In this project, we used aerodynamic concepts to build a car. The goal was to make the car be as fast as it could. We were given a block of wood to carve a design out of and the car has to weigh at least 5 ounces and be at least 10 inches long. Wheels were provided. We designed the car by thinking of the purpose of the design of real cars and trying to apply these to design features of our cars. The way we approached the building part was to design a car, cut the general shape out of the wood, and do lots of sanding of the wood until the body was exactly the way we wanted.
Technological Concepts
Two main focuses of the project were lift and drag. Drag is the air resistance opposing motion of a moving object. Lift if the force acting to bring a object off the ground. To maximize the speed of the car, lift and drag should be minimized. The car will have least resistance to forward motion is both of these things are kept to a minimum. There were other concepts that we researched, such as air foils, but these were less necessary when it came to the building and designing thus we did not use this information much.
Learning Goals
Learning goals centered around aerodynamics. We wanted to explore how different shapes of cars could affect their aerodynamics. We would also like to know how simple changes can be made o positively affect the cars speed. Another concept we would like to explore is the weight distribution of the car and how much that affects the speed of the car. Another goal was to become comfortable with using the machines in the lab again since its been a year since I've been in the lab. These things fit right into the project and we ended up learning much of the material with planning and designing the vehicles.
Description
We ended up making two cars. Our first car was pointed at the front with a rectangular back. There was a gradual curve to the car to transition from thin to wide. It ended up not being symmetrical. This car has most of the weight concentrated in the back of the car. We cut a basic triangle out of the block to start with and sandedit to be smooth. The second car has larger curves both on the top and the sides. The back was blocky and the front came to a point. The car was better planned out so the curves were more smooth and the car was symmetrical. This car was more uniform with weight distribution since the whole car was thin. This car we cut all the curves and then just sanded a little bit to make it smooth.
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| First Car |
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| Second car |
Positive Feedback
Our second car ended up being very aesthetically pleasing and well designed. It performaned better than average as compared with the class. Both of the cars went fairly fast (completed the track in less than 2.05 seconds). One car advanced into the semifinal round while the other one lost due to falling off the track. They both ran well when tested before the final race. Both of the cars had smooth edges. We worked efficiently in this project and were able to build two designs that we can up with. This helped us with building the second car since we knew the process of whatto do.
Redesign Paragraph
If given another chance, we would plan the cuts in the first car better. It would have looked better and been more similar to our original idea if we drew out the plan on the car before cutting. Another design factor that I would have incorporated is a flatter car. A flat top would allow the air to flow right over the car and it could help minimize lift. I would have also liked to explore having tilted axles so only a couple of the wheels touched the ground. This could have minimized friction the car needed to overcome to start moving and could have made the car's time decrease.
Technological Resources
Throughout the process, we used many different things. In the beginning, we did research about aerodynamics on the computer. We then had a wedge of wood to shape into the car. The limited amount of wood constrained the size of the car, but it ended up not really being a problem since we wanted the car to be small and light. When shaping the wood, we had all the power tools we would have needed to cut out designs and perfect it. We ended up using the scroll saw a lot since we needed to cut curved edges. We used the electric sander to make sure all of the edges were smooth. We had a access to all the tools we needed in cutting and smoothing the wood. The wheels were provided for us. This meant we did not have options to pick wheels that would help make the car go fast.
Biggest Challenge
One of the biggest challenges was sanding the bodies of the car to perfect. The first car ended up being rough and unsymmetrical. The idea was to create a basic shape for the car and sand the car down to what it should be after. The car was cut roughly symmetric, but when we made the edges smooth, it ended up unsymmetrical. Thus, the car was not perfect. We took more off to try to fix it but the car ended up getting shorter so we stopped changing it. We took this into account when making the second car and were able to perfect the second car with careful planning. This second car was hard to sand because of the many curves. When we sanded a part, it became more flat and changed the design. This means some of the places we left rough instead of smoothing the surface which negatively affected the aerodynamics. This challenge taught us that planning is very important in design and building of projects.
What I Learned From the Project
From this project, I learned how various aspects could affect the speed of a car. I saw different designs and saw which ones worked best. Curved designs seemed to be popular and worked well as well as thin cars. Aerodynamics ended up seeming less important than the weight of the car. The car designs were fairly similar and they all worked well. Our first more chunky car went slower than our lighter more sleek car. The weight distribution was the big difference between to the two cars. In making two cars, we learned design and redesign fairly well. Changing things with a problem was essential in making a good second car. I also learned how to more skillfully use the tools and which saws could be used for different cuts. We tried to use the band saw for many of the carving but we learned that the scroll saw was better for the complex cuts.
