I design, CAD, prototype, and test hardware. Projects below, resume to the right.
In the first quarter of my junior year engineering academy class, my group was tasked with designing and building a LEGO drag racer that would compete against my classmates at distances of 8, 16, and 32 feet. We were given a set of LEGO technic parts and 2 LEGO Ev3 motors. We were given about two weeks to design, improve, and collect data from our drag racer before the competition.
Our LEGO drag racer had one goal: to cross the finish line first. To do this, we attempted to make our drag racer as fast as possible within our constraints. Our drag racer design utilized a gearbox that took our motor output of 165 RPMs all the way up to a theoretical 1375 RPMs. For our group, this gear ratio allowed us to have just enough torque to start quickly, along with enough speed potential to outmatch our opponents in the mid to late stages of the race.
Theoretically, our drag racer was capable of a max speed of 5.5 m/s (18 ft/s); however, within the constraints of our racecourse, our fastest recorded speed was 3 m/s (10.1 ft/s). We were able to find this data by taking our motor output (165 RPMs) multiplied by 5 (our 40->8 gear ratio) then multiplying that by 1.67 (our 40->24 gear ratio). We found our max speed by measuring the time it took our drag racer to travel the second half of the 32 foot race.
Overall, our drag racer preformed very well for the second two competitions; however, during our first competition, the 8 foot race, our drag racer suffered bluetooth connectivity problems and we were knocked out in the first round. In between competitions, we switched our drag racer to a manual program, as opposed to bluetooth, in hopes that it would solve our problems. As evidenced by the results of our second and third races, it certainly did. We ended up placing 2nd out of 8 drag racers in both the 16 foot and 32 foot competitions.
In conclusion, I was very happy with the final result of our drag racer. Aside from some technical problems, our drag racer was extremely successful against the other drag racers in my class. If given more time, we possibly could have created a slightly more aerodynamic, lighter drag racer, but other than that I was very pleased with our final result: a LEGO drag racer that could reach speeds upwards of 5.5 m/s (18 ft/s).