Airbus is stepping up preparations to fly its E-Fan X hybrid-electric demonstrator aircraft as part of a long-term effort to develop a commercially viable, electrically powered airliner. The group is reconfiguring a BAE 146 RJ100 aircraft with a 2-MW electric motor replacing one of its turbofans and aims to achieve first flight in 2021.

The company recently completed wind-tunnel tests with a scale model of the 146 RJ100 in its test center at Filton in the UK. In fact, the Airbus engineering team worked in the same wind tunnel that BAE Systems used to develop the original four-engine aircraft in the 1980s.

The main purpose of the testing was to understand how the various modifications needed for the hybrid-electric aircraft will impact aerodynamic performance and handling qualities. Apart from the addition of the electric motor, the demonstrator will also be fitted with externally mounted heat exchangers for liquid-cooling systems, as well as intakes and an exhaust for the fuselage-mounted power generation system.

The wind-tunnel tests also gave designers useful insights into the aircraft’s anticipated low-speed performance and handling qualities. “The only change we discovered during the test program is that we need to modify the porosity of some of the devices in the ducts to ensure they relate correctly to the full-scale E-Fan model devices,” explained Airbus wind-tunnel test engineer Paul Gingell in a company blog.

Rolls-Royce is developing the E-Fan’s complete hybrid-electric propulsion system, which is based on its M250 turboshaft engine. The new engine will generate between 500 KW and 1 MW of power.

In April 2014, Airbus flew the original all-electric E-Fan light aircraft, which is intended for the flight training market. The E-Fan X is intended to have 30 times as much power as its predecessor. Airbus (Stand J23) is displaying a scale model of the aircraft at the Singapore Airshow this week.

Meanwhile, the European aerospace group is also making progress in the development of electric vertical takeoff and landing aircraft for so-called urban air mobility applications. Last year, the A3 by Airbus division in California completed flight testing of the single-seat Vahana technology demonstrator. This year, Airbus Helicopters intends to complete the evaluation of the two-seat CityAirbus demonstrator. The findings from these evaluations will inform design work for a passenger-carrying aircraft, for which product definition work could be complete by year-end.

Airbus has not set a firm timeline for getting an electric or hybrid-electric airliner in service but describes the E-Fan X program as “a giant leap towards achieving zero-emission flight over the next 20 years.”