When Aerofex showed off its "hoverbike" almost two years ago, the California firm received a flood of emails from people asking when they could buy one of their own. Now Aerofex has unveiled plans to begin selling a commercial model in 2017 for about US $85 000—but anyone eager for a head start on living the "Star Wars" dream can put down a preorder deposit of $5000 toward the final price.
The commercial Aero-X design combines the ducted rotors of a hovercraft with the ease of driving a motorcycle or quad bike. Such a vehicle is designed to hover above the ground at maximum speeds of 72 kilometers per hour and at heights of almost 3.7 meters off the ground, allowing it to carry two people across open terrain without the need for roads. But the fantastical vision has only become possible because Aerofex has worked to conquer tough engineering challenges involving stability and control issues that plagued similar hover vehicles in past decades.
"We’ve done a lot of work to learn how to remove the coupling effect," says Mark De Roche, chief technology officer and founder of Aerofex. "That’s the key for someone who only has motorcycle experience to be able to get on it and feel comfortable right away."
The "coupling" phenomenon comes up with both ducted rotor vehicles and open rotor vehicles such as helicopters. That means if a vehicle pilot pitches forward to go forward, the rotor vehicle may also turn left because of the aerodynamics involved in the spinning rotors—a coupling effect that pilots must normally learn to counteract by adjusting several controls at once.
By comparison, Aero-X prototype pilots can steer the hover vehicle by simply leaning and using handlebar grips like a motorcycle. The current prototypes use so-called "knee bars" to detect the pilot's leaning direction, but the future Aero-X will likely just use handlebar grips for a more natural control scheme.
De Roche envisions the Aero-X prototype eventually being capable of carrying 140 kilograms of weight and running for about 1 hour and fifteen minutes on a full tank of gasoline. The vehicle's ducted rotors have a higher fuel burn rate than a helicopter's open-rotor design, but it costs far less than any helicopter or aircraft and is much easier to control.
Aerofex has filed several patents based on solving the stability and coupling problems that plagued early ducted rotor vehicles. One of the company's solutions includes having a shroud around the bottom of both front and back rotors to add an additional level of control for the vehicle's movements. If all goes well, the company plans to begin flight tests of the full Aero-X design by 2016.
Aerofex engineers also had to solve the problem of strong wind gusts. For that they took a hint from the quadcopter drones that have become popular among both researchers and robotics enthusiasts. Such quadcopters use ordinary smartphone chipsets that include gyroscopes and accelerometers to gauge the direction and strength of wind, so that an onboard computer can automatically compensate for the wind without human operators having to do anything. Aerofex used a similar tactic in their Aero-X prototype so that the hover vehicle automatically compensates for windy conditions.
The legacy of the Aero-X goes back to a Cold War vehicle developed during the 1960s. Aerospace pioneer Frank Piasecki developed a similar "flying jeep" vertical takeoff and landing vehicle for the U.S. Army that could fly up to altitudes of thousands of feet in the air. But the Army abandoned the concept because of the stability and control issues that Aerofex set out to conquer more recently.
Part of Aerofex's effort to make Aero-X more user-friendly meant having the onboard computer throttling back on the vehicle's performance, so that human riders don't end up soaring too high or flying too fast. The company has also included a rollover bar to protect the riders in case of a crash, and is considering the possibility of a full-vehicle airbag system.
"If we can’t make it safe, we won’t sell it," De Roche says.
Restrictions on the Aero-X's future performance also ensure that users don't have to deal with too much red tape from the U.S. Federal Aviation Administration. By consulting with the FAA, Aerofex discovered that it could avoid the need for pilot licenses by limiting the vehicle's altitude to about 3.7 meters. That makes the vehicle more of an "aerial ATV," De Roche explains.
Individual U.S. states have other regulations, but for the most part a person riding the Aero-X around on their own private property—such as the wheat fields of a family-owned farm—should encounter no legal problems. Still, De Roche says he would actually prefer to be regulated by the FAA rather than operate in what he called a legal grey area.
Aerofex has also spent the past few years developing its hover vehicle technology—both manned and drone versions—for two other applications in cooperation with an unnamed agricultural corporation and the U.S. government, respectively. But the company sees the chance with its commercial "sport-utility" offering to create a third pillar to its business. Everyone from ATV enthusiasts to U.S. Border Patrol agents and park rangers could eventually take advantage of the hover vehicle's off-roading capabilities.
Some current prototypes for the Aero-X vehicle include unpowered wheels that could allow future users to move the 356-kilogram vehicle more easily out of the garage. But De Roche cautions against trying to operate the hover vehicle on ordinary streets or in urban areas where it would almost certainly be illegal. That shouldn't be a problem for most would-be buyers who want to wander the more open spaces. After all, where they're going, they don't need roads.