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CD Mechanical Car
CD Mechanical Car Project
This project is one where you learn about the physical laws of motion by designing and fabricating a vehicle that uses CD’s for wheels.
Concepts to master:
Force, Motion, Inertia, Friction, Tolerance, Clearance, Fit,
Fractional Measurement, Isometric Views.
Your car must be able to store up mechanical energy by means of a rubber band and release it to propel your car a distance of at least ten feet.
Your car may not be pushed, pulled, thrown, dropped, operated by electricity or any other mechanical or chemical device or by human power. All power used by your car must be stored up as potential energy in the rubber band.
Your car must fit into your locker.
There are three stages, or steps, involved in the
creation or fabrication of your car:
Planning: Planning will include the making of drawings, lists of materials, and an order or list of the procedures you will use to fabricate your car. For example, a list of procedures would include what parts you would make first, second, etc., and when you would perform processes like drilling, cutting, gluing, etc. Note: If you are unable to predict beforehand what steps you will take, record them as you do them for submission later.
Fabricating: The fabricating portion of this project will include the actual making of your car.
Testing and final grade: This portion of the project is where you will set your car on a measured course and test it to see if it will pass the ten foot mark. Your documentation will also be examined to compare your actual car with the original drawings, list of materials, and list of procedures to verify that they match to form an integrated whole.
Planning- having complete drawings according to the criteria above earns 100 points.
Fabricating and testing: 200 points.
Total Points: 300
Once you have completed your planning and drawings, you may acquire parts and materials from the instructor. See the photos at the bottom of this page to get an idea of the kinds of materials you will be working with.
You may work on this project with one other person or by yourself.
This project is to be done in class with classroom materials, tools, and equipment.
Check the General Info Links page for websites with ideas.
See the links to get ideas on how to create a design that will meet the criteria for this project. These links are only for you to get some ideas- you may come up with a better one.
The more rigid the frame of your car, the less friction the axles will have to overcome.
Sometimes, storing up potential energy is not the problem to overcome- it may be getting that stored up energy to the wheels in such a way that the wheels will stay in contact with the ground and transfer the energy into forward motion.
If your wheels do not stay in contact with the ground, devise a way to add friction to the portion of the wheels that come in contact with the ground.
Axel assembly details:
Use a file to expand the center CD hole in order to get a press fit with the plastic tubing. Avoid filing away too much material- you will no longer have a press fit!
This photo details the final appearance of a CD attached to a 3/8" wooden dowel.
The photos below show the material you will use for the frame of your CD car. You must design a frame that uses this material and will bear the weight of the axles, as well as provide an anchor for the rubber band. It is approximately 24 inches long by three quarters by three eighths.
State of California Department of Education Engineering & Design Pathway Standards Implemented in this Project:
A5.0 Students understand methods used to analyze simple structures:
A5.1 Understand load transfer mechanisms.
C4.0 Students use proper projection techniques to develop orthographic drawings:
C4.2 Understand the orthographic projection process for developing multiview drawings.
C4.3 Understand the various techniques for viewing objects.
C4.4 Use the concepts of geometric construction in the development of design drawings.
C7.0 Students understand sectional view applications and functions:
C7.1 Understand the function of sectional views.
C7.2 Use a sectional view and appropriate cutting planes to clarify hidden features of an object.
D4.0 Students understand how the principles of force, work, rate, power, energy, and resistance relate to mechanical, electrical, fluid, and thermal engineering systems:
D4.3 Know the six simple machines and their applications.
D4.4 Know how energy is transferred; know the effects of resistance in mechanical, electrical, fluid, and thermal systems.
D5.0 Students understand the design process and how to solve analysis and design problems:
D5.1 Understand the steps in the design process.
D5.2 Determine what information and principles are relevant to a problem and its analysis.
D5.3 Choose between alternate solutions in solving a problem and be able to justify the choices made in determining a solution.
D5.5 Understand the process of developing multiple details into a single solution.
D5.6 Build a prototype from plans and test it.
D5.7 Evaluate and redesign a prototype on the basis of collected test data.
D7.0 The students understand the concepts of physics that are fundamental to engineering technology:
D7.1 Understand Newton’s laws and how they affect and define the movement of objects.
D7.2 Understand how the laws of conservation of energy and momentum provide a way to predict and describe the movement of objects.