That would be progress in itself. Multicopter 1 looked like something from an especially iffy episode of MacGyver, complete with landing gear that involved a silver yoga ball. Senkel rode seated amid all those rotors powered only by lithium batteries. Multicopter 1 generated an average of 20 kilowatts for hovering and was aloft for just a few minutes.
There's a reason why the experimental craft flew briefly and only once.Senkel describes that first craft as "glued and screwed together." Seated on the same platform as the spinning blades, he says, "I was aware of the fact that I will be dead, maybe. Besides, we showed that the concept works. What do we win if we fly it twice?" he asks rhetorically.
Other than putting the pilot safely below the blades, the revised volocopter design would operate largely the same as the initial prototype. The design calls for three to six redundant accelerometers and gyroscopes to measure the volocopter's position and orientation, creating a feedback loop that gives the craft stability and makes it easier to fly, Senkel says.
The volocopter’s revised prototype under construction could debut as soon as next spring. The first production models, available in perhaps three years, are expected to fly for at least an hour at speeds exceeding 100 kilometers per hour and a minimum altitude of about 2,000 meters, still far shy of standard helicopter's normal operating altitude of about 3,000 meters. "This could change our lives, but I don't expect anything like that for 10 years," Senkel adds.
Given that most of the technology needed to build the volocopter is already available, "this idea is fairly easy to realize," says Carl Kühn, managing director of e-volo partner Smoto GmbH, a company that integrates electric drive systems and related components.
Like Senkel, Kühn has modest short-term expectations despite his repeated emphasis on the standard nature of the technology involved. "I guess that e-volo will have [a prototype] aircraft in three years that can do the job—that it will lift one or two persons from one point to another," he says.
The biggest immediate limitations appear to be regulatory. For instance, European aviation regulators consider any electrical system greater than 60 volts to be high voltage and regulate such systems more aggressively, Kühn says. As a result, the volocopter will operate below that threshold. The craft will also need to weigh no more than 450 kilograms to remain in the ultralight category, which is likewise subject to fewer government aviation regulations, according to Senkel.
The Lindbergh Foundation's Wulff says the organization's judges felt e-volo had "a greater than 50 percent chance of succeeding, or they wouldn't have given them the innovation award." Asked if she would line up to fly one someday, she says, "I sure would. It looks very compelling to me."