Jetpack Is Real, and It Flies

 - February 8, 2016, 1:43 PM
David Mayman, left, helps Nelson Tyler put on the JetPack.

What pilot, as a kid, didn’t thrill to the notion of strapping on a jetpack, shedding gravity’s shackles and seeing the world from up there in the sky? In recognition of both that faded ambition and the slack time pilots sometimes have to kill in an FBO lounge or a hotel room, here’s something a little off AIN’s beaten path.

In an industrial building nestled among countless small businesses in the warm San Fernando Valley not far from Van Nuys Airport in southern California, a talented mechanical engineer and his long-time pilot friend have quietly spent the past 10 years perfecting a real jetpack–a strap-on frame fitted with two tiny turbine engines, a fuel tank and fly-by-wire engine controls.

The duo–Nelson Tyler and David Mayman–stunned the world when they posted a video on the Internet of Mayman’s public flight on November 3 last year around the Statue of Liberty above New York Harbor. The flight was obviously that of a new kind of jetpack that is reliable and easy to control, but what caught viewers’ attention was the moment when the camera focused on Mayman’s wrist-worn digital clock; he had been flying for a stunning four-and-a-half minutes, well over four minutes longer than the longest flight of the original rocket belt.

It turns out that Tyler built his own rocket belt, like the others powered by pressurized hydrogen peroxide that can fly for about 20 seconds; his rocket belt was flown for the opening ceremony of the 1984 Olympics. And inside the unobtrusive industrial space where Tyler concocts these devices–Tyler Camera Systems, which makes helicopter and airplane camera mounting systems–the walls are covered with rocket belt memorabilia.

Mayman, a fixed-wing and helicopter pilot, is a highly experienced rocket belt pilot with 77 flights of roughly 20 seconds each, and he has also test flown every iteration of the current JB-9 Jetpack (JB-1, -2, -3 and so on), parts of which still decorate shelves and rooms inside the Tyler facility.

Tyler’s jetpack explorations began with available turbine engines, but the early ones were so small that many would be needed to loft a human along with all the apparatus. One of these early jetpacks used 12 engines, six per side mounted in an unwieldy frame, and it simply didn’t work. “We couldn’t keep all [the engines] running at once,” Tyler explained. “It probably would have worked otherwise. They are quite difficult because the smaller ones start on propane and then switch to fuel, and the propane would just float around and explode.” As small turbine engine technology improved, the number of engines on subsequent Jetpacks diminished, to four on each side, then came a breakthrough with a tiny drone engine, a single-stage turbojet with a centrifugal compressor that puts out 187 pounds of thrust, running at about 60,000 rpm.

“I’ve been trying for the last 30 years to make something that would work,” Tyler said. “Finally the engine technology got to the point where we could do it with two engines and still have enough thrust to fly.”

One stumbling block was that to make the Jetpack more easily controllable, one of the engines had to rotate in the opposite direction of the other, to counteract instead of magnify torque effects. Mayman put up the money to pay for tooling to build another opposite-rotating engine, and from there the program went fairly smoothly.

Initial test flights were done while tethered to an inertia reel mounted on a frame in a courtyard between two Tyler buildings. Asked whether the neighbors noticed all the activity and noise, Tyler said that people stood on cars to watch the action. One of the nearby companies was a motorcycle tuner, so noise probably wasn’t an issue. When that business closed and a marijuana dispensary moved in, well, it’s possible that the customers never knew whether what they were watching was a hallucination or the first test flights of a revolutionary new device.

Development of JB-9 took about two years, with Tyler crafting most of the parts on his company’s CNC machine tools and designing the fly-by-wire engine controls. Tyler has flown JB-9 on the tether, and Mayman was the first to fly it off tether, over a lake near Sacramento, Calif., for safety considerations.

The pilot controls the Jetpack using a twist-type throttle on the right hand and cable-operated yaw vanes on the left hand. The rear portion of the frame, on which the engines are mounted, tilts for pitch and bank control. The longest flight Mayman has made so far is six minutes. “When they see this, they drool,” said Tyler, referring to rocket belt mavens. “We’re running for 20 to 30 seconds before takeoff,” and this is more than the amount of time a rocket belt can even remain airborne. Another difference is that a rocket belt pilot has to jump to launch into the air, but the JB-9 pilot simply throttles up and lifts off. Control is far more precise.

The plan is to offer a commercial product eventually, according to Tyler. A Jetpack flying for six minutes at 55 knots (JB-9’s top speed) could move someone quickly three miles, say from a road to the site of an aircraft accident that can’t be reached by vehicle. JB-9 has an empty weight of 90 pounds and currently flies with just five gallons of fuel to stay within FAA Part 103 ultralight regulations, although it could haul up to 10 gallons.

Tyler has been discussing with the FAA how to expand the flight envelope, especially as work on JB-10 has begun. JB-10 could achieve speeds of more than 100 knots, and it may feature a ballistic parachute system, if one can be designed that not only weighs 12 pounds or less but also looks good when incorporated into the Jetpack. He is also considering adding an autopilot to the flight controls, if lightweight actuators are available.

David Mayman, CEO of JetPack Aviation, on flying the Jetpack

AIN: How many times have you flown the rocket belt?

Mayman: I’ve 77 flights on hydrogen peroxide rocket belts, which is 20 seconds per shot so it doesn’t add up to much flight time. In the Jetpack I’ve got many hours of testing time. [The various iterations go from JB-1 through JB-9.] The issue is that there’s nobody that can really train you, so you have to strap it on and make your own mistakes and learn as you go.

AIN: Does flying the rocket belt help with flying the Jetpack?

Mayman: It does, learning to fly the rocket belt does help you fly the Jetpack inasmuch as it’s a similar kind of control, motions that you’re making, but the turbine engines have a much greater lag, like turbochargers in a car, when you ask it for power, it has to spool up. So you need to get used to waiting for it to spool up but also to spool down. And that takes quite a lot of practice. Otherwise it’s a similar control mechanism, but you have a heck of a lot more time, so in terms of taking off in a rocket belt, there’s a fuel emergency as soon as you lift off the ground. You’re looking at where you’re going to land, whereas with the Jetpack, we’re already running on the ground just warming up for longer than a rocket belt can possibly run for, and then we lift off and got five, six, up to 12 minutes, depending on the pilot weight, to accomplish the mission and decide where you’re going to land. You can make that decision as you fly.

AIN: What was it like the first time you flew JB-9?

Mayman: I’ve been flying JB-9 now for over a year, and on a tether, backwards and forward across a sort-of 120-foot-long tether, and just getting slowly better and more comfortable with it. The first time I flew off the tether, it was incredible. There’s nothing to describe it. I didn’t know what was going to happen on that first flight compared to being on the tether, whether I was going to be suddenly free of the tether and then unstable because I didn’t have this balancing force, but it worked perfectly. It was stable, the thrust was good, and it did everything that it had been doing on the tether, but it was actually a lot easier because I wasn’t being pulled one way or the other by the tether line. And my heart was in my mouth–boom, boom, boom–I think it’s like anything else, you train long enough for something it becomes muscle memory and it just happens.

AIN: Would it be hard to train a non-flier?

Mayman: Not really, I think there’s some benefit in not being a pilot. I fly helicopters and fixed-wing [aircraft], and there’s certain things that you’re just used to doing that don’t apply to the Jetpack. Certainly I could train a very experienced pilot but I don’t think there’s a huge benefit in already being a pilot. And we could train pretty much anybody to do this with enough time.

AIN: What are some of the performance numbers you’ve seen?

Mayman: At the moment we’re flying under the ultralight category, so we’re limited in terms of performance to 55 knots and five gallons of fuel, which gives us the lower flight times, five or six minutes. But I’m able to take off vertically, I’m able to accelerate extremely rapidly to 55 knots, within seconds, but also stop abruptly, within several yards doing that kind of speed. Hover without any issue. Pirouette turns. While flying forward I can do pirouettes ascending and descending. There’s effectively nothing you can’t do. I can take off from the ground and fly backwards like you can in a helicopter, flip around and then fly forward. You can do that in a pirouette motion, you can do it using yaw, you can do it using roll. It really is like having a motorcycle or a bicycle in the air.

AIN: How much does it weigh?

Mayman: Empty it weighs about 90 pounds, and then with fuel you go on up from there. It’s really light. I can wear this thing all day long when it’s empty.

AIN: What happens if one engine were to stop running?

Mayman: If one engine stops working you get an asymmetric situation, and that’s why we’re working on the parachute system. And that wouldn’t be a pilot-initiated thing. It would be a computer-initiated device that would look at the parameters of the flight, and as soon as it recognizes an out-of-spec maneuver–a banking or an acceleration moment–it would fire the parachute. We’re working on another version, which is a four-engine version, and we believe that would give us redundancy.

AIN: How much engine thrust?

Mayman: About 185 pounds of thrust a side.

AIN: These are military engines?

Mayman: Normally they’re applied to a military drone, for gunners to chase down a fast-moving drone, just subsonic. Typically they operate in a horizontal flying position rather than vertical, so we had to make a series of refinements and changes to enable cooling and bearing lubrication to work in a vertical installation.

AIN: Can you describe the flight controls?

Mayman: I control thrust with the fly-by-wire throttle here [right grip handle], and then I control yaw in the left hand, which is a push-pull cable. It’s a very simple system. We always go with simple if we can. And that articulates the yaw vanes on the bottom of each of the engines. And they always work in the opposite sense. Obviously if the left engine is going forward, the right engine is going back, and that enables you to pirouette or to spin on the spot. But the rest is actually vectoring the engines themselves. So we’re not vectoring just the thrust. The way we get the maneuverability is not just by directing thrust from side to side like in the old Williams and Bell Aerospace jetpack from the 1970s. The way they did it was to just articulate nozzles, which moves the thrust. What we’re doing is moving the whole center of thrust against the center of weight by moving the engines themselves, and that gives us extraordinary maneuverability and dynamic handling.

AIN: Why the flight around the Statue of Liberty to reveal it to the world?

Mayman: We had a brainstorming session and thought if we’re going to come out of the closet so to speak, where’s the greatest place to do it, the most iconic backdrop? I’ve always loved the statue, so as the test pilot, I put my hand up and said, “Hey, you know there’s water, so that gives us a degree of safety, and what a perfect backdrop.” And we were just so lucky with the weather. It was warmish, and we had blue skies and everything was perfect.

AIN: How long a flight?

Mayman: A five-minute flight. I was playing everything conservative. I wasn’t flying too fast. I wasn’t being too radical. If you could see some of the videos of training on the tether before that, this machine is capable of so much that I didn’t do in New York. I didn’t want to embarrass myself or go into the Hudson River. It was cold!

AIN: How did it feel to be where a lot people could see this? They must have been amazed.

Mayman: They were! The Staten Island ferry was going past, and a huge cruise liner that was going past actually slowed down. It’s like this seven-story cruise liner. And as I was in the air, I didn’t pick up on any of this. I was too focused. But apparently it slowed down, and there were a whole bunch of people taking photographs from the deck. People out at Liberty State Park were stopped in their tracks when they were jogging. You can hear the turbine engines from a long way away. And we got a lot of great feedback. We got a lot of people saying, “Finally, something small that you can actually wear.” These handles fold up, you can put it in a suitcase. Finally somebody’s created what we think of as a true jetpack.

AIN: Do you like flying the Jetpack?

Mayman: I love flying it. I’m the only test pilot, so I love my job. CEO and test pilot is not a bad combination for me at the moment.

AIN: How many flights in JB-9?

Mayman: It’s between two and three hundred. They would range from one-minute baby test flights up to probably eight or nine minutes on the tether because you’re using slightly less thrust.

AIN: What’s next for Jetpack Aviation?

Mayman: It is a tipping point in this industry. There are lots of people working on different concepts, different form. We have the entertainment arm, as far as Hollywood. And we’d like to put a race series together with Jetpacks, probably flying over water initially. And then we have the more serious, practical applications like search-and-rescue. Where we come into our own is form factor and speed. So if you want to put somebody from position A where they can take this thing out of the suitcase and move them 10 miles down the track at 150 miles an hour and position them there, you can do that. Yes, now it needs manual control and the person would need to be a trained pilot to do that. But eventually with time and money, we could automate that. It’s not a difficult task to automate flight control.

AIN: I bet you’re proud of what you’ve accomplished.

Mayman: Yeah, it’s also humbling. We’re lucky in some respects. I guess you make your own luck after a lot of hard work and money, but it’s hard to believe sometimes that we’ve achieved what we have, and the flight went so well, and we’re just so thankful.

AIN: Are you seeking investors?

Mayman: We’d always talk to people. It’s true that it has to be the right type of money people with the right motivations and the right interest. We’re not interested in being a public company, at this stage anyway. And we’re not interested in taking money from just anybody; it would have to be somebody who has a real interest in this sort of thing. So far we’ve been completely self-funded. To move at the pace that we’d like to move, it would make sense to bring in some external funding, but it would have to be the right flavor.