Automotive Aerodynamics

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.

Unit 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.

Rail Car

Research - (2/7/24)

Completed the CO2 Rail Car tutorials to gain an understanding of aerodynamics in relation to automotives. Then, we ran this car through the Flow Sim to gather data.

Overview of the Parts

Design of Individual Components

Construction of the car

Designing accessories

Car Drawing

Car Render

Fat Tire/Thin Tire Research - Flow Sim Comparison

Fat Tire Flow Sim without projectiles

Thin Tire Flow Sim without projectiles

Fat Tire with Arrow Projectiles

Thin Tire with Arrow Projectiles

Fat Tire Flow Sim Animation with Sphere Projectiles

Thin Tire Flow Sim Animation with Sphere Projectiles

Fat Tire Goal Plot Chart (Lift and Drag)

Thin Tire Goal Plot Chart (Lift and Drag)

Fat Tire Values from Solver

Thin Tire Values from Solver

Custom Rail Car - (2/13/2024)

Thumbnail Sketches and Research

Construction of Rail Car (Prototype 1)

Modeling personal rail car

Completed first prototype

First prototype fully assembled

Redesigns (Prototype 2)

Adding cockpit to keep air connected to the body of the car. Also removed the front wing in front of the tires because the flow simulator showed that it was not helpful.

Adding a rear fender and mirroring it to the other side to protect the rear tires from airflow.

Bringing in the back of the car so that tires fit under the fender without extruding the fender further.

Prototype 2 - Isometric SolidWorks view of the CO2 Car

Flow Sim Data Comparison Between Prototype 1 and 2

Prototype 1

Prototype 2

The comparison of data between the first design and the redesign. There is a slight difference between the graphs showing the improvements made in drag.

The data and aerodynamic properties have been improved

Drawing of Prototype

Additive Manufacturing of CO2 Car

Part in the slicer; No test prints needed

0.30mm nozzle Draft settings, 10% infill, 3 shells; 6h31m to print

Speeeeed.MOV

Profile Cut View

Finding the Correct Values for the Front and Rear axles.

Front Axle: 65.725mm (2.6269in)

Rear Axle: 51.77mm (2.038189in)

Assembling the CO2 Car + Adding Personalization + Post-Processing

The part with support removed and sanded

Fully assembled car with axles, washers, and tires

Hydro dipping the car with spray paint

Race Day!

Team Shark-n-ators

Race 1 - 2/27/2024

IMG_9406.MOV

IMG_6205.MOV

STATS

Race Type: Fat Tires
Time: dnf

The car did not finish because there was too much friction between the axle and the car. I added straws in the axle holes to improve the friction and hopefully have a faster time.

Race 2 - 2/28/2024

Fromt view.MOV

New2.MOV

STATS

Race Type: Fat Tires
Time: 2.121
Max Velocity: 31.21 mph

Improvements were effective. I raced on the second track which had cracks and caused my car to drive on two tires. In the next race, I will race on the left track which is smoother to improve my time.

Race 3 - 2/29/2024

Race31.MOV

Race32.mov

Race33.mov

STATS

Race Type: Fat Tires
Time: 2.063
Max Velocity: 31.92 mph

The left lane improved the time for my car because there were fewer bumps on the path. For a final improvement, I will add graphite between the axles and the car because graphite is a dry lubricant that will remove some of the friction that the axles are creating.

Race 4 - 2/29/2024

11.MOV

33.mov

22.mov

STATS

Race Type: Fat Tires
Time: 2.007
Max Velocity: 32.64 mph

This is the fastest time that I have achieved. Overall, my CO2 car made many improvements throughout the races based on modifications made.

Calculating Maximum Velocity

Procedure for finding max velocity

Calculating max velocity