PURPOSE
The purpose of this experiment was to determine the effect of front and back designs on the aerodynamic drag of a vehicle.
I became interested in this idea because I loved cars, specifically fast cars. I knew that certain designs were more aerodynamic than others, and that less drag would allow for more speed.
The information gained from this experiment could help car designers choose what shape to base the design of a vehicle on. A car with less drag could be faster and also more fuel-efficient.
HYPOTHESIS
My first hypothesis was
that a square front and back design would be the least aerodynamic, and would
create the most drag.
My second hypothesis was that a hemispherical front and a conical back design would be the most aerodynamic, and would create the least amount of drag.
I based my hypotheses on Landon Arnett’s 7th grade study in 2003. He concluded, “My first hypothesis was that the hemispherical nose would be the most aerodynamic. My second hypothesis was that the conical tail would be the most aerodynamic. The results indicated that both hypotheses should be accepted.”
The constants in this study
were:
• The weight of the Styrofoam designs
• The wind setting (medium)
• The type and number of blowers
• The wind tunnel
• The lightweight spring scale
• The car base
The manipulated variable was the design of each of the cars.
The responding variable was the amount of drag created.
To measure the responding variable, I used a lightweight spring scale.
QUANTITY
|
ITEM DESCRIPTION
|
3-5
|
Styrofoam Blocks
|
1
|
Car Base
|
2
|
Leaf Blowers
|
1
|
Pocket Knife
|
1
|
Wind Tunnel
|
1
|
Lightweight Spring Scale
|
1
|
Set of Earplugs
|
PROCEDURES
1) Carve
the designs out of Styrofoam
a) Design 1:
b) Design 2:
c) Design 3:
d) Design 4:
e) Design 5:
2) Set Up
a) Set up the wind tunnel
b) Put the blowers in the right positions
c) Put the blowers to the right wind setting
3) Test the Designs
a) Place the car base inside the wind tunnel with one of the
designs on it
b) Attach the lightweight spring scale to the car base, and to the wall of the wind tunnel
c) Put the earplugs on
d) Start the blowers
e) Look at the lightweight spring scale and record the amount of drag created every 5 seconds 20 times per test. (5 tests per car, switch design after every test)
f) Stop the blowers
4) Repeat step 3 five times
5) Switch the design in the car base with one of the other designs.
6) Repeat steps 3 and 4 until all 5 designs have been tested 5 times.
7) Average the results for each design.
RESULTS
The original purpose of
this experiment was to determine the effect of frontal, back, and windshield
designs on the aerodynamic drag of a vehicle.
The results of the experiment were that Car Design 1 produced an average of 0.078 newtons of drag, Car Design 2 produced an average of 0.0515 newtons of drag, Car Design 3 produced an average of 0.0797 newtons of drag, Car Design 4 produced an average of 0.0701 newtons of drag, and Car Design 5 produced an average of 0.0342 newtons of drag.
My
first hypothesis was that a square front and back design (Design 2) would be
the least aerodynamic, and would create the most drag.
My
second hypothesis was that a hemispherical front and a hemispherical (Design 3)
back design would be the most aerodynamic, and would create the least amount of
drag.
The
results indicate that my first hypothesis should be rejected, because Design 3
(hemispherical convex front, with hemispherical concave back) created the most
drag.
The
results indicate that hypothesis 2 should be rejected, because Design 1
(triangular front, flat back) created the least amount of drag.
After
thinking about the results of this experiment, I wonder if I made more designs
with more detail, would it affect the results?
If I
were to conduct this project again I would use wood for my designs instead of
Styrofoam to (hopefully) get better results.
Researched
by ---- Brad K
