INNOVATION

Personal Flying Machines of the Future Won’t Look Much Like Jet Packs

Judging from the GoFly competition, they’re much more likely to resemble flying motorbikes

July 2, 2018

The Harmony is an all-electric vehicle designed by Texas A&M engineers. Texas A&M

Maybe it’s time to say goodbye to the jet pack. For a long while now, when someone mentioned “personal flying machines,” the image that came to mind was of people wearing devices powered by small, but loud turbine engines that lifted them, seemingly at their own peril, into the air.

But that’s so 20th century, judging from a collection of fanciful, but scientifically sound vehicles designed for an international competition. They’re competing for what’s called the GoFly Prize, but also for the opportunity to create models for how personalized flight evolves in the coming decade.

“There’s no dream more universally shared than soaring through the sky,” says Gwen Lighter, CEO of the GoFly Challenge, which is sponsored by Boeing. “One of our goals was to open up innovation to the entire world. Our innovators took that to heart and came up with many different designs and permutations.”

More than 160 teams submitted entries, and earlier this month, 10 winners were announced for Phase 1 of the competition, based on technical specs and drawings. For Phase 2, teams will have to build working prototypes, with winners named next March.

Lighter points out that a number of technological advances—from the control and stability systems that allow drones to be so maneuverable, to the dramatically improved performance of batteries—have made a wide range of flying devices much more plausible.

That’s critical since the competitors have to meet requirements that are that much more challenging in combination. Specifically, each device must be smaller than eight and a half feet, not too noisy, able to take off and land vertically, and capable of traveling at least 20 miles without stopping to refuel or recharge batteries. And, perhaps most importantly, it needs to be able to fly safely.

“If you take just two of the factors—size and noise—those two together is the difficult part,” says Lighter. “It’s easier to have a large and quiet device. It’s much harder to have a small and quiet one. It’s the combination that makes it difficult."

But there’s plenty of motivation to take on that kind of challenge. The grand prize winning team, to be awarded in the fall of 2019, will take home $1 million.

Take a look at the 10 winning entries in GoFly’s first round.

The S1

A creation of a Dutch engineering team aptly named Silverwing, the S1 can best be described as a flying motorcycle flanked by two large rotors. They are driven by two electric motors.

“We felt that the motorcycle posture would be the most appropriate, given the rules set by the GoFly competition regarding size, payload and line of sight, among other topics,” explains team member Rutger van Brouwershaven.

The biggest challenge, he says, was designing a device that can stay within the GoFly noise specifications while being able to carry a person.

The S1 would work by taking off vertically through the thrust provided by the two rotors, then transition to horizontal flight, according to Brouwershaven.

“I think the vehicle looks attractive, and even if people are not necessarily acquainted with the dynamics of flight, they can understand how to fly it,” he says. “As a team, we looked beyond making this technically sound. We want to provide a new experience for people and turn the dream of personal flight into a reality. That can only be achieved by creating something that people would be willing to ride, and they can imagine themselves doing so.”

The Hummingbuzz

Looking part flying fan, part motorcycle, the Hummingbuzz is the work of a team from Georgia Tech. Brian Eberle, the group’s flight control and stability engineer, describes it as an “all-electric, ducted fan equipped with counter-rotating coaxial rotors.”

The rider sits atop a motor bike seat, which also houses a battery pack.

Once again, keeping the device sufficiently quiet was a big challenge.

“The ambitious goals of the competition inspired the creative aspects of the design, but the strict acoustic requirements set by the competition rules ultimately drove the technical configuration,” says Eberle.

But he believes the device will pass the noise test. “The noise produced by Hummingbuzz will blend into ambient noise in most city environments, which makes it unique among existing air taxis and personal flying devices.”

The Mamba

The University of Kansas team' original notion was to develop a vehicle that could be marketed as a flying motorcycle. That thinking changed.

“As the design began to take shape, the overall profile evolved to look more like the head of a snake,” says team leader Lauren Schumacher. “Thus, the Mamba came to be.”

The Mamba is a hexacopter, using six ducted fans to enable it to hover. The two aft ducts rotate to provide forward thrust.

Schumacher emphasizes the importance of being able to ensure the safety of new forms of transportation, such as the Mamba.

“A single incident involving the harm or death of an operator or bystander has the potential to shut down not only the product line, but the entire market for this class of transportation,” she says. “As such, Mamba has an edge, as the focus has been on safety from the onset of the design process.”

ERA Aviabike

This device, created by a team from Latvia, is described as a “tilt rotor aerial vehicle” that takes off like a helicopter, then tilts its motors so it’s able to fly like a fixed-wing plane.

But it’s designed to appeal to a specific audience, according to Vladimir Spinko, the team’s captain. “We spent some time considering market prospects of several designs—all based on our tilt rotor scheme—and realized that if we chose Aviabike, bikers would become our customers.”

As with the others competing, the biggest challenge for the team was managing the tradeoffs among the different requirements related to size, noise and range, and being able to do so while keeping costs from skyrocketing.

“We do care about the vehicle’s cost,” says Spinko, “as we want to create an affordable flying vehicle, not a kind of toy for billionaires.”

He acknowledges that different power sources are options, but that for now, the team is focused on building an all-electric vehicle. “It will be able to fly in fully autonomous mode or computer-assisted mode,” he adds.

Not only is Spinko optimistic that personal flying devices are the vehicles of the future, but he also feels that the motorbike look gives his design an edge.

“The global motorbike market is huge,” he says. “So we hope many bikers will want to try it if we say ‘Hey, ERA Aviabike is like a motorbike, but it will let you fly.’ ”

The Blue Sparrow

This vehicle is another hexacopter, with thrust provided by six rotors. “Flight control is provided by modulating rotor speeds, which changes both the thrust from each rotor and the torque of each rotor,” explains team captain Jack Langelaan, an associate professor of aerospace engineering at Penn State University. “The differential thrust and torque gives us control over pitch, roll and yaw, while total thrust controls acceleration.”

He likewise says developing a design that met all the necessary criteria was taxing. But he thinks the most difficult part of the competition is yet to come.

“Building and testing it will be a significant challenge,” he says.

The Harmony

One of the more distinctive devices created for the competition is the Harmony, the work of a team of engineers at Texas A&M.

It has been characterized as “egg-shaped” and looking like a “flying lectern.” Team captain Moble Benedict, an assistant professor of aerospace engineering, is more matter of fact.

He describes the all-electric vehicle as “a quiet personal rotorcraft with the pilot seated above a set of open coaxial rotors designed to minimize noise, while maximizing hover and forward-flight efficiency, pilot safety and reliability.”

Benedict says he believes the team has designed “an efficient, safe, green and truly practical air vehicle, which is something we have always dreamed of.”

The FlyKart 2

This device was inspired not by motorbikes, but rather by go- karts, according to team captain Robert Bulaga, who is president and chief technical officer of Trek Aerospace, a California engineering firm specializing in fan-powered aircraft and watercraft.

“We’re not building a road-worthy flying car,” he says, “but we do hope we’re building a fun off-road vehicle.”

How does it work? Bulaga explains that 10 ducted propellers lift the aircraft vertically, then the entire aircraft leans forward to begin cruising in flight. Its movement—pitch, roll and yaw—are controlled through the thrusts from the various propellers.

He says he sees the FlyKart 2 as just one of many potential flying vehicles of the future. “There are so may opportunities, with various requirements, that we’re only on the cusp of what electric aircraft with distributed propulsion can do in the future.”

The Tetra 3

This creation from a Japanese team is another in line with the flying motorbike concept. The operator rides it like a motorcycle and is able to manipulate it “like a video game,” says team captain Tasuku Nakai.

He says that thrust from propellers powered by an electric motor allows the device to hover, and also to fly horizontally like a fixed-wing plane.

Nakai adds that it’s important that these devices are easy for a person to fly.

“Even though a device can fly, no one wants it be boring or unsafe," he says.

The Vantage

Put simply, Vantage is a "five-rotor air bike,” according to Bruno Howard, captain of the British team that created it.

But that doesn’t do justice to what’s involved in its ability to fly. It has an internal combustion engine producing electrical power via a generator, and that powers five electric motors, which, in turn, drive a rotor that provides enough lift to keep Vantage afloat. And two more motor-rotor combinations provide forward thrust. Finally, each rotor can be controlled independently to produce roll, yaw and pitch.

“This is not some CAD (computer-aided design) exercise,” Howard says. “It consists of real components that you can buy today. We’ve done the calculations on every sub-system and this thing will really fly. It needs no battery breakthrough or fairy dust.”

He also says he doesn’t think the future of urban air travel will be dominated by single-passenger vehicles like Vantage but rather autonomous multi-seat aircraft.

“The principles of safety, redundancy and controllability, embodied by the Vantage, will always be at the center of design considerations, especially for commercial aircraft,” Howard says.

The Pegasus 1

Alex Smolen sees his creation, the Pegasus 1, as the first step toward “safe and fun” personal flight, a machine that he thinks almost anyone could fly for 30 minutes.

Smolen, a self-taught programmer, says he takes personal inspiration from people like Julius Yego, the Kenyan Olympian who won a silver medal in the javelin throw in 2016 after learning the sport by watching YouTube videos.

“When I see someone take the initiative to learn a new skill on their own and perform at such a high level,” he says, “it makes me ask myself, ‘What am I capable of.’"

He explains that when it hovers, the device’s six propellers remain level and lift Pegasus 1 off the ground at a slow speed in any direction, much like a drone. When it needs to cruise, the propellers tilt, providing both lift and thrust. As the vehicle accelerates, the wing provides additional lift, enabling it to fly more like a plane.

Smolen says that consumers ultimately will decide what the personal flying vehicle of the future will be, but predicts that it’s likely to be one that’s “safe, easy to use, and an absolute wonder to fly”—before adding that Pegasus 1 will be “safe, easy to use, and a wonder to fly.”