Aerodynamics Lab Report

Aerodynamics of Automobiles
Kevin Daniel

Table of Contents
Introduction – Page 3
Review of Literature – Page 4
Materials – Page 6
Procedures – Page 7
Results – Page 8
Bibliography – Page 9

Introduction
Purpose: The purpose of this experiment is to determine whether different aerodynamic shapes of cars will affect how fast they will travel. The goal is to have different speeds for the different car aerodynamics.
Question: The question that will be answered is which car shape will be most aerodynamic, allowing it to travel the fastest.
Hypothesis: If a car has a narrower, flatter front, then the car will travel faster because its aerodynamics will allow air to flow more smoothly around
the car producing less air-resistance and drag.
Real-world Application: The experiment can be applied to the real world as humans use cars in their everyday life, use of more aerodynamic cars will allow for less air-resistance and lesser power need to fuel the car which can reduce the amount of emission a car may produce.

Review of Literature

Independent Variable
A car’s shape usually is made specifically for speed, economic, and/or aesthetics, the shape of the car does affect its aerodynamics and performance.
Different cars have different aerodynamic shapes to best suit their purpose. Regular cars usually have a shape to produce less drag, racecars however have a shape to help create negative lift on their bodies.

Hucho, W., & Sovran, G. (n.d.). AERODYNAMICS OF ROAD VEHICLES. Retrieved May 18, 2017, from http://www.academia.edu/9462450/AERODYNAMICS_OF_ROAD_VEHICLES

Aerodynamic drag is made of two forces: the force of air pressure drag, and surface or skin friction also known as direct friction.
Wheels are also a factor in drag as when they spin they cause friction.

Science of Cycling: Aerodynamics & Wind Resistance | Exploratorium. (n.d.). Retrieved May 18, 2017, from https://www.exploratorium.edu/cycling/aerodynamics1.html

Cars have a shape that helps them produce a greater downforce, especially racecars. Downforce is the opposite of the force of lift which the principle airplanes work on. This keeps the car on the ground and minimizes the amount of airflow going under the car. For this reason, racecars mainly have wings that are upside down to produce this
downforce.

Herring, K. (2004, Aug. & sept.). Car Development and Racing Physics. Retrieved May 18, 2017, from http://ffden-2.phys.uaf.edu/211_fall2004.web.dir/Keith_Herring/development.htm

Rear spoilers on cars also help with creating downward force on the car.

Qi, S., Ling-Shan, C., & Qing, G. (2014, December). Car's Aerodynamic Characteristics at High Speed Influenced by Rear Spoiler. Retrieved May 18, 2017, from http://www.academia.edu/10136010/Car_s_Aerodynamic_Characteristics_at_High_Speed_Influenced_by_Rear_Spoiler

The mass of the car can also effect the force of drag.

Dependent Variable
Speed is the how fast an object is travelling in a given time frame. The formula for speed is speed = distance/time. Speed is different from velocity as velocity expresses how fast something is moving and in what direction. The speedometer of a car gives the car’s speed at any given moment.

Speed and Velocity. (n.d.). Retrieved May 18, 2017, from http://electron6.phys.utk.edu/101/CH1/speed_and_velocity.htm
Control Group
The control that will be used is cars with that are flat in shape, basically a cars lower frame where the wheels are attached. This will serve as the control group as it is a car with no shape, or lacking a shape, and will serve as a comparison to cars with shapes and different shapes.
Constants
Environmental aspects that will be held constant is the air pressure and wind, all cars will be tested in the same room to ensure the air pressure does not change. The room will be enclosed so no wind can affect the car’s performance. The inclination of the ramp will be held constant as varying inclinations can increase or reduce the rate in which the car accelerates. The distance that will be used to measure speed will be constant.

Materials
• Thin wood block (1 feet long)
• Protractor
• Stopwatch
• Meterstick/Tape Measure
• Elevating surface, books
• 3 Model Cars (For this experiment, Hotwheels Rig Heat, F1 Racer, Volkswagen Gold MK7)
• 1 Flat Car
• Flat surface
• Room

Procedures
1. Set up the ramp, use thin wood sheet as the ramp, using books or any other elevating material to incline the ramp. Use protractor to make sure ramp is inclined at 45 degrees. This ramp and inclination will stay constant throughout the experiment.
2. Clear path in front of ramp, making sure the surface is flat. Using tape measure, mark a line on the ground measuring 15 centimeters away from the bottom end of the ramp. The same distance will be used for all trials of every car.
3. Release the first car from the ramp, having the back of the car align with the top end of the ramp. Start stopwatch when the car is released and stop when the back of the car passes the line marked on the flat surface. The different cars are the independent variable.
4. Repeat for 10 trials
5. Do steps 3 and 4 with other 3 cars (1 will be the flat frame car which is the control group) and record the times of each trial of each car.
6. Use speed formula (speed = distance/time) to calculate each car trial’s speed. This will be the dependent variable.

Safety precautions: the thin wood ramp could be sharp enough to cut or scratch, the ramp should be set up with caution.