Technology · Hydrogen combustion

Burn hydrogen. Keep the turbofan.

ColibriV is developing turbofan engines that burn hydrogen instead of jet fuel. Combustion releases no carbon, and the engine stays a turbofan: a machine the industry knows how to build, maintain and certify.

Why combustion

The shortest path from today's engines to carbon-free flight.

PathHow it worksWhy we chose differently
Battery-electricBatteries drive electric motorsEnergy per kilogram limits range to short hops
Hydrogen fuel cellFuel cells make electricity for motorsAdds new power systems and heavy thermal management
Hydrogen combustionHydrogen burns in a turbofanKeeps the turbofan; changes the fuel system and combustor

What changes

Burning hydrogen changes the parts that touch the fuel: the fuel system, injectors, combustor and controls. The fan, compressor and turbine concepts stay familiar.

That is where we focus our engineering.

Why gaseous hydrogen first

Simpler to build, test and certify in the first phases.

Liquid hydrogen must be stored at −253 °C, which brings cryogenic tanks, insulation and boil-off management. We start with compressed gaseous hydrogen to keep early test campaigns safer and simpler.

The honest trade-off

Compressed tanks are heavy and bulky. That suits ground testing, demonstrators and shorter missions first.

Liquid-hydrogen compatibility stays on our long-term roadmap.

The hard problems we work on

  1. Flashback

    Hydrogen flames travel several times faster than kerosene flames, so a flame can move upstream into the injector. We design injector and combustor geometry to keep the flame where it belongs, and we treat flashback risk as a hard constraint in every design study.

  2. Low NOx

    Hydrogen burns hot, and hot flames make nitrogen oxides. We design for short, lean, well-mixed flames to keep NOx low, and we measure it at every test phase.

  3. Fuel system integrity

    Hydrogen is a small molecule that leaks easily and can embrittle some metals. Materials, seals, valves and leak detection are chosen and tested for hydrogen service.

  4. Controls

    Hydrogen ignites easily and reacts fast. Control logic, sensing and shutdown paths are designed for those dynamics from the start.

What comes out of the engine

We report what the engine actually emits, not just what it doesn't.

CO₂
Nonefrom combustion
Soot and particulates from fuel
None
Water vapor
More than keroseneStudied for its climate effects
NOx
Kept low by designProduced at high flame temperature; our design target is to keep it low

Safety by design

Read our safety & certification approach
  • A hydrogen safety program starts before any hardware is built.
  • Leak detection, ventilation and emergency shutdown on every test system.
  • Safety systems are independent of control systems and of any software.
  • Written procedures and hazard analysis before every new test.

AI in the engineering loop

Geometry, staging and fuel delivery, explored overnight.

Our engineers use ColibriV Design AI to explore combustor and injector designs overnight: geometry, staging and fuel delivery. It proposes designs and recommends the next experiment. Real physics solvers confirm its results, and it stays out of the safety-critical path.

Meet Design AI

From simulation to test.

See how the technology moves from simulation to test.

See the programPartner with us