Hybrid and Electric Jets: The Airbus E-Fan, Lilium Jet and Zunum Aero
Fuel efficiency, with its benefits of cost saving, low carbon emissions and added value to buyers is a bullseye aircraft manufacturers are keen to hit. Leading the charge are three aircraft from Airbus, Lilium and Zunum which show the rapid development in hybrid planes and electric jets. We explore this fascinating developing field.
The Airbus E-Fan
The smallest of our featured aircraft at only 21.9 ft (length) by 31.2 ft (wingspan), the E-Fan jet uses electrical power alone to fuel its two 30 kW electric motor fans. Banks of lithium-ion cells in the wings provide the two-seater jet’s only source of power, with no auxiliary or backup fuel-based engine. A solely electrical aircraft has long been thought impractical or even impossible to achieve, but Airbus has disproved such concerns with this innovative aircraft.
The benefits of an electric jet are numerous: zero noise, creating an unparalleled flight experience; reduction in noise pollution over cities; no emissions during the flight; and vastly improved overall efficiency. The removal of fuel also makes the aircraft lighter (no need for a fuel tank) and cheaper to run. While the E-Fan jet is not yet available, Air Charter Service has access to a range of alternative light-jets for private jet charter, providing a highly fuel-efficient way to travel.
The downside to Airbus’ jet – and ultimately the major issue with electrical locomotion today – is range. Battery technology has stagnated over the past few decades, and though new, promising innovations are now being developed, innovation for electrical transport has been limited as a result. Due to this, the E-Fan has a flight time of only one hour, a maximum cruise speed of 137 mph and is restricted to the boundaries of the airport. The jet is therefore less a prototype for a commercial aircraft than a proof-of-concept, demonstrating that electrical flight is possible even with today’s limitations. While the E-Fan is too small for commercial use, it is a promising pilot project that Airbus hopes to build on in the future, with the ultimate goal of applying the technology to larger commercial aircraft by 2050.
The Lilium Jet
The Lilium Jet is a light electric jet aircraft, the first creation from German aerospace startup Lilium. Resembling a futuristic flying car more than a plane, the model has been tested in field trials with a working prototype. Lilium’s goal was to create an aircraft for families which boasts minimal noise, no emissions, low cost, simplicity and – above all – the ability to cover large distances at speed. Although the Lilium Jet meets many of these requirements, as with the E-Fan, range is the inevitable challenge it needs to overcome.
Lilium has made greater strides than Airbus towards increasing its aircraft’s operating range. The Lilium Jet is capable of traveling 186 miles at a maximum cruise speed of 186.4 mph, beating the E-Fan through a unique propulsion system that leverages 36 individual gimballed fans for efficient and precise flight control. Not only is the Lilium fast, it is also capable of vertical take-off and landing, meaning it can fly in a heavily developed urban environment while only requiring enough space to accommodate its 10-meter wingspan. Lilium markets the jet as perfect for commuting or a daytrip to the city, where landing pads on top of highrise buildings would facilitate the aircraft. The company also has plans in the pipeline to provide “air taxi” services, which would allow passengers with no flying knowledge to summon a Lilium Jet taxi to their closest landing pad.
While Lilium’s design has been tried and tested, the current working model is unsuitable for its target market of families: as with the E-Fan, it can only accommodate the pilot plus one passenger. However, on 5 September 2017, Lilium gained $90 million USD in funding to develop a five-seater aircraft that would fulfill their ambition of creating a practical family jet – an achievable goal if they can maintain the operating range of the current two-seater model. This ground-breaking design will take years to complete, however Lilium’s rapid progress since launching in 2015 has stirred anticipation and excitement among aerospace industry professionals and investors.
The Zunum Aero
The Zunum Aero represents the largest-scale of aircraft in our comparison. Using a method common in the automotive industry for some time, Zunum leverages both an electrical system of propulsion and a fuel-powered generator for when battery power is low. This hybrid approach allows for a 75% reduction in noise output, as well as a substantial 40-80% cut in jet fuel consumption. Zunum’s CEO Ashish Kumar hopes to launch a short-haul 50-passenger commercial Aero within a decade.
While a 50-passenger jet may seem small in comparison to fuel-powered commercial aircraft, the operating range for the battery is estimated at 175 miles, with the generator extending this range to 700 miles. This places the Zunum Aero in the unique position of being able to provide cheap flights for short journeys; perfect for connecting large hub airports within the US to small, often neglected local airports. As such, this hybrid jet has the potential to open up a new, efficient network of short flights that will allow travelers to cheaply fly to previously hard-to-reach destinations. This new sector of air travel could also further reduce emissions by enticing more people to fly by plane rather than traveling less efficiently by car.
While retaining a fuel-powered engine could be seen as a concession, it is also the Zunum Aero’s greatest strength. While current solely electronic aircraft can only carry a small number of passengers a short distance, the Aero boasts a significantly greater range, a commercially viable passenger capacity and many of the benefits of an electric engine. With these advantages, this aircraft is the most commercially viable of the three featured here and has the greatest potential to be used in the future, without requiring new infrastructure such as landing pads on high-rise buildings.
While the Airbus E-Fan, Lilium Jet and Zunum Aero are not yet available to buy, their development shows how close the aviation industry has come to creating a silent-running, clean and environmentally friendly aircraft with the potential to cater to a range of clients: commuters, families and those looking to charter a private jet.