Airbus and their ZEROe concepts
The IATA Technology Roadmap into SAF and Hydrogen Aircraft continues in Part 2 of this story. This section will explore and explain how Airbus is developing its ZEROe concepts.
Airbus aims to bring to market the world’s first hydrogen-powered commercial aircraft by 2035. To achieve this, they have proposed the ZEROe project, which will explore a variety of configurations and technologies and prepare the ecosystem that will produce and supply the needed hydrogen.
The ZEROe program is revealed to use four approaches to zero-emission flight. Each approach will use technology pathways and aerodynamic configurations to support these ideas. In brief, the first three concepts are a turbofan design, a turboprop design and a blended-wing body. The fourth concept is the fully electric aircraft.
Follow this link for an animated overview of the first three concepts.
Now for a bit more detail on these new Airbus concepts.
Turbofan
The proposed turbofan for ZEROe would be a new aircraft with a 2000+ nautical mile range (3700 kilometres or 2300 miles), which will provision two modified gas turbine engines running on hydrogen. This aircraft will carry between 120 to 200 passengers. The aircraft would be capable of operating transcontinentally. The liquid hydrogen will be stored and distributed via tanks located behind the rear pressure bulkhead.
A concept design for this new Turbofan is shown in Figure 1.
Figure 1: ZEROe Turbofan (concept only, using current aircraft design)
Source: Airbus
Turboprop
The ZEROe turboprop is Airbus’ second concept. It would be a new, smaller aircraft with a 1000+ nautical mile range while deploying two hybrid-hydrogen turboprop engines. These engines would each have eight propellers and would carry somewhat less than 100 passengers. The turboprop engines would also be powered by hydrogen combustion in modified gas-turbine engines. These elements make it a perfect option for short-haul trips.
A concept design for the Turboprop is shown in Figure 2.
Figure 2: ZEROe Turboprop (concept only, using current designs)
Blended-Wing Body (BWB)
The BWB concept for ZEROe would be a new aircraft platform. Two hybrid-hydrogen turbofan engines would be deployed for the platform like the previous aircraft. This aircraft will carry less than 200 passengers and use hydrogen as fuel. Like the Turbofan ZEROe, the BWB would operate as an intercontinental aircraft with a range of 2000 NM.
Our stories earlier on the IATA Technology Roadmap pointed out that the BWB is a new aircraft concept that was being developed by the USAF. And now, in this case, we see Airbus also working with this idea. Follow this link to catch the earlier story.
The concept design for the BWB is shown in Figure 3.
Figure 3: ZEROe BWB (concept only, using current ideas)
The Forth Concept – The fully-electric airplane
Airbus has partnered with two other aerospace technology providers to form the EcoPulse project. This aircraft is based on a modified Daher TBM 900 turboprop aircraft. The standard engine and propeller systems from that former aircraft are now augmented by six wing-mounted e-propellers, each of which is driven by a 50-kW Safran ENGINeUSTM electric engine. (See Figure 4) These engines are powered by batteries. The EcoPulse demonstrator was developed in partnership with Daher and Safran. This development program is also supported by DGAC, which is the French Civil Aviation Authority.
In such aerospace partnerships, each brings unique skills and responsibilities to the program. Airbus will be responsible for three key features. The first of these is the development of a high-energy-density battery that will be used as an electric source for the e-propellers. Secondly, they will be responsible for the aerodynamic and acoustic integration of the distributed-propulsion system, and lastly, Airbus will develop a flight control computer system.
To this time, the EcoPulse has completed 50 test flights, which added up to 100 flight hours. The EcoPulse project has now concluded (December 2024). Results achieved will enable Airbus to progress in advancing electrification technologies and their scalability for future aircraft and helicopters.
The key features of these flight tests demonstrated the successful design, integration, and safe flight of the 800 VDC high-voltage battery, which delivered 350 kilowatts of energy. Also confirmed was that drag is reduced in cruise status when thrust is distributed outboard (i.e. the outlying motors), as was predicted by prior simulations. Since the EcoPulse used six electric motors, testing this innovative new flight control approach showed that changes in thrust among the six electric propellers can change the aircraft’s trajectory. This approach proved successful and worked as expected. Lastly, noise reduction in the cabin was achieved by synchronizing the speed and the relative positions of the blades between different ePropellers, as well as through the use of vibration absorbers.
Figure 4: The EcoPulse aircraft
A subtlety of Figure 4 shows that there are actually seven motors on the aircraft. As noted earlier, the aircraft chosen for this test program was a turboprop aircraft. That original aircraft’s engine is located on the nose and uses av-gas as its fuel. The remaining six motors in Figure 4 are e-propellers mounted on the wings. The aircraft remained essentially configured as initially designed for flight safety reasons and licensure requirements, with the six additional electrical motors installed on the wings as part of the test program.
We now return to Figure 5 (previously used), referencing the SAF and Hydrogen Aircraft – IATA Technology Roadmap. In this web story, item 3 (see Figure 5) of the 2023 timeline indicated that a “major manufacturer” would announce exploring a clean-sheet narrow-body H2 aircraft. Our story covered Airbus’ announcements and progress for the ZEROe project.
Figure 5: The IATA SAF and Hydrogen Aircraft TRM
