ecological interest. Planning permission will be granted subject to soft landscaping, including tree planting, being undertaken whenever appropriate. Landscaping schemes should take account of local landscape character and should include the planting of indigenous species where appropriate. Where necessary, the City Council will seek long-term management plans, which will be secured through planning conditions or a planning obligation. Figure 6.3.3: Oxford City Council Policy on the protection of trees Furthermore, it is the aim of the ‘Launch of the Rings’ development to plant many more trees along both riverfronts as discussed above and in the centre of the field in order to reduce the effects of flooding and noise pollution, and more significantly to accentuate the natural beauty of the site and to encourage the creation of wildlife habitation. English Nature has identified Oxford and the surrounding area as a ‘Prime Biodiversity Area’15. On the other hand, the exact site of Oxpens Field has not been recognised as a Special Area of Conservation (SAC), nor as a Site of Special Scientific Interest (SSIC), nor as a Site of Local Importance for Nature Conservation (SLINC)16 so planning permission is much easier to obtain due to the lack of local natural habitats. However, it is the aim of the roller coaster development to maintain the ambitions of Oxford City Council concerning biodiversity in Oxpens Field. The plan of action is to ‘safeguard any existing features of ecological importance’17, especially during the construction process, whilst also enhancing any local biodiversity through the planting of more natural vegetation both in the field and in local aquatic habitats. According to ‘Friends of Oxpens Meadow’ over 50 species of birds have been observed in the area18 which is confirmed by the 14 Section 4.0, Natural Environment, The Oxford Local Plan 2001-2016, Oxford City Council http://www.naturalareas.naturalengland.org.uk/Science/natural/profiles%5CnaProfile64.pdf 16 http://www.oxford.gov.uk/Direct/CSCoreStrategyAdoptedProposalsMapSouth.pdf 17 Policy NE 17, Section 4.0, Natural Environment, The Oxford Local Plan 2001-2016, Oxford City Council 18 http://www.oxpensmeadow.org/environment.html 15 Arthur Coates Page 97 Oxford Urban Wildlife Group through local studies . The challenges of environmental sustainability 19 will play an extremely important role in the sustainable development of the roller coaster in Oxpens Field. Yet through not only conserving biodiversity, but fortifying the future of local wildlife habitats, a major tourist attraction can be shaped in the future. 6.4: Social Sustainability As referred to in section 6.1, it is an axiom of the ‘triple-bottom line’ theory of sustainable development to enhance the social quality and equity of the local community. This is also reinforced through the Sustainability Appraisal produced by the City Council. The redevelopment of the Thames River and Castle Mill Stream will include the introduction of a riverside walkway which will revitalise the Thames Path and will encourage many more visitors to the site. It is the aim of the development to not only increase public access to the site and to provide an opportunity for the public to enjoy the local river scenery, but also to maintain the SR5 green space in the centre of the site as in section 6.6. In addition a cycle lane will be built along the Thames riverfront which will encourage outdoor activity for the local community, and provide a way for many people to commute from the centre of town to outer districts such as Osney and Botley. As a consequence of this, two cycle parks will be constructed as shown on the proposals map below (figure 6.4.1). This will encourage people to travel in non-polluting modes of transport rather than taking their cars. Subsequently, this will act to eliminate congestion and pollution on Oxpens Road, and will realise the Area Action Plan’s motive of transforming the ‘feel and ambience of Oxpens Road’ to pedestrians and cyclists. 19 http://www.ouwg.org.uk/surveys.htm Arthur Coates Page 98 Key; Pedestrian footpath Cycle Path Footbridge Cycle Park Figure 6.4.1 Map showing the proposed developments concerning access to the site There are also plans to get the community and local schools involved with the construction of the roller coaster and the conservation of Oxpens Field including the building and maintenance of local river features. The aim is to organise day trips for the local schools to learn about construction and the engineering behind the project. This will not only promote science and engineering to the children, but will also, more significantly, encourage higher education as an ambition for the school attendees. Ultimately this will promote the ‘knowledge-based economy’ that Oxford City Council desires and that makes Oxford thrive as an economic hub, whilst simultaneously reinforcing the development’s links to the local community. Moreover day visits will be organised for the local youth community20 to help with the conservation effort taking place on the site. The development team will work cooperatively with local conservation and nature groups such as ‘Friends of Oxpens Meadow’, ‘Oxford Conservation Volunteers’ and ‘Oxford Nature Conservation Forum’. Children will actively help with the planting of vegetation, habitat maintenance and caring of local wildlife, whilst also learning about Oxford’s rich biodiversity and the importance of conservation and protection of green space in accordance with the Oxford Local Plan and the Area Action Plan. The roller coaster will become a symbol of how human development can coexist with wildlife conservation, whilst heightening the ‘vibrancy’ and social quality of life for the local community. 20 See for example http://www.thebestof.co.uk/local/oxford/local-guide/youth-clubs Arthur Coates Page 99 6.5: Economic Sustainability The most significant sustainability issues that directly affect the local population of Oxford are economically-grounded. The two main challenges that face the Oxford City Council, which can be addressed by the Oxford Roller Coaster development are; - Pockets of poverty, social exclusion and deprivation - Differences in proportion of unemployed and long-term unemployed across the city21 This can be simply tackled through the objectives of; - Developing and maintaining a skilled workforce to support the long-term competitiveness of the region - Ensuring high and stable levels of employment so everyone can benefit from the economic growth of Oxford - Stimulating economic revival in priority regeneration areas - Encouraging the development of a buoyant, sustainable tourism sector22 These have been previously described in section 6.1. In essence, through the roller coaster development, the long-term economic goal is to provide ample stable employment. For the currently unemployed, essential jobs will be created such as maintenance of the site which encompasses cleaning, security and risk management. Moreover the development will provide active employment in mechanical, civil and electrical engineering which is needed in the utilisation of innovative technology in the roller coaster. The aim is to make this economically sustainable through localising as much of the employment as possible. Increased tourism to the ‘West End’ of Oxford will be buoyed by the sustainable measures undertaken in the development i.e over 60% of the ride will be powered by ‘zero-carbon’ renewable energy. This will therefore lead to a stimulation of local retail and client businesses as Oxford widens its tourism market through another ‘world famous’ attraction. This will also encourage the growth of smaller businesses and will vitalize entrepreneurship in the West Oxford area as more opportunities become available. An ambition is to hold an annual technology fair at the site that will aim to 21 22 Table 6, Sustainability Appraisal, Oxford City Council Table 7, Sustainability Appraisal, Oxford City Council Arthur Coates Page 100 champion Oxford’s reputation as a technological centre. However, arguably the most important method of achieving sustainable development is through the numerous education workshops for the local youth as described in section 6.4. This will provide a long-term view that not only promotes education to the youth population, but a sustainable education that supports the economic competitiveness of Oxford through science and engineering. Overall the development on Oxpens Field aims to tackle Oxford’s diverse sustainable issues through encapsulating a wide spectrum of challenges that Oxford faces. Through enriching green space, enhancing biodiversity and wildlife, minimising the environmental impact of construction, increasing accessibility by sustainable modes of transport and promoting high growth and high productivity sectors, the roller coaster development will become a paragon of sustainable development. William Hancock Page 101 6.6: Council Planning Policies Planning policies are essential in controlling development across the country. Oxford has a very detailed planning policy guide (PPG) to protect the many historic buildings and famous landmarks in Oxford. For the proposed roller coaster to be approved all aspects have to be in accordance with the PPG23. One section of the policy that had to be researched was the possible archaeology present on the proposed site. It was concluded that there was no evidence of any archaeological on the site, the closest being Bronze Age barrows in Port Meadows just over 2km away.24 Interestingly, as shown in figure 6.6.125, the site is divided into two sections. The Eastern half of the site of the roller coaster is an SR.5 Protected open space. This refers to another policy from Oxford Core Strategy Examination26 which states any development has to ‘ensure current level of public accessible open space per 1000 population is maintained.’ It is one of our aims to ensure that as much of Oxpens Meadow is left available for recreational activities by the public, in particular the protected area Figure 6.6.1: Map of proposal areas in Oxford highlighted on the map in green. The next policy section HE.9 is in reference to ‘High Building Area.’ This aims to preserve the historic skyline of Oxford and states that, ‘planning permission will not be granted to any building within 1.2km of Carfax which exceeds the height of 18.2m.’ Oxpens meadow is ~0.6km from the Carfax tower so is subjected to this height restriction. When designing the track the entire construction will have to be thrilling and exciting without exceeding 18.2m in height. This creates a significant technical challenge. Finally, another important aspect that has to be considered is the lighting of the coaster. If the roller coaster is presumed to be closed during winter months, December-February, and reopens again in March this could lead to a lighting problem. In March the sun sets at 18:00 and in 23 Planning policy oxford.gov.uk/ Oxford_Local_Plan ‘Archaeological sites on Port Meadows’ R.J.C Atkinson 1956 25 oxford.gov.uk/Direct/CSCoreStrategyAdoptedProposalsMapSouth 26 Policy CS22 Oxford Core strategy oxford.gov.uk 24 William Hancock Page 102 November even earlier at 16:00 . The rollercoaster will need to be in operation past these times in 27 order to provide for the safety and comfort of the riders it will have to be illuminated by spotlights. There is a policy HE.11- Architectural lighting which ensures that the lighting is unobtrusive, will enhance the feature and have adequate safeguards against light pollution. One business idea uses the fact that the ride may be more ‘scary’ in the dark and could be a special event to advertise. For example, an advertising slogan could be “Dare you come back after dark?” This would encourage repeat customers looking for a different experience. There are also many policies that were created to encourage development which produces beneficial outcomes. One example is for the development of footpaths and bridleways particularly along the Thames Path National trail. The trail is along the edge of the site but is generally unkempt. There would therefore be an opportunity for development, as seen in the photos in figure 6.6.2. This would create a network of green scenic pathways across Oxford, which tourists would be encouraged to spend time walking whilst enjoying the beautiful views. Figure 6.6.2: Photos of the Thames Path National Trail The Thames waterway is a well used stretch of river and there is the possibility of developing small visitor moorings along the bank in accordance with policy SR.14. This could only be done as long as it doesn’t cause environmental damage or interfere with the navigation of other river vessels. Osney Mill Marina is not far downstream from our site. This is a marina with over 40 moorings and provides an example of some of the users of the river. A company already exists which gives ‘Oxford River Cruises.’ An additional stop could be created to visit the ride. It is planned to set up a small boat taxi service collecting customers from the station and the Head of the River pub. The additional mooring scheme on our site could increase the number of tourists that are likely to visit the roller coaster and would help with the development of the river side. 27 Times based on values from timeanddate.com - Accessed 3-2012 William Hancock Page 103 6.7: Flood Risk Much of Oxford is at flood risk for a number of different reasons. The floods are not caused by rain water falling in the immediate area, but from water which has fallen as far away as the Cotswolds, which then flows down the valley of the River Thames.28 This large catchment area means there are significant volumes of water travelling through the Oxford area. The most severe flooding occurs in the area immediately to the west of Oxford. There is a marked natural geological narrowing of the Thames Valley just to the South which has been worsened by the building of the railway, roads and buildings, and by landfill. Lack of maintenance to certain built up areas and causeways act as an intensifier to the floods. When flooding occurs there are insufficient flood plains to hold the additional water. Figure 6.7.1: (left) EA map of flood risk Figure 6.7.2: (right) Photo of area July 2007 The exact site of the rollercoaster is prone to flooding as shown in both figure 6.7.129 and the photo, figure 6.7.2, which was taken during the severe 2007 floods. In July 2007 Oxford suffered the worst floods for many years with rainfall levels being the highest since record began. 1,631 homes and 72 businesses were flooded across West Oxfordshire, costing millions in damages and repairs. As expected the lower corner closest to the river has been the worse effected part of the site. The type of flooding that occurs is fluvial. This is when main river channels are unable to cope with the volume of water in the river systems. River water over tops channel banks and excess water is stored in the immediate area, either flood plains or built up areas. This is likely to occur at the same time as flash flooding which is where road gullies cannot drain water away and so it collects in local low points in the area. 28 29 Information from Oxford Alliance Environmental Agency map of flood risk maps.environmental-agency.gov.uk William Hancock Page 104 The risk of flooding can be calculated and quantified using previous flood data . If the 30 floods that occurred in 2000 and 2003 were representative of a 1 in 15 years flood and the 2007 of 1 in 18; then using an example period of 6 years the risk of another 1 in 15 flood is 33.9%. Figure 6.7.2 shows the typical flood that is likely to occur at least twice in the rollercoaster’s lifetime. This shows how necessary and important good flood defences will be to protect the roller coaster against damage by flooding. There already exists the Oxford Flood Alliance (OFA) which advocates many strategies to reduce the flood risk in the Oxford area. It was set up by local people after the 2007 floods to help combat the flood risk. It is important to work with this group and try to ensure the measures that are being taken to protect the roller coaster are working towards the same goals as the OFA. Alongside this there are many government policies to ensure that new developments are designed to alleviate the causes of flooding. One policy for sustainable drainage31 quotes ‘a paved area on new development normally reduces the amount of water that can infiltrate into the ground and so increases the surface water run-off into local drains. The planning policies specifically require developers to demonstrate that they have made appropriate provision for surface water drainage that will mitigate any adverse impact from surface run-off.’ Any building on an undeveloped flood plain, such as Oxpens Meadow, has additional criteria to ensure the level of flooding is not increased in the local or greater area. To reduce the negative impact of building on a flood plain the design of the roller coaster is aimed at keeping as much of the meadow available to act as a flood plain. The roller coaster track is at a minimum of 2m from the ground which allows the ride to be operational in mild to moderate flooding events. Allowing the meadow to flood reduces the amount of water that would be displaced by the development and so would not increase the severity of flooding in the immediate area. Providing a large grass surface allows infiltration of water into the soil. An important part of flood defence is to have accurate real time data to calculate the current risk. It would be useful information to have access to data such as the water level of the river and flow rate. This is possible by using data that are currently collected from Osney Lock, which is a short distance upstream. River levels are taken every 15 minutes and recorded. 30 31 American National weather service Forecast Office Section 4.12; Alleviating causes of flooding Oxford.gov.uk/Direct/FloodingInfo William Hancock Page 105 The river levels either side of the weir can be used in the weir equation tocalculate the flow over the weir, B = CD ∗F∗G H.I . *JK.I The highest river level that has ever been recorded was 3.93m on 25/07/2007. Taking into account the sites datum of 54.7mAOD and comparing to the map in section 1.2, at the highest flood levels every area would be expected to be flooded except for part of the yellow and all of the red and orange sections. The Environmental Agency has put forward a flood defence proposal strategy with nine different options. The choice that has been opted for here involves two main engineering projects. The first is a new watercourse in West Oxford and the second is a possible flood storage area upstream of Oxford. The second project is a long term scheme with work being planned to start in 2025. These would have the effect of alleviating the flood risk, but not combating it completely. There are several different parts to the planned flood protection scheme for our site. An initial decision was made to locate the building which houses the launch mechanism in the top corner of the site nearest Oxpens Road. The cost of the launching mechanism is a large proportion of the total cost of the ride and so would be very expensive to replace and repair. Therefore placing the mechanism in the section of the site which is least liable to flooding reduces the risk of damage. For the same reason the loading platform and all the control equipment for the ride will be housed in the same building. The building will need to be designed so that it is completely flood proof. To allow natural ventilation through a building several air bricks are built into the walls, usually at ground level. Air bricks could let in up to 50,000 litres of water in an hour, so during flood warnings these will require fitted air brick covers which are water tight. There is a simple method for water proofing the actual brickwork, which is to apply a specialised outdoor paint using a spray or roller. This reduces the risk of water soaking through and also provides some thermal insulation. Another area at risk from flooding within the building is the toilets and other plumbing areas. During heavy flooding many sewers are unable to cope with the abnormal weather conditions causing a backflow of foul contaminated water which could possibly flood into a building increasing damage. To solve this problem all the water works will be fitted with a non-return valve shown in figure 6.7.3, to minimise the risk of any backflow. William Hancock Page 106 During light flooding the aim is to keep the ride operational, so as not to lose any potential customers. The advantage of having the loading and launching mechanisms inside is that they are not so easily affected by the rain and flooding. The rest of Oxpens Meadow is being allowed to flood and a mountable barrier will be placed as shown in figure 6.7.4 to stop the flood water from spreading out on to the road and entrance to the rollercoaster. There are many types of barriers and the one that is most applicable is the flip up flood barrier32. This can be operated by a single switch or automatically in response to data being sent from Osney Lock. The barrier is fully recessed whilst not in use so it doesn’t ruin the aesthetics of the site. Movement and weight sensors prevent barriers opening if the entrance is obstructed. The presence of an additional visual alarm system provides a further safeguard. Figure 6.7.3: Non return valve Figure 6.7.4: Map showing building plus location of planned flood barriers in blue and places where door protection is required in pink Figure 6.7.5: Types of flood defences; flip up barrier (left) door guard (right) Launch Loading area During heavy and extreme flooding it will be unadvisable for tourists to be travelling around Oxford. This means that although there is no need to make the ride operational it is nevertheless essential to protect the ride from damage. The entrances to the building will be fitted with mountable door barriers which completely block the water from entering.33 Another method of reducing flood risk is to increase the drainage from the meadow into the River Thames. This could be achieved by using a series of channels and connecting pipes. This will not however, be effective as the main risk is fluvial flooding, where the water is from the river. It would be better to try and increase the flow of the river through dredging, clearing the river bed of obstacles and regular maintenance of the channel walls. 32 33 Based on model manufacture by Flood control International Product from Flood-Master William Hancock Page 107 6.8: Noise Pollution Noise pollution from any new development has to be carefully monitored and strict guidelines have been put in place. Planning Policy 24 (PPG.24) gives guidance to the local authorities on the use of their planning powers to minimize the adverse impact of noise. It states that housing and residential areas are noise sensitive locations and that the nature and character of the noise source should be taken into account, as well as its level. Sudden impulses and irregular noise sources will require special consideration. There are several health effects that can be caused by noise pollution such as hearing impairment, hypertension, annoyance and sleep disturbance.34 Figure 6.8.135 predicts the reaction from the community to an increase in noise pollution. A reaction of widespread complaints or threat of legal action is undesirable, so the aim is to keep the increase of noise below 10dB. It is important to try Figure 6.8.1: Graph of community reaction to noise and maintain a good relationship with the community and the immediate residential area. The noise sources that are expected can be classified into two main areas; mechanical noise and human noise. Mechanical noise is the sound created by the launch and breaking mechanisms, and the sound of the carts travelling along the track. On a busy day these noises would be fairly constant with regular pulses of elevated noise. The second is human noise. This is created by the customers and possibly staff as well. There will be low level background noise created by customers talking excitedly and moving around whilst queuing, or by staff communicating to each other or with customers to ensure safe operation of the ride. During the ride however customers will feel the thrill and adrenaline of the many turns and high acceleration of the launch and are expected to scream and shout. This would result from the unfamiliarity and the overload of the senses being experienced. Many people scream just because they are enjoying the ride and it enhances their experience. This noise source will always occur and methods need to be created to reduce its impact. 34 ‘Noise Exposure and public health’ Passichier-Vermeer 2000 Graph from study by Inter-noise, C.W Menge, H Miller Miller & Hanson 2002 ‘Abatement strategies for rollercoaster noise’ 35 William Hancock Page 108 These noise sources are intensified by several factors. The high elevation of the ride, up to a maximum of 18m, allows the noise to propagate and reach to a wider area. The ride is operational throughout most of the day. This constant level of noise along with the periodic noise created by each cart travelling down the track increases the possible effect of a negative community reaction. Another time when noise is an important factor is during the construction of the rollercoaster. The heavy machinery and construction traffic will increase the level of noise and will be carefully dealt with to limit any negative impact. This is outlined in section 5.1. One easy method to analyse the noise at each location is to use a sound meter. There are several sound meter applications available for smart phones. These were used across the site to give an estimate of the current levels of noise. Figure 74 6.8.2 shows a screen shot of the sound meter used. 58 57 The values plotted on figure 6.8.3 are the average in 60 (65) 61 dB to illustrate the current sound distribution. The 55 50 Figure 6.8.2: (top) Sound meter Figure 6.8.3: (right) Sound distribution map 53 data in brackets are for when a train was passing by. Before and after construction a detailed sound map 52 (85) using specialist equipment would be created to show the impact of the ride on noise pollution. There are several methods to protect against noise pollution. These can be grouped into three main types; the layout and design of the site, the engineering design and administrative measures. Engineering aims to reduce the production of noise at the source, whilst the design tries to limit the effect of the sound on the immediate area. Administrative measures are to ensure the impact of the noise is reduced on the community. The red highlighted area shows where the closest noise sensitive residential area lies. This is where complaints are more likely to occur from and where protective measures are most vital. Line of natural barrier Figure 6.8.3: Residential area close to site William Hancock Page 109 The first noise abatement measure is to install double glazing in all of the houses within the area highlighted in figure 6.8.3. This insulates the buildings against noise. Resonance in the cavity can however reduce the effectiveness of the insulation. Therefore the frequency of the noise source has to be taken into account. From PPG.24 the typical noise difference from double glazing of inside compared to outside is around 30dB. Researching from Zenith windows an approximate cost of double glazing the windows would be around £5,000 per house. An estimate from the map of the area suggests around 100 would be in the area for potential double glazing. This introduces an overall addition of ~£500,000 to the budget. Secondly, an increased natural barrier of trees and shrubs is planned to be planted along the green highlighted area in figure 6.8.3. Noise reduction is achieved by a combination of deflection and absorption of the sound. Conifers or evergreen broadleaf plants provide the best all year round noise reduction, due to the densely packed leaves which inhibits sound propagation. Trees also create a visual barrier, which reduces the perception of noise. It has been suggested that people are less conscious of noise if they cannot see the source. Other deciduous trees can be planted for seasonal variation for purely aesthetical reasons. A mathematical model can be created involving the modelling of the second-order linear partial differential wave equation. A detailed numerical simulation has been conducted on the effect of trees on noise barrier performance36. Results from this study validate the use of the barrier. The trees will be obtained from a sustainable Figure 6.8.4: Example Natural Barrier source. An awareness of the effect of noise pollution was present throughout the design of the entire rollercoaster track. Research was conducted into many different factors that influence noise pollution. (See Appendix 1 for graphs of the study that was conducted). The graph in Appendix 1.2 shows how the orientation of the cart affects the levels of noise that are recorded. From this the track was designed so that the cart is tilted away from the houses during the stretch near the residential area. This causes the sound to be projected away from the houses and back towards the rest of the site. In some roller coasters plastic tubing has been built around parts of the track to 36 ‘Numerical Simulation of the effect of trees on Noise Barrier Performance’ T Renterghem D Botteldooren 2003 William Hancock Page 110 act as a sound barrier. This reflects any noise internally and reduces the amount that is spread. For this to be effective the scariest parts will need to be covered. Due to the high thrill factor of the ride that has been designed, a large proportion would have to be covered. This would have a negative effect of blocking the view of the riders. Taking this idea of encasing the source of the sound, it was decided that the launch and breaking mechanisms should be housed inside a building. These were the areas where the noise was predicted and expected to be greatest. Figure 6.7.4 in the previous section shows where the building will be situated. This is also where the loading and unloading of customers take place. Not only will the noise from the queuing customers be contained, but their comfort will be improved as they will be waiting in the warm and dry, with themed activities to amuse them. The first launch is into a loop which is likely to create a lot of noise from excited customers. The graph in Appendix 1.3 shows how the addition of passengers to a roller coaster increases the noise levels above 800Hz. To reduce this effect the launch is designed in the part furthest away from the residential area. When sound travels through a medium its intensity diminishes. Scattering is the reflection of sound in other directions, and absorption is the conversion of sound into other sources. The combined effect of these is called attenuation. The amplitude change can be expressed as: = L MNO , where P = *∗QRSTUCVUWCXWUYR∗(Z[\]^\CR)_ +∗Z`^UQQ\WUYR∗(WX^QWa\\Q)b Ao is the unattenuated amplitude, z is the distance travelled by the sound and P is the attenuation coefficient in neper per metre. Stokes’ Law for sound attenuation shows how if the source is placed further away the amplitude of sound will be less. As previously discussed, there are a number of engineering methods to reduce the production of noise at the source. Section 3.10 explains how the material of the wheel influences the level of noise created. The softer polyurethane wheels reduce the vibrations of the cart by absorbing any small defects and bumps along the rail. This also has the effect of reducing the noise caused by the wheels rolling over the track. Another study has shown that a support of circular section produces an average of 10-15dB less sound energy than that with a rectangular section, see Appendix 1.1. This is another reason for the choice of circular section for the ride. The William Hancock Page 111 difference is due to the effect of the steel rail support acting as an acoustic radiator, this can be lessened by the introduction of damping in between the supports and the track. There have been several methods to try to reduce the damping by filling the beams and the rails of the track with different materials. Sand, pea gravel and lead shots were tested and all successfully decreased the effect, see Appendix 1.4. Filling the rails and the beams led to a reduction of around 15dB across the spectrum. The weight and movement of the particles opposes the motion of the track, limiting the degree of resonance that occurs. During testing sand was found to be difficult to handle, as it didn’t flow well and became rigid over time. A mixture of pea lead and gravel is used as an alternative and has the desired effect. The disadvantage is that it increases the weight of the track, so requiring larger foundations and stronger supports. Finally, an important part of noise management is how the ride interacts with the local residents. Administrative measures can be put in place to limit the possible disturbance. Operational hours of the ride will be at reasonable times; mainly ensuring closing time is before 21.00hrs at the latest, to limit any disruption to sleeping. Only on special themed nights such as Halloween would the ride be open significantly later than the usual closing time. It is important to keep in good contact with the residents by holding regular meetings to find solutions to reduce any problems and to try and improve the quality of their local area. Through these different measures the noise pollution from the rollercoaster will be below the target levels. This therefore should not cause any significant disturbance to the local area and a good relationship can be maintained with minimal complaints. 6.9: Bomb Risk There are many potential risks to a new development; some of these are due to the historical activity in the past. During WWII much of England was targeted by the Luftwaffe for bombing raids. Fortunately Oxford was never targeted and according to the home office only two high explosive bombs fell on the entire Borough of Oxford. This information was confirmed by lodging an enquiry with Bactech in November 2011, a firm specialising in analysing potential explosive risk. The only possible risk to the site is potential explosive contamination and comes from the early 17th century. This is due to the presence of a Saltpetre works (gunpowder) approximately 200m north of the site. Any risk associated with this is deemed however to be negligible. Charlie Hill Page 112 6.10: Transport With 9 million tourists per year, and 200,000 residents of Oxford37, Launch of the Rings aims to provide an additional attraction for those already in the city, and to encourage new visitors to the city of Oxford. It is not envisaged that the roller coaster will entice casual visitors who are just looking for the thrill of the ride, without wanting to visit Oxford. This goal is beneficial for a number of reasons; the local economy benefits from increased visitor numbers, visiting for longer durations, which causes increased demand for hotels, shops, pubs, and restaurants. The other benefit is that little needs to be changed in terms of the wider transport infrastructure. Oxford, being an internationally renowned city of culture, has an estimated daily population throughput in the height of summer of up to 700,000. As the current transport infrastructure can support this number of people leaving the city, even if every visitor to our roller coaster arrived just for the roller coaster, the 2,500 people per day maximum throughput38 would result in a 0.3% change in population turnover, which can be considered negligible. Of slightly more concern, figures from the 2007 Oxford Visitor survey39 indicate that 63% of the population arrived through private transport, where only 16% arrived by bus, and 11% arrived by train. These figures are of primary concern for Oxford tourism, however, the large amount of people arriving via private transport has led to numerous park and ride schemes being run around the town. These systems have helped reduce traffic in the town, reducing congestion and crowding. The current traffic infrastructure is well suited for tourism. Oxford train station has connections to London Paddington, every 15 minutes40, and to Birmingham New Street, every 30 minutes. From these stations connections to anywhere else in the country are possible. London Paddington also provides easy access to Gatwick and Heathrow airports, both accessible within an hour and a half of Oxford, providing a global target market. The train station is a ten minute walk from our site. Gloucester Green national bus station provides bus services to major airports, numerous services to London (every 10 - 20 minutes)41, and services to attractions such as Cambridge. The bus station is a 15 minute walk from our site. For visitors arriving by car, many will want to use the 37 See section 9.4 for origin of figures See section 9.5 for origin of figures 39 Tourism South East, Oxford Visitor Survey 2007 40 http://www.nationalrail.co.uk - figures correct February 2012 41 http://www.oxfordtube.com/tubetimes.php - figures correct February 2012 38 Charlie Hill Page 113 park and ride system - the flexibility of being able to park on the edge of town. The park and ride systems run constant bus routes around the town, these buses can usually be caught at five minute intervals. Having established that the impact of Launch of the Rings on the wider Oxford transport network will be minimal, one must now consider the impact of the roller coaster on a more local scale. It is expected that most visitors to the roller coaster will arrive on foot. As mentioned above, the site is located ten minutes from the train station and fifteen minutes from the bus station. Figure 6.10.142 shows the location of our site (green), and its proximity from the Figure 6.10.1: Map showing location of ice rink compared to Oxford attractions railway station, blue, Gloucester Green bus station, red, and the typical tourist attractions of Christ Church college, white, 10 minute walk, and the Radcliffe Camera, yellow, a 15 minute walk43. The central position of our Figure 6.10.2: Map showing proposed foot routes to the site roller coaster within Oxford is further beneficial in that tourists should not be put off by the time taken to get to the roller coaster. By combining strategies of using the tourism base already in 42 43 Map courtesy of http://www.google.com/maps All walking time figures taken from http://www.google.com/maps Charlie Hill Page 114 Oxford, and then encouraging visitors to walk to the roller coaster, the environmental footprint of the roller coaster should be minimised. To aid tourists finding their way to the roller coaster, the construction of three sign posted routes is proposed, from strategic positions in the town. The routes that would be sign posted are highlighted in figure 6.10.244. Each of the red, blue and green lines highlight a proposed new route. The blue line runs directly from the train station, whereas the green and red lines run from city centre locations. All lines terminate at the entrance to the site, on Oxpens road. Signs for the route would be in keeping with Oxford, and usual tourist attraction signs. The signs would be placed at frequent intervals so as to make it clear for visitors the route they should follow. We would also approach Oxford tourism to get our roller coaster added to their tourism maps as a potential tourist attraction. Visual analysis of the route suggests that the minimum pavement width of either route is sufficient to accommodate two people simultaneously. This part of the route is between the train station, and the site, and is shown in figure 6.10.3. The rest of the route, both to the train station, and into town has sufficient width to Figure 6.10.3: Pavement leading to site accommodate three people. Pavements on this side of town are currently negligibly quiet, and thus other users do not need to be considered. Taking our maximum daily throughput as 2500 people in a 10 hour day, one might estimate daily throughput as leading to a potential maximum of 400 people per hour travelling to and from the site. Should those people all travel to the site on foot, we might consider a maximum down any of the routes as being 75% of the maximum, or 300 people per hour. That is five people per minute, maximum, walking either way down the pavements to and from the site. Considering these figures, it is clear to see that a pavement width of 2 people is more than sufficient for use as an entrance to the roller coaster. This means that no changes need to be made to the pavements in the region. 44 Map courtesy of http://www.google.com/maps Charlie Hill Page 115 Another consideration, with an increased amount of pedestrians, is road crossings. Largely pedestrianized Oxford city centre presents no problems in this respect, and thus most of the routes heading out of the city centre are suitable for pedestrian use. However, the installation of a Toucan crossing on the Oxpens road, in front of the entrance to the site, would be needed to ensure pedestrian safety. Although Oxpens road is relatively quiet, a Toucan crossing should ensure safe and easy access to any potential customer, regardless of age and ability. The route from the train station crosses the busy Park End Street. This street already has a series of Toucan crossings to help tourists and locals cross from the train station. For the increase in visitor numbers predicted above, this system of Toucan crossings should be sufficient to ensure the safety of the increased visitor numbers due to the roller coaster. On a related note, we would also approach Oxford bus tour operators. The map shown below in figure 6.10.4, taken from Oxford City Tours website45, shows that the City Sightseeing tour already passes close to the ice rink, and thus our site. We would approach this tour company, asking if they would incorporate a further stop on their route on the corner between Speedwell Street and Greyfriars Street, where they would advertise our roller Figure 6.10.4: Current Oxford bus tour coaster, hopefully also including our roller coaster as a highlighted attraction on their map, similar perhaps to the highlighting of Oxford Castle Unlocked, that can be seen in figure 6.10.4. Local bus routes also stop close to our site, with the castle street bus stop about a 3 minute walk from our site. The nearest park and ride bus stop is from the Redbridge park and ride, and is about a five minute walk from our site, however, the bus route passes close to the ice rink, so again, we would talk to the operator concerning the possibility of adding a new stop, closer to the roller coaster. 45 http://www.citysightseeingoxford.com/tour_route_map.html - accessed February 2012 Charlie Hill Page 116 For visitors deciding to arrive at the roller coaster by bike, two cycle parks are proposed: a small cycle park at the entrance to the site, and a larger cycle park behind the ice rink. These parks would provide relatively secure storage, where bikes could be locked against frames. For larger groups of visitors, a coach park is situated next to the ice rink, and next to our roller coaster sight. This would be available to visitors, via prior booking through the Oxford city council. Numerous other coach parks would also be available throughout Oxford, in line with the high summer demand for tourism that Oxford faces annually. No onsite parking would be made available for visitors wishing to visit the site by car. These visitors would have to use current parking facilities, potentially including the Westgate car park, five minute walk, and the Hythe Bridge Street car park, also a five minute walk. This is part of an attempt to discourage car use in the city centre. In conclusion, the aim of the roller coaster is to utilise the large, existing target audience already in Oxford, and provide a further attraction. The number of additional tourists attracted by a single roller coaster is likely to be small, though our maximum capacity limit means that even if all of our visitors were unique just for the roller coaster, the effect on the larger transport infrastructure is likely to be small. Within the town, changes to bus routes, maps, and signposting have been discussed, leading to increased accessibility of the site. Even at the height of operation, visitor numbers are not sufficiently great as to require changes in pavement width along Oxpens road. The installation of a Toucan crossing leading to the site is recommended. As vehicle access is limited, there is no requirement for any road changes due to the development. Overall, the transport disruption due to Launch of the Rings is minimal, and the existing infrastructure is sufficient to cope with the visitor numbers that we expect. There is no reason why transport should damage the feasibility of the proposed roller coaster. SECTION CONCLUSION Launch of the Rings aims to cause minimal disruption to the park upon which it is sited. Through careful planning, the natural flood plain has been maintained, and noise that might disrupt neighbouring houses has been minimised. The development also has negligible impact on transport in the city, and pedestrians will be able to safely access the site. Edward Jamie McDonald Page 117 7: SAFETY A roller coaster is a very complicated and hazardous ride, with the potential to cause serious injury or even death. Employees of the ride, riders and indeed the general public in the vicinity of the ride all have the potential to be harmed. It is therefore important to actively manage the risk of an accident and take all reasonable measures to ensure the ride is as safe as possible. This section fulfils this by comprising a full risk assessment as well as details of the ride’s thorough maintenance programme and the legal position regarding safety. 7.1: Risk Assessment The probability and severity of hazards are each measured out of five. The risk rating is the product of the probability and the severity. A risk rating of five or less indicates low risk, from six to ten moderate risk, from eleven to fifteen high risk and above fifteen extremely high risk. Hazard Who is Affected? Original Risk Probability Mitigation Measures Severity Risk Residual Risk Probability Severity Rating Slips, trips, falls, Maintenance cuts or other minor personnel 4 2 8 Rating Employ good lighting in maintenance clean up spills immediately. Have first maintenance aid kit present in shed. Ride operator carts or person hit and riders 2 1 2 1 3 3 shed. Keep floor areas clear and injuries during Collision between Risk 3 3 9 Include safety system so ride automatically shuts down before track Edward Jamie McDonald Page 118 by cart when adding can be moved to allow trains to or removing carts access maintenance shed. Assault by member Ride operator 3 2 6 of the public Train staff in conflict resolution. Have 2 2 4 2 4 8 1 4 4 1 4 4 2 2 4 2 3 6 1 2 2 first aid kit present in station. Fall on tracks or hit Ride operator by train in station and riders 3 4 12 Gates in station to hold riders away from track. Safe areas staff must stand for ride to operate. Electrocution Ride operator 3 4 12 Insulate all electrics and use circuit breakers Hit by train on Public in park 4 4 16 outside track Hit by object falling hit a person. Monitor park with CCTV. Public in park 5 2 10 from cart Fire in building Fence off all areas where train could No loose objects allowed on ride. Nets placed to catch falling objects. Riders, staff 3 5 15 No smoking in building. Emergency and people exits clearly signed. Good fire alarm queuing and suppression systems installed. Power cut in Riders and building people 5 2 10 Have emergency power supply. Edward Jamie McDonald Page 119 queuing Assault/Illness/Accid People ent queuing, associated signage. Have first aid staff, riders trained staff and first aid kit available. Illness on Ride Riders 5 3 3 3 15 9 Monitor area with CCTV and People with pre-existing medical 3 2 6 2 2 4 1 5 5 2 1 2 2 1 2 1 4 4 1 5 5 conditions not allowed on ride. Have first aid trained staff available. Restraint system Riders 3 5 15 failure Backup system with manual clip. Enforce maximum and minimum rider sizes. Launch breakdown Riders 4 2 8 Good maintenance. Have safe method of evacuating train. Ride does not Riders 3 3 9 complete circuit Collision between Good maintenance. Have safe method of evacuating train. Riders 3 5 15 trains Install bumpers on trains. Use control system to ensure only one train can enter each block at a time. Brakes failure Riders 3 5 15 Good maintenance. Use failsafe Edward Jamie McDonald Page 120 braking system. Electrocution and Trespassers 3 other accidents 4 12 Secure ride area, turn off all electrics 2 2 4 and monitor ride by CCTV at night. Following application of the mitigation we have only three risks classified as a moderate risk, with the rest low risk. This is an acceptable level of risk and so this mitigation is sufficient. Further risk assessments will be conducted at regular intervals to identify any new risks that arise and attempt to reduce current risks as far as possible. Edward Jamie McDonald Page 121 7.2: Maintenance A key part of ensuring the safety of a roller coaster is a strict maintenance regime. This is underlined by the detailed requirements of the Health and Safety Executive (HSE) in this area as set out in the document “Fairgrounds and amusement parks: Guidance on safe practice”1. This maintenance plan is entirely based on the principles set out in this document. The case for a strong maintenance programme is furthered by the fact that even excluding the safety benefits there is an economic incentive to follow good maintenance practice. This is because reduced maintenance results in increased down time of the ride which can be very costly, particularly if it occurs at a peak time. The maintenance programme consists of three strands. The first of these is a daily inspection which must take place each day before the roller coaster enters into public use. As a minimum, one complete ride cycle must take place in addition to a thorough inspection of all brakes, safety barriers, safety harnesses, pins and other critical aspects of the ride. This should be a thorough check and if there is any doubt about the good running of any part the ride must not be opened. The next part of the regime is the periodic inspection. This will be conducted once every four weeks, at a time of the week when the roller coaster is not heavily used so as to minimise disruption for users. This is a more thorough check than the daily check and involves checking the ride all over in minute detail for any potential problems. This check will always be conducted by a highly qualified individual following closely all procedures specified by manufacturers. Finally, an annual inspection of the entire ride will be conducted by an external inspector. This will be arranged with the Amusement Device Safety Council who operate the Amusement Device Inspection Scheme (ADIPS). This scheme registers inspectors as competent to perform an annual inspection of a ride. We will ensure that an ADIPS registered inspector has unfettered access to the ride as required and will implement any recommendations arising as a result of inspection before the roller coaster is reopened to the public. In order to minimise disruption, the annual inspection will take place over the winter months when the roller coaster is closed to the public. 1 nd HSE, Fairgrounds and amusement parks: Guidance on safe practice, 2 edition, 2007, HSE. Edward Jamie McDonald Page 122 7.3: Legislation As the owner of a roller coaster there is a legal obligation towards safety under the Health and Safety at Work etc Act 1974 (HSW Act). There is a duty to maintain the ride in a safe condition as well as operate it safely. Under the terms of the Act this requirement extends to the safety of both employees and members of the public whether or not they are using the ride. It is therefore extremely important that safety procedures are implemented and followed correctly. The HSE has produced a document “Fairgrounds and amusement parks: Guidance on safe practice” which attempts to aid ride owners to comply with the law. Whilst the document is not legally binding the expectation is that if it is followed then that will be sufficient to comply with the HSW Act. It was therefore decided to follow the guidance in full throughout the design, build and operational life of our roller coaster. An additional legal requirement is for the roller coaster to comply with standards set out by the European Committee for Standardisation (CEN). The standard which applies to our roller coaster is EN13814:2004 “Fairground Amusement Park Machinery”. The ride will also demonstrate best practice by complying with certain voluntary standards. These include ASTM International’s F-24 standard “Fairground amusement park machinery and structures – safety” and membership of the International Association of Amusement Parks and Attractions which has safety regulations. To ensure that these standards are being met the detailed design and construction of the roller coaster will take place in partnership with companies with a proven track record of working within these standards which will be required to be demonstrated as part of the tender process. One crucial element of the standards which is sufficiently overarching that it has been necessary to take account of it during the outline design is the maximum accelerations that can be applied to riders during the ride. These are measured as G-forces in ‘Gs’ with 1G equivalent to 10ms-2 of acceleration. The maximum permitted positive vertical G-force is 6G, negative vertical is 2G and lateral is 1.8G. However forces close to these maxima are generally considered more uncomfortable than exciting for riders so design is limited to 4G positive vertical and 1.5G negative vertical. Lateral acceleration has been minimised as far as possible. In order to make our ride as thrilling as possible G-forces have been kept as high as possible within these limits. Edward Jamie McDonald Page 123 Section Conclusion As can be seen from the risk assessment the risks associated with the roller coaster can be sufficiently mitigated that they are reduced to an acceptable. Further safety enhancements are made by the full and comprehensive maintenance routine that will be in place. This will have economic as well as safety benefits, reducing the amount of down time the ride experiences. Finally, procedures are in place to ensure that the legal obligation to safety is both met and exceeded. Charlie Hill Page 124 8: THEME 8.1: Commercial Oxford is a city typically known for large numbers of educated tourists. Perhaps those after a cultural retreat, or a quiet weekend looking around historic buildings. Perhaps not so well known for those fun-loving, thrill-seeking adventurers who are typically going to embark on a roller coaster. As such, the theme of Launch of the Rings needs to tie together the culture of Oxford, providing a link with the city. The decisions about theme were thus dominated with the reputation of Oxford, and discussion of what Oxford is known for. A Lord of the Rings theme1 was eventually decided. Due to the recent cinematic releases of the Lord of the Rings trilogy, and the upcoming cinematic release of the Hobbit, it was decided that this theme is relevant to our target audience. The success of the films continues the long running success of the books, leading the belief that the Lord of the Rings theme has longevity, even after the initial film excitement has died down. The link with Oxford is somewhat more subtle. The ride would play on Tolkien2, potentially having part of the themed indoor Figure 8.1.1: Lord of the Rings theme section, moving out of the former Merton Professor of English’s study, and into the world which he created. The Tolkien Oxford link is relevant in the city, with the “Eagle and Child” pub celebrating its frequenter through plaques and advertising. Reference is also made to Tolkien on many of the guided tours, both bus and foot that occur in the city. Only offering a small roller coaster, Launch of the Rings would not expect to attain the sole rights for a Lord of the Rings based roller coaster. Aside of this, rumours have circulated that Universal Studios, Florida, are planning their own Lord of the Rings attraction 3. Theme parks are generally built by the studios owning the rights to films, therefore there is little precedent for licensing, however, a franchise where 2% of the ride profits were payable to Warner, who currently own the film rights, seems likely. This figure has been used in all subsequent calculations. 1 Image shown courtesy of http://www.picgifs.com/wallpapers/lord-of-the-rings/ Tolkein information courtesy of http://en.wikipedia.org/wiki/Tolkien 3 http://blog.moviefone.com/2010/08/17/universal-considering-a-lord-of-the-rings-theme-park - accessed February 2012 2 William Hancock Page 125 8.2: Implementation The main place in which the roller coaster will be themed is the indoor section of the ride. The indoor section has a slow start to build the anticipation of the ride. This will be increased by the presence of characters and other related models. Figure 8.2.1 shows a map of the indoor section. The ride experience starts during the queue for the ride. Throughout the queue Reception Area Photo Desk Lord of the Rings based activities will be displayed on the walls. A few examples are quizzes and interesting facts and stories from the book. Situated at intervals along the queuing Queuing area Loading platform area will be small games consoles built into televisions. The cost of games consoles has dramatically decreased over the Launch Figure 8.2.1: Map of indoor section of ride past few years so this is economically viable. The system for queuing is novel. To allow customers to use and enjoy the activities each customer will be given a ticket with a number and time written on it. On a busy day they will be allocated a slot and have to attend at their assigned time. It will allow the customers an opportunity to enjoy Oxpens Meadow and the other facilities whilst waiting to go on the ride. There will be a small amount of waiting time to build up the suspense of the ride. The design of the ticket received by the customers is unique. It can be folded round and attached to itself to form a cardboard ring which the customer can wear. This will act as a memento and also advertising to others. Figure 8.2.2: An example ticket that can form a model ring There will be small details which will all add up to link into the theme. For example, each of the seats in the cart will be named after protagonists from the book. One cart will have each of the four hobbits and another with the other characters from the Fellowship of the Ring. During the indoor section there will be an animation of Gandalf talking directly to the riders warning them of the perils of their journey with the ring ahead. This again will build up excitement and anticipation. William Hancock Page 126 As the riders are on their back much of the animation will be projected on to the ceiling. One example is from existing roller coasters such as Saw at Thorpe Park. Here riders are passed close to a spinning saw, giving the impression they will ride into it, before turning away at the last minute. This gives a different type of adrenaline rush. A similar design will be used on the corner of the indoor section where a ‘scary’ looking model orc swings an axe at the riders but the track curves round to the side so missing the riders. The indoor section will be in the dark with lights illuminating different parts of the themed section. There will also be loud speakers to create a full Figure 8.2.3: Example Orc atmosphere and almost disorientate the riders. There is a famous poem in Tolkien’s ‘Lord of the Rings’; ‘One ring to rule them all, one ring to find them, one ring to bring them all and in the darkness bind them.’ This will be read out during the pause before the launch. The carts will then be launched out of the indoor section through five large golden rings straight into the loop, as shown in figure 8.2.4. This change from dark into the light will have the effect of disorientating the riders, enhancing the experience when travelling around the loop. Figure 8.2.4: Launch through five rings Situated at the end of the first loop will be an automatic camera which will take a photo of the riders as they pass along the track. This will be available to buy at the desk shown in figure 8.2.1, mounted on a Lord of the Rings background as a souvenir of their trip. Underneath the ride, there is space in part of the meadow nearest the building. This will be divided into portions which businesses can hire out to situate mini stalls, adding another source of revenue for the rollercoaster. Typical stalls could include balloon vendors, food merchants or fairground games. These could be linked to Lord of the Rings as well. Lord of the Rings was published in 1954 and has maintained its popularity since then. The indoor section can be refurbished if the theme becomes outdated or a newer style is deemed more appropriate. This allows the roller coaster to keep up to date and remain popular. 3D technology has recently become commonly used in cinemas. This could be adapted for use during the ride to increase the overall experience even more. Max Jackson Page 127 8.3: Ring Location It has been decided that a large-scale model of the ring used in the film should be utilized to strongly highlight the theme of the ride to potential customers and draw them from afar. If the public were to travel to the site in order to look at the impressive gold ring, it is very likely that they would pay for a ride. In light of this, several possible options were explored for the placement of the ring. Firstly a large ring could be placed in either the loop or the helix. These two work particularly well because of the geometry of the elements, especially the circular 540°helix turn which completely encircles the ring at a more or less constant distance from it. Figure 8.3.1: Ring in Helix Turn The ring appears to be a part of the ride and looks completely at home in these positions. A large ring atop the cobra roll was also considered. Although it doesn’t possess quite the same level of tessellation as the previous two examples, having the ring at the highest point of the ride will mean that it would be visible from further Figure 8.3.2: Ring in Loop away, with the possibility of drawing in yet more customers. Next a slightly smaller ring in the inside section of the track was considered. This section of the track is vitally important in enhancing the theme of the ride and building anticipation for the lunch. It will already Figure 8.3.3: Ring in Cobra Roll contain many props and so the ring would fit in rather well. Furthermore as the passengers are on their backs and performing a banked turn around the ring, they will be able to look in some detail at the script on the ring which reads "One Ring to rule Max Jackson Page 128 them all, One Ring to find them, One Ring to bring them all, and in the darkness bind them." in the ‘Black Speech’ script4. A final option was having 5 consecutive rings, through which the riders are launched. As they are thrusted from the dark indoor section of the track into the bright outdoors, the 5 rings (which symbolise the ‘5 rings’ from the books , will enhance the feeling of speed and acceleration. In the end it was agreed that a combination of Figure 8.3.4: Ring in Indoor Banked Turn two of the above ideas would be best, namely the 5 rings at launch and the helix ring. Combining these two fits well with the books, where the 5 rings and in particular the ‘One ring to rule them all’ feature. Furthermore both of these options are very pleasing to look at, while also improving the ride as a whole for the passengers. Figure 8.3.5: Five Rings Around Launch 8.4: Building Design Three options were explored for the design of the building to be used to house the indoor section of track. The purpose of these designs is to enhance the theme of the ride, possibly transporting riders to the scene of the film before they experience the thrill of the ride, whilst complimenting unobtrusively the views associated with Oxford. Good, well thought out scenery has the potential to draw in customers, and keep them coming back in just the same manner as Figure 8.4.1: ‘Ruins of Osgiliath’ Building Design 4 www.mordorlife.tripod.com accessed 4/2012 Max Jackson Page 129 an exciting ride. In the first design, the building will be designed to resemble one of the castles present in the film, namely the ‘Ruins of Osgiliath 5’. There will be large stone archways for the cars to enter and to leave the indoor section, with the possibility of having large, automated wooden doors. There will be pillars either side of the arches, and recesses all along the outside of the building to resemble windows from that time. The building itself will be built out of old grey stone to resemble the ruins and will be made to look aged and cracked with statues all around. This design would fit well with the feel of Oxford, complimenting the skyline, without drawing too much attention from it. The second design is simpler; here the building is proposed to resemble one of the caves or tunnels that feature heavily in the film . The whole building will be made to appear like rock, with the entrance and exit in the form of old crumbling caves. The natural look of this design Figure 8.4.2: Cave Building Design means that it will fit in well with the park within which it is situated, whilst giving passengers a view of what the protagonist in the book was seeing himself. However the large amorphous shape is not particularly aesthetically pleasing and may not be to everybody’s taste. For the final design, the building will have the text from the outside of the ‘One Ring’ along it’s circumference, completely encircling the building. It also features a billboard on the Osney Road side, with the aim of attracting even more passing customers. This is the simplest and cheapest way of enclosing the indoor section, as the regular, square sections used to make it Figure 8.4.3: ‘Black Speech’ Text Building Design 5 www.tolkeingateway.net accessed 4/2012 Max Jackson Page 130 can be manufactured and assembled with ease. However this design does not add a great deal to the ride, and in fact the boxy nature and garish advertising present in this design could be enough to cheapen and turn people away from the ride. Overall it has been decided that the ‘Ruins of Osgiliath’ design will be used, as this not only fits in well with both the theme and Oxford itself, but also looks impressive and adds a sense of class to the ride. Using effective props, along with this elegant design, a story can be told to riders as they are queuing, allowing them to be transported to this parallel word to experience first-hand what it would be like to be in the Lord of the Rings book. Below is a more detailed design of what the southern face of the building would look like6. Figure 8.4.4 More Detailed Image of ‘Ruins of Osgiliath’ building design SECTION CONCLUSION A Lord of the Rings theme will be used for the roller coaster, which plays on the ties between Tolkein and Oxford itself, as well as utilising the upcoming release of two Hobbit films. The theme will be implemented in several ways to ensure it is not lost on the passengers. 6 Image designed using parts from http://forge-quest.blogspot.co.uk accessed 4/2012 Charlie Hill Page 131 9: COMMERCIAL Having designed and developed a sustainable, low environmental impact roller coaster, this section considers the commercial feasibility of our solution. 9.1: View Analysis Judging by the large amount of tourists walking around Oxford in summer, with cameras, and touring colleges, one of Oxford’s appeals is the visual appeal of the old buildings. Launch of the Rings will capitalise on this, by offering customers an all new view over the city; where one can see many of the picturesque landmarks from above. Our site, being located just to the South West of the city centre provides potential for good views. To analyse these views, it was assumed that Oxford city centre is largely flat. Cross sections towards the city centre where then considered at intervals of every 15 . A representation of the lines along which the cross sections were taken is given Figure 9.1.1: Cross sections of city for view analysis in figure 9.1.1. The diagram also shows a personal classification of the ugly (red), and attractive (green) parts of the city, based on the author’s opinion. The diagram shows how the roller coaster is surrounded by quite an ugly part of the city. Thus, a view worth seeing would require the roller coaster to overlook all of its immediate surroundings, and be tall enough to see into the centre of the city. Due to the 18m height restriction on the roller coaster, and the distance to the buildings shown, a roller coaster offering views of the city became unfeasible, and it was realised that such a roller coaster could not be built. Figure 9.1.2: An example height profile along a cross section line shown above Charlie Hill Page 132 9.2: USPs Launch of the Rings offers customers a thrilling roller coaster experience, in the middle of a historic city. Our marketing campaigns will be driven according to our unique selling points (USPs). Competitive analysis has proven that the USPs of a roller coaster typically fall into four categories. Due to the engineering experience of the design team, Launch of the Rings should present an engineering triumph by being something new, exciting and different. The engineering triumphs of Launch of the Rings have been discussed at length throughout this project. Height and size constraints limited the scope of our ambitions, although, through use of a launched ride, and a fast, twisty outdoor section, an exciting experience has been created. With the maximum height of the roller coaster at 18m, and maximum speed of 45mph, the roller coaster is capable of keeping up with, and providing as thrilling an experience as other rides out there. The second USP considered was the view. However, as discussed in section 9.1 above, views of picturesque Oxford were not attainable from our roller coaster. The Lord of the Rings theme we have opted for presents a third USP. As discussed in section 8, the link between Oxford and Tolkien, Lord of the Rings creator, is exploited, in creating a thrilling themed ride. By use of a slow, themed indoor section of the track, we hope to bring Lord of the Rings to life. Pressure from other theme parks, however, may lead to this selling point not being unique for long. The final USP is location. Rather than having to search for customers, we hope to deliver an additional service to a location where potential customers are plentiful. The city centre location of a roller coaster is, in itself, pretty unique, however, building a roller coaster in the centre of a city with such architecture and planning protection should ensure that our roller coaster would be the only roller coaster built in Oxford, giving us a monopoly over the market, and ensuring unique status. Launch of the Rings has opted to combine our world class location, a relevant theme, and engineering triumph to create a thrilling and exciting experience that presents value for money for customers. The USPs of Launch of the Rings need to be particularly strong, as, unlike most theme parks, Launch of the Rings does not have the draw of multiple rides in one location. Charlie Hill Page 133 9.3: Economics Model The feasibility of Launch of the Rings depends on the return to investment it creates. An economic model has been created to balance flows of money and to prove the profitability of the roller coaster. The model runs through a balance sheet for every year of the roller coaster’s predicted lifespan, allowing for inflation, capital interest, changing energy efficiencies and rates, and can produce an estimated balance sheet for every year of the roller coaster. Modelled into the equation, include average annual income (section 9.4-5) from the ride, and estimated costs, both continuous and single payment (section 9.6). The model is then drawn together in section 9.7, proving the profitability of the roller coaster. The model draws together ideas discussed in Varian, 20101, and Mankiw and Taylor, 20072. 9.4: Ticket Prices Oxford, known internationally for being a university city, has a permanent population of 150,000 people, including 40,000 students in the two universities. Due to the high number of students, the population turnover is the highest of any city or town in England3. Coupled with Oxford’s 9 million15 tourists per year, the 7th most popularly visited city in the UK4, Oxford gives a large, constantly changing audience at which to market a roller coaster. In line with most other theme parks, Launch of the Rings will offer tickets in four different categories. Adult tickets as standard, that cover any category of person not given below. Student tickets will cover all riders up to the age of 16, and those over the age of 16, who are able to show a valid student ID. Concessionary tickets will be available for all over the age of 65. Family tickets will provide discounted entry for families, where a family qualifies as 2 adults, and 2 children. There will also be a discount for buying tickets in advance, whether online, or through any associated sales point in Oxford. 1 th Introductory Microeconomics: Hal Varian 2010. 8 edition th Macroeconomics: Taylor and Mankiw 2007. 7 edition. 3 Figures courtesy of http://www.oxford.gov.uk/PageRender/decC/Population_statistics_occw.htm - accessed February 2012 4 http://www.mediafiles.thedms.co.uk/Publication/OSOX/cms/pdf/Oxford_Tourism_Study_FINAL_REPORT_V2_201008.PDF - accessed February 2012 2 Charlie Hill Page 134 According to the Oxford Tourism study , 10% of visitors to the city stay overnight, with 50% of 16 these visitors being overseas tourists. With tourism volumes having grown 5 - 10% over the past decade, the tourism market in Oxford shows no sign of slowing down. The typical demographic for a roller coaster ranges between 14 and early 40s. The 2007 Oxford visitor survey5 shows that the majority of the visitors to the town are aged between 55 - 64, this band making up 21% of the entire visiting population. The report also shows that 37% of visitors fall into the key 16 - 44 age bracket we wish to target. With 64% of these visitors visiting for a holiday, and an average daily expenditure per visitor of about £40.00, the market place for new tourism activities seems prosperous. Knowing that leisure is a normal good6, meaning that as price decreases a population will demand more of it, we might assume a typical Cobbs-Douglas type demand curve (figure 9.4.1) between ticket price, and the uptake of tickets. This suggests that most people’s willingness to pay Figure 9.4.1: Relationship between ticket price, and quantity of tickets sold is lumped around one point, which seems in line with common observation. The Cobbs-Douglas demand curve represents: ( ) Where are constants that can be changed to manipulate the demand function to the required position. The demand curve fails in the extremes as and . As such the demand curves will be fitted to known data points, and the curves should then not be used for extrapolation outside of these data points. This demand curve will need to be calculated and parameterised individually for each of the customer groups. It is assumed that customer groups have a different distribution of willingness to pay, thus resulting in discounts. By charging individual 5 http://www.mediafiles.thedms.co.uk/Publication/OS-OX/cms/pdf/Oxfordshire%20Visitor%20Survey%202007.pdf accessed February 2012 6 Geographical abstracts: Human geography, volume 15, issues 1 - 4 Charlie Hill Page 135 groups closer to their willingness to pay, one is acting as a discriminating monopolist, and better maximising one’s profit13. The other half of the problem is supply. For a roller coaster, the additional outlay in running the ride, as opposed to not running the ride, is small. The only real costs to be considered are the power used in the launching mechanism. All other costs, ride, staff, even largely maintenance are fixed. As such, we can provide any quantity of rides (within reason) at a fixed price. The model starts to fall apart when changes to the track, i.e. extra loading space, need to be incorporated due to overloading, but in a region near to the design capacity, the supply model is largely linear, and is shown here against the demand Figure 9.4.2: Supply and Demand curve for the roller coaster curve, as a horizontal line (figure 9.4.2). For the roller coaster operator, there is one variable: the price. This can be shifted vertically to maximise profit. The profit function is given as: ( ) We can substitute in the Cobbs-Douglas formula for p, and argue that here ( ) , where k is a constant, leaving our maximisation problem as: Solving by taking the first derivative and equating to zero, we find: ( ) For general n, the solution to this is to make the price infinitely high. This comes as a result of limitations of the Cobbs-Douglas model. However, the message from this analysis is that greater prices will lead to greater profit, therefore, prices should be sufficiently low as to cause a constant throughput, but as high as possible within that bracket. We should also consider that by setting the price, the ride operator indirectly sets the quantity of tickets sold. This quantity can be calculated from the equilibrium point where the supply Charlie Hill Page 136 and demand curves cross. A price level should be chosen that equilibrates a quantity of passengers that is possible on our ride. The price levels are to be chosen by fitting sample data to our curves. From this we can calculate the required values of the constants: . Sample data from each group should be used to establish a suitable range of prices compared to tickets sold. From this, the quantity of visitors, and subsequent throughput can be calculated. It has been determined that a thrilling, high speed roller coaster does not have a large attraction for the concession price group. As such, the uptake of concession tickets will be negligibly small, that is 0% of the riders on the roller coaster. To allow for any elderly individual who does want to ride the roller coaster, and is in a suitable state of health to do so, a discount rate equal to that for students will be implemented. The student population of Oxford is 40,000, which, assuming an average degree length of 3.5 years, equates to a student turnover of about 11,500 per year. That is, 11,500 new customers moving into the area of the roller coaster. Those students can be classified into three groups: those that will never go on the roller Figure 9.4.3: Quantity of student tickets sold by price coaster; those that will go once; and those that will go multiple times. Observation and extrapolation show us that 40% will fall into the first category. They will have no demand for our service, regardless of the price. Splitting the remaining 60% of the population between the other groups, some plausible data points can be considered. Taking the students who will want to ride once (20% of turnover = 2300 students per year), uptake is likely to be: Price £3.00 £6.00 Uptake 95% 40% Number 2185 920 Charlie Hill Page 137 Substituting these points into the Cobb-Douglas expression above, calculated values of are . This particular function is shown in figure 9.4.3. Also shown in figure 9.4.3, is the revenue created from ticket sales. This revenue is the ticket price multiplied by the quantity of tickets, as expected, but here it is easy to see how the area of the rectangle, representing the profit made, changes with price. As the roller coaster has zero variable cost, this rectangle also represents the marginal profits for each extra seat sold, that is to say, that above the breakeven line, 100% of revenue becomes profit. Also of note is the length of the demand curve. As stated above, the model does not work outside of the data points from which it was parameterised. These data points were at £3.00 and £6.00, and thus the curve has only been drawn for this range of values. Similar analysis for multiple riders, however using the number of rides each rider would take at each price level, per year, provides figures for the multiple student rider group described above. The remaining 40% of the student population must fall into this group; that is 16,000 students. If a £3.00 ticket would lead to 5 rides per year, per student, and a £6.00 ticket would lead to 2 rides per year, per student, we can again characterise the demand with . Total student demand will be the superposition of the above groups, that is: ( ) In practise, this number is likely to be substantially more than that calculated here, due to visiting friends and tourists. As discussed above, maximisation of profits is not realistic, thus by comparing to other similar attractions, and considering prices to give us a good throughput, we can use this model to calculate that at £4.00 a ticket, we should sell 11,500 student tickets per year. For the adult group 31.5% of tourists lie in the interest range of 20 - 45, that is 2.9 million people. Due to the magnitude difference between tourism and residents, we will chose to incorporate residents in this figure of 2.9 million. The same analysis as above leads us to conclude that at £4.75 per ticket, the roller coaster would see annual adult throughput of 1 million people per year. The Oxford visitor survey16 states that 5% of visitors visited in a group of at least 2 adults and 2 children - a family group for Launch of the Rings. That is 500,000 people. By the above Charlie Hill Page 138 technique of parameterising functions, and also by considering discount rates at competitive theme parks, a conclusion was drawn to charge family tickets at £3.75 per person, with an uptake of 375,000 people. Finally, we will assume a realism factor of about 50%. The above figures assume that large amounts of people want to visit the roller coaster, and this assumption seems a little ambitious. By halving the expected visitor numbers, the figures should be nearer to those that we could reasonably expect. After analysing the competition, Launch of the Rings will also offer a pre-purchase discount, across all tickets of 12%. Expected uptake of pre-purchase tickets is about 60% of the total population, and these tickets would be available to buy at many of the tourism centres of Oxford, including tours, and tickets available for purchase online Figure 9.4.4 summarises the key points. The total annual throughput of the roller coaster is 693,500, with total annual turnover of £2.3 million. Our main target will be adults, and the majority of these will Table 9.4.4: Groups, ticket prices and quantities of tickets sold come from tourism. This suggests that we should work with Oxford tourism and tourist companies in the town to market our attraction. Prices will also rise annually, in line with inflation, thus the present day value of the turnover should remain constant over time. As Launch of the Rings is an additional attraction to those already in the area, the throughput should not decrease with time, as it might if the roller coaster were used as an attraction on its own. This leads to the conclusion that Oxford has a sufficient population to support our roller coaster, without having to market for individuals to travel to Oxford just for the roller coaster. This proves the feasibility of our proposal, but is also in keeping with our aim of utilising the existing customer base in the area, as opposed to bringing in a completely new set of customers. Charlie Hill Page 139 9.5: Commercial Throughput The visitor numbers calculated for Launch of the Rings need to be subjected to other considerations. To pass this number of visitors through, the roller coaster will operate for 10 hours a day, 7 days a week. In line with many other theme parks, and what we perceive to be the peak tourism times for Oxford, the ride will operate from the beginning of February, to the end of November, with a two month down period over winter. This means average throughput will be 250 people per hour, or, with carts of four people, about 1 ride every minute. In line with general tourism trends, and observations at other theme parks, throughput is not expected to be uniform throughout the year. Instead, we might expect a quadratic variation as the year passes. Figure 9.5.1 shows our maximum throughput, indicating when the ride is closed, in green, alongside the seasonal demand, in blue. The shaded area shows the number of customers Figure 9.5.1: Seasonal Variation in throughput, we can serve, and this number has been calculated at theoretical and actual 620,000. We aim to be able to accommodate peak summer demand and, as shown here, actual throughput is contained within the ride maximum. Here, demand has been modelled quadratically, with winter demand being 40% of maximum demand. To maintain this level of throughput, the ride will also need to be appropriately scary. If the ride is not sufficiently scary, then it will not be exciting enough to draw in customers. If the ride is too scary, then it will scare potential customers off. This has been taken into consideration when developing our ride. Another concern is that visitors will not arrive uniformly throughout the day. During peak periods visitors will have to queue for the ride. Tickets will be sold with a time slot at which visitors can start queuing. This means that visitors will be enjoying the park instead of standing in a queue waiting. However, allowing 0.5m of space for every person to queue, if people start queuing 10 minutes before their allocated time, i.e. 40 people, room for queuing of length 20m needs to be made available leading into the station for the roller coaster. Charlie Hill Page 140 9.6: Costs The other side of the balance sheet for the roller coaster is made up of outgoings. These fall into two categories. Initial start-up costs, such as the construction of the roller coaster, and getting underway, and continuous running costs. By definition, initial costs are only paid once, continuous costs have to be accounted for on an annual basis. Annual costs run to a present day value of about £1 million, as summarised in table 9.6.1. A large part of the budget will be spent on advertising. This would include local television advertising during the prime season at £225,000, alongside Oxford tourism advertising, and internet Table 9.6.1: Continuous costs advertising, costing about another £250,000. Ride staff will be paid hourly, and this includes an on duty ride manager, and maintenance officer being paid £15 per hour, alongside 3 ticket sellers, a shop assistant and 2 ride operators, each on £7 per hour. More than this number of employees will be on the books, however, this quantity of staff will have to be on duty at any given time. The ride manager and maintenance manager will not always be on site, and will be paid a full time salary, equivalent to 37.5 hours per week, at the rate mentioned above. Multiplying part-time workers by the 3000 hours per year worked, and summing over all employees gives a wage budget of £154,000 per year. To allow for taxes, provision of cover etc., another £100,000 has been added onto the budget. Business rates have been calculated from government websites, and have been shown here7. Maintenance includes an annual maintenance budget for the maintenance staff of £50,000 per year to cover the ride and buildings. General site and grounds maintenance, e.g. keeping the site clean, is then incorporated at £5,000 a year, and the responsibility will be leased to an external contractor. Insurances, covering public liability8, employers liability, and general site cover have also been incorporated. Energy costs will vary over time, due to a combination in predicted energy 7 8 http://www.businesslink.gov.uk - Accessed March 2012. http://www.voa.gov.uk - Accessed March 2012. http://www.martininsurancebrokers.com - Accessed March 2012 Charlie Hill Page 141 price increases above inflation, and also decreasing renewable energy returns from the photovoltaic cells installed at the site. Due to this, energy bills in year 1 are expected to be in the region of £5,000, whereas in year 40 they are expected to be at a present value of £50,000. To reflect this, an average present value figure has been used of £26,000. This results in ride running costs of just under a million pounds per year. Initial costs have been much harder to allow for. A table breaking down the costs of the construction work is given here, see figure 9.6.2, and the total cost of the roller coaster is about seven million pounds. Finance for the project will probably come from a variety of places. The investor who initiates the project will probably provide funding, alongside bank loans, and loans from tourism companies. As such, the cost of the roller coaster will be written in the balance Table 9.6.2: Construction costs of the roller coaster sheets, as it would be for tax purposes. That is to say, in the first year of running, 40% of the cost of the roller coaster will be written off. For the next 20 years between 25 and 50% of the ride will be written off each year, before the whole cost of the ride is Price written off in year 20. The aim is to reflect the differing finance sources, and thus interest rates payable. Figure 9.6.3 shows the breakdown of these costs with time. Time Figure 9.6.3: Depreciation of construction costs of the roller coaster Charlie Hill Page 142 9.7: Spreadsheet Having considered both sides of the balance sheet, let us now tie together the financial situation. The spread sheet9 developed for Launch of the Rings creates a forecasted balance sheet for every year of operation. This balance sheet then calculates annual, and cumulative, profit. The inputs to the model are highlighted in green in figure 9.7.1, and provide complete control over all of the factors of the model. Net annual profit, is calculated from: Profit dependant sums can then be calculated. First, as noted in section 8.1, the Table 9.7.1: Inputs and Outputs of spreadsheet franchising of the theme is deducted at 2% of profits. If no profit is made, then no franchising charge ensues. VAT is then calculated and removed from earnings in all years when profit is positive. When profit is negative, VAT can be offset against purchases, and no VAT is payable to the government. Here, VAT has been charged at the current rate of 20%. Interest is then calculated on the accounts of the roller coaster. This model allows a separate interest rate to be specified for loans, to that of savings. Figures of 1% interest on savings and 6% interest on loans reflect the current conditions, and are necessarily cautious, and as such have been used in the model. Interest is added to the model for the account balance of the previous year. The model also reflects inflation. It has been taken here at a typical 3% per annum rate. Inflation has been applied uniformly across all factors, apart from energy, where a higher inflation 9 Spreadsheet available at http://www.adhill.info/CharlieHill/Oxford/ORC.xlsx Charlie Hill Page 143 rate of about 6% has been applied, in accordance with section 9.6. To see the effects of these variables, the model also provides the option not to run the interest and inflation models. From the above, the gross profit is then calculated for every year of the 40 year lifecycle. The profit is calculated as the future value of the profit, and the present day value of the profit can be calculated simply from: ( Where ) is the present value of the money, the future value of the money, the inflation rate, and , the number of years in the future being calculated. The model then validates form the input ride figures the throughput of the ride each year, which is given as 622,000. This is in line with our expectations calculated in section 8.8, allowing for the two month winter period during which the ride would shut. Figure 9.7.1 also shows the key outputs from the model, shown here in yellow. The first is the number of years until the ride breaks even. The cumulative profit chart in figure 9.7.2 shows the amount of money Launch of the Rings would bank given the above assumptions, writing off the construction debt over a 20 year period, and also given that all profits stayed in the account until the end. This chart shows the breakeven point as being in the 5th year of the roller coaster. This chart has been calculated in future value of money, hence the quadratic nature, particularly over the latter half of the roller coaster’s life span. The reason for the initial negative slope is the high Price Years Figure 9.7.2: Cumulative Profit Charlie Hill Page 144 value of repayments made against the construction costs of the roller coaster. Given, as is the case here, that income is constant year on year, then we can see that the minimum in the graph must correspond to the point where expenditure is equal to income, that is to say the repayment value is lower than income less continuous expenditure. Figure 9.7.2 also explains a number of the other findings from figure 9.7.1. The largest deficit for Launch of the Rings has been calculated at -£1.4 million. This corresponds to the minimum mentioned above, and represents the largest loan we would require access to, to keep the roller coaster running. However, if all of the roller coaster had to be written off against a loan in year 0, the largest deficit would be much greater, at -£5.5 million at the end of the first year. In this case the roller coaster would make a year on year profit in every year of running. We can also read from this graph the life time profit. For Launch of the Rings, this has a future value of £79.0 million, which equates to a present value of £24.2 million. This represents a 220% return on investment over the life time of the roller coaster. Compared to alternative investments, this makes Launch of the Rings risky, with relatively low returns, yet the project is definitely feasible. The project is also set to increase tourism in Oxford, and provide a further attraction for visitors, increasing the feasibility of the roller coaster from a wider point of view. This analysis does not include the future value of the land, the buildings or any part of the roller coaster that may be sold on. Figure 9.7.3: Year on year roller coaster profit Charlie Hill Page 145 The final output of the model is the first year in which the roller coaster makes year on year profit. This occurs in year 2, as shown by the x-axis crossing in figure 9.7.3. This also corresponds to the minimum in figure 9.7.2, which, as we would expect, represents the point at which debits become greater than credits. Profitability in the 2nd year of operation is promising considering how the roller coaster initial costs are repaid. Figure 9.7.3 shows the profit made on the roller coaster in any given year. A loss is made in year 1, due to the high repayments made on the roller coaster. However, as the repayments decrease each year, 25% of remaining value is repaid, the roller coaster makes a profit. This gives rise to the curve between years 2 and 9. Profits decrease in year 10, as the roller coaster changes from a 25% payback rate to a 50% payback rate. When the entire roller coaster is repaid in year 20, the repayments are sufficiently small (< £600 per annum) that the doubling of payback rate does not affect the profit margin. Launch of the Rings thus provides a £2.5 million per year turnover investment, with average profits of just under £0.5m per year; a roller coaster that should break even within the first 5 years, and then profit in every subsequent year. From a commercial point of view, the roller coaster is financially sound, and a viable investment. As the population turnover figures used have been conservative, it is likely that the profit made from the ride will be greater than that calculated here, and due to the throughput setup mentioned in section 9.5, the ride is capable of handling greater numbers of people if needed. The main commercial hurdle is keeping people interested in the ride, and keep people coming back. A short mention of this has already been given, but we shall now develop this further. 9.8: Long Term Business Plan The commercial feasibility of Launch of the Rings has been based around a 40 year lifecycle. Although there is limited precedent for this, as roller coasters weren’t around in great numbers 40 years ago10, and manufacturing techniques have altered greatly over time, this should not be a problem. To allow for the 40 year lifecycle, the roller coaster has been designed to be durable, and 10 http://www.rcdb.com/ - accessed March 2012 Charlie Hill Page 146 with suitable maintenance as outlined in section 7.2, the ride should be more than capable of lasting this amount of time. However, we cannot guarantee customer interest in our roller coaster for this period, so a number of considerations have had to be made. Primarily, the majority of visitors to Launch of the Rings are in the city as tourists. Current visitor numbers have grown 5 - 10% over the past decade11. As Oxford’s main attraction is its old picturesque colleges, these are unlikely to be lost in the life time of the roller coaster, and with current fascination in history and architecture, it seems unlikely that the interest in the buildings will be lost. As such, it seems likely that the client base for the roller coaster is safe. Another concern may be “the passing of the roller coaster fashion.” However, people have searched for thrills throughout the entire history of mankind, so a roller coaster than can offer an exciting thrill is pretty safe. Of course, as our roller coaster becomes older, and newer, more daring, and technologically challenging roller coasters are built, we will expect to see a decline in visitor numbers. Because Launch of the Rings is not at the forefront of today’s technological marvel, and appeals to visitors more because of its location, Launch of the Rings should be relatively immune to technical surpassing. As our roller coaster uses renewable energy, it is also less at risk of any future energy crisis. This security would enable the roller coaster to keep operating, should the grid ever run short on power. To keep interest in the roller coaster, it is proposed that the theme is changed after 20 years, half the life time of the roller coaster. Although the initial Lord of the Rings theme is currently popular, and should be able to stand time, a revamp of the roller coaster that freshens up the whole experience will be necessary to keep customer interest. The theme will be decided in the future, and the theme should appeal as much to tomorrow’s customers, as today’s theme does today. Launch of the Rings is thus able to stand the test of time. With its unique tourist customer base, the attractions of Oxford are sufficiently great to keep customers at our doorstep, and with 11 http://www.mediafiles.thedms.co.uk/Publication/OSOX/cms/pdf/Oxford_Tourism_Study_FINAL_REPORT_V2_201008.PDF - accessed March 2012 Charlie Hill Page 147 green energy sources we are able to provide a permanent experience for any thrill-seeking adventurers. With a payback time of 4 years, and lifetime profits in the region of £24m, Launch of the Rings represents a unique experience, that co-ordinates the new into a city of culture and architecture. It is predicted that 25 million people will visit Launch of the Rings over its 40 year lifetime, and Launch of the Rings is able to provide every single passenger a safe, exciting and enjoyable experience. 9.9: Conclusions This project set out to build a world class attraction, on a relatively small site in the middle of one of the world’s most renowned cities. Against limitations of height, crowd control, flooding, and noise restrictions, Launch of the Rings has shone through, and promises riders a themed, exciting experience. Whilst not in a traditional theme park, Launch of the Rings looks to use a different kind of great tourist attraction to help provide visitors. When considering the risk of flooding, the team decided to allow the site to continue to flood. Any flood prevention would only make flooding worse somewhere else. To allow for this, all buildings have been designed at the higher points on the site, and the track foundations have been designed to withstand water flooding for small periods of time. The track also remains at a height well above the known flood levels. To reduce noise pollution for local residents, a large building stands along the part of the field nearest the houses. The roller coaster track was also designed such that the exciting twists and turns are as far away from the houses as possible. These features, that may induce screaming, thus have the maximum distance for the noise to be dissipated. The tracks will also be filled with pea gravel such as to minimise the track noise. By utilising the customer base already in town, the roller coaster does not add excessively to the congestion and traffic in town, so minimal transport changes are required. However, a new pedestrian crossing is to be installed, and the site will be signposted, ensuring customers can easily find the site. Charlie Hill Page 148 Site safety has been checked through a bomb risk check, and continued site safety will be ensured through requirements that have been laid out for contractors, and ultimately the risk assessment and safety aspects considered in section 7. Launch of the Rings has also proven its commercial feasibility, with prospective returns of £24m over a 40 year life cycle, alongside an annual turnover of £2.5 million. The roller coaster also helps tourism in Oxford by offering an additional attraction for those in the city. The roller coaster itself has been designed with a slow, themed indoor section, to build excitement, before being launched as a flying roller coaster, one of only a few in the country. The launch will see the carts accelerated to their maximum speed of 45 mph, before the carts undertake a series of rolls and turns. Launch of the Rings is a viable proposition that will bring new life to the city of Oxford, and will provide an exciting new attraction for coming generations of tourists. William Hancock Page 149 10.1: Appendix to 6.8: Noise Pollution Ride A - Rectangular Section support Ride E – Circular support section Ride B, C, and D – Different types of roller coasters The variation seen from the different lines for each roller coaster is due to slight differences in speed and acceleration forces and to different levels of screaming during tests Figure 6.11.1: Roller coaster sound pressure at 15m Figure 6.11.2: Spectra at different car positions Figure 6.11.3: Coaster spectra by scream level Figure 6.11.4: Noise reduction of support beam and rails All graphs shown and conclusions are from a study by inter-noise 2002: The International Congress and Exposition on Noise Control Engineering, Dearborn MI 2002. ‘Residential impact criteria and abatement strategies for roller coaster noise’ C. W Menge, H Miller Miller & Hanson Inc.