CO2 Dragster Design- Aerodynamics by ePn0RMft

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```									CO2 Dragster Design

Mr. Montague
2009
Research and Development
Objectives
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
• Testing your solution- comparing results with your
classmates to see what works better;
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
 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
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
location of the seams, speed,
and spin all impact the
airflow around the ball and
thereby determine what the
ball will do.
Research- Aerodynamics
 Frontal Area is the total of all surfaces in the
front of your vehicle which cause drag.
Area = Length x Width
Review Tips- Aerodynamics
 Avoid flat upright surfaces in the front of
 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

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
How does the angle of your CO2 cartridge
affect the efficiency of your car?
Review Tips- Physics
 Avoid unnecessary extensions and ornaments that add
 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.

Where will you find friction forces acting on
Research- Triboloby
Does the paint job affect your car: Why or
why not?
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
 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
 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- 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.

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