Airbus engineers are unveiling a new configuration as part of the ZEROe program that could enable a passenger aircraft to fly farther than ever without emissions.
The innovative approach consists of six, eight-bladed pods mounted beneath the aircraft wing. While the pod engine is not a new concept in aviation, these pods are designed to be driven by hydrogen fuel cells.
“The pod configuration is essentially a distributed fuel cell propulsion system that delivers thrust to the aircraft via six propulsors arranged along the wing,” explains ZEROe Aircraft Lead Architect Matthieu Thomas. “Hydrogen fuel cells have very different design considerations, so we knew we had to come up with a unique approach.”
Indeed, hydrogen fuel cell technology has yet to be scaled up to a passenger-size large commercial aircraft. Smaller experimental hydrogen aircraft, comprising up to 20 seats, can rely on a traditional fixed-wing configuration with two propellers. But more passenger capacity and longer range require another solution. This is why Airbus is studying a variety of configurations, including pods, to determine which option has the potential to scale up to larger aircraft.
Each pod is essentially a stand-alone propeller propulsion system powered by hydrogen fuel cells. It consists of:
- A propeller
- Electric motors
- Fuel cells
- Power electronics
- LH2 tank
- A cooling system
- A set of auxiliary equipment
Hydrogen and air are supplied to the fuel cells to generate electric current. Power electronics convert the current to power the electric motors. Thanks to this energy, the motor shaft rotates, thereby turning the propeller.
Another striking feature of the pod configuration is its removable fixtures. This means each pod can be disassembled and reassembled in record time. This approach could provide a practical and rapid solution for maintenance and potentially hydrogen refueling at airports.
The pod’s eight-bladed propellers, made of composite materials, are shaped to provide added thrust during the takeoff and climb-out phases of flight. The advanced airfoil design is expected to lead to improved efficiency and performance.
Although advanced in its design, the pod configuration still requires a lot of work to determine whether it could be a suitable solution. To date, it remains one of many exciting technology options that Airbus engineers are considering as they work towards launching the ZEROe program.
“This pod configuration is a great starting point to nurture further inquiry into how we can scale up hydrogen technology to commercial aircraft,” explains Glenn Llewellyn, VP of Zero-Emission Aircraft. “This is one option, but many more will be conceptualized before we make a final selection, a decision that is expected by 2025.”
Airbus submitted a patent application for the pod configuration in 2018 and expects to submit several more patent applications as R&D continues on the ZEROe program.