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Engineering IA3 FInal - This was my ia3 assignment. 18/25.

This was my ia3 assignment. 18/25.

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Engineering Studies- Unit 3

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Palm Beach Currumbin State High School - Palm Beach

Academic year: 2024/2025

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Contents Page

Part A

Explore Pg3- 5

- Problem Exploration

- What are the known about the problem?

- What are the unknowns about the problem?

- Determining a Success Criteria.

Develop Pg 6

- Developing Ideas

- Proposed Solution

Generate Pg 7- 8

- Technical Drawing

- Structural Justification

- Generate the Solution

Evaluation Pg 9

- Prototype testing and recommendations

Part B Pg 10

Summary Report

Summary of The Task

"Straight roads are for fast cars, turns are for fast drivers." Colin McRae The Broadmoor

Pikes Peak International Hill Climb (PPIHC), also known as The Race to the Clouds, is an

invitational automobile hill climb to the summit of Pikes Peak – America’s Mountain in

Colorado, USA held on the last Sunday of June. An independent engineering company

is now working on the development of a PPIHC Race Car and have been exploring the

possibility of developing an automated mechanism that changes the car's back wing's

angle of attack. This will vary the car's downforce and drag ratios on different parts of

the track with the potential of improving the car's performance.

Control Technologies for precise control and automation in a wide range of applications.

Different Sensors used to generate a solution:

Engineering Technologies (3D Printing)

The process of 3D printing, also referred to as additive manufacturing, involves building designs and structures out of the chosen material layer by layer to produce 3D objects. Here are some crucial 3D printing facts that should be considered when coming up with ideas.

Plastics, metals, and ceramics are just a few of the materials that can be used in 3D printing.
The general consumer goods, aerospace, medical, automotive, and aerospace industries are some areas where 3D printing is used. Additionally, 3D printing is used to create smaller prototypes, shapes, and moulds.
These 3D models must be created using online design tools like Fusion and CAD. Once created, the models can be improved for printing or testing by considering things like internal support structures (like I beams), percentage of infill and layer height.
Advantages: Compared to traditional manufacturing methods, rapid prototyping, extensive customization, and the capacity to recycle some materials for later use are some benefits. Limitations: There is a smaller variety of materials available for use with 3D printing, and for larger projects, the printing speed may drop noticeably and become less efficient in terms of time. Additionally, finishing, and post-processing are required.
Precautions for safety: For larger machines and specific materials, it's important to use the proper ventilation and safety equipment because some materials can release hazardous fumes during the printing process. Keeping them in well-ventilated areas is essential because they can get hot and present a fire risk.

Engineering Technologies (Mechanism 1 )

Rotational motion is the type of motion in which an object rotates around an axis in a circular manner. Oscillating Motion refers to a movement that oscillates back and forth across an anchored point. Reciprocating Motion is characterized by linear back and forth movement. Linear Motion is described as straight-line movement without rotation or oscillation. A pendulum clock is a perfect illustration of a mechanism that generates oscillating force; this happens when the pendulum is pulled away from its starting position and returns after travelling a specific distance in both directions. At least one of the variables must change and repeatedly go back to having the same value for a system to be said to be oscillating. Pistons, which are used in engines, are a great illustration of a machine that generates motion through reciprocating motion. The reciprocating motion of the piston in an automobile engine is converted into circular motion of the crankshaft. The rotational movement that is created when a car's wheels are turned on their axis propels the vehicle. A car's wheels and steering wheel rotating around their axes is an example of rotatory motion. A mechanism that moves straight and linearly can be any vehicle, including a car, that travels in a straight line.

The Coanda effect and Bernoulli’s' principle

Engineering Technologies (Mechanism 2)

Using a connecting link (2) in the link mechanism, a crank (1) that rotates around the 0 axis (drive shaft) is connected to another crank (3) that swings around the other rotation shaft known as the 0' axis. As the crank rotates around the 0 axis by one turn, the crank (3) begins to swing side to side. Now, the location where the connecting link (2) and crank (1) are arranged in a straight line determines the swinging range of the crank (3) (from point A to B).The two parts are set up in a straight line at point an in [Fig]. After reaching point A on the right edge, the swinging crank (3) reverses direction. Again, they are arranged in a straight line at the point b, which determines the swinging range point B. The figure below demonstrated, is the conversion mechanism with an adjusting screw, allowing quick adjustment of the swing angle. This mechanism is useful for performing position control during operation or designing a simple structure compatible with various models. The rotary motion of the crank that lays on the 0 axis causes an oscillating motion in the slider (connected to the 0’ axis) connected by a pin joint. The servo can also be adjusted with the handle and adjusting screw. Mechanism 1 Mechanism 2 According to Bernoulli’s principle when a fluid flows, its speed and pressure are inversely related. An increase in the speed of the fluid occurs simultaneously with a decrease in pressure. This principle explains how faster air flowing over the top of a wing creates pressure, which generates lift. However, the lift generated by wings can sometimes be undesirable as it reduces stability and traction (refer to figure 2). A rear wing on a car, in engineering and physics terms, is an aerodynamic device that generates downforce to improve stability and handling. By manipulating airflow, it creates a pressure difference that pushes the car down, increasing traction and grip. This enhanced grip allows for improved cornering ability, better control during high- speed manoeuvres, and increased overall stability. The rear wing helps optimize the car's performance by balancing downforce and drag, ultimately enhancing its handling capabilities. Especially around corners that is seen through testing using the power anchor. Positive Minus Increased downforce improves traction, grip, stability, and handling. Enhances high-speed performance and aerodynamic balance. Adjustability allows for fine-tuning based on track conditions. Increased drag reduces top speed and fuel efficiency. Adds weight, affecting overall performance and acceleration. Costly to design, manufacture, and install.

Rear Wing

Figure 1 Figure 2 In fluid mechanics, the Coanda effect is the tendency for a flow along a solid surface to follow the curvature of the surface rather than diverge. The Bernoulli theorem, which demonstrated that a fluid's speed increases concurrently with a decrease in pressure or potential energy, may be used to explain the phenomenon. Distance sensor How they signal for a change in rear wing angle? Distance sensors (proximity sensors) can be used as they send an outputting signal often in the form of a laser, IR LED, or ultrasonic wave by then which the change in signal is read and analysed either by a change in time or intensity of the returned signal. The sensor could be used if a large circular shaped wall-like structure could be made around the track so that the waves could bounce off/reflect and send distance signals back. Once the change of distance or time reaches a certain value it can send a signal to the actuator to change the degree of the mechanism with internally changes the angle of the wing. Solenoid How they signal for a change in rear wing angle? An electromagnetic field is produced when the coil is subjected to an electric current. The plunger rises or falls due to this electromagnetic field. Solenoid valves employ this mechanism to open and close the valve. This mechanical motion can be used to open or close a set of electrical currents. A solenoid can create a different type of motion compared to an actuator, its forwards and backward motion can be used to activate the rear wing angle mechanisms by generating the reciprocating linear motion. Actuators (Servo) How they change in rear wing angle based on an input? Actuators are devices that convert electrical signals into mechanical motion often in the form of oscillating motion. When a certain signal is received, a certain input from the sensors causes the servo to change in angle or direct based on the assigned code or scenario. The mechanical motion they create can be used to provide the initial motion the rear wing angle mechanism. They have great reliability and are widely used thus they will be a sufficient actuator for the solution. Microcontrollers: How they signal for a change in rear wing angle? Microcontrollers incorporate within them memory banks and input and output port interfaces that enable straightforward interfacing between different subsystems facilitating device control tasks easily. Microcontrollers are mainly used for memory and a processor can process the data from the sensors to generate an output to the actuators. An example of a microcontroller is an Arduino board which is connected to the power supply and the input and output devices. They act and a middleman between two interfaces and help transfer data which will be useful in the creating the solution. Accelerometers: How they signal for a change in rear wing angle? Accelerometer’s primary function is detecting changes in motion in terms of velocity or progression along designated axes. Whenever these sensors encounter motion forces is it translated into electrical signals for communication with processing devices such as microcontrollers. The theoretical velocity of the car before it begins to slide can be found and thus when this velocity is reached the accelerometer can detect this and generate an output signal to the microcontrollers which will cause a change in motion in the actuators. Pros: Can operate at higher temperatures, reliable, low cost, have become less sensitive to dirt and water. Cons: fixed sensitivity, range and time are constant, less robust Pros: easy to use, inexpensive, cross platform supported Cons: Lack of multitasking, not optimized for performance Pros: High output power, efficient and accurate, produces accelerated torque Cons: Potential damage from overload, higher cost Pros: failsafe design, high life cycle, very fast processor Cons: some valve types have lower flow, no manual override, some can clog Pros: accurate, repeatability, different option, cheap Cons: affected by a number of factors like dust and water

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####### for precise control and automation in a wide range of

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Research information PMI Analysis

Downforce Positive

Increased Traction: When cornering at high speeds, downforce enhances grip and traction, giving the driver more control.
Better Handling: It improves all-around handling and lowers the chance of oversteer, giving the driver more control.
Improved Stability: The car is stabilised by downforce at high speeds, which reduces aerodynamic lift and maintains stability.
Increased downforce increases the effectiveness of the brakes and shortens the stopping distance.
Improved Straightaway Performance: Downforce improves straightaway performance by increasing traction and minimising drag, allowing for higher top speeds. Minus
Rear wings have more aerodynamic drag, which lowers top speed and fuel efficiency.
Stability and Imbalance: Rear wings may result in an uneven distribution of front and rear downforce, which can have an impact on handling.
Rear wings add weight and could put stress on the car's structure if they are not properly integrated.
High-mounted rear wings may compromise visibility, which could affect safety and manoeuvrability.
Rear wings can be pricey and not always practical depending on the vehicle or driving conditions. DRS Positive
Reduced drag to increase straight-line speed.
For better overtaking opportunities, the slipstream effect has been improved.
Aerodynamics that can be adjusted for best performance under various track conditions.
Encourages thrilling racing by bringing battles closer and strategically activating DRS.
Fuel efficiency was increased by lessening resistance at higher speeds. Minus
Reduced downforce: DRS reduces the angle of the rear wing, which lowers the amount of downforce and compromises traction and stability.
Changed balance: A reduction in rear downforce can lead to an imbalance in the front and rear aerodynamic forces, which will impact the handling and stability of the vehicle as a whole. Mechanism 1 Positive
Simple and efficient design due to not many members. Therefore, it can easily be set up.
Lower cost due to lower amount of mechanisms
Can turn rotary motion into oscillating motion across a member so it will be a valid mechanism to use in the design.
Durable design which will help as less materials may need to be used lowering the weight and cost. Minus
Can only produce two types of motion being oscillating and reciprocating.
Only can be used in certain ways (not many uses) Mechanism 2 Positive
Coverts the rotary motion of the crank on the 0 axis to a slider oscillating motion, therefore it produces a easy conversion of motion that is adjustable through a screw and handle.
Simple and effective design that can easily be built and produced. Minus
Requires a few more parts to create, thus adding more materials and further costs

####### for precise control and automation in a wide range of

####### applications.

Material Research

PLA: Polylactic acid (PLA) is similar to the substance used in biodegradable plastic packaging and is made from biological materials such as cornflour or sugarcane. PLA is a strong, resilient material with an opaque matte finish, but it does not withstand heat as well as ABS. Because PLA is not water or chemical resistant, corrosion is a possibility. At temperatures above 60 degrees Celsius, PLA also begins to deform. The preferred material for low-cost 3D printers is typically PLA because it is stickier than ABS and thus simpler to print with. It is compatible with All FDM printers. Material Properties : high strength, high stiffness, hard, brittle, tough Pros : Easier to print with than ABS; Biodegradable Cons : Prints degrade over time; rougher texture Cost : $20-50 per kg. Due to its strong material properties and easy accessibility, this will be a valid and optional material for the prototype. Nylon: Nylon is any of a number of synthetic polymers that were initially created as alternatives to silk. Given its durability and high tensile strength, nylon can support a sizable amount of weight without breaking. Nylon is inexpensive because it is widely used in other industries and resistant to the majority of typical chemicals. However, 250 degrees C is a temperature that many extruders cannot withstand, so nylon must be printed at high temperatures. Compatible with FDM printers that can heat the extruder to 250 degrees C. Material Properties : Strong, stiff, chemical resistant, very tough Pros: tough; Inexpensive printing material Cons: Requires high temperatures to print Cost: $18 per kg. Although nylon is a strong, durable, and tough material it may be difficult to have accessibility to printers that can produce high levels of heat. Carbon fibre Typically, a polymer with multiple uses is combined with carbon fibre material. The cars' weight and centre of gravity are reduced thanks to the carbon-only fibres. Carbon fibre material has the advantages of being lightweight and typically being stronger than both regular steel and aluminium. Cost is without a doubt one of its drawbacks. The material costs more because it requires more labour and technological resources. Although it has become more affordable. Material Properties: High mechanical strength, high stiffness, lightweight, very low thermal expansion, and superior chemical resistance. Pros: lightweight, strong, stiff, and excellent chemical resistance Cons: very high cost and require more labour and resources to acquire Due to its strong material properties as well as being widely used in rear wings for Formula 1 cars, this will be a valid material for the final solution. Aluminium Aluminium is a popular substitute for steel. Aluminium tends to make the bodies lighter and more energy efficient because it is lighter than steel as well. To compensate for the heavy weight of the electric battery, aluminium is frequently used in electric vehicles. The advantages of aluminium vehicles include their lower cost when compared to carbon fibre and their superiority as daily drivers. Aluminium is more prone to corrosion than other materials, including paint jobs on the car, which is a drawback of aluminium vehicles. Last but not least, producing aluminium requires a lot of labour and carbon and is not as eco-friendly as marketed. Material properties: ductile, lightweight, prone to corrosion, strong Pros: cost effective and lightweight when compared to carbon fibre, very abundant. Cons: Easily dented or scratched when compared to steel, not as strong as steel, not very eco-friendly A critical component in any vehicle is its rear wing that aids stability as well as traction at high rates of speed. Within competitive racing settings like Formula 1, alteration of this assembly's angle occurs thanks to unique oscillatory and reciprocal movements performed by select components within its adjustment mechanism; initiating certain back-and-forth motions that allow for optimum calibration levels throughout varying race conditions. These rectilinear movements are achieved through specific devices like a linear actuator operated by an electric motor utilizing gears or lead screws, the motor transforms electrical energy into rotational motion that is then converted to linear motion. This linear motion can push or pull, changing the angle of the rear wing. Additionally, oscillating motion may be included in the rear wing adjustment mechanism. Utilising parts connected to the actuator, such as linkages or levers, can achieve this. The rear wing pivots around a fixed point or axis as the linear actuator moves back and forth in its reciprocating motion. The linkages or levers convert this motion into an oscillating motion. The angle of the rear wing can be precisely controlled by combining reciprocating and oscillating motion. The downforce produced by the wing can be changed by varying the angle, balancing the need for more grip in corners and less drag on straight sections of the track.

Time Project Management

The time management diagram that is provided below will be used to assist in making the most of the available time. Due to the fact that it is possible and more effective to manage two tasks at once, tasks may have overlapped in some weeks. As a result, better ideation and connections between the designs, ideas, and concepts related to the procedure below are made possible. The sections that will be finished by the due date of week 3 term 3 are those that have been highlighted.

Rear Wing Motion

Levers

The Drag Reduction System (DRS) rear wing can be classified as a "second-class lever." A lever with the load's point of resistance situated between the point of effort (the application of force) and the fulcrum (the point of support or axis of rotation).In the case of the DRS rear wing, the fulcrum is typically located at the pivot point where the wing can be adjusted. The driver or a control mechanism applies the effort force to activate or adjust the wing. The load in this case is the rear wing itself, which may have an aerodynamic element or mechanism that extends or retracts the wing to reduce drag.

PMI Analysis (Wing angle)

Coding Concepts (Logic Gates)

Physical Testing

Physical testing was done to provide further data in determining a valid solution for the wing angle. The prototype was placed on a scale and weighed. It was then set to 0 so the downforce (in weight) could be calculated. A temporary base was set up at the given angles for the rear wing. The prototype and weighing scale where then put in front of a fan which was set to 13 km/h. The downforce was then collected once the measurement remain steady for a given amount time. This was repeated. 10° test Fan (13/h) Temporary base DF (weight) Rear Wing The graph above represents the relationship between wing angle and added weight of downforce. The line of best fit was seen to be non-linear equation with an R 2 value of 0 meaning that it is accurate. Analysis and identification of the trends show that from 10°- 50 ° the downforce increased gradually with its max being at 50 °. After reaching its max at approx. 7g of DF (weight) the DF decreased at angles 60° and 70°. This data directly corroborated with the virtual CFD testing and both graphs display similar relationships and trends across each angle. Both have the same minimum and max points. These findings will be taken into consideration during ideation as they can help us choose the best wing angle solution. 45 ° Pro

Good downforce to drag ratio. Cons
The wing's downforce increased by about 0 while the drag increased by about 0. This shows that the increased surface area of the wind contact points at 45° may be causing drag to increase more rapidly than downforce. 40° Pro
Best Downforce to drag ratio.
With a 10° increase from 30° - 40° the drag has been seen to double while the DF increased by approximately 0. Cons
no unique cons Logic gates are an essential part of the solution as they provide automation to the movement of mechanism. If the accelerometer was to read a certain higher velocity (or change velocity) it would generate a signal to a logic gate which would determine an output from the input. The logic gate used in the solution will be a NOT gate as we only have two possible readings from the accelerometer being either on or off. If the accelerometer read no change, then the servo would be on if it read a change in velocity, it would cause the servo to be turn a different output and move the mechanism internally changing the angle of the wing.

Wing Size CFD Analysis Calculations

After calculations of the wing angle, the effects on the size of the wing were tested. The diagram on the left displays the outcomes of the CDF that examined the effects of airflow on a 100mm by 50mm ABS (solid) rear wing when it is angled at 4 0 ° to the surface, with the same pressure of 13 km/h (3 m/s). According to the results, the model experiences 0 of downforce and 0. 0658246 N of drag. This resulted in a drag to downforce ratio of 1 .104.

Friction Force and Theoretical Velocity

The effects on the size of the wing were evaluated following calculations for the wing angle. The results of the CDF, which investigated the effects of airflow on a 1 25 mm by 50mm ABS (solid) rear wing when it is angled at 40° to the surface and travelling at the same speed of 13 km/h (3 m/s), are shown in the diagram on the left. According to the results, the model experiences 0 of downforce and 0 of drag. This resulted in a drag to downforce ratio of 1. Following calculations for the wing angle, the effects on the size of the wing were assessed. The diagram on the left depicts the findings of the CDF, which looked at how airflow affected a 150mm by 50mm ABS (solid) rear wing moving at the same speed of 13. km/h (3 m/s) and angled at 40° to the surface. The model experiences 0 of drag and 0 of downforce, per the results. The ratio of drag to downforce as a result was 1. The resistance that two surfaces experience when they come into contact and move in relation to one another is referred to as friction force. It is the force that resists the tendency of motion between the surfaces or the relative motion between them. It can be calculated through the formula of: 𝐹𝐹 = 𝑢𝑅𝑁 𝐹𝑓 = 𝐹𝑟𝑖𝑐𝑡𝑖𝑜𝑛 𝐹𝑜𝑟𝑐𝑒 𝑢 = 𝑐𝑜𝑒𝑓𝑓𝑖𝑒𝑛𝑐𝑡 𝑜𝑓 𝑓𝑟𝑖𝑐𝑡𝑖𝑜𝑛 𝑅𝑛 = 𝑁𝑜𝑟𝑚𝑎𝑙 𝐹𝑜𝑟𝑐𝑒 The normal force can also be calculated as weight of the car + downforce which is what was used to generate the graph above. The graph represents the relationship between friction force and the angle of the wing. From analysis of the trends, it can be noticed that the friction force portrays similar trends to the downforce graphs calculated earlier. As from angles 10°- 4 0° the FF gradually increased and then peaked at 50° before it decreases at 60° and 70°. The normal force can be calculated by the weight of the car * 9 (force of gravity). 𝑅𝑛 = 𝑀𝐴 𝑀 = 𝑀𝑎𝑠𝑠 𝑜𝑓 𝑡ℎ𝑒 𝐶𝑎𝑟 𝐴 = 𝐺𝑟𝑎𝑣𝑖𝑡𝑦 ( 9. 8 ) Therefore, the Normal force was found to be 245*9 = 2401N The vehicle will rotate around the power, which will be used to test the prototype's velocity. Therefore, the formula for centrifugal forces can be used to determine the theoretical maximum speed of the car before it breaks static friction. 𝑟 = 𝑚𝑣 2 𝐹𝑓 𝑟 = 𝑟𝑎𝑑𝑖𝑢𝑠 𝑚 = 𝑚𝑎𝑠𝑠 (𝑘𝑔) 𝑣 = 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝐹𝑓 = 𝑓𝑟𝑖𝑐𝑡𝑖𝑜𝑛 𝑓𝑜𝑟𝑐𝑒 In order to calculate the theoretical velocity, the formula must be rearranged to create this new formula for v 𝑣 = √ 𝑟𝐹𝑓 𝑚 The variables will now be found to determine the velocity. The car will be tested on a power anchor will the wire being 2m in length thus meaning the radium = 2 The mass of the car (m) including the mechanism and all components was weighed at 0. Therefore m = 0. The formula for friction force is. 𝐹𝑓 = 𝑢 ∗ 𝑅𝑛 𝑢 = 𝑐𝑜𝑒𝑓𝑓𝑖𝑐𝑒𝑖𝑛𝑡 𝑜𝑓 𝑓𝑟𝑖𝑐𝑡𝑖𝑜𝑛 𝑅𝑛 = 𝑛𝑜𝑟𝑚𝑎𝑙 𝑓𝑜𝑟𝑐𝑒 Physical testing was done to determine the coefficient of friction (u) by attaching a hook to the car until it broke static friction the force of the pull was then measured and found to be 0. Reaction force can be found by multiplying the weight of the car by gravity. This was written as. 𝑅𝑛 = 0. 245 ∗ 9. 8 𝑅𝑛 = 2. 401 Once reaction normal and coefficient of friction were found friction force was then calculated. 𝐹𝑓 = 0. 8 ∗ 2. 401 𝐹𝑓 = 1. 92 Finally using the rearranged formula, the theoretical velocity of the car is: 𝑣 = √ 2 ∗ 1. 92 0. 245 𝑣 = 3. 96 𝑚/𝑠 As a result, the vehicle can travel at a maximum speed of 4 m/s before static friction is broken. This implies that before the car reaches this speed, the machismos must be engaged. The car will be able to generate more downforce as a result, increasing its track- traveling speed. Using this information, the accelerometer may be preferred sensor for the solution as it is able to measure the velocity and generate a signal.

Success Criteria

The rear wing must effectively increase downforce to the car to increases static friction especially around corners.
Through the use of sensors and actuators, the car must automatically change the wing angle depending on certain variables (e. speed, distance)
The mechanism and rear wing must effectively increase the velocity of the car using downforce generated from the rear wing.
The rear wing and mechanism must effectively change the angle of the rear wing.
The protype must be to a 1:18 scale.
3D printers will print our pieces to the scale and size set and designed on our fusion 360 CAD drawings. This will ensure that all our pieces are the correct sizes and fit together perfectly as designed so reduce risks of damage or breakage.
The full 1:1 scale model must also be durable as it will need to be able to withstand the outdoor weather and faster travel speeds. Therefore, the steering mechanism and other parts must not be fragile and build as strong as possible.
It is crucial that we make the prototype cheap, cost effective and easily affordable, so that many different people will have access to buy one in the greater future. Servo Rear Wing Small mount

Developing Ideas

During research and analysis on mechanisms it was found that the DRS systems used in F incorporate the triangle shaped members as an excellent way to convert motion. The servo’s oscillating motion causes the first member to move in a horizontal reciprocating motion which is then converted into a vertical reciprocating motion. The diagrams below show how all of the members are connected with other on fixed points. This large member produces a vertical reciprocating motion that allows for the rear wing angle to change. As seen above it is connected to the triangle member structure at one point and the rear wing at the other. This provides a sufficient way of transferring motion and will be further explored to generate the final solution. PMI analysis will be conducted for Mechanisms. As the rear wing supports exceed the size of the lower rear chassis (hang over the edge), small rectangular sections were added and connected to the pillars so that there could be screwed into the chassis via the hole sections (see figure to the left) Designs for the connect point between the mechanism and rear wing were explored through the use of a simple connecter to minimise unnecessary risks and faults. = Fixed rotation points

####### Top View of Mechanism

During physical sketching for ideation, the design for the wing supports and rear wing were explored to develop the most effective solution that offers a simple yet structurally sound design. This diagram above shows the top view of the rear wing when in flat upright position. It then returns to the neutral position of 40° which was chosen due to it having the highest drag to downforce ratio. A small, fixed mount will be connected to the chassis floor to provide as an anchor to the bottom left member connection points. Without the addition of this mount, the members couldn’t not effectively transfer the motion generated by the servo to change the rear wings angle. To ensure that the members stay in place the rods were extended to allow for a small clip to be designed. From research it was found that the servo was the most effective control technology to generate motion. In this design the servo creates the oscillating motion that kickstarts the mechanism and transfer of motion. During sketching, ideation, and research the mechanism above was created that incorporates a servo to create reciprocating motion that can be transferred to create a multitude of rear wing angle devices that as the mechanisms to the right. Both include the triangular shaped design which was researched thus it will be used to generate the predicted solution. A PMI analysis was conducted to further synthesize the solution.

####### Top View of Rear Wing

The diagram below displays the separation/ distance between all the members and components. Extra space was left empty to allow for further technological parts. Thus to create extra space below and reduce the length of the large member connected to the wing the servo and mechanisms could be mounted higher up on a 3D printed mounting stand.

Testing, Evaluation and Refinement

As previously mentioned, the prototype was tested by positioning a power anchor in the middle of the room and connecting the steering mechanism of the car to a 2 m long wire. After that, the vehicle travelled 12 metres around the track in a circle with a 2-metre radius. In order to measure the velocity while filming the car's movement, a line of tape was laid out on the ground to serve as the vehicle's starting grid. The times were then recorded. It was noted that the average lap time (12) was 3 seconds during the initial laps (wing not activated/neutral position) around the track (refer to figure 1). The speed = distance/time formula can then be used to calculate the car's velocity. 12.57/3 = 3/s As the car’s velocity increased, due to a higher setting on the power anchor, the car was able to reach 3/s (theoretical velocity). This caused the rear wing to be activated and the angle to change from 0° - 40° (refer to figure 2). The car experienced more downforce as a result of the angle change, which increased the car's speed as it travelled around the track. This speed was then measured, and calculations revealed that it could complete the track in 3 seconds, increasing the speed to 4 m/s. The speed of the power anchors was then raised further to determine the point (4. 77 m/s) at which the car lost static friction. Therefore, it can be seen that the activation of the rear wing allowed for an increase of 0/s or 0 seconds faster, while it allowed the car to reach a maximum velocity of 4. 76 m/s before breaking static friction.

Prediction Solution Prototype 1 Testing, Evaluation and

Refinement

N Figure 1 CV Wing not Activated. Figure 2 CV Wing Activated (40°)

Prediction Solution Prototype 2 Testing, Evaluation and

Refinement

After analysis from previous results, it was found that the rear wing was activated prior to the previous theoretical calculation and that the actual velocity for the car to break static friction was 4/s. Thus, the accelerometers coding was changed to produce an output signal slightly before this velocity is reached to ensure that the mechanism has enough time to change the rear wing angle before sliding out. The cars initial velocity during the first few laps with the wing not activated remained similar to previous testing at an average of 3. 3 - 3 seconds. The power anchors speed was gradually increased until the car neared the velocity of 4/s. Then at approximately 4/s the accelerometer detected the velocity coded and caused the angle of the rear wing to change. Because of the angle change, the car had more downforce, which increased its speed as it circled the track. Following the measurement of this speed, calculations showed that it could cover the track in 2. 6 seconds, bringing the speed to 4. 83 m/s. This increase in speed resulted at a constant power anchor speed so the power anchor was not the reason for the increased speed. Therefore, it can be seen that the rear wing's activation resulted in an increase of 0. 2 m/s, faster. However, it can be seen that the rear wing activated prior to the car breaking static friction. Thus, further changes in the coding must made in terms of the accelerometer so that the wing activates at a greater velocity. This may be due to two factors, one being the calculations made earlier in the explore section were only theoretical and a number of factors including small slopes or bumps in the track and slight inaccuracies in the power anchors output speed may have affected the cars performance. Secondly calculation made used the old weight of the car (did not include electrical components like Arduino, accelerometer, or battery). Thus, the centripetal force calculations will be done again to determine the amount of downforce produced. The first calculation needed will be to determine downforce using the friction force: 𝐹𝑓 = 𝑢 ∗ 𝑅𝑛 𝑅𝑛 = (𝑤𝑒𝑖𝑔ℎ𝑡 ∗ 𝑑𝑜𝑤𝑛𝑓𝑜𝑟𝑐𝑒) The coefficient of friction with the final prototype was 1 with the new weight being 0 𝐹𝑓 = 1. 1 ∗ (( 9. 8 ∗ 0. 322 )𝑥) 𝐹𝑓 = 1. 1 ∗ 3. 155 𝑥 We now use the following formula to find the downforce of the new solution using the maximum downforce. 4. 77 = √ 2 ∗ ( 1. 1 ∗ 3. 115 𝑥) 0. 322 𝑥 = 1. 07 This calculation nearly directly correlates with the actual velocity data of the car before it broke static friction. Therefore, the accelerometers code will be changed to active the rear wing mechanism at approx. 4/s to ensure that there is sufficient time for the angle to change to avoid losing static friction. Figure 1 CV Figure 2 CV Wing not Activated. Wing Activated (40°) at approx. 4/s

CFD Testing for Predicted Solution

The predicted solution was placed under a computer simulation that looked at the effects of airflow by the rear wing ABS (material) when angled at 40 ° to the surface and is demonstrated in the diagram above. At a velocity of 13 km/h (3 m/s), positive x-axis air pressure was pressing against the front of the wing. The results indicate that when the model is placed at this angle the model experiences 0 2427 N of downforce while experiencing 0 8 N of drag creating a drag to downforce ratio of 0 which is much smaller that all previous CFD meaning the difference in drag and downforce is much larger. However, the large amount of drag can be seen due to the inclusion of the tyres in the CFD, thus this high amount of drag is suitable as the rear wing is the main component being tested. According to the diagram it can be seen that the air fluid that comes into contact with the wing changes in z value (highlighted in orange above) and thus meaning the wing creates downforce suggesting why there is a large amount of downforce in relation to the size of the wing. Similar to the previous angle, a small amount of lift is produced that counteracts the downforce because lift is produced when air passes underneath the wing. A computer simulation that examined the effects of airflow by the rear wing ABS (material) in its neutral position was run on the predicted solution. Positive x-axis air pressure was pushing against the front of the wing at a speed of 13 km/h (3 m/s). According to the results, the model experiences 0 N of downforce and 0 N of drag at this angle, for a drag to downforce ratio of 0, which is much lower than all previous CFD and indicates that the difference between drag and downforce is much larger. As the rear wing is the main component being tested, the high amount of drag is acceptable. However, the large amount of drag is visible due to the inclusion of the tyres in the CFD. The diagram makes it clear that very little air fluid (highlighted in orange above) comes into contact with the wing changes in z value, indicating that there is very little downforce.

Evaluation from Success Criteria

The rear wing must effectively increase downforce to the car to increases static friction especially around corners. During both physical and virtual testing, it was found that the rear wing was able to increase the downforce from a neutral position to 40° by 0 (virtual testing) and 1 in the physical testing thus it can be deemed that the car completed this criterion and can be deemed as successful. Through the use of sensors and actuators , the car must automatically change the wing angle depending on certain variables (e. speed, distance) With the use of an accelerometer and servo the car was able to automatically detect when to change the angle of the rear wing when it reached a certain velocity (calculated with centripetal forces). While the servo effectively created the initial motion in the rear wing mechanism. Therefore, this section of the criteria can be viewed as successful. The mechanism and rear wing must effectively increase the velocity of the car using downforce generated from the rear wing. During testing it can be seen that the rear wing's activation resulted in an increase of 0. 2 m/s, faster. This was due to an increase in downforce that allowed for greater friction and overall a greater velocity therefore the car successfully increases the velocity. Servo and Accelerometer Arduino

Improvements and Recommendations

Recommendations and Improvements to Predicted Solution Possible Materials Recommendations

Following testing and analysis, it is critical to identify design elements that could be improved and make future suggestions to ensure that the prototype is used to its fullest potential. During the testing of the car, it was discovered that the theoretical velocity calculated in the explore section was inaccurate for the predicted solution as the weight of the car increased due to changes in the mechanism and addition of certain components such as batteries. Thus, the coding for accelerometer was changed in the level of velocity it processes to approx. 4/s. As the level/ amount of testing increased over time it was found that the large scale of Arduino board had to slightly lean over the edge of the chassis and the accelerometer being placed above the servo. Internally this could have affected the balance of the car so this must the mechanism seemed so provide small little tweaks that causes some of the members to move around affecting the overall performance. To reduce this, small bolts were glued to the end of each member connection points to lower the amount of sliding or the risk of a member coming off. Furthermore, the scale meant that there was very little spare space for the remaining components causing a need for a change in design. Finally, it was noticed that the slider section attached to the rear wing occasionally came in very slight contact with the motor which irregularly caused more stress on the system (especially the servo). Therefore, it can be synthesised that due to these limitations the need for a remodel is very apparent. Colour After further ideation, the mechanism was completely remade and redesigned with a similar idea however, with it being a much similar version, it greatly increased the overall reliability and efficiency of the mechanism. Th servo was placed directly under the wing to allow for greater space on the chassis while eliminating the risk of the rear wing or mechanism coming in contact with the motor. The number of members was greatly reduced from 6 (plus and anchor and slider) to only two members. This creates an overall large decrease in the weight of the car. Finally, research was done into the wing shape and was found that the most effective shape was curved. This is due to the Bernoulli’s principle and Coanda effect. The curved shape utilises the difference in air pressure between the top and bottom surfaces to produce downforce. This difference in air pressure is the result of how the air moves around the wing shape as the air fluid follows the shape of the wing. The higher the speed of a given volume of air, the lower the pressure that air will have, according to Bernoulli's principle. The curved wing helps maintain vehicle stability and enhances overall handling and performance by increasing downforce. Due to restrictions during the prototyping process, PLA and ABS were the only materials that could be tested; however, for the final solution and when there is a wider variety of materials available, more research will be done to choose a final material for the design. Strong and resilient nylon is a synthetic material renowned for its adaptability. It is a form of polyamide with a high tensile strength, low friction coefficient, and resistance to abrasion. Because of its chemical resistance and light weight, nylon is a preferred material in many different industries. Despite absorbing moisture, nylon is still a vital material because of its low cost and diverse uses. Alloys are substances created by mixing two or more elements, at least one of which is a metal, in order to create a substance with unique properties. Steel, stainless steel, aluminium alloys, and titanium alloys are some examples of different types of alloys. Some properties and advantages include: - Stronger for structural applications. - Outstanding resistance to corrosion, perfect for rust-prone environments. - In electrical applications, improved electrical and thermal conductivity is useful. - Specialised fields may benefit from properties like magnetism or superconductivity. - Better ductility and malleability, which facilitate shaping.

CFD

Wing Activated Wing Inactivated

Original Sized Ring Supports Small curved upper wing and support (fixed) Small gap between wings to allow for airflow. Original Sized lower Supports New Servo location Member connection points. The circular pole in one member and the cut- out hold in the other allow for rotary motion. The improved solution was put through the CFD testing with a wind speed of 3/s. According to the results, when the model is positioned at this angle, it produces 0 of downforce and 0 957 N of drag, for a drag to downforce ratio of 0. It can be seen that the downforce nearly doubled from the predicted solution with the downforce to drag ratio also increased by 0. The diagram shows that the air fluid that comes into contact with the wing changes in z value, which indicates that the wing creates downforce and may explain why there is a lot of downforces in relation to the size of the wing. This change in z value is highlighted in orange above. As the wind travels along its curved shape, the wind path also exhibits the Coanda effect. Due to the fact that this improvement permits a doubled downforce, it can therefore be considered a highly relevant future solution.

Reference List

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