TOP TECH AV DEVELOPMENT 2015

Airbus Group flies E-Fan and will build, certify and sell it

All-electric technology demonstrator made historic crossing of the English Channel. E-Fan 2.0 will be side-by-side LSA. Coming is 4-place GA E-Fan.

By Mario Pierobon
Contributing PP Writer in Europe


Global warming, climate change, green economy, environmental management, emissions trading schemes and many other expressions and words have enriched the 21st century's language and lexicon, as humans come to terms with the reality of the side effects of the industrial revolution.

Ever since it started in the early 19th century, the industrial revolution has supported an increase in living standards that is unprecedented in history. However, it has also produced some dysfunctionalities in the process, and the natural environment is among the recipients. Humans are consuming Earth's natural resources at a rate that is short-sighted. This situation can be likened to a household spending annually 50% more than what it earns.

However, the human intellect is very gifted and engineers are increasingly finding ways to use technology to better serve humans while at the same time respecting nature. Perhaps also supported by the impetus given by skyrocketing oil prices up until 1 to 2 years ago, the last decade has witnessed the development of a variety of technical applications that are suitable for industrialization and are meant to significantly reduce the global carbon footprint.

(L–R) E-Fan Test Pilot and Designer Didier Esteyne and Airbus Group Chief Technical Officer Jean Botti celebrate the successful crossing of the English Channel on July 10, 2015.

While electric cars are already being produced and sold, electrically-powered aircraft are next in line. Airbus Group's E-Fan is a total game changer with regard to electric aircraft propulsion, and it's making its way into commercial aircraft applications.

What is the E-Fan?

Think of an aircraft that instead of a fuel tank has a large rechargeable battery, and instead of noisy engines has 2 very discrete electric fans. This is Airbus Group's E-Fan technology demonstrator. Fuel efficiency has long been considered a discriminating factor in the art and science of fleet planning and aircraft acquisition, almost irrespective of dominating fuel prices. But this will change with the E-Fan, although not immediately.

Airbus Group's E-Fan is an innovative concept for a new generation of electric aircraft that targets training schools and general aviation (GA). As part of Airbus Group's focus on developing more eco-efficient aircraft, the E-Fan program is aligned with the European Commission's "Flightpath 2050" goals, which call for significant reductions in aircraft CO2 emissions and noise to ensure the aviation industry's sustainable development.

According to Airbus Group, the E-Fan's modern connected cockpit will also make learning to fly more intuitive, while the full authority digital controls (e-FADEC) will handle electrical functions. The e-FADEC is an optimized, fully digital energy management system for electrical aircraft that simplifies the monitoring and control of systems, reducing pilot workload and allowing the instructor and student to better concentrate on flying the aircraft and to focus on the training mission.

Aboard the E-Fan, the connected cockpit introduces a new flightdeck concept that is tailored for the operation of an electrical aircraft. Its electronic flight displays incorporate a simple and intuitive symbology that facilitates the pilot's understanding of flight conditions, simplifies the management of aircraft systems, and enables a flight to be performed based on the maximized use of onboard electrical energy.

The success of Airbus Group's E-Fan technology demonstrator, used for test and demonstration flights (including a crossing of the English Channel in July 2015), has led to the definition of 2-seat and 4-seat production versions.

Why did Airbus Group do it?

Instead of fuel tanks in its wings, Airbus Group's E-Fan has large rechargeable batteries that power 2 discrete electric ducted fans.

The answer lies in the company's aim to be, once again, a game changer in the aircraft manufacturing business thanks to innovative technology. With the A320, the Group's Airbus division introduced the concept of "computerized flying" and led a revolution in terms of operating efficiencies that have supported a wider "digital revolution" in aircraft manufacturing.

The Airbus Group's Corporate Technical Office (CTO), headed by Chief Technical Officer Jean Botti, is the proactive arm in charge of caring about future technologies within the Airbus Group. The CTO looks at incremental improvements, such as product and process enhancements, and it also looks at technologies that can be revolutionary in the marketplace.

Within the Airbus Group CTO team, the technology leaders think of the future role of aircraft going ahead 20 to 30 years, and even further down the line. "Have we been missing something that could change the game?" This is the sort of question that engineers at the Airbus CTO ask themselves and attempt to answer. It was within the CTO that the potential for electric aircraft propulsion was identified as worth investing on.

"As part of our technology screening process, we realized that, with regard to aircraft propulsion, aircraft engine manufacturers are optimizing their engines for more effective and cleaner operations. In this respect, we asked ourselves what could really be a breakthrough. Our conclusion was that electric propulsion, if done the right way, could have the potential to act as a game changer, not only for the propulsion of air- planes, but also for the integration between airframe and engine manufacturing, whereas today engines are sold separately from the airframe," explains Airbus Group's CTO Sr Technical Advisor and Sr VP Detlef Müller-Wiesner.

Pros and cons of electric power

Research and early commercial applications of electric engines have demonstrated that these have a better weight to power ratio, compared with traditional combustion engines. Electric motors react considerably faster than internal combustion engines in terms of revolutions per minute. There is also no need for oxygen to power an electric engine, and this is a real advantage for air operations given that oxygen density in the air decreases at higher altitudes.

However, there is also a significant disadvantage inherent to electric engines, which involves energy storage: At the current state of the art, 1 kilogram of kerosene has 50 times more energy content than 1 kilogram of batteries. "We realized that if we only continued to perform research, nothing is really going to happen.

Given our aim of producing something larger, such as a regional jet that is electrically powered, we needed to tackle the challenge of limited energy storage in the current generation of battery applications available. We found it workable to start with a small demonstrator since it involves relatively little financial and technical risk while providing a significant potential. This way we can develop significant learning for larger applications in the future," says Müller-Wiesner.

The E-Fan technology demonstrator is not the 1st airplane with electrical propulsion developed by the Airbus Group. This was actually the Cri Cri, a 3rd party non-certified 1-seat ultralight design, which Airbus Group equipped with electric engines. This Cri Cri version was demonstrated at LBG (Paris-Le Bourget) in 2011. "We showed that the Cri Cri would fly with 1 pilot onboard for 20 minutes or so and that it could even be flown in an aerobatic maneuver. Then we asked ourselves what the next steps could be," comments Müller-Wiesner.

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