Meet the Joyful Man Behind This Incredible Jet Engine Go-Kart Video

Robert Maddox is a self-taught thrill-seeker who has been known to jump out of planes attached to a pulsejet engine.

byKristin V. Shaw|
Culture photo

When I spoke with inventor Robert Maddox on Friday, he was strapped to a pulsejet engine alone in the middle of the desert, waiting for the sun to set. In daylight, it’s more difficult to discern the blazing edges of the fire roaring from the back of his jet-engine go-kart; for both effect and safety, he likes to run it at night.  

Maddox's newest creation is a triple valveless jet kart he calls “The Beast." It’s powered by injected propane and diesel and the builder has run it up to 90 miles per hour. Spewing flames behind him, Maddox can be found yelling in delight as he wrings it out. 

Now in his early 60s with a mountain-man beard he grows because his lady likes it that way, Maddox has been fascinated with thrust-powered machines since childhood. At age 10, he began building rocket-powered balsa wood airplanes and found a certain kinship with a cartoon character that liked to create explosions, often to its detriment.

Robert Maddox YouTube

“I was born in the 1960s and grew up with the space race and Wile E. Coyote, which was the biggest influence in my life,” Maddox told me. “During the Vietnam War there were fighters going ahead and sonic booms going off and I was fascinated by anything with thrust. At a young age, I started playing with jet engines.”

When he wasn’t building, Maddox read encyclopedias for fun and developed an incredible memory for details. This came in handy in his 20s, when he made his first of more than 2,000 skydives and decided he needed to harness a jet so he could go further on his jumps.

“I looked around and couldn’t find a jet engine other than micro engines for model airplanes, and they were very expensive,” Maddox said. “I remembered reading about a pulsejet in the encyclopedia, and I decided to build it myself based on what I knew.”

After a month or two, Maddox had completed fabricating a jet engine with 50 pounds of thrust. Then he jumped from planes three separate times with it strapped his chest. (If you could see my face while he was describing the experience, my expression would look like Edvard Munch’s famous portrait in the painting The Scream. I am not brave in that way.)

Since then, Maddox has appeared on Mythbusters and Jesse James’ Monster Garage. Last year, a new Monster Garage episode aired showing off James and Maddox's joint creation: a 1965 Jaguar S-Type powered by a 13-foot-long pulsejet engine producing 1,200 pounds of thrust. 

Pulsejets are straightforward machines and have the capability to run on a variety of fuel types. It has its downside, as well. Tom Farrier, retired USAF command pilot and expert in aviation safety, said on Quora that a pulsejet “is as inefficient as the dickens in comparison with internal combustion or turbine engines, although a good one can squeeze a lot of flying out of its fuel load. It's also incredibly loud (the reason why V-1s were referred to as "buzz bombs").”

Robert Maddox

If you have any ambitions of building one yourself, know that you're going to need to invest in solid hearing protection. Pulsejet expert Larry Cottrill told Popular Mechanics that these engines can damage your hearing permanently if you are within a few feet of it. Maddox learned this lesson the hard way and wears ear protection every time. 

"I am wearing earplugs," he said to me with a laugh. "They are an absolute must; I broke an eardrum once when I fired up an engine.

What does it feel like to pilot this thing? I asked. He chuckled again when he answered me. 

"It is not scary, because I’ve been doing this a long time and am fairly comfortable," he said. "I'm probably not gonna crash or end up with a big fire. People are watching my videos and connecting with this crazy old [expletive deleted] out in the desert and leaving super cool comments."

That beard of his is five inches shorter than it used to be; Maddox ventured too close to the fire one day and singed the hair on his face. Yet, he is undeterred; as you read this, Maddox is probably on his new pulsejet-powered skateboard. It sports a red nose as a tribute to his hero Wile E. Coyote, and it's similarly explosive. If you see him, ask him for a ride. And don't forget to bring earplugs. 

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