Robert Maddox, also known as Rocketman, builds pulsejet engines and installs them in motorcycles and go-karts. In a thrilling video, he and a friend take two of these incredible machines for a high-speed ride across a dry lake bed.

Both vehicles are truly impressive. The blue machine resembles a motorcycle with four wheels, featuring a large exhaust chimney at the back. Meanwhile, the red kart is equipped with three stacked pulsejets, giving it a cartoonish appearance.

Motor1.com reached out to Maddox for more information about these builds. The blue vehicle is powered by a 250-pound-thrust pulsejet engine called Maddoxjets, which runs on gasoline. It has a reed valve that allows air into the combustion chamber but closes off during the explosion. According to Maddox, starting the valved engine requires a significant amount of air, and using a leaf blower is easier than compressed air.

The red kart, on the other hand, uses a valve-less design with no moving parts. It generates a total of 150 pounds of thrust from the three pipes. According to Maddox, if he made a single engine with the same thrust, it would be too large to fit on a kart.

This vehicle uses liquid propane to start and then runs on diesel. Maddox mentioned that he has developed his own fuel injection for the kart and believes it should be patented. He uses both diesel and propane because diesel provides more power, runs cooler, and is easier to refuel, allowing him to run for a longer time without having to fill the propane tank.

The video above demonstrates how Maddox constructs his pulsejet engines as he assembles a larger one for the red kart. He uses a waterjet cutter to create the components, rolls them into tubes, and welds everything together.

If you’re interested in the science behind pulsejets, you can check out a senior project by students from California Polytechnic State University. They designed a pulsejet with a dual intake and a single exhaust.