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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. In this challenge, you will not only learn about how build and design a race car but will also realize how the design the surface of a car can help minimize drag and improve its motion through the air for better performance.
Teamwork
As a team, we discussed multiple different ways to make our cars faster. One was to put a plastic straw around the axle, to reduce friction, therefore making the car faster. I was initially going to use this idea, but once my car was printed, I realized that the holes were not big enough for the straws to fit into. We also discussed the use of spoilers to produce downforce, but I did not use this idea, in order to reduce friction with the ground, and to reduce the weight of the car.
Research - Rail Car Build
Creating the blank
Cutting out the general car shape
Cutting out the general car shape cont.
Creating a cockpit using loft
Creating the front and rear fenders
Inserting axle holes
Adding fillets to smooth out shape
Final Car Assembly
Camera Render of Rail Car
Research - Rail Car Build Accessories
Wheel Axle
Washer
CO2 Cartridge
Rear Tire
Rear Wheel Rim
Front Wheel Rim
Front Tire
Research - Rail Car FlowSim
Animation 1.aviCustom Car Build
Using the Loft feature to create the main body of car
Using the revolve feature to create the nose of the car
Inserting Axle holes using the Cut Extrude Feature
Cutting off the bottom of car to make a smooth base
Creating the cartridge hole
Creating the wheel cutouts to reduce drag
Cutting out the guideline hole
Cutting out the bottom to provide easier access to the guideline holes
Filleting the back edges for better aerodynamics
Making a cut through the car body to allow air through it, to resolve some of the vortices in the back
Final Car Body
Torgesen - Final Fast CO2 Car.pdfFinal CO2 Car Drawing
Surface Plot
Flow Sim
Flow Sim Results -
Lift = 2
Drag = -28
Torgesen - Flow Sim 3.aviFlow Sim Results -
Lift = -.247884
Drag = -40.102
Torgesen - Second Test Simulation.aviFlow Sim Results -
Lift = 4.09922
Drag = -22.2604
Torgesen - Flow Sim 4.aviFlow Sim Results -
Lift = 3.39614
Drag = -21.8239
Percentage Improvement Overall
Lift = Increase of 69% lift. I decided that a little lift was good, as it would reduce friction between the tires and the ground.
Drag = Decrease of 22% drag.
Final Car After Printing and Assembly
IMG_8508.MOVTime = 1.953 seconds
IMG_8510.MOVTime = 2.090 seconds
IMG_8509.MOVTime = 2.116 seconds
IMG_8512.MOVTime = N/A (malfunction with track)
IMG_8513.MOVCar after Crash
Calculating Maximum Velocity
.25 sec + 1.953 sec = 2.203 sec
.5*2.203 sec = 1.1015 sec
60 ft/1.1015 sec = 54.471 ft/s = 37.139 mph
Test Prints
These are images of the test print which tested the fit of the wheel and the body of the car. As you can see, it fit perfectly, but i was unable to use this type of wheel in the actual competition, due to some chips around the outside of the wheel.
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