CO2 Dragster Design
Research and Development
Objectives
Research in CO2 auto design involves the study
of a few sciences related to the motion of your
dragster.
• Aerodynamics- the study of how solid objects displace fluid
air and other gases;
• Physics- the study of matter in motion;
• Tribology- the study of friction;
Research and Development
Objectives
Development of CO2 auto design requires• Understanding the problem or purpose- trying to achieve the
fastest speed and/or best appearance;
• Knowing your limitations- being aware of safety regulations,
materials allowed, specifications, tolerances and
functionality;
• Making intelligent decisions- taking what you learn and using
it to your best advantage;
• Testing your solution- comparing results with your
classmates to see what works better;
Terms to Know- Aerodynamics
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Fluid
Mass
Aerodynamics
Drag
Lift
Rear Suction
Down Force
Frontal Area
Research- Aerodynamics
 Air– Is a type of fluid such as water that can be
directed or displaced;
– Has mass and is measured in terms of pressure;
– Applies direct and frictional forces to objects in
motion;
Research- Aerodynamics
 You should be aware of four aerodynamic
principles–
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Drag
Lift/Down Force
Drag Coefficient
Frontal Area
Research- Aerodynamics
 Drag is a combination of two forces that will
work against the acceleration of your CO2
car.
– Frontal Pressure occurs when tiny molecules of air hit the
front of your car and is forced away to make room for
other molecules to hit it.
– Rear Suction occurs when an empty pocket of air is
created in the back of your car resulting in a vacuum
cleaner effect that tries to pull your car backward.
Air Flow
Rear Suction
More Science on Suction
Since we know that air has
mass with weight measured in
pressure, we take notice that
liquid is pushed up a straw
when the balanced air
pressure is removed. When
fluid air is removed from a
surface around your car, air
pressure causes the empty
space to be filled in by the
weight of the atmosphere.
Research- Aerodynamics
 Lift is similar to rear suction in that a thin
empty pocket occurs as air passes over a flat
surface causing the car to lift.
 Down Force is due to high pressure in curved
surfaces that causes the car to be pushed
down. (Up next, notice how the windshield
takes the shape of a spoiler.)
Air Flow
Lift
Down Force
Air Friction and Lift
When a ball rotates in motion,
it causes the air around it to
flow with the rotation, often
changing the direction with
lift and down force.
The dimples in a golf ball are
also used for reducing air
friction with the surface.
Research- Aerodynamics
 Drag Coefficient is a way of expressing how
slippery a car is.
 Here is a tip to increase your speed and lower
your drag coefficient(the more ways you can eliminate drag, turbulence,
rear suction, lift and down force, the faster your
car will go)
Research- Aerodynamics
 Frontal Area is the total of all surfaces in the
front of your vehicle which cause drag.
Area = Length x Width
Review
With one hand, which can be
thrown further, a football . . .
or a soccer ball?
Review Tips- Aerodynamics
 Avoid flat upright surfaces in the front of
your car to reduce turbulence.
 Avoid flat upright surfaces in the back of
your car to reduce rear suction.
 Shield as much air at the bottom of your car
to maintain traction.
 Keep the surface area exposed to
oncoming air to a minimum.
Research- Physics (Preview)
Which ball can I hit
farther, a base ball or a
softball?
how about a golf ball?
Terms to Know- Physics
 Force
 Acceleration
Research- Physics
Force = Mass x Acceleration
Heavier objects require more effort to move at the
same speed;
It is easier to push a CO2 car out of the ditch than to
push an actual car out of the ditch.
Research Physics
Heavy Mountain Bike
•Durable
•For Rough Terrain
•Requires more Energy
Light Racing Bike
•Fast
•For Long Distance
•Requires less Energy
Research- Physics
How does the angle of your CO2 cartridge
affect the efficiency of your car?
Review Tips- Physics
 Avoid unnecessary extensions and ornaments that add
weight to your car.
 The lighter you design your car, the more power will be
used out of your CO2 cartridge.
 Make sure that your drill holes are straight and accurate to
reduce extra forces acting on your car.
Research- Tribology
Tribology is the study of friction between solid
surfaces.
 Friction is a force that resists movement.
 Friction is found between moving parts and
surfaces.
 Without friction, objects would never come to
rest.
Where will you find friction forces acting on
your car?
Research- Tribology
How many wheels should you have and why?
Research- Triboloby
Does the paint job affect your car: Why or
why not?
Research Physics
Heavy Mountain Bike
•Wider Ground Contact
•More Surface Friction
Light Racing Bike
•Narrower Ground Contact
•Less Surface Friction
Review Tips- Tribology
 Painting your car will reduce aerodynamic
friction.
 Axel design is important to reducing friction.
 Lubrication of the axels can reduce friction.
 Less ground contact wheels have with the
ground, the less friction will be present.
Review Tips- Aerodynamics
 Avoid flat upright surfaces in the front of
your car to reduce turbulence.
 Avoid flat upright surfaces in the back of
your car to reduce rear suction.
 Shield as much air at the bottom of your car
to maintain traction.
 Keep the surface area exposed to
oncoming air to a minimum.
Review Tips- Physics
 Avoid unnecessary extensions and ornaments that add
weight to your car.
 The lighter you design your car, the more power will be
used out of your CO2 cartridge.
 Make sure that your drill holes are straight and accurate to
reduce extra forces acting on your car.
Review Tips Painting your car will reduce aerodynamic
friction.
 Axle design is important to reducing friction.
 Less ground contact wheels have with the
ground, the less friction will be present.
Wisconsin Applicable Teaching
Standards
By the end of 8th grade, students will be able to:
A.8.1 Show that technology has allowed us to further the efforts of science and, in
turn, science has enabled us to develop better technology
A.8.2 Explain the need for and application of knowledge and skills from other
disciplines when engaging in technological activities
A.8.3 Identify and contrast the connections and differences between technology and
other disciplines
A.8.4 Determine that technological knowledge is valuable but not always available to
everyone on an equal basis
A.8.7 Discover that human will or desire can lead to the design of new technology in
order to seize an opportunity or solve a problem