Every few thousand miles, we pull into a shop, wait our turn, and let a technician drain and replace the golden liquid that keeps our cars running. Jet engines, however, operate on a completely ...

Bob Maddox’s stage name, Crazy Rocketman, is a misnomer. Maddox doesn’t build rockets. He builds pulse-jet engines. There’s a difference. As for the crazy part—that may be true. Maddox is the world’s ...