CO2 Dragster Design

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CO2 Dragster Design

• Mr. Montague
• 2009

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Research and DevelopmentObjectives

• 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

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Research and DevelopmentObjectives

• 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

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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

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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.

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Air Flow Rear Suction
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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.)

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Air Flow Lift Down Force
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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.
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Research- Aerodynamics

• Frontal Area is the total of all surfaces in the
  front of your vehicle which cause drag.
• Area Length x Width

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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.

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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.

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Research- Physics

• How does the angle of your CO2 cartridge affect
  the efficiency of your car?

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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.

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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
your car?
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Research- Triboloby

• Does the paint job affect your car Why or why
  not?

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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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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.

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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.

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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.