Pulley Motor Car
Design ideas

This page provides some pictures and ideas on how a pulley motor car may be constructed. It is not meant to serve as a step-by-step recipe or assembly instructions. You may use these ideas to complete your own design and construct your own model of pulley motor car. Some pictures may show parts that are different in shape, size or color from what you may have in your kit.
 Introduction:

Pulley motor car is an electric car using pulleys to transfer the mechanical energy from the motor to the wheels. MiniScience's Pulley Car activity introduces students to compound machines and simple machines including pulley, wheel and axle while incorporating problem solving, mechanical design and modeling. In addition, students will experience using hand tools as they construct their Pulley Motor Car.

Students can explore:

  • Propulsion types and drive concepts
  • Basic soldering techniques and electronic concepts
  • Simple electric circuit including battery, motor and switch
 Teacher Preparation:

During construction of the Pulley Motor racer vehicle, students can experiment and comprehend methods of power transfer, soldering (optional), wheel alignment and calculating pulley wheel ratios. It is up to the teacher to make sure this background information is provided to students in some manner.

 Materials Checklist:

Before using the kit please make sure you have all the items listed below. This kit has the supplies to build one pulley motor car model. A pulley motor car is an electric car that uses pulleys and belts for its transmission system.

  1. Battery Holder
  2. AC motor
  3. Rear Slicks 1 9/16" diameter x 5/8" wide
  4. Front Wheels 1 3/8" diameter
  5. 1/8" dowel for axles
  1. Traction Bands
  2. Eyelets or washers
  3. Straw
  4. Eye Screws
  5. Pulleys
  6. Wood Sheet 5" x 2" x 3/32" (or larger, so you can cut to any size)
  7. Axle Guards, Basswood 1/5" x 1/5" x 2" (5mm x 5mm x 5cm) sticks
  8. Motor Mount (With straps if needed)
  9. Procedure Sheet
Propulsion Systems:

Propulsion systems include using two AA batteries  and a DC motor with a Pulley and Rubber band drive.

Advanced students are encouraged to experiment with different size pulleys.

 

Basic Tools Required

These items may be required to build the pulley motor vehicle: (You can make your car model without them as well)

  • craft knife, used to cut or trim soft wood.
  • White glue, wood glue or glue gun
  • Soldering Iron, needed if you need to solder wires.
  • Pliers, used to connect and twist wires together if needed
  • rulers, used for measurements
  • Pencil, used for marking

Safety Recommendations

During the construction of the vehicle, the following safety precautions should be observed.

  • Wear safety glasses
  • Use care with sharp cutting blades
  • Avoid touching the tip of the glue gun or soldering gun
  • Put safety first

Competition Categories

Competition between students can be based on design, drawings, final appearance, distance-traveled, speed, etc.

Races can be held between cars in a track. Due to the very high speed, design flaws can seriously damage the vehicle in its first strike to a wall or any hard object.

In addition, teachers could implement a problem-solving category for advanced or older students. Teachers would provide students with the pulley car kit then instruct students to make use of additional materials in the classroom to construct a customized vehicle. additional items could include wood scraps, stickers, paint, CD, colored wheels and more. How elaborate or complex the pulley motor cars are depends on imagination and resources.

Standard Assembly Steps

Make your pulley motor car model in 3 simple steps.

Step 1:

 Construct the basic car chassis with 4 wheels
Cut a strip of wood that is 2" (5cm) wide.

Mark the location of axles by drawing two lines, one on each end of the car, parallel to the front or back side. Axle lines must be about 1 inch away from the front or back.

On the axle lines, mark two points that are 1/4" (6mm) away from each side. Insert one eye screw in each of the points.

Eye screws are used to hold the axles. Insert the axle and make sure it is level and it can spin freely. If necessary, adjust the eye screws.

For the back wheels cut a space for the pulley before inserting the eye screws. Without cutting a space for the pulley, one wheel will stay out about 3/8" more than the other.
Cut some plastic tubes or straws and use them as the spacer in both sides. If you have metal washers, insert them between the straw pieces and the eye screws.
Insert the wheels. Wheels may be inserted while the axle is in position.

You can also insert the axle into one wheel and then pass it through the eye screws.
At the end your simple car will look like this. You can use it the way it is or you can turn it over as shown in the picture bellow.
In the model shown here, the gears are built in the rear slicks (rear wheels). With plain wheels, you had to insert a pulley or gear in the same axle with one wheel.

If you don't need to install pulleys or gears, continue with step 2.
To mount a pulley or gear next to one wheel, it is a good idea to cut some space for that on your chassis; otherwise, one wheel will stand out and your model will not have a symmetrical shape. The size of this space may vary depending on the size of your pulley or gear.

(3/8" x 1 1/2" cut is shown in this example)
This is how a pulley or gear may be mounted beside one of the wheels. The pulley or gear must have a hole matching the axle diameter and must feet snugly. Some pulleys and gears require a plastic insert and some drilling in order to adapt the diameter of the axle you are using. After mounting, make sure that the wheels can spin freely. If necessary, mount a metal washer between the spacer and eye screws.

Other methods of mounting the axle

You may not have eye screws for mounting the axles. This is an alternate method for mounting wheels and axle.

Insert the axle in one wheel, slide a washer onto it. Insert a 5 1/2" straw over it and finally insert another washer and another wheel.
Your final wheels and axle will look like this. Hold the straw and spin the wheels. Make sure the wheels can spin freely. If necessary, make some adjustments.
Cut 4 pieces of 2" (5cm) long wood strips and glue them about 1/5" (5mm) apart where you want to mount the axles.
Insert the axle in the space between the strips and secure them in place using some glue. Cover it with a strip of cardboard or heavy construction paper.
Note that the glue will touch the straw, not the axle. This is how the bottom of your car will look like after covering the axle holder with a strip of paper.
Step 2:  Mount the motor
Insert the small gear or pulley onto the motor's shaft. Place the motor on the self adhesive motor mount and strap it securely and snugly.
Place the motor on the car while the car is on a flat surface. Move it towards the gears until the gears engage. Mark the location of the motor. Avoid too much pressure on the gears because it will increase the friction and make it difficult for the car to move.  
If you use pulleys to transmit force, motor must be mounted away from the pulley so that the rubber belt is slightly stretched.

Carefully peal off the protective cover of the adhesive pad. Make sure you will not remove the adhesive pad itself. Place the motor where you already marked. Push it down firmly to stick in place.

Mount the rubber band belt between the wheel pulley and the motor pulley.
Step 3: Mount the battery holder
Place the battery holder on the car, secure it in place with some glue. Connect the black wire of the battery holder directly to the motor. Connect the red wire of the battery holder to the switch, then connect another small piece of wire from the switch to the motor. Insert the batteries while the switch is open.  

Test the car while it is still in your hands. Do the wheels spin? In what direction? If the wheels are spinning backward, switch the wires around on the motor. Place the car on a race track and test it.  Does it run on the ground?

  
The final pulley motor car you make may be different based on the materials you use, the design implementation and additional decorations you may add.  
Decoration may include wooden or cardboard pieces you can add or paints you may use.  

Alternate Assembly Procedure for gear driven solar car

The following steps relate to the construction of the basic pulley motor vehicle. Steps relating to the completion of the propulsion systems are left to the student's discretion.

  1. Make sure your kit contains the items listed.
  2. Locate the grid planning sheet in the kit.
  3. Using a pencil and ruler, design the body of the vehicle and propulsion system.
    Remember, the lighter the vehicle's body, the further it will travel.
  4. Show the drawing to the teacher when ready.
  5. Locate the balsawood sheet from the kit
  6. Transfer the vehicle body pattern to the balsawood.
  7. Using the craft knife and straight-edge, carefully cut out the vehicle body.
  
  1. Locate the straw from the kit. Also get scissors and glue gun.
  2. Cut straw in half
  3. Using the glue gun, attach the straws to the bottom of vehicle, one at each end (parallel to the end)
  4. Locate the axles through each straw.
  5. Push one wheel into each axle.
  6. Insert and axle through each straw.
  7. Carefully place the remaining wheel onto each axle.
    Note: This completes construction of the basic solar vehicle.
  8. Locate the solar cell Panel and the required parts for the propulsion system chosen gears, pulleys, propeller, or rubber band. (Gears are supplied, Pulleys and propellers are optional.
  9. Assemble and attach the propulsion system as designed.
  10. Finish your solar racer as desired using paint, markers, etc.
  11. Race the assembled vehicle on a flat surface in a sunny day.
If you don't have this kit, you can order it now! It is available both as a single pack and class pack. Kit content may be different from the images shown in this page.


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