Building an Autonomous Vehicle: The Batmobile

Contributors: Nate
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Small Drum Brake

Go-kart drum brakes on eBay

The Razor chassis had the classic drum brake, perhaps the weakest link of the Razor. While the stock brake was probably the appropriate size for a 75lb child with stock 24V batteries, our brakes got really squishy once we added an additional 125lbs of meat bag, batteries and plastic bits. We rarely, if ever, used the brakes during races, but the PRS rules stipulate that your qualifying lap must end with the driver crossing the finish line and braking to a stop:

At the end of the hot lap, your car will have to come to a complete stop within 18ft of when its transponder crossed the start/finish line. Deliberately skidding, swerving or spinning out is not an acceptable method of braking for the brake test.

Alicia had to do an impressive combination of hard braking, swerving, skidding and sliding with such a dramatic flair that she wooed the judges into not noticing how dodgy our brakes were. We’ll have disc brakes installed before we roll in the 2017 race.