Introduction

Objective

The main objective of this project is gain a real world engineering experience during end period of the associate degree program under given regulations. Throughout the project student get a chance to demonstrate their academic and professional capabilities they have brought forward so far. At the end of the project every car made has compete to achieve maximum speed of 100km/h within 20m length track

Process

Throughout the process for over three months in the tasks such as Modeling of the first car, testing its aerodynamics, drag force, the weight and then designing of a new car and going through the same process and the final target was to finish designing and finally machining it using CNC programs by two weeks before the deadline due to some difficulties that I had to face the project was lagging behind and I could not finish machining it on time as result of running out of materials and changing CNC program settings before the exact due date of the project.. Therefore I was unable to accomplish my final goal on making it real F1 which may achieve target of 100km/h within 20 m long track.

Initial Design

The main idea was to design a car which is aerodynamically and mechanically efficient. The initial design was done by simple hand sketch and it was helpful to get an idea of the final product for some extent. Therefore the final design may have taken influence of the initial sketch but it vary during design the actual CAD model design while making it more dimensionally correct and accurate with given dimensions

Limitations F1 car body meant to machined by a single block of balsa wood and main limitation during the whole project process was creating fillets which are lengthier than 3mm.becasue minimum radius which can undergo by CNC machines are 3mm

CAD design

This project requires a use of versatile software such as Solid Works or Catia which can be programmed in CNC machine. During the project I have used the Solid works to build up the CAD design. The reason for choose Solidworks it offers special features that allow us to test the product in near real life conditions by putting the model through stress tests and so forth. This makes Solidworks an important design tool that we use in this project. The project gave me a great opportunity to develop my skills in using SOLIDWORKS software to design a 3D model.

Design Overview

After going through some researches about F1 cars it wasn’t harder to go get in to idea of F1 car model.Basically there were few sketches were made by free hand but finally this one was selected as the main car concept then the final design was subjected to modifications as needed.

The main consideration during the sketch and car body design was making it more aerodynamically shape. Which can helpful to get rid of resistance forces while the car moving on track and it has found 60% of generated power is wasted to drag forces of the car. So making car aerodynamically efficient means it produces more power to move front. Past studies of the associated degree program such as thermo dynamics 1 and 2 was very helpful to make correct decisions while making the body aerodynamically correct as it has thought about fluid dynamics and analysis.

This is the first Solid works 3D rendering of my F1 design, there were some design issues while building up the model. So had to recreate the model few times due to clashing with some project regulations throughout the designing process. My aim was to create a sleeker design and avoid the mistakes I made in earlier design process.

In this design I tried to achieve good aerodynamic shape to its body going under specification that I given to the free hand sketch and decided to closely follow the requirements because by limiting our choices it provides us with a real life scenario where we need to work with limited resources.

The addition I had to change the front aero foil few times after completing the car because it had too many complications and machining process could not archive such complications. The rear aerofoil going besides the carbon cartridge and it was made on the car body without assembling another part to the body. Same method followed to front aero foil. Also I set the cockpit transparent to make it light weight

Design Specifications

Specification Type Allowable dimension (mm) Model dimension (mm)Min Max

Car BodyFull body length 170 210 185.73Body height above track 3 10 7.52Width at side pods 50 65 50

Total width + wheels or body 60 85 74Body weight without canister 85.75g -Maximum body height - 38.31

WheelsNo of wheels 4 4 4Front wheel diameter 26 34 30Front wheel width 15 19 17Rear wheel diameter 26 34 30Rear wheel width 15 19 17

Power PlantCanister chamber diameter 19.1 19.9 19.5Lowest point of chamber to the track

22.5 30 25

Depth of cavity 50 60 60Wall thickness around canister 3 - -

AerofoilFront aerofoil span 40 65 60Front aerofoil thickness 1 12 1.89Rear aerofoil span 40 65 60Rear aerofoil thickness 3 12 4.06Front and rear Aerofoil chord 15 25

Tolerances For all specifications

Dimension tolerance ± 0.1 mm Weight tolerance ± 5 Grams

Results and Findings

This section is dedicated to all the information we have gained through research. Here we will briefly discuss the basic principles used in the calculations and the physics that go into the work to help us achieve our goal.

Usually a project of this scale will require considerable amount of calculations that need to be carried out before actual testing can commence. But since Solidworks provides us with a tool called FlowSimulation we are able to recreate real life conditions within given parameters in a virtual environment allowing us to carry out experiments on the model. Normally these kinds of calculations require us to put the model through rigorous testing which includes a wind tunnel to determine the aerodynamic properties. Thanks to FlowSimulation most of our work load is done virtually.

FlowSimulation provides us with numerous ways to test our model but for the sake of time saving we will only use air as the fluid to do our calculations. Because of this we do not have

to do any actual calculations on paper or do any math by hand but in this section we will discuss some of the useful equations and theories that would allow us to do them by hand.

Findings

Newton’s Laws of Physics

The Second Law

“The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object.”

From this we can deduce the following equation

F = m*a

And from that,

a = F/m

Where,

m = Mass of the objectF = Resultant force acting on objecta = Acceleration of object

The power source for our F1 model will be a compressed canister of CO 2. The resultant force acting on the car will be the reaction force of the gasses escaping the nozzle. To explain this we need Newton’s third law in which Newton states,

“For every action, there is an equal and opposite reaction.”

In this case the escaping gasses push on the nozzle and the reaction is movement.

Aerodynamics

Drag Force

Aerodynamics play a crucial role in the cars design as it directly relates to the maximum attainable velocity. Objects moving through a fluid experience dag. The drag of an object is the resultant force due to pressure and shear forces acting on the surface of the object. This, in other words is friction between the air molecules and the car body.

The drag force can be calculated by the following equation

Fd = Cd ρV2A*1/2

Where,Fd = Drag ForceCd = Drag CoefficientV = Velocity of objectA = Characteristic frontal area of the bodyρ = Density of fluid

The drag coefficient is a known constant and can be found by looking up a table.

Image 5.1Drag coefficients of common object faces (see Appendix A)

Downforce

Downforce is created when air moves through or over parts of the car. A F1 cars wings and body are designed in a way so that air is forced upwards when traveling at high speeds. As stated before in Newton’s third law, for every force there is an equal and opposite reaction. The reaction of the air pushed upwards is the car pushed lower to the ground. This essentially makes the car heavier without the added force. Downforce allows drivers to take corners at higher speeds with increased control.

Discussion

Throughout each phase this project has offered us opportunities to implement what we have learned so far in project management in our previous semester. Following those guide lines have helped us to be on top of the project and stick to the given timeline. Being mechanical engineering students, most of the research done on this project may or may not be directly relevant to our main field of study. But that is not the main objective of this project.

In our design of the F1 car, we decided to adhere to a minimalistic design. This is so that the complexity of the model will be reduced. What most students fail to realize is in engineering design if the model is unnecessarily complex you are prone to run in to a large number of problems ranging from manufacturing to assembling and maintenance. By reducing the number of parts and the complexity of the parts we increase our chances of success in a way.

Conclusion

So far our project has been a success and we have found most solutions to the problems we faced by ourselves. Personally our team has been acting strong throughout the whole process and both of us have contributed equally to the success. Research done during this project will come as added benefit when we have to work with fluid dynamics in our higher education course.

The only major hurdle remaining is the delayed spoiler and we hope to bring the project back to speed before the last week of April. Our main concern is whether splitting the spoiler will lose much of our structural integrity.