Arizona State University engineering student Jason Kerestes' jetpack won't let its wearers fly -- but running like the wind may be the next best thing.
Kerestes, a graduate student and welding expert, is the "mastermind" behind the 4MM project, a combined effort by ASU and the Defense Advanced Research Projects Agency to create a machine that assists soldiers who need to run somewhere really fast.
4MM represents the project's goal of allowing an average runner to achieve a four-minute mile.
Reminiscent of the rocketpack in Chitty Chitty Bang Bang, the 4MM jetpack is strapped on low, near the hips, and provides continuous thrust for several minutes out of two jet nozzles.
Thomas Sugar, a professor of the Human Machine Integration Laboratory had been working on bionics-like projects that could help amputees when DARPA asked the lab to come up with something that could assist anyone run better. Kerestes, an engineering student who owned a welding company, was chosen to help lead the jetpack project.
In time trials this summer, the jetpack was seen to cut a runner's 200-meter and one-mile times down noticeably. While the reductions were only of several seconds each, which wasn't bad considering the jetpack burdened the runner with an additional 11 pounds. In the mile run, for example, the test runner completed a mile in five minutes and 20 seconds without the jetpack, and five minutes and two seconds with it.
In other trials, the jetpack helped test subjects run at a steady 15 mph.
Not bad for a project that's still just out of the starting gate.
The unit's powered by lithium polymer batteries that can produce bursts of 100 amps of current, (your home's maximum current intake is about 30 amps), Kerestes says.
Liquid fuel takes too long to ramp up to a good thrust level, so the project is 100 percent electric. Essentially, the jets are little more than electric fans designed to shoot intense, instantaneous bursts of air through small nozzles, causing thrust in the opposite direction, per Newton's Third Law.
"At full thrust, you can get about four minutes of it," Kerestes says. The "sweet spot" of thrust power, researchers found, is about 15 percent of the users' body weight. More thrust than that and the runner would topple forward; less, and the runner isn't getting much help.
It turned out, that the military wasn't too interested in the jetpack because the boost is so short-lived, and because it created a loud, jet-like whine, Kerestes says.
Other running-assistance devices in which the military's still interested are featured on the undergrad's personal website. Those include more exoskeleton-type inventions that "push and pull at your legs," Kerestes says. The ASU projects are the only similar prototypes in the country that are designed strictly to make people run faster.
Kerestes and Sugar are now funding the jetpack project themselves, though they hope to launch a Kickstarter donation program in the next few weeks to take the invention to another level. Kerestes says he believes it's possible to mount several directional jet-nozzles on an athlete, allowing not only faster forward running times, but sudden, augmented motion in any direction.
"In a year or two, this could become a marketable product," Kerestes says.
A multi-directional thruster could be a game-changer, literally, in the basketball court. Kerestes says the initial applications for a personal thrusting jetback might be in extreme sports -- people using it on a skateboard, or while skydiving.
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On the other hand, it also might help to wear the jetpack before bed -- to make getting up in the morning a little easier.
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