Airbus’s ambition is to develop the world’s first zero-emission commercial aircraft by 2035, thereby becoming a world leader in commercial green aircraft.
A380 MSN1 – the first-ever A380 to roll off the production line is being converted to test the technologies that will be vital to bringing the world’s first zero-emission aircraft to market. The size of the A380 makes it ideally suited to the role of a test platform. A demonstrator aircraft is fundamental to developing new aviation technology as they can test designs and innovations both on the ground and in the air.
First announced publicly on 30 November this year at the Airbus Summit, the iconic A380 MSN 1 will be modified externally to carry the fuel-cell engine pod, while inside the aircraft’s rear fuselage Airbus will install a unique cryogenic tank to contain the liquefied hydrogen. The A380 was the obvious choice as ‘host’ for the hydrogen fuel-cell engine demonstrator. “It has plenty of space internally – so there are no constraints in terms of accommodating everything we need, as well as the ability to test multiple configurations,” says Mathias Andriamisaina, Head of ZEROe Demonstrators and Tests at Airbus.
“The A380 MSN1 is an excellent flight laboratory platform for new hydrogen technologies. It’s a safe and reliable platform that is highly versatile to test a wide range of zero-emission technologies. In addition, the platform can comfortably accommodate the large flight test instrumentation that will be needed to analyse the performance of the hydrogen in the hydrogen-propulsion system.”
Airbus says in terms of aerodynamics, the A380 is a very stable aircraft, so any pods attached to the rear fuselage won’t pose much of an issue as the airflows from the pod and its propeller do not affect the airflow over A380’s tail surfaces.
Two years ago, Airbus unveiled several possible aircraft concepts – known collectively as ‘ZEROe’ – which are helping to define the world’s first zero-emission commercial airliner which could enter service by 2035. While these concepts explore various size categories, aerodynamic layouts and propulsion system architectures, they all have one thing in common: they are hydrogen-fuelled.
Three of them have engines which use hydrogen combustion to drive their gas turbines – similar to the way that turbofans and turboprops burn JetA1 but without CO2 emissions. Another uses a pure electric engine, powered by fuel cells.
Hydrogen technology for combustion engine aircraft
In these experiments, the A380 will carry four liquid hydrogen tanks in a caudal position, as well as a hydrogen combustion engine mounted along the rear fuselage. The liquid hydrogen distribution system will feed into a conditioning system in which the liquid hydrogen will transform into its gaseous form before it is introduced into the engine.
Engine manufacturers have been working hand-in-hand with Airbus on demonstrator programmes for decades. CFM International (a joint venture between GE and Safran), will modify the combustor, fuel system and control system of a GE Passport™ turbofan to run on hydrogen. The engine type was selected due to its physical size, advanced turbo machinery, and fuel flow capability.
Hydrogen fuel cells for electric aircraft
Fuel-cells were originally invented by Sir William Grove in 1838 to generate electricity through an electrochemical reaction, rather than via combustion. Fuel cells differ from batteries since they require a continuous source of fuel and oxygen, usually from air, whereas in a battery, the energy comes from substances which are already inside the battery.
Fuel cells can therefore produce electricity continuously for as long as fuel and oxygen are supplied.
Because one single fuel cell is only a few millimetres thick and roughly the size of a letter envelope, it does not release much energy. Therefore, in order to realise sufficient power levels for use in an aircraft, hundreds of these fuel cells need to be electrically connected in series to form a “stack”. Subsequently, several such stacks are combined into multiple fuel cell “channels”. With this modular approach, the megawatt levels of power – which are needed for an electric aircraft – are very much achievable.
Another Demonstrator aircraft
Meanwhile, a fourth ZEROe concept aircraft, representing a high-wing 100-seat regional airliner, features six eight-bladed propellers attached to engine pods.
While outwardly resembling turboprop powerplants, these pods actually contain hydrogen fuel cells which produce electricity as the result of an electro-chemical reaction to power electric motors. It is in this context that Airbus has been conducting feasibility studies and laboratory tests to realise a fully working megawatt-class fuel-cell engine and demonstrator which could be tested in flight by the middle of this decade – around 2026.
(Source and images – Airbus Industries)