Busch blower supports Switzerland’s first hydrogen plane

A Swiss student team has built the H2-Sling, a hydrogen-powered aircraft that uses a Busch Vacuum Solutions recirculation blower to reuse excess fuel-cell hydrogen. The project points to the engineering hurdles and near-term promise of hydrogen aviation as the plane awaits Swiss certification and a first test flight.

Why it matters: - Aviation is under pressure to cut emissions, and hydrogen is one of the leading options being explored for cleaner flight. - The H2-Sling shows how fuel-cell components can support practical hydrogen aircraft development, not just lab research. - Reusing unreacted hydrogen helps reduce tank size, weight and fuel waste, which are critical constraints in aviation.

What happened: - Busch Vacuum Solutions donated a MINK MH recirculation blower to ETH Zurich to support the H2-Sling research project. - The aircraft was developed by Swiss students working through the Cellsius association, a non-profit founded in 2022 to research sustainable aviation. - The rollout and first public presentation of the airplane took place in October 2025. - The aircraft is awaiting certification from Switzerland’s Federal Office of Civil Aviation before a first test flight planned for spring 2026. - The long-term goal is a flight over the Alps.

The details: - The H2-Sling runs on hydrogen in gaseous form and uses a 100-kilowatt fuel cell system. - The fuel cell turns hydrogen and oxygen into electricity and heat through a reaction between an anode and a cathode separated by an electrolyte membrane. - Hydrogen is stored in two tanks beneath the wings, with each tank holding 2.6 kilograms. - The aircraft is designed for a range of 200 kilometers, or about two hours of flight time. - Water is the only by-product of the reaction, so no climate-damaging greenhouse gases are emitted during flight. - The MINK MH blower returns unused hydrogen from the fuel cell outlet back to the inlet, where it mixes with fresh hydrogen from the tanks. - The blower’s claw-shaped rotors compress the hydrogen and feed it back into the anode side to keep the reaction cycle running. - Busch describes the MINK MH as a TÜV-certified recirculation blower developed for fuel cells. - Andres Neff, technical lead of the H2-Sling project, said the team had good results with a smaller MINK MH in a test circuit and found the larger version user-friendly.

Between the lines: - The project underscores how hydrogen aviation depends on system-level efficiency, not just fuel choice. - Recirculation matters because extra hydrogen is needed to avoid “starvation” in the fuel cell, but wasted hydrogen would force the aircraft to carry heavier tanks. - The student-led project also reflects how universities are becoming testbeds for aviation technologies that are still too early for broad commercial use.

What's next: - The next milestone is certification review by Swiss authorities. - If approval comes through, the H2-Sling’s first test flight is expected in spring 2026. - The project will then move toward its stated goal of an alpine flight, a real-world demonstration of hydrogen aviation capability. - Broader progress in hydrogen aircraft will still depend on advances in storage, infrastructure and fuel-cell reliability.