When the all-electric Solar Impulse 2 touched down in Abu Dhabi last summer after an around-the-world voyage, it trumpeted a future of fossil fuel-free flight. Now, André Borschberg, the Swiss entrepreneur and pilot who launched the mission, has returned to the stage, ready to realize that vision. Last week, he announced the launch of his new company, called H55, and revealed its first aircraft, the Aero1.
Compared to the Solar Impulse 2, which matched the wingspan of a 747 and could stay aloft for days on end, this new plane feels like a letdown. It’s not a new design, but a retrofit of a one-seat aerobatic flyer. It doesn’t have any solar panels, just batteries in its fuselage and wings. It doesn’t promise to transform mobility, like the vertical takeoff and landing (VTOL) “flying cars” Uber wants to deploy.
But Borschberg didn’t design the Aero1 to elicit oohs and ahs. He made it to show that when it comes to developing practical, usable electric aircraft, you go with what’s most realistic. And in the regulation-ruled world of aviation, that means going for certification first and revolution later.
“I believe you have to go step by step toward VTOL in order to prove the safety of the systems, or they will not be implemented into transportation solutions within cities,” Borschberg says. “Of course it’s good to test different solutions through demonstrators, but it’s important to think about how to certify these aircraft, as well.”
Borschberg would know. Among Solar Impulse 2’s greatest challenges wasn’t making the 5,000-pound plane fly on electricity—that tech is generally familiar and reliable—but achieving the certifications that allowed him and fellow pilot Bertrand Piccard to fly over populated areas on its way around the globe. He says his new team at H55, which includes folks from Solar Impulse 2, is using the Aero1 to develop new technologies with those regulatory processes in mind. Rather than producing airplanes, H55 will develop and certify electric propulsion systems, which others can integrate into their aircraft.
H55’s engineers started with the Twister, an aerobatic plane made by Germany’s Silence Aircraft, whose lightweight and aerodynamic design made it a natural fit to go electric. Before loading it with
batteries, the team reinforced the wings. They compensated for balance changes after dropping the fuel tank and adding a 65-kW electric motor.
In the early days, Borschberg says, planes carrying H55’s system— the battery technology, its management systems, the electric motor, the pilot interface, and all the control systems—will serve for flight school training, aerobatics, recreational flying, and other applications where the planes typically depart and return to the same airport—limiting the required charging infrastructure. Meanwhile, H55 will work on a system capable of hauling two-passengers, and then even larger aircraft for greater payloads.
If some of this sounds familiar, it should: Airbus recently experimented with a small battery-powered electric trainer, called the E-Fan, before abandoning the pure electric setup for a sequential hybrid system, using an onboard engine to bolster the batteries’ capacity. Borschberg prefers simplicity.
“Hybrid systems are interesting if there really is a benefit from pure electric propulsion,” he says. “They’re actually more complicated. You need three different technologies to make them work.” Stick with batteries, he says, and you keep things simple: no maintenance, no checking oil and fuel levels or preheating the engine. “It simply works. You check the battery level, turn it on, and go.”
Eventually, Borschberg expects, H55’s electric propulsion systems will forge a path for more radical aircraft designs, including those that could someday hop around cities like crickets. But he prefers starting with established aerodynamics, figuring out the electric propulsion system, and moving ahead from there.
“I agree with them on the philosophy of using classical aerodynamics if they want to pursue viable commercial products,” says Richard Pat Anderson, director of the Flight Research Center at Embry-Riddle Aeronautical University. However, the advantages Borschberg sees may not stick around for long. It will certainly be easier to certify a conventional, if electric, aircraft and get it airborne, but the regulatory environment in the US and Europe is adapting to allow for new tech.
And H55 still has to face down the bigger challenge of electric aviation: making power without burning fuel. “The specific energy of batteries is still just 2 to 3 percent of that of conventional liquid fuel,” Anderson says. “Electric airplanes will continue to have fairly limited uses even in the best case scenarios.”
Borschberg intends to change that. And after the pomp and circumstance of flying around the world, he’s willing to be just a bit boring to make it happen.
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