Our Materials List and Reasoning:
- Carboard for the base and frame of our car – lighter for more speed and less weight
- Rear wheel drive with four wheels from the Maker Space – faster than front wheel drive when the car accelerates as the weight shifts backwards towards the opposite end of the car allowing more taction to occur on the wheels
- A rear wing made of cardboard – reduces the low-pressure zone behind the car meaning less turbulence and less drag force to create a downforce so the car has more stability at a higher speed
- Two AA batteries – power our DC motor
- A battery pack – holds our two batteries
- A DC motor – powers our car to move backwards and forwards
- A driver gear of ten teeth that is attached to the motor – powers the driven gear to move
- A driven gear of 40 teeth (Designed using TinkerCad) – powered by the driver gear
- A 4:1 gear ratio made by the 3-D Printer – this will increase the torque of our car and its ability to do work (the more torque the car has, the more power the engine can produce and this allows our car to accelerate from rest)
- A hot glue gun – this will hold the bas and frame of our car together
- A 0.4mm wooden axle – how our four wheels will rotate (the axle will be cut into two pieces)
- Two plastic straws for each axle to go into – helps the rotation of the axle and wheels
- A painted design of Lightning McQueen – the king of speed
- An H-Bridge circuit – allows our car to move both forwards and backwards with switches to open and close the circuits for current to flow in opposite directions (negative to positive and positive to negative)
Pictures of our Work:
Our Motor Car Design:
The Driven Gear:
Our Circuit:
Our Bibliography:
17, Dave on April, et al. “H-Bridges – The Basics.” Modular Circuits, www.modularcircuits.com/blog/articles/h-bridge-secrets/h-bridges-the-basics/. Accessed 10 June 2024.
Korf, Ian. “RWD vs. FWD: Part 1 – Preliminaries.” You Suck at Racing, 8 Nov. 2021, yousuckatracing.com/2021/11/08/rwd-vs-fwd-part-1/#:~:text=There%20are%20a%20lot%20of,line%2C%20RWD%20wins%20every%20time.
Nath, Devang S., et al. “Drag Reduction by Application of Aerodynamic Devices in a Race Car – Advances in Aerodynamics.” SpringerOpen, Springer Singapore, 28 Jan. 2021, aia.springeropen.com/articles/10.1186/s42774-020-00054-7#:~:text=The%20low-pressure%20zone%20behind,2).&text=The%20wing%20is%20another%20essential,is%20different%20in%20its%20functioning.
Rozum. “How to Calculate Gear Ratio and Not Get Mad.” Rozum Robotics LLC, Rozum Robotics LLC, rozum.com/how-to-calculate-gear-ratio/#:~:text=If%20the%20gear%20ratio%20is,speed%20but%20boost%20the%20torque. Accessed 10 June 2024.
“What Is Torque in a Car?” Kia British Dominica, www.kia.com/dm/discover-kia/ask/what-is-torque-in-a-car.html#:~:text=Simply%20put%2C%20torque%20is%20a,vehicle%20is%20beginning%20to%20start. Accessed 10 June 2024.
Our Final Results
Throughout the week that we have been working on the electric car project, our hard work and dedication to move our DC motor car has become a success! This wouldn’t have occurred without the use of our knowledge from this Physics 11 class that we used throughout the project with our designing and problem solving skills. This knowledge includes what we learned during our Kinematics 1, Kinematics 2, Dynamics and Energy units. All together, we brought in the concepts of speed, acceleration, force, power and electricity to help our car move.
With our designing process, some examples of us using our physics concepts were with our cardboard base, gears with the gear ratio, front wheel drive, rear wing at the back of our car, as well as an H-bridge circuit controller to move our vehicle back and forth. Each one of these were vital with the success of our motor car. To start, the cardboard base was to make the frame of the car sturdy and light, and was held together by light amounts of hot glue to assure that everything was being held together in its place. Next, with our gears and the gear ratio, we had to find a driver gear that would attach to our motor and from there, we designed a driven gear with more teeth than our driver gear using the gear ratio, so then the gears could turn the axle and wheels. The decision to make our motor DC car front wheel drive instead of rear wheel drive was because it is faster for when the car accelerates as the weight of the car shifts towards the back, which then leads to the car having more traction – or friction, a term used from the Dynamics unit. The rear wing of our car is in the design to reduce the pressure behind the car so it runs smoothly with less friction and more speed. Finally, we chose an H-bridge design for our circuit because it allows our car to move both forward and backwards. This happens with the opening of the connection to the circuit and allowing the current of electrons to flow in opposite directions.
Towards the part where we were trying to have our car move forwards and backwards, we ran into a few problems. Initially, it was the size of our driven gear which was slightly larger then our wheels from the Maker Space. To solve that, we simply resized the original gear using the Thinker Cad program, re-printed our driven gear and found another driver gear that was smaller. Not only that, but the driver gear had to also fit with the teeth of the new driven gear, as well as fit in the hole connected to our motor. After that, we realized that our car wouldn’t move as the car was too heavy for the motor to move it. As a result, we took apart the sides of our car and cut down the sides of the base to make it lighter so our car could move faster. Finally, once the base of our car was downsized, we had to resize our wheels. In order for that the happen, we decided to take off the Maker Space wheels and print two wheels using the 3D printer. In the end, we had our own two 3D printed wheels for the rear of our car with our driven gear attached to the axle, as well as a smaller wheel in the front so our motorized car could still be front wheel drive with more speed.
In conclusion, we had success with our designing of the car, even though we came upon a few hiccups along the way, our group still managed to power through with our problem solving skills in order to have an electric DC motor car that moved both forwards and backwards. As a bonus, we even finished our race in 7.90 seconds!