The entire HYFLY team is happy to have achieved a major milestone with the maiden flight of the DS-2C/HY test aircraft for the HYFLY H167 electric hydrogen fuel cell propulsion system.

After a long wait for good weather, the DS-2C/HY with test pilot Sören Pedersen take off from Aalen-Heidenheim/Elchingen airfield (EDPA) on November 21, 2024.

This is a major step forward in our development program for a hydrogen fuel cell propulsion system for ultralight aircraft, motor gliders and Light-Sport Aircraft (LSA), classic fixed-wing drones / UAVs and medium-sized eVTOLs.

This milestone follows three years of work to develop the propulsion system, convert the aircraft used as a test bed and prepare the supporting documents for the Permit to Fly (PtF).

The HYFLY H167 hydrogen fuel cell propulsion system:

The HYFLY H167 system is a modular electric hydrogen fuel cell propulsion system with a buffer battery for load changes and load peaks. The high level of modularity ensures simple and efficient installation in virtually any type of aircraft and easy maintenance.

Product properties and configuration:

As a modular electric hydrogen fuel cell propulsion system for aircraft, the H167 is characterized by the following key features and technical data:

• Performance: The prototype H167 system delivers a take-off power of 70 kW, making it a fully-fledged replacement for conventional combustion engines (such as the Rotax 912) for ultralight aircraft, motorgliders and LSA.
• Energy efficiency: With a spherical tank holding 7 kg of hydrogen, a similar flight duration can be achieved as with conventional combustion engines, far beyond what is possible with battery electric systems. Depending on the aircraft configuration, a total flight duration of up to 7 hours can be achieved.
• Safety features: The H167 system fulfills all currently valid requirements according to LTF-UL. With regard to the use of hydrogen, the necessary certification requirements are currently under development. Here, the requirements from the automotive sector are being used and adapted if necessary. In addition, some self-developed safety devices are being tested.
• Modular design: The system is characterized by a high degree of modularity and can be flexibly integrated into a variety of aircraft types, including ultralight aircraft, motorgliders and LSAs, but also drones / UAVs and eVTOLs. This modular architecture proves to be particularly valuable both for integration into newly developed aircraft types and for retrofitting existing aircraft.

Market potential and application options:

The HYFLY H167 hydrogen fuel cell propulsion system not only offers technological innovation advantages, but also opens up an enormous market potential. In a global environment in which aviation must increasingly switch to emission-free propulsion, the H167 system represents an efficient and environmentally friendly propulsion solution for ultra-light and lightweight aircraft.

• Sustainable development: With growing pressure on the aviation industry to reduce CO₂ emissions, the H167 system offers a zero-emission solution without compromising on performance. The use of hydrogen fuel cells makes the H167 system a viable and economical option for sustainable aviation.
• Cost-effectiveness The H167 hydrogen fuel cell propulsion system not only reduces operating costs through lower fuel consumption, but also maintenance costs thanks to its simple and modular design. For OEM manufacturers and aircraft owners, the system is extremely cost-effective.
• Versatile applications: The H167 hydrogen fuel cell propulsion system can be used in a wide range of applications, from private aviation and training aircraft to long-range commercial and scientific missions. The wide range of applications makes the H167 system an attractive option for the market.

Further testing:

After the first flight, the further test campaign will initially focus on the electric drive and the flight battery. Flight performance, characteristics and behavior in flight operations will be determined before the fuel cell system for power generation is put into operation and all operating conditions are subsequently tested. The current system forms the basis for testing and optimizing the hydrogen fuel cell system in further performance stages.

The HYFLY test carrier DS-2C/HY:

The DS-2C/HY test aircraft for the H167 hydrogen fuel cell propulsion system is based on a prototype of the Dornier DS-2C, which was made available to HYFLY by Dornier Seawings. With the registration D-MFLW the aircraft already served as the test aircraft for type certification during the development. Further modifications were then tested on this test aircraft before it was handed over to HYFLY. After being taken over by HYFLY, the aircraft was extensively refurbished by project partner Kasaero and modified for use as a test aircraft for the H167 hydrogen fuel cell propulsion system. The necessary documentation was prepared for all modifications compared to the certified type design and for the propulsion system, and ground and load tests were carried out so that the German Ultralight Flying Association (DULV) was able to issue the provisional traffic approval (VVZ) for the start of test flights on 17.10.2024.