This is a car using a lightweight design using mainly balsa wood to create a hollow base for a car. The solar panel is supported by four balsa wood beams to create a flat solar panel on the top of the car that we were able to get after many other designs. through trial and error we found that this solar panel design worked best because it was able to work well consistently. Because if it were slanted forward then we risked not being able to get direct sunlight on our car.

Junior Solar Sprint Design Log

Car Name: Dave

Team MemberGradeStrengths
Logan B8Designing and measuring angles.
Jamie H8Building and being cool and has experience with competition.

Time and Design Progress

DateTime SpentActivities
December 2, 20221 hourWe made a rough sketch of our car and a more accurate sketch that had measurements of lengths and angles. It also had the correct proportions to our car at a 1:2 ratio.

December 16, 2022
1 hourWe made the base for our car with balsa wood. and followed the plan we made last week. We had to measure out each piece to the marked measure on our design, we also had to make sure the base was symmetrical.
January 6, 20231 hourWe worked on the wheels and axles on our car. It was hard to align them correctly so that the car would run straight. We also worked on fixing up our car if anything had not worked.
January 13, 20231 hourWe added the motor and battery pack and used a test run. It ran crooked so we had to do some axle adjusting. It did not run completely straight even then.
January 20, 20231 hourWe readjusted the gear on the motor in an attempt to make it more aligned. This is a problem but we just have to keep testing out different gear ratios to find the correct fit.
January 27, 20230 hoursMissed due to school trip.
February 3, 20231 hourWe aligned our gears more and added a support for our motor. We had to get the correct measurement so the support wouldn’t touch our wheels. We also tested new solar panel designs and worked on this log.
February 10, 20231 hourWe tested out different ways of putting the solar panel on the car to have a balance of lightness, and aerodynamics. We initially planned to put our panel at a 10 degree slant for aerodynamics but after testing it, we realized that it made it way harder to catch direct sunlight. We decided that we wanted to have the panel lay flat on top of our car. 
February 17 20231 hourLogan was absent so Jamie worked on another way to attach the solar panel but it ended up not working out so he had to scrap it. It had four slanted beams supporting the solar panel. It was too delicate so there was a risk of the car falling apart, and it was too heavy because it required extra supports that would not have been there if he didnt slant the beams.
March 8th30 minutesWe used a new front wheel design that was placed differently and used different wheels. This is because we felt that our current design rattled around too much and overall slowed down the car. The new design also significantly decreased the weight of our car. (it just made it look kinda weird)
March 21st.1 hourWe used a new way to set up the solar panel and attached the wheels in a way that it would go in a straight line and stay on sturdily. We also took photos and the video for our car.
March 23rd2 hoursWe worked on the website and the log and shot the video where we talked about the car. 

Design obstacles and changes made: 

We had a large problem with how we set up the solar panel because initially it was slanted but the issue with that is that while it worked well it could only go when it was facing the sun which hindered its performance greatly this is where most of our issues were for the design.

Dimensions of car: (height, width, length)

8.5cm 16cm 33cm


206 grams

Wheel size(s):

≈14.13717cm circumference back wheels ≈12.56637cm circumference front wheel

Gear ratio (# of teeth on motor / # teeth on axle):


list of materials

All materials used are repurposed or recycled.

  • coreplast
  • 4 large gears: back wheels
  • 2 thick wheels: front wheels
  • four rubber bands for the wheels and one for the milar
  • Balsa wood for the frame of the car and the 4 columns
  • 1 Battery pack
  • 1 motor
  • 1 really small gear for motor
  • 1 small gear for axle
  • 1 metal axle
  • 1 plastic axle
  • tape
  • Foam
  • 3 bushings
  • milar
  • 1 piece of comb binding

4 thoughts on “Dave

  • I love the design and the flat top. Great job on the documentation!

  • Love the simple, clean design. I know that y’all worked really hard to get it pared down to the minimum weight. Also, appreciate that all of your components are repurposed or recycled. Great use of your resources. Good luck in all aspects of the competition. We’ll be pulling for y’all.

  • Your webpage offers a good synopsis of your design process. Good luck!


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