UPDATE – A joint study between ZeroAvia and Mitsubishi Heavy Industries Regional Jet Aviation Group (MHIRJ) has identified that there are no showstoppers in converting the Bombardier/Mitsubishi CRJ series into a hydrogen-electric aircraft with fuel-cell technology. The program still has a long way to go, but the basic principles have been validated, ZeroAvia CEO Val Miftakhov said at the Paris Airshow.
ZeroAvia is working on multiple versions of its hydrogen fuel-cell technology. It is currently in a flight test program out of Cotwolds Airport in the UK with a converted Dornier Do-228, on which the starboard engine has been replaced with a 600-kilowatt electromotor that gets its electricity from fuel cell packs and gaseous hydrogen.
Miftakhov said that nine flights have been done with the Dornier since January, circling around Cotwolds Airport and lasting no longer than twenty minutes. The next phase will be to do flights from A to B. ZeroAvia then plans to install the system in a Cessna Grand Caravan and certify this aircraft around 2026.
United and American
At the same time, ZeroAvia is working on a more powerful, 2.0 to 6.0-megawatt version of the fuel cell engine that is suitable for regional aircraft. In December 2021, United Airlines Ventures announced an investment of $35 million in ZeroAvia and the purchase of fifty powerplants to propel converted Mitsubishi CRJ550s from 2028. In August 2022, American Airlines made an unspecified equity investment in ZeroAvia and signed an MoU to purchase 100 engines, also to be used on converted CRJs.
After Bombardier decided to exit the commercial aircraft business, it sold the CRJ program and intellectual properties to Mitsubishi’s Canadian subsidiary MHIRJ. They own the type certificate of the aircraft family. MHIRJ and ZeroAvia announced an MoU for a partnership on the hydrogen version of the CRJ in October 2021 and expanded this in May 2022. Mitsubishi said it would offer all its expertise on the CRJ for integration of the hydrogen system in the regional jet. With some 1.400 CRJs out there in the field, they could find a new lease of life thanks to hydrogen.
No compromising
A technical study of the aircraft has recently confirmed that a complete hydrogen system, including the fuel cells, tanks, and electromotors can be incorporated within the CRJ500 of 990 without compromising the maximum takeoff weight, center of gravity, aerodynamics, and structural allowances. The aircraft could still seat sixty passengers and fly 560 miles/900 kilometers, which covers most of the regional flights.
In a media statement, ZeroAvia said this week: “The technical assessment identified that the loss of turbine core thrust could be overcome within the constraints of the original airframe with increased fan diameter, while further efficiency gains were possible by adopting novel propulsor technologies such as geared, ducted electric fan or open rotor designs.”
“Critically, the system would drastically reduce operating costs by virtue of hydrogen fuel use and reduced maintenance costs, creating opportunities for new routes, as well as more flights on existing routes to match or increase passenger volumes.”
Lots of work remaining
Asked by AirInsight where ZeroAvia stands on a scale of 1 to 100 when it comes to the development of the system for the CRJ, Miftakhov said on Wednesday: “At this point, we are maybe at 9 of 10 out of 100. There is lots of work remaining, but we have confirmed the feasibility of this because that was a big question. It is a large, high-performing aircraft and we were able to confirm that actually build a commercially viable vehicle. It is not just about getting the aircraft up into the air, but also how many seats you can have, the economics of operations, and getting to refuel the aircraft in a reasonable amount of time. That is a significant achievement, but it is the start of the journey.
The CRJ will require a 2.0 MW version of the ZA2000RJ version of the hydrogen fuel cell system that is still under development. This is the so-called High-Temperature Proton Exchange Membrane (HTPEM), which can generate higher power output of up to 5.4 MW while operating at higher temperatures. On the CRJ. This reduces the need for bulky heat exchangers that are evident on the Dornier testbed, which uses the low-temperature LTPEM version that needs more cooling.
ZeroAvia’s high-temperature fuel cell is developed for larger aircraft. (ZeroAvia)
ZeroAvia’s competitor Universal Hydrogen is preferring the LTPEM version for its fuel cell system, as it thinks it will take too long for the HTPEM version to mature. “We already have on the high-temperature fuel cell side substantially the type of technology that we are looking to scale operating in our lab. We have pressurized high-temperature fuel cell stacks already operational and under test. Obviously, there is a roadmap here that gets us to a point, scale, and performance. We need about two to 2.5 years to get to a design lock. We are much closer to a lock on the small engines that are based on low-temperature fuel cells, but the high-temperature ones will come. That fits into the launch timeline of 2027,” said Miftakhov.
Higher power demonstrated in tests
The CRJ study is based on the HTPEM fuel cell system with a specific power of 2.4 kW/kg. In tests, ZeroAvia has demonstrated 2.5 kW/kg at the cell level of its HTPEM stacks. The plan is to deliver a 3.0 kW/kg system-level specific within two years. “Over time, this technology is applicable to all sizes of aircraft. It will take probably about ten years to get to an engine that is applicable to a single-aisle aircraft. We think that we can bring the level of power to the sub-100 regional jets by the end of the decade, but a single-aisle, larger aircraft such as the 737 or A320 is probably ten years out,” said Val Miftakhov.
During the Paris Airshow, ZeroAvia converted an MoU for 100 ZA600 engines with Monte Aircraft Leasing into a definitive purchase agreement. It also signed an agreement with French company Green Aerolease for a number of 600 kW engines that will power 9-19 seater aircraft.
On Thursday, ZeroAvia announced it had signed an agreement with Los Angeles-based Flyshare, which intends to launch services in California and the US West Coast as Air Cahana in 2027. The start-up has ordered 250 ZA2000 systems. The press release showed a De Havilland Canada Dash 8-400.
