gcse resistant materials coursework by nathaniel olson

GCSE RESISTANT MATERIALS

COURSEWORKBy

Nathaniel Olson

Nathaniel Olson GCSE Resistant Materials

The Design BriefBelow is the design brief:

I would be making a Greenpower kit-car. Greenpower is a charitable organisation that runs a series of races in the UK for school-built electric cars. Many schools would like to participate in these races, but lack the basic expertise to built a car from the ground up. This is my target market; a kit-built car for schools that could campaign a car and make modifications, but want a sound base to work from. The car will be largely built from wood, to promote the sustainability and ecological ethos of the Greenpower organisation.


Target AudienceThis would be aimed at secondary schools that want

to be involved in Greenpower, but lack the experience, knowledge and the equipment to do so. Also this would be more attractive to the pupils that come from feeder schools which have been participating in the Goblins. The pupils that are interested in engineering and racing need a kit-car that is competitive, because the current kit-car that is being supplied by Greenpower is uncompetitive in most cases and extremely heavy.

As a fact, there are more Goblins in the South West than any other region.

Task Analysis


MaterialsWood•Organic, non‐ toxic, energy efficient, 100% environmentally friendly, biodegradable, •It’s re-useable, recyclable and renewable in your lifetime. •Wood is tough due to the fibres in the grain but can snap if bent too far.•Strong in compression and very light.•For bending: soak, steam or laminate.•Easy to mark, cut and join. Can be easily shaped.•Join by jointing, gluing, screwing or bolting.

Steel:‐ It’s strong, hard wearing, heavy, malleable, machinable.‐ Can be cast into complicated shapes when heated a high temperatures. ‐ Using heat to bend, roll or shape is called forging.‐ Join together by solder, brazing, welding, bolts or rivets.


What I am going to use for Materials and Finishes

I chose plywood for my project because it comes in broad flat sheets which are very strong, it can be painted or varnished.

It is sustainable because it is made from commercially forested wood and has little waste. It is also biogradeable.

I chose to use a solvent-based paint to protect the chassis. This isn’t a sustainable finish as it forces the car to be unrecyclable and have to go straight to landfill sites. However because it should protect the car so well that it wouldn’t need to be replaced for a long time.


JointsThe joint on the left is a good permanent effective joint. Once it’s glued with PVA or other glue, it cannot break easily. This joint is designed for strength.

The joint on the left is an easy to make common woodworking joint that is usually seen in furniture. The strength is not as great as the mortise and tenon joint.

MORTISE AND TENON

CROSS HALVING

BRIDLE

This is a similar joint to the mortise and tenon , except there is an opening at the corner which means that it’s weaker. This can be replicated along the edge to form a structure.


Design Specification

DESIRABLE Low as possible to make it more aerodynamic

Make it narrow as possible to make it more aerodynamic

Structural rigidity (torsional and longitudinal) . This will improve the car’s handling

State-of-the-art steering geometry – to improve handling for new drivers and improve safety

Target weight distribution of 50/50 front to back to improve handling

As most of the car will be made from sheet materials, optimise design to fit on the minimum number of sheets.

To provide the metal components (steering and drivetrain) in a pre-assembled form for schools that lack the ability to weld.

Minimum number of components

MUST Must fit the regulations set by Greenpower (See in two slides)

Be able to fit wide range of people into it.

To be built largely from wood or other sustainable/recyclable materials.

To be designed to take advantage of modern computer controlled manufacturing techniques such CNC routing and waterjet cutting. This will reduce costs, increase manufacturing accuracy, and keep material waste to a minimum.

Will be easily modified by student clubs to their preferences

Have the ability to put a aerodynamic body over it

Be easily repaired after a crash

To provide instructions/documentation that show how the car is assembled, and the design principles behind the car. This allows the school to use the Greenpower car as part of the curriculum.


Greenpower Regulations 1

Batteries T2.6. Batteries must be separated from the driver by a bulkhead, or contained in a

rigid, covered, ventilated box, which must not be able to short circuit battery terminals. Batteries must be located within the bodywork of the vehicle.

Wheel & Track T3.1. Tyres must not be less than 300mm or greater than 520mm in diameter. T3.2. There must be four wheels located as a matching front and matching rear

pair, symmetrically about the centreline of the vehicle. T3.3. The track of the vehicle must not be less than 500mm front or rear. The track

is deemed as the measured width between centres of tyres where they contact the ground. The track may vary front to rear.

T3.4. Tyres must be pneumatic. Centre of Gravity T4.1. The base of the batteries must be at or below 100mm from ground level. A

6mm diameter hole should be drilled through any solid floors adjacent to the batteries to allow height measurement.

T4.2. The driver’s seat including any padding must be at or below 100mm from ground level. A 6mm hole should be drilled through the base of the seat to allow height measurement.



Dimensions

T5.1. The vehicle must not exceed 2800mm in length, 1200mm in width, and 1200mm in height.

T5.2. Ground clearance must not be less than 30mm.

Seating

T6.1. The vehicle will have one seat firmly fixed to the vehicle chassis for the driver who will remain seated at all times whilst racing.

T6.2. The driver must be seated in a conventional feet forward, head to the back position. Drivers may not kneel, sit astride a seat, or lie down in any way such that their chests and head are forward of their waist.

T6.4. There must be a solid floor under the whole of the driver.

T10.4. The vehicle must be fitted with a minimum four fixing point, 50mm width safety harness, with secure fixing points on the roll bar or chassis. Harness shoulder strap fixing points should be close to shoulder height and neck width. Lap straps must be able to be fully tightened before shoulder straps and must fully tighten around the driver’s lap without additional padding in front of the driver.

T10.5. Drivers in low reclined seating positions with a raking angle of less than 45 degrees if the seat has a flat base, or 30 degrees with a front angle of 15 degrees will require a five or six point safety harness.



Bodywork/Chassis T7.1. The vehicle will have bodywork reaching to at least the back of the driver, and at

the sides must always cover the elbows of the driver. Bodywork must not prevent hand signals from being made.

T7.2. There must be a permanent cockpit opening, large enough for the driver to exit the vehicle, without the use of doors or the movement or removal of any panels or coverings.

T7.5. Medium-high density energy absorbing flexible closed cell foam of minimum 25mm thickness must be attached down the cockpit sides to protect a substantial part of the driver’s body, from the floor to the cockpit opening.

T7.6. There must be a structural cage around the driver’s position. External bodywork either side of the driver’s body to a minimum height of 250mm from the seat base, or elbow height if above this level, shall be of rigid material such as aluminium, rigid plastics, carbon fibre, grp or other composites of at least 1.5mm thickness. Plywood needs to be a minimum of 3mm thick. Corroflute type material or foam on its own is not permitted for this area. This bodywork shall be lined internally with foam as per regulation T7.5.

T7.7. There must be a solid bulkhead forward of the driver’s feet in the front of the cockpit, with 100mm depth of medium-high density energy absorbing flexible closed cell foam forward of this bulkhead, to protect the driver from frontal impact.

T7.9. Bodywork must not prevent scrutineers being able to check the integrity of steering linkages, wheel bearings and wheel security. Vehicles must be able to have these items exposed during scrutineering.



Roll Bar

T9.1. The vehicle must have front and rear roll bars offering protection in accordance with the diagrams shown here – the helmeted head of all drivers must be at least 50mm below the line A-B as shown.

T9.2. Roll bars must be firmly secured to the chassis of the vehicle. At least one triangulated brace must be fitted to the rear roll bar. This brace should attach to the chassis of the vehicle at one end, to not more than 200mm from the top of the roll bar at the other, and must be capable of taking forward and rearward loadings.

T9.3. Aluminium or steel roll bars are to be used and must be strong enough and of sufficient dimensions to perform satisfactorily. If in doubt check material suitability with Greenpower before construction. Composite roll bars are not permitted.

Steering

T11.1. Steering systems must have minimal play in joints. Control rod geometry must not be able to over centre.

T11.2. Steering must be by mechanical linkages only.

T11.3. Steering must be by front wheels only.

T11.4. Steering must be operable by hand only.


Inspiration Rotary Racer


Inspiration 2

The back end is what I am interested in. The motor, roll bar and back cross axle are all connected to one piece. This is then bolted to the chassis. This is an easy way of doing the motor, roll bar and back cross axle.

Richard Lander Racing


Inspiration 3 The battery box on the left is a good way of doing it. It is sitting on rails so when the driver gets out, they slide the battery box out and change the batteries. Then they slide it back in. The advantage of this is that there is no opening to get the batteries in and out and this gives it a aerodynamic advantage. But this means that the driver must get out before changing the batteries which means slower pit stop.

Penair School – Raptor Fusion


Inspiration 4

The picture on the right shows the jagged teeth on the bottom of seat. This inserts into the jagged teeth on the left and makes a adjustable seat.

Penair School – Raptor Fusion


Research PlanWhat do I need to find out?

Where do I find it? How would it help me?

What is the average school technology department best equipped to do?

Interview This would tell me what materials I should make it out of.

The main thing that a kit car has to do?

Interview I would need to decide what my car would need to do.

The size of the biggest driver and smallest driver.

Interview It would help me to design the car around a wide range of people.

What form would the club like to recieve their kit-car?

Interview When selling the kit-car, I need to know how they would want to receive the kit-car

How much would they spend on a kit car?

Interview This is to help me to build the car within the parameters

Product Analysis #1

What materials have been used to make it?The materials are super light steel and plywood. We used steel because it’s very strong and versatile. After making the chassis, wood was required to fill the gaps so the driver can sit in it. We also used the wood as a board where we can fit electrical wires and devices.

What processes could be used to make it?The car is made by brazing and welding.

Advantages: You can very easily change the shape or add parts onto it.Can be lightDisadvantages:The high heat of this car can cause a twisted frame or a distortion of the metalWould need equipment that is dangerous and hard to learn. More expensive.

Is the steering any good?This car has a lot more steering than is required in Greenpower racing. The track is very big and has big corners that does not require a great degree of turning. This affects the overall size of the body and chassis. The only use of the extra degree of steering, is navigating around the Greenpower paddock and the pit-lane and getting out of the classroom.

What sort of body shapes work and why? How does that affect the chassis?The body shape is crucial in the performance of the car, so the body needs to be long, thin and low in order for the car to cut through the air efficiently. So the chassis would need to have that ability to be aerodynamic. Unfortunately this car is very wide and high off the ground so immediately the car has a big disadvantage.

Is the positioning of the battery box any good?The battery box is under the seat to help the weight distribution and the handling . If we put the battery at the front of the car, it would make the handling horrible.

Is the positioning of the seat any good?The seat is in the right place except the angle is wrong. The seat is very upright compared to the way it should be. If the seat is flatter, it would improve the aerodynamics, as the driver is lower, therefore we can make the body lower.In order to make the car thin to make it more aerodynamic, the back wheels would need to go behind the driver and the front wheels need to be tuck right next to the legs.

Penryn CollegeHot Ice

Product Analysis #2

What materials have been used to make it?The material is carbon sheets with a honeycomb core in between. This makes a super light, super strong car. This is used for the majority of the chassis. The steering linkages are made of metal. The roll bar is also made of aluminium as it’s required.

What processes could be used to make it?This car is glued together with epoxy resin. This is an harmful substance to use and a parent must have done it away from the school.They would’ve need to use this substance as they are using carbon fibre with as honeycomb core which is a hard material to glue together.The advantages of this is the strong end product that won’t come apart easily. The epoxy resin helps to the make the car lighter as well.The disadvantages of this method is the substance itself that has been used to glue the car together.

Is the steering any good?The car, visually has barely no steering, but it does have enough steering to drive around the track which is the objective. The car has a 11 metres turning circle so it’s more manoeuvrable than a ordinary car. The disadvantages of this is that the car has to be lifted around to get out of class rooms, or tight spaces in the paddock. The small degree of turning helps them to have a smaller body which makes them faster.

What sort of body shapes work and why? How does that affect the chassis?The body is hugely critical in the performance of the car, so the body needs to be long, thin and low in order the car to cut through the car efficiently. So the chassis would need to have that ability to be aerodynamic. This does exactly that, so this is a good car to be aerodynamically good, and this show in the national final where they came 4th out of 75 cars.

Is the positioning of the battery box any good?The battery box is one of the good features of this car because, it’s built on a set of rail, so when the driver gets out, it can slide out. This enables the car to have no hatches on the body which gives them a aerodynamic advantage.

Is the positioning of the seat any good?There is no seat in this car because there is no space for it. This makes it unconformable to drive in. The driver’s position in this car is right, He/she would lying down, with the majority of their body laying on the floor with the head leaning forwards toward the front so he/she can see out of the car.

Penair SchoolRaptor Fusion


Interview with Chris Parker

I had an interview with Chris Parker, a Director at Inspired Cycle Engineering, who mentors the Greenpower club at Penair School. I have worked part-time at I.C.E.

We discussed his ideas for a light, easily built chassis.

First, he talked to me about the construction of the lightweight car. He sees a main structure which has two 4x2 wooden posts on either side of the car. The two cross axles (supplied by ICE) would be attached to the two posts via block of wood attached to posts. Then the roll bar would be bolted to the wooden posts. So the posts are crucial as everything on the car would be attached to them. There are a small number of bulkheads which give the box it’s basic shape, and a sheet of bendable material which wraps around the bottom of the car and attaches to the 4x2’s. The driver would lay inside this folded material.

He talked about the steering, which consists of a similar system to the one that ICE uses on their trikes. It uses a handlebar from a bike attached to a bike stem and that would rotate round a pivot. That would be linked with two track rods, one for each wheel. They would be attached to the edge of the handlebar to the kingpost (rotatable mounts for the wheel). This is a basic steering system that is easy to build. Also on the handlebar, he said you can put two brake lever on it, one for brake and one for turning the motor on/off. The ends of the handlebar could be used for other options.

We also talked about the battery and motor layout. Firstly between the two timber posts at each side, there would be a partition behind the driver, and one at the back of the car. Between the two partitions, there would be pieces of wood spanning the gap and that would be where the batteries and motor would go. The batteries would have a lid which would rotate on a pivot; built into the lid is the contacts. The reason why there aren’t any plugs or wires is to improve reliability and reduce the maintenance on the batteries and car between each race.


Interview with Chris

He talked about the centre of gravity and the weight distribution and how that would improve the handling and the load on each wheel. I need to consider this as it would determine the position of the front wheels. Ideally the weigh on each wheel should be the same – a 50-50 distribution between the 2 axles. It is also important to keep the weight out of the end of the car, as it affects the handling (how quickly the car can turn and how easy it is on it’s tyres) and how the car handles bumps (weight in the ends can cause pitching, which can change the loading on the wheels)

Then he went on about the importance of aerodynamics compared to the importance of weight of the car. The main point that he was trying to make is that the aerodynamics is vital and making a light car is although important, but it doesn’t affect the car in the way that aerodynamics does. He then gave me a sheet which explained the point that he was trying to make. One thing that surprised me the most, is that the 3 times winner Rotary Racers, their car weighs 75 kg which is significantly heavier than the most of the field and this shows the aerodynamics is crucial to doing competitively.

Then we went back to the car and talked about the gearing and what would be the best way of setting it up. He suggested that mounting the cassette on the motor shaft would work with a derailleur shifting the gears around. This reduces the amount of strain put on the system, and reduces the length of chain being used and therefore less to break. Then I suggested a system that I thought that would be used in a lot of car all of the country.


Interview with Chris

Summary Basic car built of 4x2 with attached structures for the steering and the drive system is a good

idea. The bent material forming the main part of the body may not be the best idea. It limits the shape of the car to a cylindrical or conical shape that can be bent from sheet material. It might be better to construct a coffin-like box from several panels that would allow some control over the final shape, especially if the box is going to be the outside skin of the car (aerodynamic shape is very important). I am not sure if the 2 of 4x2’s will make a stiff enough body; stiffness is important to the handling of the car, although a small amount of torsional flexibility helps keep all 4 wheels on the ground in a car with no suspension.

Steering is something that has to be considered with the shape of the body. A steering system that requires a lot of room to build or to operate can increase the size of the car. Raptor Fusion, the Penair Car, uses side sticks in order to reduce the height of the car.

The weight distribution information is important. An easily handled car will be quicker and cause less driver fatigue.

Although aerodynamics is important, keeping the weight low is worth doing. It may not make a big difference, but it does make some difference.

Gearing can help in setting the car up for a particular track, and can help keep the motor running at it’s most efficient point. Putting a cassette on the motor shaft could be a problem, as it is backwards from how normal bicycle parts work, and may require a lot of custom work to get right. It also has to be considered that we have drivers of differing abilities, and a shifting system that is not foolproof stands a good chance of breaking and putting the car out of the race. To finish first, first you have to finish!


First Idea

This chassis is loosely based on a design from Penair School, Their car came 4th in the national championship so I thought it would be a good starting point. This idea uses the space beside the legs to fit the wheels in. This makes the car thinner and more aerodynamic. The motor sits underneath the driver’s seat. This is both a good and bad idea. It’s a good, neat place to put it, but the motor can get very hot while driving and the lack of air flow would burn out the motor. The batteries are behind the driver as it’s most convenience place to put. It make the access to it easier because fast pit stops are necessary in order to do well in the race. Steering is a push and pull system which steers the car. This method is very easy to do and allows a large degree of turning.

I chose this car because it was the most practical and most developed out of my three ideas.


Second Idea

I didn’t get very far with this idea as I struggled to find places to mount the batteries, motor, wheels, roll bar and steering components.

The idea was a simple wooden box would be mounted to two long timber posts. The cross axle would be mounted onto the timber posts. The motor and batteries would be mounted on a partition that hangs from the posts. This idea would end up being too complicated and very tight spaces which would decrease the efficiency of the motor.

The big disadvantage of this car is that it’s not very aerodynamic which is vitally important in in Greenpower racing. There wasn’t any place to put the body on it . I didn’t choose this idea because it wasn’t practical and it has a aerodynamic disadvantage.


Third Idea

This is a modification on the previous idea. The box underneath has been replaced by a Raptor fusion chassis shape. This car has more support for a aerodynamic body. This would work the same way as the previous idea, but would have more space for components.


Final Idea


Complicated Version

After making the basic version of my car, I need to make the proper version of the car with individual pieces all mated together to make a functional car. The left picture shows what my basic idea was turned into and then the right picture shows the near completed car. In the next slides I will be showing the progress of the car and how each element of the car will be made and function.


Slots that builds the car

The each piece of the car would be have slots and tabs that can slot into another piece that has the matching slots and form a solid joint.


Top Piece and the Man The top piece will be added onto the top of car,

making the car stronger and more durable. This is crucial as the car to be lasting for 4+ years. The top will be attaching itself to all of the top edges and will have a cut out for the driver to get in and out.

What happens in a race is that the car travels over 1000 decent size bumps, even on a race track, during the 4 hours of racing. All of the loose parts in the car such as the body can amplify the vibration. This vibration needs to be sustained by the car otherwise it will fall apart after a race or two. In order for my car to be able to fit a normal human being, I need one in my car, so I downloaded a man from the internet and inserted him into my car. Things that I have found out about the car:

The motor layout won’t work

Car is too thin

Car is too long


Batteries and Motor Layout and The Shape of Chassis

There are several advantages from this layout.

Firstly the heat that the motor is emitting can be direct into the batteries making them perform better. This can be done by mounting the motor on an aluminium sheet which would bend over the wall that surrounds the batteries and into the box.

Secondly, the layout helps the weight distribution to be more central which then would help the manoeuvrability and difficulty of steering the car.

Thirdly the motor is neatly tucked away under the seat, which gives up space behind the batteries which then can be used for electrics and the jack shaft that will drive the wheel.

The shape of the chassis has been design to take advantage of a human body’s shape. As the shoulders are a lot wider then the hips and legs, I make the space around the legs a lot thinner. This allows space for the wheels to be there and able to move. This would allow the car to be thinner and have more aerodynamic advantage.


Frontal Support & Wheel Positions Because my car is a effectively a rectangle that can be swayed side to

side to form a parallelogram. This is bad for the car structure and should never happen. After building my first model, I thought it needed more support.

So, I created a wooden triangulated brace that attaches to the base and the sides. The reason for the triangle shape is that it’s a good shape to support the forces the car can subject to during the race, the hole are there for making it lighter. This will improve the stability and structure of car.

The wheels positions are important as they determinate the weight distribution and manoeuvrability of the car. The front wheels are on the edge of the car rather then being inside as they need as much space as possible to rotate to achieve tighter turning circle. This current setup can do a 10 metre turning circle which is more manoeuvrable than a road car.

The back wheels are inboard so the body can go around the wheels and not be interfered by them. This is designed to be more aerodynamic.


Cross Axles and Roll Bar + Braces The cross axles and plates are the most important parts of

the chassis as the wheels will be bolted on it. Therefore I needed to make it out of steel as they are much stronger then wood but much heavier. Fortunately it is a small component and wouldn’t affect the weight much.

The only logical way that I can think of that allows the cross axle to be attached securely to the wooden chassis was to weld a steel plate onto the cross axle. Then I could bolt the whole component to the chassis. This wouldn’t need much skill to make and it’s easy to do.

The roll bar will be a 1 inch tubing bent in shape and welded to two plates which then would be bolted through the base of the chassis and another plate underneath to ensure that the bolts don’t rip through the floor. To ensure that the roll bar will be in the right position when putted into the car, I have made a jig that you can bolt the plates to and then weld the tubing to it.

The braces will be welded to the roll bar at one end and the other end of the ¾” square will be bolted to one of the holes in the axle plate.


Steering Layout and Drivetrain

This was my first idea for the steering. Using aircraft style handle you would push and pull to rotate the wheels. This idea hasn’t been fabricated but is a suitable one. There would be 3 trackrods, one to keep the wheels aligned, this would be done by attaching the two kingposts together. Also there would be one end of another trackrod attached to the kingpost of the one wheel and the handle that is on the same side and would be the same for the other side.

This would be a easy and functional way of doing it. Also it’s very similar to the Penryn’s Greenpower car steering layout.

My original idea for the drive train was that to have the motor in front of the battery box but due to limited space, I had to put the motor behind the battery box. This has a big effect on the weight distribution which affects the steering and the manoeuvrability of the car.

So I chose to use a jack shaft to transfer the power from the motor to the wheel. This is done by a free rolling shaft that has 2 gears on it. The motor will drive the first gear on it and that will transfer to the second gear on the shaft. That gear will then drive the wheel. This is shown in the top picture on the right.


Harness Mounting and Electrics The harness that we are using is a 5 point harness, two

above the shoulder, two next to the hips, one between the legs. This is required as the rules stated that if the seat is less then 30 degrees which in this case is less then a 5/6 point harness is needed.

I used the model man to determine the mounting position.

The harness strip will be weaved through 2 flatbar bolted to the surface. This makes it very rigid and easy to adjust. The shoulder harnesses will be bolted from the battery box and the rest will be bolted to the floor of the car.

The electrics will be mounted near the motor to reduce the amount of energy lost in transferring the power. Also because the motor will be cooled from the top, it will also cool down any hot electrics.

The electric will be almost identical to our school’s car which is simple as it gets, but it will have a motor controller which would a circuit controlling the solid state relay. The picture below shows the layout of the electrics


Changed the Steering and Motor Layout

I have changed the motor and drive train layout as I have concluded that my previous version was too complicated and more liable to break. This has lead to me changing the drive system from a jack shaft arrangement to a direct drive system.

This arrangement is being used by many cars on the grid and it’s the most simplest way of doing it. It has one chain running from the motor shaft gear to the big gear on the wheel. What it does is that the motor has to be move back to allow the chain to be direct and the motor needed to be moved over.

The advantages of this way is that it’s very unlikely that it will break, it’s also increases the efficiency of the drive train and allows us to use more power. Also it will be easier to cool as isn't pressed against the surface. The disadvantages of this arrangement is that the weight distribution is not as good as before as the motor has been moved back.

I changed the steering layout as there wasn’t going to be enough room for all the linkages between the handle and the wheel.

So I have adopted a system that is similar to Richard Lander and vaguely to Rotary Racers (No.1 in the country). This uses a handlebar which is welded to a steering shaft. Further down the shaft is a plate that is also welded. When you turn the handlebar, the shaft rotates and moves the plate side to side. 2 arms are bolted to the plate and the ends of each arms will be attached to the wheels.

This is a simple, straight-forward way of doing the steering. The sensitivity of the steering can be adjusted by changing the height of the steering plate hole.


Refinements

The front section has been tapered narrower so it allows smaller bodies to be fitted over. It also saves weight by about 2kgs

Doubler piece is placed where the motor is mounted. This is to ensure that the motor won’t rip through the floor and cause the car to have a failure. This is simply another piece of 12mm plywood glued and screw to the base.


Body Shape and Exploded View

I made a body to see how it would look like in real life and also see if there is going to be any problems such as the chassis poking through the body at certain points.

On the left and below are some pictures showing the exploded view of the car and how most of the components go together.


Orthographic Drawing

Model Evaluation #1

How will you change your design now that you have made a model?

As this is a computer model, I made lots of changes to the design as I went along. Slide 27 – 37 shows what I changed in the model.

What have you learned from making the model?

I have found out numerous things about my initial idea, how some of it will work and some of it won’t. I learnt that it was going to take longer than I had expected for me to design the car. Initially I intended to design for 1 month but in the end it took 3 ½ months to complete a working model on the computer. All of the changes and development that I have done are from slide 27 to 37. What processes could you use to make the real thing?

I would use a state of art router to machine all of the pieces with super accuracy. Then I would use a electric hand drill to do the rest. Some filing and sanding is also required to make sure everything fits together.

What materials would you use to make the real thing?

I would use wood and metal screws. There would also be wheels and metal parts for the steering, roll bar, and wheel components.

12 mm plywood would be used for most of the chassis. All of the metal parts will be standard carbon steel. Also for the steering shaft holder will be made out of hardwood. To increase the strength, I am also using timber for corner blocks.

What finishes would you use to make the real thing?

The steel would have a coat of primer and 2 coats of black on top. The plywood would need to be waterproof, as if the water soaks into the plywood, it could warp the car and affect the performance, so I am using a solvent-based paint to cover the wooden chassis.

ComputerModel

Model Evaluation #2

How will you change your design now that you have made a model?

The model needs to be developed a lot more to make sure all of wheels and steering components will fit into the car without clashing with each other. The joints needs strengthening, so I am going to put timber blocks in ever corner inside the cockpit and around the battery box area.

What have you learned from making the model?

I learnt that I needed to make the chassis stronger and less liable to sway side to side. It needed some braces around the front wheels. Also the car needs some wood to restrict it from flexing lengthwise.

The overall structure and layout looked good and in proportional with the human body shape.

The car need to be developed a lot more.

What processes could you use to make the real thing?

I would use a state of art router to machine all of the pieces with super accuracy. Then I would use a electric hand drill to do the rest. Some filing and sanding is also required to make sure everything fits together.

What materials would you use to make the real thing?

I would use wood and metal screws. There would also be wheels and metal parts for the steering, roll bar, and wheel components.

12 mm plywood would be used for most of the chassis. All of the metal parts will be standard carbon steel. Also for the steering shaft holder will be made out of hardwood. To increase the strength, I am also using timber for corner blocks.

What finishes would you use to make the real thing?

The steel would have a coat of primer and 2 coats of black on top. The plywood would need to be waterproof, as if the water soaks into the plywood, it could warp the car and affect the performance.

Simple Card

Model

Plan of Make


Stage Process Equipment Needed Possible Problems Safety Checks to carry out1 After finishing the 3D model of the car,

arrange the parts onto a flat sheet.Computer, Solid works. Concerned about the amount

of space available as I am hoping it will fit on 2 sheets of plywood

No safety checks needs Make sure that the pieces don’t overlap each other and the right scale factor.

2 Use a state of the art CNC Router. to cut out all of the wooden parts

Computer, CNC Router, 12mm plywood.

There shouldn’t be any problems

Make sure you are away from the machine when operating.

Make sure the water jet cutter is programmed right.

3 Use a state of the art water jet cutter to cut out all of the flat metal parts

Computer, Water Jet Cutter, 3mm sheet metal.

There shouldn’t be any problems

Make sure you are away from the machine when operating.

Make sure the water jet cutter is programmed right.

4 When got all the parts to make the car, do a dry run to make sure that all of the pieces fit together seamlessly.

Hands, Parts for the car. If the pieces don’t fit together then there is a big problem.

Avoid the sharp edges. Make sure all of the pieces fit together.

5 If successful in the dry run, put the wooden parts together with wood glue following the instructions below

Clamps, Wood glue. There shouldn’t be any problems unless the dry run didn’t work out.

Avoid the sharp edges. Make sure all the pieces fit together in the right order otherwise it will go wrong very quickly.

6 The front side pieces needs to be glued to the middle piece and the two shaft holder. Use the base holes to align the pieces while gluing.

Clamps, Wood glue. There shouldn’t be any problems

Avoid the sharp edges. All of the joints have to be right angled.

7 When glued together completely, glue the front component from the last step to the base piece. Make sure the base is on the right side.

Clamps, Wood glue There shouldn’t be any problems unless the base is glued the wrong face around

Avoid the sharp edges. Make sure the base is on the right side

8 When the last step is done, glue the bulkhead piece onto the front of the car.

Clamps, Wood glue. There shouldn’t be any problems.

Avoid the sharp edges. Make sure you put it on the right way around.


Plan of Make 2Stage Process Equipment Needed Possible Problems Safety Checks to carry out9 Put all of the battery box pieces

together with glue. Use the base holes to align the pieces while gluing.

Clamps, Wood glue. There shouldn’t be any problems.


10 When the last step is done, glue the battery box to the base.

Clamps, Wood glue There shouldn’t be any problems.


11 After that, glue the middle section onto the sides of the car.

Clamps, Wood glue There shouldn’t be any problems.


12 Using all of the corner blocks previously made, glue and screw them in all inside corners.

Clamps, Wood glue, power drill.

There shouldn’t be any problems.

Avoid the sharp edges and hands should be clear of where you are drilling

Make sure that the right corner block goes in the right place.

13 All of the woodwork is finished, next is the brazing of the metal parts.

Brazing equipment There shouldn’t be any problems as long the metal pieces are cut out right.

Wear fireproof overalls and face masks.

Make sure the pieces are aligned properly before brazing them together.

14 Firstly, the cross axles supplied to us needs to be cut up to the right length. Then each side of the cross axle needs to brazed to the mounting plate. Repeat this 4 times.

Brazing equipment There shouldn’t be any problems.



15 Steering plate, shaft, handlebar all needs to be brazed together, all aligned properly.

Brazing equipment There shouldn’t be any problems unless the components weren’t made properly.



16 Braze together the back wheel alignment plates together.





Plan of Make 3

Stage Process Equipment Needed Possible Problems Safety Checks to carry out17 Braze together the kingpost parts to

form a kingpost. Repeat 4 times. At the end, grind off a section off the steering column so the gear can be mounted on without contact.




18 Bend a 1” tube in to a roll bar. Then weld a metal plate to each end of tube.




19 After all the brazing has been completed, time to put it all together with nuts and bolts

Hex keys, Nuts and bolts, There shouldn’t be any problems unless the components weren’t made properly.

No safety checks needs Make sure the pieces are where they are supposed to be.

20 Slide each cross axle in their hole and into the sleeves which then needs to be tightened.

Hex keys, Nuts and bolts, There shouldn’t be any problems unless the components weren’t made properly.

No safety checks needs Make sure the pieces are where they are supposed to be.


Instruction Manual

As this is a kit car that can be sold in the shops, it would need a instruction manual of how to build the car. So I created one specifically for this car.


Working Diary - Router

I needed to cut all of the parts out. I founded a place in Falmouth that can cut a full sheet of plywood for a reasonable price.

The process only took about 1 and a half hours which was quite surprising.

The pictures on the right shows the process taking place and the components involved.

This router uses a vacuum pump to suck the pieces to the base and secure them.The pictures shows the pieces being cut out. The process was that it would cut 6 mil into the wood and when it has done that for all of the lines, it would then go down another 6 mil to complete the process.

The parts that are being cut out on the right are the 2 middle sections, bulkhead and 1 side piece.


Working Diary – Water Jet CutterThe same company also does water jet cutting, which involves shooting very high pressured water out of the nozzle and cutting the material.

This process was used to cut most of my metal parts such as gears, cross axles plates, harness plates, motor backing plate, roll bar plates and so on.

The process was fairly quick, about 1 hour to produce 20 or more pieces.


Working Diary -Sand & Filing and Pieces slotted together.


The pictures on this slide show all the pieces slotted together except the top piece which would be fitted to the car after the gluing and screwing is complete because the wood may warp and there is other components to be fitted to the car beforehand.

In order for the all the pieces to fit together firmly, I designed all the pieces to the millimetre. When putting all the pieces together, it became apparent that the slots would go together in a perfect world without any expansion or warping of the wood. This meant that I had to sand down some slots and holes to ensure all of the pieces fit together correctly.

This process took about a week to complete.


Working Diary – Corner Blocks

Knowing the car now slots together, I got on with the gluing and screwing the car together. I used corner blocks to improve the structural strength of the car. Using the band saw with supervision, I cut 6 pieces of 25mm square that are 2.4 metres long.


Working Diary – Glued and Screwed & Painting

After doing most the of corner blocks, the actual shape of the car to beginning to appear. The glue is performing well and the whole chassis is bonded together firmly.

The only concern is that the way that the glue works, it reacts with moisture and therefore it foams out of the joints. This can cause trouble because the foam set off quickly and becomes a really tough substance. When this happened a couple of times during the build, I would have to get a sharp chisel and try chisel all of the hard foam off the surface.

After all of the wood work was done except the top piece, I got on with the painting of the car as it needed to be waterproof otherwise it will warp and affect the car’s performance in wet weather.

I used a solvent based garage floor paint because it’s a tough, waterproof paint that will hopefully last for a reasonably long time. All of the surfaces needed to be painted with 2 coat to make sure no water will go into the wood.

I painted the top piece and the chassis separately because it’s easier to paint the inside of the car without the top.


Working Diary – Top Piece, and More Painting

After all of the surfaces on the chassis and top pieces were painted, I glued and screwed the top onto the chassis using the same method as before. After some finishing touches with the paint, the wooden part of the chassis is finished!


Working Dairy – Metal Work Next I needed to make all of my metal pieces which are

very critical to the functionality of the car. Firstly I began making the cross axles parts which would hold the kingposts and the wheels. I had to cut up the cross axle in to the correct length as they were too long. Then I had to prepare the plates that will be welded to the cross axle as on their own, there is no way the axle can be attached to the car securely. The cross axle were designed to be welded on a tricycle.

After the plates were prepped with a light filing and was welded to the cross axles, I moved on to the kingposts. They didn’t need much modifications as we designed the car around it. The tabs that controls the steering wasn’t needed on the front kingposts as it would be moved. I chopped them off with an angle grinder with supervision. The back kingposts needed the tab but because the tab was flipped upside down, I heated the brass weld up and twisted the kingpost around while the tab was in the vice.

After that was completed, the 2 tubes that will clamp the 4 cross axles together needed to be made. A 1 5/8 inch tubing was cut down into two pieces, 300mm long and 280 long. A long slot was cut away at each end of each clamp tube.


Working Dairy – Metal Work 2 After making all of the wheel components,

I moved onto the rollbar. The materials were a 1” inch steel tube and some pieces from earlier on from the waterjet cutter. Firstly I used a tube bender to bend the tube as shown on the left. This process took a short 5 minutes to complete. Then I welded the mounting plates onto each end of the tube so the roll bar can be firmly secured to the chassis.

Then I had to do the steering component which includes several 7/8” steel tubes welded to together. To make sure they fit together properly, I used a pattern software that allows me to cut out all of the joints perfectly so the handlebar can be perfectly perpendicular to the steering shaft.


Working Diary – Metal Painting

After all of the metal was completed, I painted the parts as I don’t want them to rust due to the horrible weather conditions during a wet race. A coat of grey primer was applied to the surface of the metal, followed by 2 coats of high gloss black.


Working Diary – Bolting the Parts Together

After all of the metal parts were completed, I simply bolted them on with nuts and bolts. All wheels were attached within 2 hours which is good as I wanted to be easy enough for little kids to put it together because most cars at the moment have the chassis welded together and this requires skill and time that the student don’t have.

The top picture shows the 2 batteries and the motor in the car because I wanted to test the strength of the chassis with the majority of the parts and myself in it. I am pleased to say that it’s a rock solid chassis that doesn’t flex or crack. This means that the chassis is suitable for racing even on bumpy road surfaces.

Roll Bar •Socket Button M8 30mm (X6)•Nylock Nut M8 (X6)•M8 Washer (X6)

Harness Mounts•Socket Button M8 45mm (X10)•Nylock Nut M8 (X10)•M8 Washer (X10)

Cross Axle Plates•Socket Button M8 30mm (X10)•Nylock Nut M8 (X10)•M8 Washer (X10)

Motor Gear•Grub Screw M12 16mm (X2)

Total•Socket Button M8 30mm (X16)•Socket Button M8 45mm (X12)•Socket Cap M8 20mm (X2)•Grub Screw M12 16mm (X2)•Socket Cap M8 50mm (X4)•Nylock Nut M8 (X34)•M8 Washer (X36)

Roll Bar Brace•Socket Button M8 45mm (X2)•Nylock Nut M8 (X2)•Washer?

B-Wheel Alignment•Socket Cap M8 20mm (X2)•NylockNut M8 (X2)•M8 Washer (X4)

Motor•Socket Cap M8 50mm?? (X4)•Nylock Nut M8 (X4)•Washer?


Comparing the Kit Car with our Old Car

Our school already have a Green power car that is reasonably competitive. I used this as a base for designing my car. I wanted it to be shallower, thinner in order to have less frontal area and as you can see in the pictures that it is.


Kit Car Manufacturing SpecificationManufacturing in School Materials: Plywood and plain

carbon steel Sizes: 2 Sheets of 12mm

plywood Weight: 25kg Printing Method: A Router that

can do full sheets. Manufacturing Processes: Sand

paper, square files, electric drills, Router.

Finishes/Assembly: Solvent-based paint, polyurethane glue

Manufacturing in Industry Materials: Plywood and plain

carbon steel Sizes: 2 Sheets of 12mm

plywood Weight: 25kg Printing Method: A Router that

can do full sheets. Manufacturing Processes: Sand

paper, square files, electric drills, Router.

Finishes/Assembly: Solvent-based paint, polyurethane glue The manufacturing specification for school

is the same as the specification in industry because it can’t be made any other way.


Problems that I have encountered during the build of my car

I have discovered that I have forgot to make holes for 3 tabs on the car. It was two tabs on the bottom of the back bulkhead and a slot for the back of right hand side of the battery box. This doesn’t compromise the car very much in its structural strength. But it does affect the shape and warping of the wood which can cause problems when fitting and gluing the pieces together.

One after school session that I have attended, I manage to screw and glued the battery box into the base. The following morning, I came in to check on if the glue was successful. What I came to discover was that the back bulkhead has warped itself as said in the previous point. This meant that one side fitted on perfectly, but the other side has somehow moved by 3mm. This didn’t do me any favour as I then had to make the hole bigger so the slot can go in.


Evaluation 1

What did you plan to make?I planned to make a Greenpower kit car that can be supplied to schools that are wanting to compete in Greenpower Races. It had to be simple to make and environmentally friendly. It also had to be reasonably competitive at the national final, achieving a top 15 place. Therefore it also needed to have the ability to put a aerodynamic body onto it and it also needed to be light.

What did you actually make?I made exactly what I planned to make. It’s light, small and environmentally friendly. It is also durable as it should last for half of a decade of racing.

What are the differences?It isn’t as sustainable as I hope it would be as I have used a solvent-based paint which renders the most of the car useless for recycling, but however by using a tough, durable paint, the car shouldn’t need to be repaired or replaced which means it doesn’t use up anymore of the environment after it has been made.

Name 3 positive things about the design?It’s a very safe, light and strong design as it has support on all 4 sides (base, left side, right side and the top). This contributes to the lightness of the car which is about 25 kg without batteries and motor.

What improvements would make the product better?One thing that struck me was that the car was wider than expected. This can affect the performance of the car as it increases the frontal area of the car. If I was to redesign the car again, I would make the chassis 50mm narrower. This has big consequences on the structure of the chassis as it will intersect with the wheels.


Evaluation 2 How does the product meet the specification?

Must fit the regulations set by Greenpower.

The entire kit car fully complies with the rules.

Be able to fit wide range of people into it.

It can fit a person that can be from 4ft5” to 6ft5”

To be built largely from wood or other sustainable/recyclable materials.

It is made from recycled metal and sustainable plywood.

To be designed to take advantage of modern computer controlled manufacturing techniques such CNC routing and waterjet cutting. This will reduce costs, increase manufacturing accuracy, and keep material waste to a minimum.

It uses a state-of-the-art CNC router to manufacture all the wooden pieces and a waterjet cutter for the metal parts.

Will be easily modified by student clubs to their preferences.

As it’s made out of wood, it can be cut up and modified easily.

Have the ability to put a aerodynamic body over it

The shape of the chassis allows a very aerodynamic body to go over it.

Be easily repaired after a crash

As it’s made out of wood, it’s easy to attach new parts and pieces on it.

To provide instructions/documentation that show how the car is assembled, and the design principles behind the car. This allows the school to use the Greenpower car as part of the curriculum.

The instruction manual can be seen on slide 44.


Evaluation How have you tested the product? Was this a suitable test?

I have asked students and staff about my car and what they think of it. I have received good feedback saying the car is very good overall. Students have been climbing into the car, trying some features of the car and getting a feel for it, all students felt that the car was big enough for themselves and had no trouble with it. When I showed it to other students in the school, my car wasn’t completed as I didn’t have the roll bar and the steering in it. A more suitable test would be have the whole car done, give it to the students and they drive it around and they tell me their feedbacks.

Can you suggest 2 improvements as a result of the testing?

Make the car narrower and shallower as they felt there was too much room in the cockpit. The steering system need to be changed as they would preferred side sticks to a handlebar.

How did you use the research?

I used my research to determine what was needed for my car and what it didn’t need. For example, I did some research on Raptor Fusion which came 4th in the National Final, the overall shape of it uses the space in the car efficiently and I have incorporated that in my design as you can see in my development on slide 30.

What extra research could you have used to improve your design?

I could’ve done some research on weight distribution and on how that affects the steering geometry and the feel of it as I have absolutely no idea on how sensitive it will be. This can affect the rolling resistance of the car around the track.

Have you investigated environmental, ethical, social, and cultural impacts of the product?

This can be seen on slide 4. How have you evaluated your work throughout the project?

I have had several opinions about my design from other teams and schools and how to improve it. I have made a couple of models to test certain things that was concerned about such as I need to test the structural integrity of the chassis, so I made a card model to see how stiff it was. In my computer model, I need to see whether a person would fit inside the car so I downloaded an ergonome off the internet and used him to evaluated my model and see if it works.

gcse resistant materials coursework by nathaniel olson

Documents

nathaniel olson slide

greenpower kitcar

tenon joint

current kitcar

similar joint

greenpower organisation

common woodworking joint

task analysis slide