"Sikorsky was in the race, and we thought they would be flying quickly, and we really wanted to fly before them," says Chretien. "Solution F didn't want to be the second one." He admits that he took some calculated risks with his design to get it into the air fast and that his prototype is far from anything you could sell. As it turns out, Chretien did have some close competition for the honor of building the first manned electric helicopter to fly untethered—but not from Sikorsky. It came from a German team that accomplished another manned electric-helicopter flight [video] at the end of October, the third milestone in electric rotorcraft technology in the span of just four months.
Work leading up to that flight began in 2009. It was then that Thomas Senkel (a physicist who has worked on various electric vehicles), Stephan Wolf (a software developer), and Alexander Zosel (a businessman) started thinking about building an electric quadrocopter—like the four-rotor designs that many radio-control modelers fly, only big enough to carry a person. "After discussing it for three months, we said, 'Okay, let's do it,' " says Senkel.
The design they ultimately came up with resembles four radio-controlled quadrocopters flanged together—16 rotors in all. "If you have less, there's not enough redundancy," says Senkel. "If you have more, it would be too complex." Lithium-ion batteries and motor controllers are strapped to the spidery contraption's aluminum frame near each motor, eliminating the need for heavy cabling. The physical design is stunningly simple, although there's more to it than meets the eye, Senkel says.
Their first craft is just a proof of concept, but the German trio has formed a company, called E-volo, to explore commercialization of their design for the ultralight-aircraft market. Senkel thinks such a vehicle would cost considerably less than a conventional helicopter—more in line with the cost of a car. "Most helicopters have a lot of mechanics that have to be maintained and could fail. We don't have that much stuff," he says.
"We congratulate [Solution F and the E-volo group] for moving the needle forward," says Jonathan Hartman, who heads Sikorsky's Firefly project. Given the head start and resources that Hartman's team had, Chretien remains surprised that he was able to beat Sikorsky into the air. But, he says, "One thing's for sure: The day they start flying, it'll fly a lot better than ours."
