Small Capacitor Car - Never Need Batteries!

   This small kart was designed by us three students in our Engineering Class. We hope you enjoy our step by step tutorial on how to build this slick, unique solar capacitor kart!  

Our cart is unique, sleek and is designed to win. We took the best features from some of the speediest two wheel vehicles and combined it with the shape of a canoe. Our cart is made out of ABS-plastic to ensure a light chassis; we also used a copper axel with custom black wheels. Our chassis is approximately 5 inches long and 2 inches wide. Our custom black wheels are near 1.48 inches in diameter with 5 quarter inch spokes. We have only one motor with a rated RPM at nearly 12200. The average amp draw waves between a fraction of an amp to nearly 2.2 at stall. The rated volt operation is about 6 volts, and our capacitor (.pfd file below) will hold 6 volts and will operate the motor for nearly 1 minute and 10 seconds. Our cart is going to be designed with direct drive and will operate on the back wheel. On both sides of our chassis is stabilizing pins that have wax paper attached to attain a low coefficient of friction to reduce drag when the cart is getting started. As the cart speeds up it will stabilize and keep from tipping to one of the training pins.
Each and every part will have a separate slide with a picture giving dimensions and material also if we can supply a link to the product we will do our best to do so.

This wheel is approx 1.48 in in diameter and 0.74 from the center of the hole in the wheel. The wheel has approx thickness of 0.2 in. The wheel is a very smooth plastic well made and black. It has a total # of 5 spokes.  We installed the wheels in the center of our boat body frame design, just far enough away to fit our motor which is approximately 1 and a quarter inches wide.
We apologize for the inconvenience but we cannot supply a link of this item.  

This axle was made out of a thin rod of aluminum and was later glued to the wheel because of our choice of drive train. Our drive train uses a rubber band belt system and is combined with two pieces of heat shrink to supply enough friction that it will spin the axle as well as the wheel. The axle has a length nearly 2 inches in length, and a diameter of ~0.15 in. This was designed to be larger than the width of the kart but not to long as to prevent any catching with nearby items or walls. The rear axle is the one that is attached to the drive train therefor the heat shrink is on that one.  
We apologize for the inconvenience but we cannot supply a link of this item.

This kart body is produced through a 3D printer, Demention 2500, and utilized ABS-Plastic. This gave us free reign over the design of the body. We choose to do a 2 wheel canoe shaped method because it was light and sleek. This takes a common thought of how a boat floats on water and balances like a bicycle. 
We apologize for the inconvenience but we cannot supply a link of this item.

Out initial ideas for the support beams were to have them in the middle of each side of the kart.  Since it is shaped like a boat and only has two wheels it can not stand up straight on it's own.  We designed our first attempt on solid works and attempted to print them on the dimension 2500 3-D printer.  But the beams where two small and required to much detail thus they cud not be printed.  our next idea was to use the curved end of a paper clip.  Our first attempt at attaching the paper clips  We ran out of time to attach them to the side of the kart.  We provided the solid works drawing for the original idea for the support beams.

The process of deciding the capacitor was a long and drawn out process. We originally started out with large capacitors that were over a decade old that ran for just over a minute. Then we looked into some newer capacitors, according to what we knew to be true about capacitors this capacitor would run twice as well as the old and be about one fifth of the size, we were amazed. When we finally got the new capacitor it did not run the motor nearly as fast as the old capacitor and only ran for a total twenty seconds. We originally thought that capacitors were based solely off voltage and capacitance (farads). That is when we learned about ESR (equivalent series resistance) which is the total internal resistance of the capacitor. The new capacitors ESR was too high. We finally settled on a final capacitor PB-5R0V105-R was the model number. The capacitor had a 1F capacitance was rated for 5V and had a ESR of 1 ohm. The following link is for the full data sheet and website we bought it from http://www.digikey.com/scripts/dksearch/dksus.dll?vendor=0&keywords=283-2789 . This whole project was based around alternative energy. We charged the capacitor with a solar array attached to a wooden plank (pictures included). Solar energy is free energy and that is something we should all capitalize on.

This is our motor. It is an old Erector set motor this is non existent in today market and is difficult to find. We have an overstock of them because our teacher bought many in the past. The motor is 1 inch in length and 1.5 in width looking with the motor shaft pointed down. Our kart was specifically designed to house the motor with no extra parts and clips in perfectly. This allowed us to cut down with a lot of weight and friction. We used a tourqe and motor calculator to give us a general figure on how the motor will run. The site is called Team Tentical (http://architeuthis-dux.org/torquecalc.asp).
The image is a screen shot of all of our info!

Through our testing of our rubber band drive we came to the conclusion that we did not have enough torque to move the wheel once it mad contact with the floor.  I tried various things to increase our coefficient of friction on the drive but we were unable to achieve a higher coefficient  than the wheel to the floor.  Our ideas to increase the drive train's friction were to wrap a rubber band around the axle and have another rubber band acting as a chain but that came with no success.  Then we thought we could use heat shrink because a rubber to rubber contact would have more friction than the rubber to the metal axle.  Also when testing we were generating current with Nakamura Hand-Operated Generator which could of put out more volts than the motor could take thus damaging the motor.