Participating in the flying display here at the Paris Air Show is Airbus’s E-Fan 1.0 electric aircraft, which has benefited from a number of improvements since it was on the static display here in 2013. Production of the two-seat trainer type is planned to begin in a new factory to be built in Pau, southwest France, starting in 2016. Airbus Group, through its Voltair subsidiary, is thus the first major manufacturer to join the growing number of companies that aspire to create a new, more environmentally friendly way of flying.
Since March 2014, the E-Fan 1.0 demonstrator has performed 78 test flights, logging 38 flight hours.
Leading up to this year’s show, the aircraft has been heavily modified. “We have reduced the structural weight and made the front landing gear retractable,” Detlef Müller-Wiesner, who is responsible for Airbus Group’s E-Aircraft program directorate, told AIN. He said battery capacity has been increased by 30 percent, but would not identify a percentage on resulting increase in endurance. As of mid-May, developers were evaluating possible ways to counter potential thrust asymmetries (in case of a motor failure, for instance), Müller-Wiesner explained.
The production version, the E-Fan 2.0, will offer two seats in a side-by-side configuration (the demonstrator had an aft seat but the space was filled with data transmission equipment). The E-Fan 2.0 will weigh less than 600 kg (1,323 pounds), as Airbus is planning to certify it in the light sport airplane category and that is the upper weight limit. It will be powered by two 30-40 kW motors, up from 30 kW on each of the demonstrator’s motors. The current official estimate on endurance is 75 minutes (including reserve).
Neither the demonstrator nor the E-Fan 2.0 will be able to charge batteries during descent. “It would complicate the design of the control unit and the cost-benefit ratio would be unfavorable,” Müller-Wiesner explained. Another Airbus Group source told AIN that the issue is with the heat such charging activity would generate in a confined space. [Czech Republic-based Pipistrel has a competing program–the WattsUp–in which the propeller would act as a ram-air turbine to recharge the battery. Thirteen percent of the battery charge would be recouped on every approach, according to Pipistrel.]
On the E-Fan 2.0, a full charge takes one hour on the ground. This is good news for flying clubs or schools, as the aircraft should be able to fly five hours per day. Another positive part of the equation is the much lower noise level (thanks to the electric motor and ducted fans), which should expand operating hours at noise-sensitive airports. “The direct operating cost will be 30 percent lower than that of existing, comparable aircraft,” Müller-Wiesner added.
Total development cost is on the order of €50 million, shared between Airbus (€20 million) and partners, including Safran, Zodiac and Siemens. Part of the cost is covered by launch aid from state and local authorities.
Daher is a subcontractor and is in charge of “operating the design office” in Tarbes, Müller-Wiesner said. The location of Daher’s design and manufacturing facility in Tarbes was a factor in choosing Pau (a 40-minute drive) for the E-Fan’s final-assembly site. Construction on the factory is planned to begin in the middle of next year. The first delivery of an E-Fan 2.0 is scheduled for the end of 2017, according to Müller-Wiesner.
Airbus Group sees the E-Fan program as a first step toward larger electric or hybrid aircraft; the company has already run a 700 kW motor on a test rig.
