While electric aircraft have gotten plenty of gee-whiz press coverage, they lack one thing: credible production airplanes. At Redbird’s Migration training conference this week, Aero Electric Aircraft Corp.’s George Bye pledged to change that by showing up at next year’s event with a prototype of the Sun Flyer, a two-place electric that may become the first certified electric-powered trainer.
At a short talk at Migration, Bye told the audience that the Sun Flyer represents a synthesis of several technologies, including improved DC motors, higher-capacity batteries, materials technology and the ability to tweak airframe and propeller aerodynamics to reduce drag and extend flight duration, which remains the unaddressed weakness of electric aircraft. However, Bye insists that improving battery technology will address this, specifically new battery chemistries from Panasonic that he said are expected to deliver power densities of up 250 watts/kg, compared to about 160 watts/kg that are typical for the best contemporary production batteries.
That will give the Sun Flyer a flight endurance of about four hours or a practical training time of about three hours at an energy cost of about $1 an hour. In addition to quick-change battery packs, the Sun Flyer will also be equipped with wing-mounted solar cells that generate about 15 to 20 percent of the aircraft’s low-speed cruise power requirement, thus extending its range.
Bye said Aero Electric has heard complaints about light sport aircraft lacking the durability to withstand the rigors of training so the company will produce a certified aircraft. “This is not an LSA and we don’t want it to appear to have those challenges,” he said. What about the regulatory challenge? Bye said the company has mapped out a two-year certification program with the FAA which, conceptually, has revealed no showstoppers.
“If we can do that, we’ve got a solution. If this is real, we’ve got a solution,” Bye said. Cost-wise, Bye’s data showed that proposed all-in direct costs for the Sun Flyer, including battery replacement costs, will be about $4.65 an hour, compared to $73 for a gasoline-powered Cessna 172.