• 02 Apr 2025 04:26 PM
• 0

World’s First Piloted Hydrogen VTOL Lifts Off in Quebec

By Kenneth I. Swartz

The first piloted aircraft to make a vertical takeoff and landing (VTOL) powered by a hydrogen fuel cell made its first flight at Roland-Désourdy Airport (ICAO: CZBM) in Bromont, Québec, Canada, on March 27, 2025.

The milestone first flight of the modified Robinson R44 was revealed by Dr. Martine Rothblatt, CEO of United Therapeutics (UT), during a keynote presentation at the Vertical Flight Society’s 4th Annual H2-Aero Symposium in Long Beach, California, on April 2, 2025. 

The three-minute, 16-second test flight demonstrated the hover and maneuvering capabilities of the hydrogen powertrain.

Ten years ago, UT embarked on a journey to spur the development of zero carbon footprint VTOL aircraft to deliver manufactured organs — then in early development — to hospitals for lifesaving human transplant surgeries. Rothblatt’s company was an early investor in several electric VTOL (eVTOL) programs (see “Electric VTOL for Organs on Demand,” Vertiflite, March/April 2019), a launch customer of Beta Technologies’ Alia eVTOL aircraft, and in 2015 also sponsored a team at Tier One Engineering to develop a battery-electric retrofit (see “Tier 1 Engineering Pioneers Electric e-R44,” Vertiflite, July/Aug 2022) of the popular Robinson R44 piston helicopter. 

Last year, United Therapeutics’ revenues reached a record USD$2.88B, reflecting a 24% growth over 2023, primarily through the development of “medicines for stalling the need for organ transplant among the tens of thousands of people diagnosed with end-stage organ diseases,” said Rothblatt, adding that “the other arm of the company is trying to expand the supply of transplantable organs, so nobody will end up having to die waiting on an organ transplant list.”    

The battery-electric e-R44 went through three design iterations (with two different motors and two different battery packs. Testing culminated in a record cross-country flight for an electric helicopter over the scenic Coachella Valley of California on Oct. 29, 2023, covering the 24-mile (39-km) route in a flight time of 20 minutes (see “Tier 1 Engineering’s Electric e-R44 Makes First Cross-Country Flight,” Vertiflite, Jan/Feb 2023).

The 2023 cross-country flight also highlighted the limitations of a helicopter powered by today’s lithium-ion batteries and triggered UT’s quest to integrate a hydrogen fuel cell into a helicopter.

The “H2eR44” R44 (Canadian registration C-FXUB) was flown by company test pilot Ric Webb, who had also made the first flight of the first-generation e-R44 at Los Alamitos Army Airfield (KSLI) in California on Sept. 13, 2016 (“Tier 1 Engineering Reveals its Second Battery-Electric Robinson R44 Helicopter,” Vertiflite, Sept/Oct 2021).

Development of the hydrogen fuel cell-powered R44 is being led by Unither Bioélectronique, a wholly owned Canadian subsidiary of United Therapeutics Corporation, which is also overseeing the development of UT’s multiplatform organ delivery system.

“Our first test flight successfully demonstrated the hover and maneuver capabilities of our innovative hydrogen powertrain,” Mikaël Cardinal, Vice President, Program Management & Business Development, Organ Delivery Systems for Unither Bioélectronique, stated in a press release. “Our next phase of development will focus on integrating a liquid-hydrogen storage system, which we believe is an essential technology for enabling our extended-range missions to deliver manufactured organ alternatives to patients in need.”

Last summer, the Canadian unit partnered with Robinson Helicopter Company (see “Unither Bioelectronics and Robinson Helicopter Partner on Hydrogen,” Vertiflite, Sept/Oct 2024) on what’s been revealed as “Project Proticity.” Rothblatt said it took its name from biology: proticity refers to the flow and force of protons (H+) across the inner mitochondrial membrane, which drives the synthesis of energy storage. “Just as protons from hydrogen atoms drive the mitochondrial powerplants in each of our bodies’ cells, we look forward to using protons from green hydrogen to drive the membrane-based fuel cell powerplants in our Robinson R66 organ delivery electric helicopters,” she said in the press release.

“The importance of this milestone in aviation history cannot be overstated,” said David Smith, president and CEO of Robinson Helicopter Company. “Project Proticity has taken an incredible first step forward in the path to long-range, zero-emission vertical flight. We are excited to continue developing this technology with our partners at Unither Bioélectronique.”

Unither Bioélectronique started ground running the H2eR44 with a fuel cell in December 2023 in Bromont, which is 50 miles (80 km) east of Montreal and 20 miles (32 km) north of the Canadian border with Vermont.

Considerable effort was required to optimize the external cooling system needed to dissipate heat from the fuel cells when hovering, as well as the software used to control a combination of energy flowing from the fuel cells and the boost battery packs to meet transient power requirements during takeoffs and landings.

Photos of the hydrogen-electric R44 test aircraft show two low-temperature Proton Exchange Membrane (PEM) fuel cell stacks installed in the rear cabin, a magniX electric motor with DC/DC converters and buffer battery pack replacing the Lycoming IO-540-AEA5 in the engine bay, a “Type IV” non-metallic gaseous hydrogen fuel tank installed externally under the tail boom and a cooling system with fans mounted in nacelles on each side of the cabin. 

Approximately 90% of the energy used for the first flight was derived from the helicopter’s hydrogen fuel cells, with the rest coming from the buffer batteries.

UT selected the Robinson R66 for its organ delivery system because its maximum takeoff weight is 200 lb (90 kg) more than the R44 — 2,700 lb (1,225 kg) versus 2,500 lb (1,135 kg). The five-seat R66 also has a separate, full-width, 18-ft³ (0.5-m³) baggage compartment, which — together with the space used for the R66’s 73.6-gallon (279-liter) fuel tank — UT believes is large enough to install a lightweight liquid hydrogen tank now being developed by Gloyer-Taylor Laboratories (GTL) of Tullahoma, Tennessee.

UT hopes that the composite GTL tank and feed lines “will allow us to maintain liquid hydrogen without cryogenically cold temperatures and will allow us to refuel the tank in just minutes with a very, very minimum amount of boil off,” said Rothblatt.

Rothblatt said the company plans to integrate the propulsion system and tank into an R66 in 2026 and by “the end of 2027, we should be demonstrating 250-nm [460-km] ranges in the liquid hydrogen R66 [and] 2028 would be a logical time to apply for a STC [Supplemental Type Certificate]” from Transport Canada, so new and preowned R66s can be retrofitted for the organ delivery fleet.

Last year, Unither Bioélectronique (also written “Unither Bioelectronics”) became a founding member of H2CanFly, the Canadian not-for-profit corporation created to bring together industry, academia and government stakeholders and accelerate the commercialization of hydrogen propulsion aircraft.

Rothblatt confirmed at the H2-Aero Symposium that UT’s organ delivery system will also utilize the Beta Technologies Alia A250 VTOL aircraft, adding that the aircraft had a much better lift-to-drag ratio than a helicopter and could achieve 250-nm ranges on battery-electric power alone.

And if “you snap a hydrogen-electric powerplant into the Beta Alia, the range goes from 250 nm to north of 750 nm [1,400 km]. That's something that I think we can very reasonably expect to happen.”

On April 2, the first day of the H2-Aero Symposium, Beta’s first production Alia CX300 (N916LF) completed a cross-country journey that included visits to more than 20 states and 82 airports, which the company reflects the aircraft’s ease of integration in the national air space.

UT recently opened its first solar-powered organ manufacturing plant for genetically modified pig kidneys and pig hearts in Christiansburg, Virginia, which has the capacity to produce several hundred organs per year. Two more plants will come online in Rochester, Minnesota, and Houston, Texas, in 2027 to support preclinical xenotransplantation studies required by the US Food and Drug Administration (FDA) before full transplant use can be approved.

(Updated April 10, 2025)