Where sustainability takes flight

Developing and testing of sustainable aircraft propulsion systems since 2020

Our partners

Our goal

Our mission is to develop a sustainable alternative to the current, climate-damaging aviation.

Carbon footprint of aviation and impact

Every year, aviation causes 2-3% of global CO₂ emissions and thus contributes irreversibly to climate change. However, CO₂ is only part of the problem, as other greenhouse gases such as nitrogen oxides or the formation of contrails also contribute to global warming. This means that the total climate impact of aviation is around three times that of pure CO₂ emissions.

Our Solution

In order to reduce the overall climate impact of aviation, it is essential to minimize non-CO₂ emissions as well. We are therefore developing and testing completely emission-free propulsion options. Our first project involved a battery-electric system, and we are currently working on the development of an innovative hydrogen system that enables environmentally friendly, long-range flying.

Promoting Innovation

As a non-profit organization of ETH students, we are committed to actively promoting climate-friendly innovations. At the same time, students gain valuable hands-on experience during their studies. This initiative is not only a platform for education but also a place to drive progress in sustainable aviation.

Who is behind this

The CELLSIUS Interview: In-Depth

H2-Sling

The H2-Sling is powered by a 100 kW fuel cell system that converts vaporized hydrogen into electricity, which drives the electric motor. This electrochemical process produces only water as a byproduct and enables a significant range due to hydrogen's high energy density.

0g CO2

Emissions

200 Km​

Range

2 hr

Cruise flight

e-Sling

Over a period of two years (2020–2022), 20 ETH mechanical and electrical engineering students worked on the development of the e-Sling as part of a focus project. The aircraft kit, based on the Sling TSi, was equipped with a modular battery system and a self-developed propulsion system. The electric aircraft is now nearing the end of its flight testing phase and is regularly taking to the skies.

0g CO2

Emissions

180 Km

Range

1 Std 15

Cruise flight

Coming Soon

Ideas are bubbling, visions are forming—something exciting is in the air. We're ready to break new ground and plan our next big steps.

Stay tuned and be there when it all starts!

0g CO2

Emissions

? Km

Range

? hr

Cruise flight

H2-Sling

e-Sling

coming soon

How we do it

Hydrogentechnologie

Hydrogentechnologie

As an environmentally friendly and lightweight alternative to conventional fuels, we use the latest hydrogen technology.

Battery technology

Battery technology

Our power batteries are designed, optimized and assembled in-house from the cell level.

Power electronics

Power electronics

Our power converters are used to efficiently supply the energy of a fuel cell or battery to the engine.

Aircraft structure

Aircraft structure

We develop customized components such as wing extensions or mounting brackets that are perfectly tailored to our requirements.

Aerodynamics

Aerodynamics

Modern simulation techniques help us to integrate additional components such as tanks and radiators into the aircraft structure in an aerodynamically efficient way.

Security

Security

Through comprehensive safety concepts, we ensure that our aircraft meet the highest safety standards both on the ground and in the air.

This is CELLSIUS

40+

members

2020

Start date

200+

Sponsors

The team consists of 12 mechanical and electrical engineers leading the project, supported by motivated freelancers and the organization's board. Together, we are CELLSIUS, united by the vision of achieving sustainable aviation.

40+

members

2020

founded

200+

Sponsors

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Our sponsors

support us in various ways, ensuring that our dreams don’t remain mere aspirations but can be turned into reality.

Explore stories

Hydrogentechnologie

Thanks to its enormous energy density, hydrogen is an attractive energy carrier for aviation. In the fuel cell system, hydrogen and air is converted into electricity, heat, and water vapor. To maintain a stable and efficient reaction, subsystems are required to prepare each reactant for its specific reaction. This involves active control of pressure, mass flow, humidity, temperature, and concentration. The entire process—from design and testing to integration, including mechanical components and software—is handled by our team.

Battery technology

Ein Wechselstrommotor, wie er in unseren Projekten verbaut ist, kann mit einer Batterie oder einer Brennstoffzelle angetrieben werden. Bei einem Wasserstoff-System braucht es ein zusätzliches modulares Batteriesystem welches der Brennstoffzelle die nötige Energie für Leistungsspitzen und für den Start zur Verfügung stellt. Die Batterie wird während dem Flug von der Brennstoffzelle wieder aufgeladen. Bei rein elektrischen Flugzeugen reicht eine grosse Leistungsbatterie, welche die gesamte Energie für den Flug bereitstellt. Mittels Flüssigkeitskühlung wird die Batterie auf einer konstanten Temperatur gehalten und Überhitzungen werden vermieden.

Power electronics

Um den Motor mit der Batterie oder der Brennstoffzelle anzutreiben, braucht es einen Stromwandler. Dieser ermöglicht es, die gewonnene Energie zum Aufladen und damit Antreiben unseres Motores zu verwenden. Damit dieser einerseits perfekt zu unserem Motor passt und den Anforderungen sowohl einer Batterie als auch einer Brennstoffzelle und dem gesamten Antriebsstrang entspricht, werden Stromwandler von uns entwickelt.

Aircraft structure

Die Basis der von uns entwickelten Flugzeuge bilden Kitflugzeuge, welche in Einzelteilen geliefert und von Cellsius selbst montiert werden. Der Hauptvorteil eines Kitflugzeugs liegt in den geringeren Anschaffungskosten sowie der Möglichkeit, während des Baus Modifikationen direkt in die Struktur zu integrieren. Zusätzlich zur Grundstruktur entwickelt Cellsius verschiedene eigene Anpassungen. So werden beispielsweise Halterung oder Flügelverlängerungen von Grund auf neu konstruiert. Diese Komponenten werden zunächst am Computer entworfen und simuliert, bevor sie anhand technischer Zeichnungen gefertigt werden.

Aerodynamics

Die grundlegenden aerodynamischen Flächen unserer Flugzeuge entsprechen dem ursprünglichem Flugzeug-Kit, wodurch die bewährten, gutmütigen Flugeigenschaften, die in zahlreichen Flugtests des Herstellers nachgewiesen wurden, erhalten bleiben. Um zusätzliche Komponenten wie Flügeluntertanks oder Radiatoren optimal zu positionieren und aerodynamisch zu gestalten, nutzt CELLSIUS modernste Technologien, darunter computergestützte Strömungssimulationen.

Security

The safety of our pilots and students remains our top priority. We collaborate with external companies that provide specialized training in handling high-voltage systems and hydrogen. Additionally, we have implemented comprehensive safety concepts for each of our testing areas, which are externally reviewed and approved.
Concerning the safety of the pilot, we are proud about our close collaboration with federal office of civil aviation and Experimental Aviation of Switzerland (EAS). Together we are working on an elaborate security concepts for the construction and operation of our aircraft.