H55 battery technology contributes to advancement of RTX hybrid

The flight demonstrator, led by Pratt & Whitney Canada and Collins Aerospace (subsidiaries of RTX), aims to demonstrate an improvement of up to 30% in the energy efficiency of regional aircraft through a hybrid-electric propulsion architecture combining a cutting-edge thermal engine, a 1-megawatt electric motor, and the H55 battery system.

Pratt & Whitney Canada designed the battery architecture and H55 safety mechanisms to form the certifiable basis of the demonstrator’s propulsion system. The H55 energy storage system, validated by numerous flight operations, provided the compliance and safety basis that allowed the program to progress quickly.

Regarding the partnership between H55 and Pratt & Whitney Canada, Rob Solomon, CEO of H55, stated: “There is a significant difference between being selected as a component supplier and being chosen as a basis for certification. Pratt & Whitney Canada did not just buy our batteries: the company built the compliance reference base of its prototype on an architecture that H55 has already used for more than 2,000 flight hours without incident and which has been validated during testing campaigns conducted by EASA. This is what eight years of certification work allow: when a program on the scale of a regional aircraft needs to move quickly, it turns to a system that has already proven itself. This important step – the first full-power ground test of a hybrid-electric propulsion system at this scale – is the work of the entire team.”

H55’s ESS is specifically designed to meet aeronautical certification requirements. The system is designed to be lightweight and modular for flexible integration on aircraft and optimal weight distribution, based on a cellular architecture that has already been tested by the European Aviation Safety Agency.

This technology builds on H55’s broader experience in developing electric propulsion systems for aviation. The company has conducted extensive safety validation campaigns for its battery modules, an essential step in certifying next-generation electric propulsion architectures.

Sébastien Demont, technical director and co-founder of the company, explains the significance of this development for H55: ‘This integration milestone represents a pivotal moment for H55 and for electric aviation as a whole. The certified battery architecture we developed for CS23 aircraft has proven its scalability: the same safety philosophy at the cell level, the same engineering discipline, is now powering a battery system at the core of a hybrid-electric CS25 demonstrator under the supervision of Pratt & Whitney Canada. We are not adapting a concept, we are scaling up a proven and validated platform. That is developing a certifiable technology from its inception.”

H55 stems from the pioneering Solar Impulse project, which demonstrated that electric propulsion could enable long-duration flights. Building on this legacy, H55 has since developed and flown multiple electric aircraft platforms, accumulating operational experience that continues to inform the development of next-generation propulsion systems.

As the RTX hybrid-electric flight demonstrator now enters the integration phase on board an aircraft and flight testing on a modified De Havilland Canada Dash 8-100, H55’s battery technology will validate hybrid-electric propulsion on the scale of regional aircraft.

The program also represents a significant step in expanding H55’s propulsion technology to smaller electric aircraft platforms to the Part-25/CS-25 category of regional transport aircraft. By supporting a hybrid-electric propulsion system on the scale of regional aircraft, this demonstrator allows H55 to further validate the architecture of its energy storage system in an environment representative of future commercial applications.

Entering the regional aircraft category represents a significant expansion of market access for H55’s propulsion technology, as hybrid-electric architectures are increasingly considered for next-generation regional aircraft platforms.

As aircraft manufacturers explore hybrid-electric propulsion to improve efficiency and reduce emissions, scalable battery systems capable of meeting aeronautical certification requirements are expected to play a central role in the architecture of future regional aircraft.

Rob Solomon added: “Programs like this one allow us to demonstrate that the same certifiable battery architecture developed for small aircraft can be adapted to the regional aviation market. This transition marks a decisive step in realizing the commercial potential of electric propulsion.”

This significant milestone reflects the growing maturity of electric propulsion technologies and their role in establishing a more efficient and less polluting air transport. With the introduction of hybrid-electric aircraft, energy storage systems will also become an essential element of the aircraft life cycle, creating long-term opportunities for certified propulsion technology providers.

About H55

H55 is a Swiss company specializing in certified electric propulsion systems and energy storage for aviation. The company is advancing electric aviation by transforming commercial lithium batteries into aviation-specific energy storage systems, approved by regulatory authorities, covered by insurers, and deployable by equipment manufacturers as a certified propulsion platform for various aeronautical programs. This is possible through independent cell characterization, thorough input selection, redundant safety architectures, and regulator-aligned testing designed from the most unfavorable failure scenarios.

Built on the technological heritage of the Solar Impulse program, H55 leverages over two decades of practical experience in electric aviation. The company has designed, built, and flown multiple electric aircraft, accumulating over 2,000 hours of fully electric flight with no battery-related incidents, providing the operational experience necessary to successfully execute certification programs, not just comply with them.

H55 has a strong and experienced leadership team that combines deep expertise in technological business development with tangible operational execution. Together, these capabilities ensure a reliable transition from certified design to reproducible series production. H55’s platform-based approach, where certification evidence combines across programs, reduces adoption risk while efficiently facilitating the deployment of electric and hybrid-electric aircraft in terms of capital.

Press Relations

Axelle Krummenacher +41 79 464 22 60 [email protected] www.h55.ch

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