Bob "Rocketman" Maddox, known for his outlandish inventions, demonstrates his DIY go-kart powered by three valveless jet pulsejet engines. Yes, you read that correctly." Maddox's newest invention, dubbed "The Beast," spews flames behind him and has a top speed of 90 miles per hour. It runs on propane and diesel fuel. It's extremely loud, as you might expect, which means that sitting in the driver's seat isn't an option unless you invest in good hearing protection