Airbus is working on concepts for possible hydrogen-powered airliners that it says could be ready to enter service by 2035. Announcing plans for what the European airframer said will be the world’s first “zero-emissions” commercial aircraft, Airbus on September 21 unveiled three designs being developed under a project designated ZeroE.
According to chief technology officer Grazia Vittadini, Airbus will make a final decision on the hydrogen technology platform in 2024 and ready a technology demonstrator for a first flight during 2025. Its engineering team expects in 2021 to have a hydrogen ground demonstrator ready to help it to address complex technology risks around the ecosystem for hydrogen power, such as the fuel’s volume and cryogenic (low temperature) characteristics.
However, the company added that electric batteries may still prove sufficient to support its plans for developing much smaller all-electric eVTOL aircraft for urban air mobility and other applications. It said it will complete flight testing of its CityAirbus four-seat technology demonstrator through the end of 2020, before deciding on the next steps in its eVTOL plans.
The most novel of the three designs presented to a media briefing on September 21 is a blended wing airframe that Airbus indicated would be able to carry up to 200 passengers on flights of around 2,300 miles. The exceptionally wide fuselage, in which the wing merges with the main section of the aircraft, would provide space for a cabin as well as for hydrogen storage and distribution. The design builds on the Maveric model that Airbus has been working on in stealth mode since June 2019.
Airbus also presented a more conventional narrowbody model that would carry between 120 and 200 passengers on sectors of around 2,300 miles. The propulsion system would be based on a pair of modified gas turbine engines powered by liquid hydrogen that would be stored and distributed via tanks located behind the rear pressure bulkhead. The design features swept-back outer wing surfaces.
The third design is a 100-seat twin turboprop. It too would feature modified gas turbines fueled by hydrogen and, said Airbus, would fly to a range of up to around 1,000 nm.
Jean-Brice Dumont, Airbus’s executive vice president for engineering, told a September 21 media briefing that the final configuration of the first hydrogen airliner to enter service is still to be determined. “These are concept aircraft. These are not demonstrators and this is not a program, because we cannot yet say what the market is for these aircraft,” he explained, indicating that Airbus will aim the early development work at aggregating the most suitable aspects of the technologies under evaluation and determining how they meet key parameters, most notably safety.
While hydrogen can deliver the same energy as kerosene, it is around one-third of the weight of fossil fuel. “The catch is that its volume is four times as much as kerosene,” explained Vittadini. “So fuel tank design and integration are fundamentally important, and this could mean longer and wider fuselages that have an impact on aerodynamics.”
Airbus’s announcement confirms that it now views hydrogen propulsion as the key enabler for zero-emission air transport. In late April, the company announced the cancellation of its E-Fan X project with Rolls-Royce to develop a hybrid-electric-powered regional airliner. Just a few months earlier, the partners had said that a technology demonstrator based on an Avro RJ100 aircraft would start test flights during 2021. The program had received £58 million ($75 million) in UK government funding through the Aerospace Technology Institute and Clean Sky 2 organizations.
Over the past two or three years, Airbus has tested a pair of all-electric technology demonstrators for small eVTOL aircraft. In 2019, it completed testing of the single-seat Vahana model, and it is due to finish flight evaluation of a four-seat CityAirbus design by the end of 2020.
Glenn Llewellyn, Airbus’s vice president for zero-emissions aircraft, said that electric batteries do “have a place” for smaller aircraft, such as those intended for short-range mobility in urban areas, but that they cannot support larger commercial aircraft. Dumont mentioned that hydrogen propulsion might actually find its way onto an Airbus helicopter before the larger airliners are ready to enter service.
Vittadini maintained that Airbus will not waste the research and development investment in the trial projects. “All our learnings about electrification will flow seamlessly into any of these new concepts,” she said, adding that Airbus has been examining new ideas such as modified gas turbine architecture, new fuel injection principles, combustion chambers, and embedded electric motors.
Llewellyn said that hydrogen propulsion will deliver significantly more energy per kilogram of weight than electric batteries. “This is what [aviation] needs to meet the Paris Agreement [carbon-reduction] targets, and as the scale [of hydrogen use] is increased the costs will come down,” he stated.
Airbus has already started to work with multiple undisclosed airlines, energy companies, and airports to address the complex infrastructure needs to support hydrogen propulsion for aviation. “The entire ecosystem [for air transport] will have to change,” said Llewellyn.
The ZeroE announcement from Airbus came just four days after rival aerospace group Boeing confirmed that it is closing its Boeing NeXt innovation division just over two years since its launch in July 2018.
Vittadini said that Airbus is willing to invest “billions” in hydrogen technology and that its efforts will lower the entry barriers to using the fuel. Asked by reporters why the company is boosting investments at a time when it is suffering historic reductions in revenues and profitability, she insisted that the effort is imperative to securing the long-term sustainability of the air transport industry.
“Why are we doing this now in a crisis?” she asked rhetorically. “We do not have a choice.”