LEGO Racecar (Part 2 of 2)

Trial 6

 After the 5th iteration, we wondered if we could lower the gear ratio a little bit in order to make our car go a little faster. We made a new car with 3 24-tooth gears that had a gear ratio of 27:1. We kept the same design as the previous car.

 It took a lot of thinking to get the 3 24-tooth gears to fit in a small space, and eventually, we had to move the motor off to the side of the car so the gears could fit. But the structure of the car was still stable.

Left-5th iteration, Right-6th iteration

The new car was not as organized as the previous car, but it was much lighter.


To compare the two cars' speeds, we did a side-by-side race of the two cars.

The new car was faster than the old car by 2-3 seconds. It took about 12-13 seconds with the new car to clear the finish line while it took about 14-15 seconds with the old car.

The Race!

At the beginning of class on Tuesday (2/25), we raced our cars as a class. Sunnia and I decided to only race our best car (which had a gear ratio of 1:27). Our time was 12.7 seconds, which was second fastest out of all the cars!


In general, I think we were successful in building a stable yet fast car. If we were to make another iteration, we would try to make a better compartment for the weight since we noticed that it shifted slightly during our race. We would also try to make our car as slim and light as possible without making it structurally unstable.


Summary
Final Gear Ratio: 1:27
Gears Used: 3 24-tooth gears, 3 8-tooth gears