Cellsius

What Cellsius does

Cellsius is a non-profit student association (Verein) founded in 2020 and based in Dübendorf/Zurich, Switzerland, operating out of ETH Zurich and developing experimental zero-emission aircraft propulsion systems. The organization builds modified Sling TSi kit aircraft across three sequential projects: the e-Sling battery-electric platform (180 km range, 1h15 cruise, currently in flight testing); the H2-Sling gaseous hydrogen fuel cell aircraft (200 km range, 2-hour cruise, 100 kW fuel cell, reaching final design in October 2025); and Project Liquid H2 using cryogenic liquid hydrogen at -253°C, targeting 500 km range and a 4-hour cruise. Proprietary work includes custom battery cells, DC-DC power electronics, cryogenic LH2 storage, a model-based fuel cell control system, and structural airframe modifications such as wing extensions.

The team is governed by ETH mechanical and electrical engineering students, comprising a 12-person focus team supplemented by freelancers, alumni, and an association board, totaling 40+ members. The organization is not a commercial enterprise: it generates no product revenue and is funded exclusively through sponsorships, material donations, and individual patronage from 200+ supporting organizations and individuals. Named backers include Pilatus Aircraft (Director-level patronage from Dr. Urs Thomann), Sling Aircraft, ETH Zurich, the Swiss Federal Office of Civil Aviation (BAZL), Experimental Aviation of Switzerland (EAS), Olympic skier and pilot Dominique Gisin, pilot Carlo Schmid, and ETH Rector Günther Dissertori.

The go-to-market model is research-and-demonstration rather than commercial sale: Cellsius engages with BAZL and EAS to develop certification frameworks for experimental hydrogen aircraft, and uses each successive platform (battery-electric, gaseous H2, cryogenic LH2) as a stepping stone toward longer-endurance zero-emission flight. The strategic intent is to build technical credibility and regulatory know-how at the experimental aircraft tier rather than to commercialize airframes directly.

Name

Cellsius

Legal name

Cellsius

Website

https://e-sling.com

Company type

Private

Founded year

2020

Operating status

Operating

Headcount range

11–50 employees

Short description

Cellsius is a non-profit ETH Zurich student association developing experimental zero-emission aircraft propulsion across battery-electric, gaseous hydrogen fuel cell, and cryogenic liquid hydrogen platforms based on modified Sling TSi kit aircraft.

Ownership category

akta.pro rank

Product category

Sustainable Aviation Propulsion

NAICS

Other Aircraft Parts and Auxiliary Equipment Manufacturing (336413), Battery Manufacturing (33591)

SIC

Aircraft Engines & Engine Parts (3724), Aircraft & Parts (3720)

akta.pro primary industry

Aerospace Fuel System Components (Tanks, Lines, Valves) (IMABANAJ)

akta.pro secondary industries

Hydrogen Energy Storage & Power-to-X Equipment (electrolyzers, storage, fuel cell systems) (IMAGAHAM), Battery Modules & Packs (Industrial/Commercial pack assembly) (IMAGAHAB)

Keywords

• Hydrogen aircraft propulsion
• Electric aviation systems
• Fuel cell technology
• Zero emission flight
• Sustainable aviation research

Headquarters

HQ city

Dubendorf

HQ country

Switzerland

HQ region

Europe

Offices1 record

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Personnel, Technology or R&D, Operations, Supply Chain, Marketing or Sales

Revenue model

1. Sponsorship and Donations: As a non-profit association (Verein) of ETH-Students, Cellsius operates primarily through sponsors and donors ('Gönner') who support their sustainable aviation research. Sponsors provide financial and material support enabling the development of emission-free propulsion systems.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels6 records

Core offering

Cellsius develops and tests fully emission-free aircraft propulsion systems, building experimental hydrogen fuel cell and battery-electric aircraft based on modified Sling TSi kit platforms. The three core projects are the e-Sling (battery-electric, 180 km range), the H2-Sling (gaseous hydrogen fuel cell, 200 km range, 100 kW), and Project Liquid H2 (cryogenic liquid hydrogen at -253°C, targeted 500 km range).

Product overview

Cellsius is a non-profit association of ETH Zurich students developing sustainable aircraft propulsion systems since 2020. The portfolio consists of three aircraft projects: (1) e-Sling — a battery-electric aircraft currently in flight testing phase with 180km range; (2) H2-Sling — a hydrogen fuel cell aircraft with 200km range achieving final design milestone; and (3) Project Liquid H2 — an advanced liquid hydrogen system targeting 500km range. All projects are based on modified Sling TSi kit aircraft with proprietary battery systems, fuel cell integration, power electronics, and custom airframe modifications including extended wings and aerodynamic integrations.

Differentiator

Problem solved

Functional benefit

Products and services

• e-Sling Battery-electric aircraft based on the Sling TSi kit aircraft, equipped with a modular battery system and self-developed drivetrain. Developed by 20 ETH students (2020-2022), currently in final flight testing phase with 180 km range and 1 hr 15 min cruise flight.
• H2-Sling Hydrogen fuel cell powered aircraft using gaseous hydrogen to generate electricity via a 100 kW fuel cell system, driving an electric motor. Produces zero CO2 emissions with 200 km range and 2-hour cruise capability. Final design milestone reached October 2025.
• Project Liquid H2 Enhanced hydrogen propulsion system based on H2-Sling, utilizing liquid hydrogen stored at -253°C in cryogenic tanks, fed to fuel cell via heat exchanger. Designed for significantly higher energy density enabling 500 km range and 4-hour flight capability. LH2 tank entered manufacturing phase March 2026.

Quantifiable outcome

• 0g CO2 emissions during flight operation
• +2 more outcomes

Segments1 record

Ideal customer profiles3 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature7 records

Partnerships

Five partnerships are on record, tiered core, strategic and foundational.

• Bundesamt für Zivilluftfahrt (BAZL)coreOthersSwiss Federal Office of Civil Aviation provides regulatory oversight and certification support for Cellsius experimental aircraft. Long-standing multi-year collaboration on safety concepts for construction and operation of hydrogen-powered aircraft.
• Experimental Aviation of Switzerland (EAS)coreOthersWorks with Cellsius on comprehensive safety concepts for building and operating experimental aircraft. Close multi-year collaboration on certification requirements.
• ETH Zurich (Eidgenössische Technische Hochschule Zürich)coreStrategic or Co-development PartnerHost institution and primary organizational base. Rector Günther Dissertori endorses Cellsius as providing students practical aviation project experience during studies. Students from Maschinenbau and Elektrotechnik departments participate as focus project team members.
• Pilatus Aircraft LtdstrategicStrategic or Co-development PartnerDr. Urs Thomann, Director Technologies, Processes, Sustainability at Pilatus, serves as active supporter and advisor. Brings industry expertise in aviation technology and sustainable aviation practices to Cellsius projects.
• Sling Aircraft (Kit Manufacturer)foundationalTechnology or IntegrationSouth African kit aircraft manufacturer whose Sling TSi aircraft serves as the base platform for Cellsius projects. The kit aircraft is delivered in parts and assembled by the team, with modifications integrated directly into the structure.

Scale indicators6 records

Recent moves6 records

Expansion highlights5 records

Direct peers

• magniX: magniX produces electric propulsion systems (motors and power electronics) for small commercial aircraft such as the Eviation Alice. Comparable to Cellsius in focusing on electric aviation powertrains, though at commercial certification stage.
• ZeroAvia: ZeroAvia is a hydrogen-electric aviation propulsion company developing fuel cell powertrains for commercial aircraft — the closest direct peer to Cellsius's H2-Sling and Project Liquid H2 work, with a similar fuel cell + electric motor architecture, but operating as a venture-backed commercial venture pursuing type certification.
• H55: Swiss-based H55 develops electric propulsion systems for aviation, spun out from the Solar Impulse project. Comparable to Cellsius as a Switzerland-based aviation electric-propulsion innovator targeting certification, though with a venture-funded commercial orientation.
• Pipistrel: Pipistrel (now part of Textron eAviation) is a producer of light electric aircraft including the Velis Electro, which is the only type-certified electric aircraft in commercial operation. Comparable to Cellsius's e-Sling in target market and form factor, though at a far more mature commercial stage.
• Eviation: Eviation is developing the Alice, a fully electric commuter aircraft. Comparable to Cellsius's e-Sling in targeting zero-emission regional flight using electric propulsion, though Eviation targets 9-passenger commercial operations versus Cellsius's experimental kit-aircraft platform.
• Heart Aerospace: Heart Aerospace builds the ES-30, a hybrid-electric regional aircraft. Although battery-electric rather than hydrogen, it pursues the same target market — small sustainable aircraft — making it a closely comparable peer to Cellsius's e-Sling and H2-Sling platforms.
• Universal Hydrogen: Universal Hydrogen develops hydrogen powertrain kits and modular capsule-based fuel logistics for regional aircraft, pursuing FAA and EASA certification — directly comparable to Cellsius's hydrogen aviation propulsion mission but with a commercial capital base.
• VoltAero: VoltAero is developing the Cassio hybrid-electric aircraft family using a parallel hybrid propulsion design. It overlaps with Cellsius's pursuit of sustainable light-aircraft propulsion, although VoltAero is pursuing a hybrid rather than pure hydrogen architecture.

Others

• DLR (German Aerospace Center): DLR operates institutional hydrogen aviation research programs (e.g., HEAVEN, BALIS). Comparable to Cellsius as a publicly funded research organization developing hydrogen fuel cell propulsion for aircraft, but at much larger scale and with a different institutional structure.

Broad incumbents

• Airbus ZEROe: Airbus's ZEROe program targets hydrogen-powered commercial aircraft by 2035. Comparable to Cellsius as a hydrogen aviation propulsion initiative but operating as a large incumbent pursuing full-scale commercial platforms, not experimental light aircraft.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks7 records

Key highlights7 records

Customer concentration

• LinkedInlinkedin.com/company/e-sling
• Instagraminstagram.com/cellsius.aero
• Facebookfacebook.com/CellsiusAviation

Revenue estimate

Valuation estimate

Number of profiles

Funding overview

Funding rounds

Investors

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M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Cellsius