Solar-powered aircraft could offer a low-cost way to train future pilots, if the partners developing the Sun Flyer succeed in their ambitious plans. A technology demonstrator–a PC-Aero Elektra One–for the Sun Flyer solar-powered airplane made its first flight earlier this month in Munich, Germany, and can be seen at EAA AirVenture 2014 at the Redbird Flight Simulations display (Booth 320). While the Elektra One technology demonstrator didn’t fly with solar panels, the panels will be installed on the Elektra that is on display at AirVenture.
The Sun Flyer is under development by Aero Electric Aircraft, Bye Aerospace and PC-Aero. Simulator manufacturer Redbird will be the training system provider. Bye Aerospace is led by George Bye. The company developed an electric-powered Cessna Skyhawk that flew about a dozen times in 2012 during tests at Centennial Airport in Englewood, Colo.
Plans call for further testing of the Elektra One technology demonstrator at the Aero Electric facilities at Centennial later this year. “The data we gather during these extensive flight tests will help us continue to define and refine the design requirements and objectives for the future complete prototypes of Sun Flyer,” said Aero Electric president Charlie Johnson. “Our primary focus will be flight schools with a higher utilization rate and aircraft rental operation compared to personal use aircraft. We believe that the lower operating costs, along with the simplification of the frequent maintenance checks required by the FAA for training operators, will result in lower overall costs for Sun Flyer.”
According to Aero Electric chairman and CEO Bye, electric motor and battery technology has advanced rapidly in the past two years, enabling longer-endurance electric flight at a low operating cost. “Our goal is to get general aviation revitalized,” he said. “We realized the possibility of flying at a low price point is exciting for current pilots and people considering the adventure of flying.”
One of the lessons learned from the Skyhawk project is that a purpose-designed electric airplane is more suitable, from a structural and aerodynamics standpoint. Electric motors are relatively small compared to air-cooled piston engines and thus the nose of the airplane can be much slimmer and lighter. And longer, higher aspect ratio wings provide lots of surface area for solar panels.
The Sun Flyer will be a two-seat, all-composite, electrically powered light sport airplane using solar cells mounted on the wings to supplement lithium-ion batteries. The batteries are made by Panasonic, and the battery management system and motor controller is made by Germany’s Geiger Engineering. Operating costs compared to a typical two-seat, gasoline-powered trainer will be two to five times lower, according to Aero Electric.
“This is such an important challenge,” Bye said, “and that’s why I think the team we’ve assembled is up to the task.” Among the senior leadership team are early TBM developer Alexandre Couvelaire, Redbird founder Jerry Gregoire, Adam Aircraft co-founder John Knudsen and Gretchen Jahn, chairman of DeltaHawk Engines and former CEO of Mooney Airplane.
At AirVenture, Bye added, “We will talk about the [development] schedule, but it will be driven by conservatism and appropriate measures to ensure that this is a great quality product and that we’re doing it the right way.”
PC-Aero’s Elektra One Solar features six square meters of solar cells on the wings, which provide about half the power needed for flight, while the rest of the power is provided by high-density lithium-ion batteries. The Elektra One’s thrust is provided by a dual-redundant electric power unit, which includes two electric motors, controllers, battery management systems and batteries. The two motors operate on a single axis using their own controllers; each system can run independently. According to Geiger Engineering, the Elektra One can still climb with just one system running.