Aircraft

Micro jet turbine-powered Jet Vest developers seek a Kickstart

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Mock-up of the Jet Vest, currently under development by Jet Machines Extreme (Photo: JME)
Mock-up of the Jet Vest, currently under development by Jet Machines Extreme (Photo: JME)
Three-quarter view of the Jet Vest mock-up (Photo: JME)
Test firing of the Seymour micro jet turbine engine (Photo: JME)
Close view of the Seymour micro jet turbine engine (Photo: JME)
Indoor test cell for the SWB-100 micro jet turbine engine (Photo: JME)
Close-up of the SWB-100 micro jet turbine engine (Photo: JME)
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The Bell rocket belt captured the world's imagination when it was featured in the 1965 James Bond movie Thunderball. Now, the folks at Jet Machines Extreme (JME) are designing a modern version not powered by rockets, but by a set of four miniature turbojets. The new Jet Vest is expected to offer free flying times nearly four minutes in duration. Having run short of development money, JME is exploring another modern innovation by reaching out to crowd-funding site Kickstarter for a boost.

In the late 1960s, Bell Aerosystems attempted to overcome the short flight times of their rocket belt by developing a turbojet-powered version that could fly for half an hour instead of half a minute. The Bell jet flying belt used an early Williams International turbojet with a thrust of 430 pounds (195 kg) to extend flight times from the 20-30 seconds of the rocket belt to 20-30 minutes. A number of test flights were made, but the inventor's death from a heart attack resulted in cancellation of the program.

Three-quarter view of the Jet Vest mock-up (Photo: JME)

Nearly 50 years later, Dieter Sturm and Jeff Seymour of JME want to bring their Jet Vest, a personal flying system powered by miniature turbojets, into reality. In the present design, the Jet Vest is powered by a set of four SWB-100 micro jet turbine engines, originally developed for the Navy Affordable Weapon System (AWS) program. This program sought to introduce a cruise missile constructed mostly from parts available "over the counter" to reduce costs. Costing only a small fraction of the million-dollar Tomahawk cruise missile, the AWS cruise missile would have an operational range and speed similar to that of the Tomahawk, but would carry a smaller warhead (200 lb vs 1,000 lb (91 kg vs 455 kg)).

Test firing of the Seymour micro jet turbine engine (Photo: JME)

SWB Turbines, the company developing the jets for the AWS program, is owned by Jeff Seymour, now one of the partners in JME. He brought with him a wealth of experience, construction and testing facilities, and several surplus SWB-100 turbojets. His long participation in the AWS development program resulted in these engines having undergone and passed the US Government Certification Program, landing the SWB-100 turbojets at a different level of reliability than the numerous small turbojet engines presently being sold for radio controlled airplanes. A test firing of an SWB-100 jet engine fitted with an afterburner appears in the video at the bottom of the page.

Close-up of the SWB-100 micro jet turbine engine (Photo: JME)

It is interesting to compare the design of the Bell jet flying belt and the Jet Vest. The SWB-100 weighs 11.5 lb (5.2 kg), and provides a nominal 100 lb (45 kg) of thrust, although it can be run at 107 lb (49 kg) for brief periods. The thrust-to-weight ratio is 8.7:1. While at full power the SWB-100 consumes about 130 lb (59 kg) of Jet A fuel per hour.

In comparison, the Williams WR19 used in the Bell jet flying belt weighed about 60 lb (27 kg), and produced 430 lb (195 kg) of thrust, giving a thrust-to-weight ratio of 7:1. The WR19 consumes about 300 lb (136 kg) of fuel per hour. As four of the SWB-100 engines are required to provide the same level of thrust, the WR19 engine, although heavier than the four SWB-100 engines, was far more fuel efficient, burning a bit more than half the fuel required by the modern engines.

Both jet packs have roughly equal thrust and take-off weight (350-365 lb, or 160-166 kg), so have very similar performance profiles. The main difference is that the superior fuel efficiency of the Williams WR19 gave the Bell system a flight time of about 20 minutes, compared to about four minutes for the JME Jet Vest.

The sad part of this is that the Kickstarter campaign doesn’t seem to be doing very well. We asked Dieter about the chances of meeting the US$30,000 funding goal by the deadline at year's end. "As we know from research, the Kickstarter program appeals to backers who would like to own one of their own 'widgets' that is being offered," replied Dieter. "Clearly understandable. In our case and the same for a few other unique types of projects that are not being mass produced for purchase, we bring our Project before the world to see if people would like to give fellow inventors a helping hand. Simple as that. We have funded the project to date out of our own pockets, but we could accelerate our progress with better funding. We know the Jet Vest will fly someday, it's just a matter of how quickly we can keep the momentum going. Our goal is to be flying on tether by the next EAA Oshkosh AirVenture show in late July 2013. That's our focus."

Source: Kickstarter

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20 comments
Juan de la Cruz
Good Lord! Can you imagine having four of those ear-bursting fire brands surrounding your body? Not only unpleasant, downright nuts.
sk8dad
Lovely, let's position the engines such that their planes of rotation lines up with the operator's skull. That way, in the event of catastrophic failure of one or more of the spinning grenades, there wouldn't be any need to secondary safety features like parachutes. Even if the operator were to survive the exploding engine(s), the 170 lbs of jet A is sure to make landing highly exciting.
Vanilla Cat
Strap on this contraption and you are guaranteed to fly. Only problem is you will be using angel wings and not be able to get back down. The picture of Bobby Joe and his cousin Bobby Jack tinkering with their "craft" while next to pressurized tanks containing highly combustible material, with lit cigarettes dangling out of their mouths, tells me this is not JPL at work.
snowmaker55
Well after reading the indepth Kickstarter project summary, it appears that these guys are not amateurs when it comes to micro jet turbine design and construction. They have worked on projects for the US Navy Weapons Systems and with NASA. Not your guys out in the garage welding together some muffler pipes and strapping a tank of propane on their backs. I applaud them as Inventors and will contribe to their kickstarter program. We need more guys like seen on GizMag to keep the creative projects rolling.... good luck guys!
Gadgeteer
Why would anybody want this? The Solotrek and Martin Jetpack have much longer flight durations but still haven't proven to be practical.
Oztechi
The video they put out makes them look like complete amateurs!
The Martin Jetpack is a much better product and the only reason they are not in production is a shortage of money to finish safety testing etc. Their product would not burn the hairs off your leg either or glow red hot!!! (like the turbine in the video).
If a turbine was to be used for this kind of thing, maybe a small geared turbo fan like the ones under development currently would be more fuel efficient and therefore give you a longer flight time.
Onihikage
"In the late 1960s, Bell Aerosystems attempted to overcome the short flight times of their rocket belt by developing a turbojet-powered version that could fly for half an hour instead of half a minute."
You mean this? http://www.wimp.com/flyingmachine/
According to Wikipedia, it was a military project that was cancelled because it wasn't deemed useful, not because of anyone having a heart attack.
swissrocketman
Your project is not serious! What do you do if a reactor loses power? Well this is the immediate fall! Remember there have been two similar projects that have not flying! Swiss Rocketman
tkj
"Their product would not burn the hairs off your leg either or glow red hot!!! (like the turbine in the video)"
Actually, it was white-hot .. i was waiting for liquid metal to come flying out .. pointing out the sheer stupidity of these less-than-safety-conscious jerks! .. Smoking cigarettes ??? standing directly in front of the running engine?? another idiot standing so close to the turbulant outflow ??? Did they not even consider that the entire device coul have exploded , disintegrating into thousands of pieces of shrapnel ??? I dont care what their 'professional resume's ' say : these guys are nut-cases!!
jerryd
Jets just won't work well no matter what you do because at low speeds they are extremely ineff.
To do a personal flying pack you are going to need 2 couterrotating props of about 10' or 3m in dia to get the lift needed for any kind of range. A 50hp or so motor would then do.
Plus using 4 jets increase the chance of dying 12-16x's? vs 1
Add the ear destroying noise and I'm happy it died.