Problem Overview: Our group is charged with the task of building the fastest possible solar powered car using a standardized solar panel and a standardized motor on a 60 cm wide track for 20 m.
Design Constraints: The car must be able to fit a 12 oz can into it's chassis that can be contained in the event of a roll. The car must use an unmodified standardized solar panel and a standardized motor and the solar panel may be the only source of energy to the motor. It also must not be bigger then 12" wide by 12" high by 24" long.
Pre-Existing Solutions: Solar sprint competitions have been around for years. With each competition, comes different constraints, leading to different designs, however all leading to the same goal of an efficient solar powered vehicle. Team Nuon of Delft University of Technology in the Netherlands has had a consistently successful design in the World Solar Challenge, winning four consecutive titles. The Tokai Challenger of Tokai University is the most recent winner. Both cars have the same general shape. These would be ideal bases for our design.
Design Goals: Our goal is to make the car go as fast as possible with the given constraints taken into account. Here is the list of our goals to maximize the speed:
1. Maximize mechanical efficiency
2. Minimize the mass of the car
3. Minimize the coefficient of rolling resistance
4. Minimize the mass of the wheels
5. Minimize drag
6. Minimize frontal area
This will be done by:
1. In order to do this, we will increase gear ratio.
2. Minimizing the mass of the car will involve using the least dense materials and making the inside of the car hollow.
3. To minimize the coefficient of rolling resistance, we will use the most efficient material as a wheel, not necessarily what comes in the kit.
4. In order to minimize wheel mass, we will use rings as wheels, not disks.
5 and 6. To minimize drag, we will employ a flattened football shaped design with a low cross sectional surface area being presented in the forward direction. This will increase aerodynamics and increase speed.
Deliverables: Besides keeping the design and progress blog updated, the only deliverable for the project is a functioning solar powered sprint car that meets the design criteria and fits within the design constraints of the Junior Solar Sprint Challenge. Those constraints can be found here.
Schedule:
Week 1: Create blog and begin researching designs
Week 2: Research solar car designs, focusing mainly on previously successful designs
Week 3: Discuss and decide on final car design, start the modeling using CAD programs
Week 4: Finalize the CAD plans
Week 5: Begin constructing the prototype
Week 6: Test the prototype and fix any issues that arise
Week 7: Compete in the Junior Solar Sprint Challenge, Open Division
Week 8: Adjust any issues that arose during the competition
Week 9: Finalize the prototype for grading, making sure all requirements are met
Week 10: Submit car for grading
Budget:
The proposed budget for this project is $89.72.
This figure was produced by factoring the already bought solar car deluxe kit by Pitsco and the added balsa wood that will be needed.
Ray Catcher Sprint Deluxe Solar Kit
With shipping, this cost $57.62.
The kit contains the required solar panel and electric motor plus two 10-1/2" x 4" balsa wood sheets, four nylon spacers, two alligator clips, two 5-1/2" axles, four wheels, four rubber bands, one plastic gear font, and two screw eyes.
Balsa Sheets
This includes 10 sheets of balsa wood with the dimensions 1/8 x 6 x 36.
References:
"Rules and Regulations for 2011" in Northeast Regional Championship Junior Solar Sprint Competition. USA.
FR Whitt and DG Wilson, Bicycling Science, 2nd ed., MIT Press, 1982, p. 157.
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