Airbus is conducting studies to determine how scalable a hydrogen fuel cell “pod” configuration, among others, could be to large commercial aircraft. The aviation industry has developed numerous configurations—twinjet, s-duct, winglets, contra-rotating propellers—over the last five decades that have enabled aircraft to fly higher, faster and longer. Now, Airbus engineers are unveiling a new configuration as part of the ZEROe program (earlier post) that could enable a passenger aircraft to fly farther than ever without emissions.
The innovative approach consists of six, eight-bladed hydrogen-fuel-cell-powered “pods” mounted beneath the aircraft wing.
The ‘pod’ configuration is essentially a distributed fuel cell propulsion system that delivers thrust to the aircraft via six propulsors arranged along the wing. Hydrogen fuel cells have very different design considerations, so we knew we had to come up with a unique approach.
—Matthieu Thomas, ZEROe Aircraft Lead Architect
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.
This ‘pod’ configuration is a great starting point to nurture further inquiry into how we can scale up hydrogen technology to commercial aircraft. This is one option, but many more will be conceptualised before we make a final selection, a decision that is expected by 2025.
—Glenn Llewellyn, VP of Zero-Emission Aircraft
The pod configuration features six standalone turboprop motors based on a distributed hydrogen fuel cell propulsion system and removable fixtures for quick assembly and disassembly.
Each pod is essentially a stand-alone propeller propulsion system powered by hydrogen fuel cells. It consists of the following elements:
- A propeller
- Electric motors
- Fuel cells
- Power electronics
- LH2 tank
- A cooling system
- A set of auxiliary equipment
Another 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 the technology options that Airbus engineers are considering as they work towards launching the ZEROe program.
A patent application for the pod configuration was published in December 2020, 18 months after its initial submission. This highlights that Airbus has been working on ZEROe since at least 2018. Several more patent applications are expected to be submitted over the coming months and years as R&D continues on the ZEROe program.