1. Electric Car Project
Riley Walz, 7-7

2. Presentation Contents
Problem Situation
Research and Investigate
Generate Alternative Designs
Choose and Justify the Optimal Solution
Develop Your Prototype
Testing & Evaluation
Redesigning and Improving
Communicate Your Achievements

3. Required Items Designed:
Problem Situation
We have made a model electric car. The car utilizes 4 wheels, 2 wheels of corresponding size for front wheels and 2 wheels also of corresponding size for the rear wheels. The wheel are ‘joined’ with axles. We were given a pack of pulleys we used to plan and make our design realistic. Our transmission of pulleys was used to reduce our car’s speed to 10 miles per hour or less.
Materials Available:
push button switch
AA battery holder
wheel sets
gears
motor
axles
rubber bands
wood for base/side rails
pulleys
Required Items Designed:
Transmission that will reduce speed of car to 10 miles per hour or less.
Frame that is cut from pine wood so it includes side rails, a center section that will hold the motor and battery holder, and wheels and axles.
Propulsion System that consists of a series circuit [motor, power source, switch & wires].

4. Research & Investigation
We needed to research and plan our car so we did not run into any flaws or problems in the building process. We needed to look up key vocabulary, also verify gear and pulley ratios so our transmission was accurate.
Key Vocabulary Terms
Gear Ratios
Work is the means by which energy is transferred from one object to another.
Energy is the ability to do work.
Kinetic Energy is energy that is moving, or is in motion. It is the opposite of Potential Energy.
Potential Energy is energy that is stored, and used later. It is the opposite of Kinetic Energy.
Heat is thermal energy that is transferred from something that is warmer to something that is cooler.
Joules [J] is the amount of energy required to move an object 1 meter using 1 newton of force.
The Law of Conservation of Energy states that energy cannot be created or destroyed, but that it can change from one form to another.
Transmissions transfer power from the motor to the wheels. It will also reduce the speed for our case.
Drive Gear is the gear that turns other gears.
Driven Gear is the gear that gets turned by other gears.
Gear trains are series of gears that can change the speed of the output. They are used in transmissions.
Gears/pulleys used
Ratio
Speed
12:20, 40:30
1:5
9.818 mph
12:40, 20:30
P1:P3, P2:P4
1:6
8.180 mph
P1:P4, P2:P3
12t:30t, P2:P4
9.816 mph
12t:40t, P2:P3
12t:40t, P2:P4
3:20
7.362 mph
P1:P3, 20t:40t
P1:P4, 20t:30t
P1:P4, 20t:40t
1:8
6.135 mph
P1:P4, 30t:40t
3:16
9.203 mph
I decided to use all pulleys in my car, because they were most dependable and were the easiest to build. I also used a P1:P3, P2:P4 gear ratio, for an inverted 1:6 ratio. The speed of my car is about 8 miles per hour.

5. Research & Investigation
Frame
Propulsion System
To build our car, we were required to build a frame out of the pine wood block we were supplied. The frame needed a bed, with which to place the components our circuit (ex. motor, AA battery case, etc).
To build our frame, we needed to:
drill our axle holes using the drill press
cut the body of our car, and smaller piece of wood for the bed using the band saw
sand the frame to give it an edgier look, using sandpaper
To build our car, we were required to construct a propulsion system made out of a series circuit, which will consist of:
motor
power source (battery)
switch
wires
Before we started to build our car, we planned ahead and drew a diagram of our circuit on our car:
push switch
axle holes
battery holder
motor

6. Generate Alternative Designs
Task: We are making a model electric car. It will be made of pine wood and has to under 10 miles per hour. We need to use a transmission, a frame from the pine wood provided and a propulsion system made from a series circuit.
Explanation of Design: I choose the design for my electric car because it had a large bed (to ensure I had enough room for my battery holder, motor, etc). My design met the specifications because I had propulsion system, transmission, and a frame. My designed speed was calculated to be about miles per hour, which was below the specification of a 10 miles per hour or less on the designated speed
Materials Available:
push button switch
AA battery holder
wheel sets
gears
motor
axles
rubber bands
wood for base/side rails
pulleys
11,000 (Motor RPM) x
6:1(Gear Ratio) x
4.712 in. (circumference of drive wheel ) /
3 (20 seconds) =
estimated distance traveled (with no load) : ~269 feet
Diameter of Drive Wheel: 1.5 in.
Circumference of Drive Wheel: in.
Gear Ratio: 1:6
Motor RPM: 11,000
Approximate Speed: mph

7. Choose & Justify Optimal Solution
The car design I chose to build is the one in the drawing as shown on the top right. Is has a flat, long and vast bed, ensuring that I have enough room to place things like the push switch, battery holder and motor. I chose all pulleys for my transmission because they were most reliable (as in they weren’t likely to spin out), and they were the most easiest to build. I also chose the P1:P3, P2:P4 over the P1:P4, P2:P3 pulleys because they fit the most nicely on my car.
Gears Selected: P1:P3, P2:P4
Gear Ratio Selected: 1:6
The sketch used to create the electric car
A diagram of the pulleys used in our car (a 1:6 gear ratio, which includes the P1:P3, P2:P4 pulleys)

8. Develop Your Prototype
Here the steps we used to develop, build and assemble our car:
We knew we needed to plan our prototype before we started to build, so we drew a sketch with, for example, where the axle holes would be drilled, or even where to saw through. Our drawing also included while pulleys to put where, and more.
Once we were done planning, we got to work right away building. We used different machines to build with.
We used a drill press to drill the holes for the axles to eventually go into. We needed axles for a set of pulleys (the P2, P3), and for two sets of wheels. We needed to drill 3 holes altogether.
We used the band saw to cut/saw our car into the shape we had designed. We cut out the spot for where the bed would be and the bed itself. After that, we cut width of the car in half (so we could squeeze our pulleys and bed into).
We also used the electric sander and sand paper to sand our vehicle to fix any rough spots, etc that may have happened during the time we used the band saw. It made the car smoother and easier to hold. The sand paper helped us fix any spots the electric sander had missed.
After we had cut, drilled, and sanded the necessary parts for our car, we needed to assembly everything.
We first had to put our axles and see how well they fit and go from there. Everything seemed to work fine. We used a hammer and a clamp to cram our wheels onto the end of the wheel axles and the pulleys into the middle of the axle for the pulley.
We also had to test our series circuit to make sure the directions of the wheels would be correct once the circuit was closed. To do this, we used the battery holder (that we did not glue yet), and put the circuit in different directions to see which one was the direction that we wanted.
After everything was hooked up and in place, we needed to make it solid and put everything into place.
We used the hot glue gun to place our battery holder, push switch and motor onto the bed of our car.
We also used the soldering iron to solder together the various parts of our series circuit for our propulsion system. We put a string of metal over the two wires that needed to be connected for approximately 5 seconds and it would melt those two wires together.

9. ✔The soldering work was still working during the third test.
Testing Your Vehicle
Test
Propulsion
Transmission
Frame
Test #1
April 1, 2015
× The soldering work on one side of the motor was incorrectly done; the wire fell out.
× The transmission gave us one problem, the rubber band for our pulley flung off the motor.
✔ The frame was in tact and didn’t give us any problems in the first test.
Test #2
✔ After redoing the soldering work, the circuit was working correct during the second test.
× The transmission’s rubber band on the pulley was still falling off during the second test.
✔ The frame was in tact and didn’t give us any problems in the second test.
Test #3
April 14, 2015
✔The soldering work was still working during the third test.
✔ The third time was the charm. After advice from Mr. Vickery, we reglued the motor in the correct position and it worked.
On our third and final test, we accomplished the problem. Our specifications to include working and correct parts in our car were met.
✔ = Good Test × = Bad Test

10. Redesigning the Problem
Solution
The bed was too wide.
We measured for the right width and cut the piece of wood again in the band saw.
The bed was stopping pulley P2 from turning; stopping the car altogether.
Before gluing the bed onto the car, we cut off a chunk of the bed so the pulley could properly turn.
The motor was glued at a tilted angle and the rubber band that connected the motor and pulley would sling off.
We took off the motor and planned where we would glue the motor prior to using the hot glue gun.
The soldering work preformed on one end of the motor that connected to the battery was not holding. The circuit didn’t work.
We soldered again at another angle to fix the connection, and held the iron above the connection for a different amount of time.

11. Communicate Your Achievements
This PowerPoint used pictures, gave details of the vehicle throughout all of the design process steps, and the group member is present for this presentation. We hope you liked it; thank you for viewing!