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.