Embedded Files
Automotive aerodynamics is the study of the aerodynamics of road vehicles. Its main goals are reducing drag and wind noise, minimizing noise emission, and preventing undesired lift forces and other causes of aerodynamic instability at high speeds. Air is also considered a fluid in this case. For some classes of racing vehicles, it may also be important to produce downforce to improve traction and thus cornering abilities.
Automotive aerodynamics is the study of the aerodynamics of road vehicles. Its main goals are reducing drag and wind noise, minimizing noise emission, and preventing undesired lift forces and other causes of aerodynamic instability at high speeds. Air is also considered a fluid in this case. For some classes of racing vehicles, it may also be important to produce downforce to improve traction and thus cornering abilities.
Rail Car - Test Construction
Objectives -
Describe three factors important to the performance of a CO2-powered rocket car
Calculate the area of a solid’s planar face
Calculate the volume of a solid, and, when given the density, calculate the mass
Create a new assembly
Insert components
Add mating relationships between components.
Use Additive Manufacturing to build it and make it ready for racing.
Created a triangular shape for the body of the car
Extruded the shape
Style Spline tool used to create canopy
CO2 cartridge hole
Front wheel dimensions
Rear wheel design
Fillets on body for aerodynamics
Rear wheel assembly
Front view
Front wheel assembly mirrored
Rail Car final design with components and assemblies mated together
Surface plots
Engineering Drawing
Excel Data Capture
Excel drag plot
Flow trajectories
Flow animation
Thumbnail Sketches and Research
Honda Civic with 2 spoilers
Honda Civic with low spoiler/ large tire in front
https://dsportmag.com/the-cars/features/8-second-honda-civic-ek-dragger/
My design was based off of a 2000 Honda Civic. Civics used for drag racing have a larger tire in the front since they are front wheel drive. They also have a air deflector under the front bumper to help create down force.
Energy is needed to move a vehicle. In order for this movement to occur a vehicle must overcome drag. Turbulence is caused as air flows over a vehicle. This flow must be as smooth as it can be to be aerodynamic.
My first design had a spoiler on the back and a solid hood. The overall body is smooth
The second part of my first design was similar but now it has a hole in the spoiler so air can flow through. The spoiler still adds downforce and helps aerodynamics.
The second design had more rounded edges, several airflow holes, a deflector for down force, and a front end design to promote lift. There is a barge board on the side to help deflect air. The front end is wider than the rear end, with a large front tire and a small back tire. This is still based on a front wheel drive car.
This car design should minimize the drag on the car. The cutouts should allow for an area of high and low pressure. The front end design allows for lift to occur.
The Design
Honda Civic
Honda Civic with decals
Various pictures of the original design
Surface plots - the front end was somewhat aerodynamic. the hole in the spoiler really helped with aerodynamics. The angle of the windshield caused a little bit of undesired aerodynamics.
Civic Lift plot
Civic DRAG plot
Surface plot with flow sim overlay
Flow sim
Engineering Drawing
Civic Drag and Lift
"Redesign" - The Axoloti
This new design was also designed to have the large tire on the front of the vehicle. The front end included a pointy design with air inlets that went completely through the car. Some of the inlets went through the car and down so that the air didn't have to travel over the car. An axolotl is an aquatic salamander. The picture on the car is an Axolotl.
Various views of the design
Surface plots - Keep in mind, the bigger side is the front
AxolotlLift
Axolotl Drag
Flow Sim of Axolotl
Engineering drawing
As you can see from the two diagrams below, the original design of the Civic did not have desirable drag and lift. The second design which I called the Axolotl had significantly better aerodynamics. The values for drag and lift were nuch better for the second design. (Each chart has been paired with its respective design to the left for reference.) My second design improved upon the drag and lift.
Race Day
Below is the 3D printed CO2 car. It had a 4% infill. In hindsight, I should have done 0% because 4% made the car ALOT heavier. My car weighed 190 grams.
Tunnels through the car so air did not have to travel over the car. This helps provide lift and downforce at the same time.
Front end
Rear end with CO2 cartridge hole
Bottom with hole for string
Side view - I had to sand in the wheel well in order that the wheel would not hit the wheel well. I think this was caused by the 4% infill.
Top view
Although my car was aerodynamic, it struggled to get to the end of the track while still maintaining a fast speed. My car was very heavy. It started out fast but slowed after 1/2 track.
Race Results
My first race had a max velocity of 31.088 ft/sec
The second race I was absent for
The third day of racing, the max velocity was 30.928 ft/sec
The average velocity was 31.008 ft/sec
Overall, my car was very aerodynamic, but it was heavy causing it to come in 3rd from last.
Page updated
Google Sites
Report abuse