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CO2 Dragster Cars

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					CO2 Dragster Cars




      Mr. Kassel
Technology Foundations
 Technology Education
Purpose of CO2 Activity

• Understand how a
  CO2 car works

• Design your CO2 car

• Build your CO2 car

• Race your CO2 car
Overview




• Intro to Racing CO2 cars
• Student examples
• Engineering Principles
• Designing your CO2 Car
• Manufacturing your CO2 Car
CO2 Car Examples
Intro to Racing CO2 cars
           • 2 Cars are set up
           • Cars ride on guide wire
             from start of track to end of
             track
           • Co2 cartridge is punctured
             –propelling car forward
           • Two cars race
           • Cars go through end gate
           • light goes for fastest car
           • Race time is recorded for
             each car
What do you use for the track?

 • Many times when people are new to
   CO2 racing, they hear about cars
   running on a "track" and think that a
   track specially made for CO2 cars is
   needed to race them.
 • You can easily build a simple and
   inexpensive race track
CO2 Racetrack

• The only track required is 50# test fishing line.
• Fishing line is used as a guide line that the
  eye-hooks on the bottom of the cars attach to.
• The fishing line runs between the start gate
  and the finish gate
• We will likely run our races using only fishing
  line along the concrete floor of my lab. The
  smoother the surface, the faster the times will
  be.
          length of the track
• The length of the track is also important.
  You need to have at least 60 feet without
  any obstructions. Any shorter distance
  than this, and the cars will destroy
  themselves upon finishing a race.
• The optimum track length is 66 feet (20
  Meters), which is in scale with real
  dragstrip lengths of a quarter mile.
How fast are these things?
 • Up to 60 mph (100 kmh)
What is CO2?



• Power is created by CO2 gas propulsion -
  CO2 gas is in the metal cartridges.
• CO2 is the chemical abbreviation for Carbon
  Dioxide. Not to be confused with the
  poisonous Carbon Monoxide (CO) ,
• Carbon Dioxide is made up of two Oxygen
  atoms and one Carbon atom sharing
  electrons.
      Engineering Principles
The following Engineering Principles
Relate to how and why a CO2 car works
• Newton’s Laws of Motion
• Mass
• Drag
• Friction
Newton’s 2nd Law of Motion
• greater force = greater action.

• Acceleration is dependent upon the mass and force of
  the car.
      F = ma
         – F = force
         – m = mass
         – a = acceleration


• For a fast car, you need:
   – Big force
   – Light car
     Mass

• The Balancing Act:

– Advantages: Cars with less mass go much faster.

– Disadvantages: Cars with less mass are less stable
  and less durable.

• Does takes more or less force to push 40g than it
  does to push 130g?
            Acceleration
• Acceleration is produced by the CO2 gas cylinder.



• The CO2 canister produces thrust when you
  puncture it – propelling the CO2 car forward

• It works similar to sticking a pin in a balloon - The
  balloon is propelled around the room by the thrust
  created by the escaping gas.
   Forces of Resistance
• Drag (from air resistance) (FW)
• Friction
                Drag

Take a piece of wood, slap wheels on it,
shoot it down a track at 60 MPH and the air
rushing over the body and wheels will try to
slow it down.

• Scientifically this is called drag: the
  resistance of wind moving over an object.
    Minimizing DRAG
The Balancing Act:

– Advantages:
Aerodynamically shaped cars have
  less
drag so they go faster.

– Disadvantages:
Aerodynamically "clean" cars are more
                  Friction
 Friction is a product of gravity
• On a CO2 car,
  friction occurs primarily in three places:
– between the wheels and the ground,
– between the axles and the car body,
– between the eye-hook and the fish line
track.
         Minimizing Friction
• Make sure the axle & tires are free rotate.
• Make sure the wheels are not rubbing on
  the car body.
• Be sure to install your eye-hooks properly.
  Poorly aligned eye-hooks often the cause
  of a slow car.
What's the best design for a CO2 car?

  • Your Car must meet the size and dimensional
    requirements of TSA.

  • The best design is the one that wins. There is
    no "one design" that is best.

  • Generally, the two best indicators of a good
    car are clean aerodynamics and high
    craftsmanship. Often, really good designs that
    are built poorly will loose to so-so designs
    built well.
              What is Design
• 1.to intend for a definite purpose
• 2.to form or conceive in the mind;
• 3.to make drawings, preliminary sketches, or
  plans.
• 4.to plan and fashion the form and structure of
  an object, work of art, etc.
• 5.an outline, sketch, or plan, as of the form and
  structure of a work of art, or a machine
• 6.the art of designing
      Designing your CO2 car
• Step 1: Fill out the design Brief
  – The client is you (it is your car)
  – The problem is?
  – The design statement explains what you are
    trying to design
  – The constraints are listed on the “overview
    and specifications” sheet *read this thoroughly
    before proceeding*
         Design Statement
• A Design Statement should be one of the
  first tasks undertaken in the design
  process
• It should explain how you are going to
  solve your design problem (what you have
  to do to solve the problem).
• The design statement is your vision – it
  should not be an afterthought merely to
  justify a pre-determined solution
     Designing your CO2 car
• Step 2
  – Brainstorming (think about what you want
    your car to look like)
  – Sketch 6 different possible design ideas
  – Create detailed sketch
     Designing your CO2 car
• Step 3
  – Complete technical drawing for CO2 car
  – You must have a high quality, accurate
    drawing
  – Drawing must be 1:1scale (actual size)
  – Drawing must be dimensioned
    (all dimensions must be in millimeters (mm) –
    note: 10mm =1cm)
      Designing your CO2 car
• Step 4
  – Fill out list of the parts you will be using


• Step 5
  – Fill out plan of procedure (fill out using pencil, incase
    you need to change this later)

• Step 6
  – Get instructor to look over your drawings and activity
    booklet.
  – You must get instructor sign off before beginning to
    manufacture the car that you designed
  Overview of the CO2 Car
   Manufacturing Process
• http://co2.technologyeducator.com/cars/ba
   - Sample CO2 car being made

• http://co2.technologyeducator.com/steps/s
   - Step by step overview
Manufacturing your CO2 car
• Step 7 - Create a template
  – Draw or trace the outline of your car on the
    graph paper. Attached it to the side and top of
    your basswood block - using clear or masking
    tape.
  Manufacturing your CO2 car
• Step 8 - drill the holes for the axles (using the drill
  press).
   – Make sure the axle holes are in the right spot and
     are straight
   – The holes should be perpendicular to the center
     line of the car and parallel with the bottom surface
     of the car.
   – * Take care to make sure these holes line up
     evenly and are drilled accurately. Crooked holes
     mean a slow car! Use a drill press and take your
     time! *
   Manufacturing your CO2 car
• Step 9 - Using the
  Bandsaw, cut out your
  shape.
• When using the band saw
  to cut curves, you must
  use relief cuts (or you will
  break the band).
• Follow the shape that is
  on the template that is
  taped to your CO2 car.
 Manufacturing your CO2 car
• Step 10 – Shaping and Sanding
  – Use a rasp or wood file ( you may also use the belt or
    spindle sander) for the initial sanding, in order to create
    desired roundness and curves
  – Hand Sand your CO2 car until you have reached the
    desired shape
  – Hand sand with fine sand paper to prepare the CO2
    car for finishing.
Manufacturing your CO2 car
• Step 11 – Finishing
  – Finish cars with wood stain, wood oil, varnish or
    spray paint.
  – Allow to dry and finish sand between coats.
Manufacturing your CO2 car
 • Step 12 – assembly
   – Assemble all the parts of the
     CO2 car
         –   Wheels
         –   Axels
         –   Body
         –   Eyelets
         –   CO2 cartridge
           CO2 Cars
• If you need more info on the Design and
  Manufacturing Process check out:
• http://co2.technologyeducator.com/steps/steps1

				
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posted:10/12/2013
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