Go Kart

The frame is MIG welded mild steel tubing; we found a good deal on the material and bought enough for the full frame plus some extra for any mistakes. Overall dimensions were about 6 feet long with a 4-foot wheelbase.

This project was where I first learned to weld; we messed up plenty of welds early on with poor penetration or porosity, but we ground them down and redid each of them. By the end of the build, our welds were noticeably cleaner than when we started.

Power comes from a single-cylinder engine we pulled from a golf cart. The centrifugal clutch feeds a chain drive to the rear axle, so there's no manual shifting, and the rear axle is supported by pillow block bearings bolted to the frame rails. We tuned the drive ratio for acceleration rather than top speed to keep things manageable during testing.

Tensioning the chain correctly took a couple of tries; too loose and it would skip, too tight and it bound up. We also wired in a keyed kill switch, both to cut the engine in case anything went wrong and to ensure no one messed with the go kart while we weren't around. Before we had this precaution in place, since we stored the go kart in our school's engineering building, other students would take it for joyrides and accidentally break something.

Steering is through the front wheels via tie rods, which caused some tire scrub during turns. The steering column runs up to a quick release hub for the wheel so the driver can easily get in and out.

Braking is handled with a hydraulic disc brake on the rear axle. This system gave us the most trouble; we discovered on the first test drive that the brakes weren't working properly (scary to find out after you've started moving!). It turned out that we had slow leaks at the fittings that bled pressure until the pedal went soft. I tried tightening fittings, replacing crush washers, and rerouting lines before finally finding a hairline crack in one of the fittings; replacing it and bleeding the system fixed the issue.

The kart runs well, and it has been very fun to mess around with. We spent second semester junior year and the summer on the frame and drivetrain, then first semester senior year fixing brakes and enjoying the go kart.

Second semester senior year, we started an FSAE team and spent the rest of the year designing and building as much of that as we could before graduation. The team is still running today as a design challenge at my high school.