Hydrogen Fuel Cell Applications in Aerospace
The IATA Aircraft Technology Net Zero Roadmap has a considerable section dealing with Sustainable Aviation Fuels (SAF) and hydrogen-powered aircraft. These ideas are all part of mapping how aerospace will change to reduce its carbon footprint on the way to 2050.
Our following web stories will now delve into the second phase of that report, which covers SAF and hydrogen aircraft.
Figure 1, which follows, shows the first four elements of the SAF and hydrogen aircraft – Aircraft Technology Roadmap. For this posting, we will cover items 1 and 2 only. Noted is that on the second column, these TRM (Technology Road Map) items are indicated to have a “Before 2023” timeline.
Figure 1: The Aircraft Technology Net Zero Roadmap -SAF and Hydrogen
Dornier 228
As we try to understand Figure 1, we will need to unpack the acronyms before proceeding.
The (Fig 1) Milestone column indicates that a flight test for a retrofit for a 19-seater aircraft is planned for a sub-Megawatt Hydrogen Fuel Cell aircraft (sub-MW HFC). The retrofit is stated as the selected aircraft will need to be retrofitted to hold a hydrogen fuel cell for one of the propeller-driven engines. Also, the power level of this configuration is less than 1 million watts, hence the “sub-MW” nomenclature.
The Description (column) for item 1 shows that the sponsor of this project is ZeroAvia. This firm was founded in 2018 to develop and build hydrogen-electric propulsion and fueling solutions for aircraft. ZeroAvia is targeting a 300-mile range for its airplanes and plans to scale to larger aircraft and longer distances over time.
The Dornier 228 (Figure 2) was chosen for this project. It is a twin-turboprop STOL (Short TakeOff and Landing) utility aircraft. The aircraft is large and box-like and has a lot of room inside. Dornier GmbH of Germany designed and first manufactured this aircraft. Figure 2 shows this aircraft with some of the test kit on the left engine.
Figure 2: The Dornier 228
More or less consistent with the original TRM timeline, the first flight of this aircraft in the new configuration took place in the UK on January 31, 2023. This first flight lasted only 10 minutes. Test flights of new aerospace technologies are all taken in short increments. Further testing will continue, and subsequent flights will each be longer.
ZeroAvia refers to this project as the HyFlyer II project. Their R&D programme was backed by the UK Government’s flagship ATI Programme for approximately $20m CDN.
The Dornier 228 twin-engine aircraft was retrofitted to incorporate ZeroAvia’s [1] hydrogen-electric engine on its left wing, which then operated alongside a single Honeywell TPE-331 stock engine on the right. In this testing configuration, the hydrogen-electric powertrain comprises two fuel cell stacks, with lithium-ion battery packs providing peak power support during take-off and adding additional redundancy for safe testing. This testbed configuration housed hydrogen tanks and fuel cell power generation systems inside the cabin. External fuel storage would be used in a commercial configuration, allowing for the passenger seating to be restored.
ZeroAvia will now work towards its certifiable configuration to operate commercial routes using its Hydrogen Fuel Cell technology by 2025. Meanwhile, the Dornier 228 will conduct a series of test flights from Kemble (in SW UK) and later demonstration flights from other airports.
In earlier related activities, ZeroAvia conducted more than 30 flights of a six-seat Piper Malibu aircraft almost two years ago using a 250kW hydrogen-electric powertrain.
Dash 8 300
The second SAF and Hydrogen Aircraft milestone (see Figure 1) indicates a flight test of a 40-seater retrofit for a sub-MW HFC aircraft. Unpacking this text from the TRM, a retrofit aircraft will also be selected for this project. In this case, it will be a 40-seater. Despite the choice of a larger aircraft, the energy requirement will still be that of a sub-megawatt Hydrogen Fuel Cell (sub-MW HFC). As stated earlier, the power level of this configuration is less than 1 million watts, hence the “sub-MW” nomenclature.
The related Figure 1 “Description” indicates that the operator of this project will be Universal Hydrogen[2], which has selected the De Havilland Dash 8-300 turboprop for their testbed. Their project has been nicknamed ”Lightning McClean”. This fuel cell-powered aircraft (see Figure 3) made its first flight on March 2, 2023, at the Grant County International Airport in Moses Lake, Washington. The first flight lasted 15 minutes, with the aircraft reaching an altitude of 3,500 feet. The plane, in this case, was equipped with one conventional turboprop engine and one magni650 electric propulsion unit (EPU), which received electricity from the hydrogen fuel cell system.
Figure 3: Universal Hydrogen – Dash 8 -300 – HFC first flight
In this case, the hydrogen fuel cell was fitted into one of the aircraft’s nacelles (i.e., engine housing).
By the end of 2023, Universal Hydrogen had completed over 10 test flights and was planning for its technology to reach commercial entry into service by 2026.
Universal Hydrogen will use its flight test campaign to optimize the performance of the hydrogen fuel cell powertrain for several related applications. New hardware and a custom aviation-grade turbocompressor are anticipated to further enable flights to climb to the Dash 8 original design altitude of 25,000 ft. Universal Hydrogen also plans to introduce its patented modular liquid hydrogen fuel storage system and initiate certification testing to prove that the production configuration of its retrofitted aircraft meets all FAA-mandated airworthiness and safety requirements. In essence, this firm plans to provide a complete package of hydrogen-related services for both the aircraft and the airport.
Farnborough International Airshow – HFC updates
Every two years, the Farnborough Air Show brings together an international gathering of users and aerospace product developers. This past year’s airshow took place from July 21 to 26. Two demonstrations related to the topic of this web story took place here and are now briefly discussed.
Two related updates on this topic are now raised, which were presented at this recent airshow.
ZeroAvia Amphibious Flying Boat goes HFC
The first example is ZeroAvia’s[3] (Hollister, Calif., US) fuel cell power generation system (PGS) technology, which was used to demonstrate the concept of using a fuel cell variant in an amphibious flying boat design (Figure 4).
Figure 4: Jekta and ZeroAvia partner on hydrogen-electric amphibious aircraft project
The aircraft selected for this project is Jekta’s PHA-ZE 100. This composite amphibious aircraft has already been configured as an electric aircraft (i.e. with a battery power plant and electric motors as propulsion motors). Their new design is intended to achieve a range of 500 to 600 kilometres. An additional feature of the new configuration is that the payload can be increased by up to 1 tonne. A readily apparent difference when examining Figure 4 is that the PHA-ZE 100 has ten electric motors set on its wings. This design choice allows for smaller, lighter electric motors to be used compared to traditional (and fewer!) turboprop engines.
KLM, ZeroAvia plan zero-emission demonstration flight using liquid hydrogen
Another interesting announcement at the Farnborough Air Show was that ZeroAvia and KLM Royal Dutch Airlines (The Hague, Netherlands) are working toward a demonstration flight using ZeroAvia’s ZA2000 zero-emission, hydrogen-electric engines for a large regional turboprop aircraft. As a first major target milestone, the companies aim to conduct a demonstration flight between two airport locations in 2026.
Figure 5: ZeroAvia airframe with KLM livery
ZeroAvia proposes to launch its ZA2000 (Figure 5) in 2027 after appropriate regulatory approvals. The aircraft will be suited for regional flights with about 80 passengers. Its range would also be in the order of 1000 nautical miles.
Our storylines in the coming weeks will cover additional features to the SAF, battery and fuel-cell-based innovations aimed at reducing the carbon footprint in the aerospace sector.
[1] https://zeroavia.com/do228-first-flight/
[2] https://www.ainonline.com/news-article/2023-03-02/universal-hydrogen-flies-hydrogen-powered-dash-8
[3] https://www.compositesworld.com/news/farnborough-airshow-2024-brings-together-aerospace-innovation-collaboration