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Technology

The hard part is the arrangement.

Fuel cells, batteries, inverters and machines can all be bought. What cannot be bought is the way they behave together inside one airframe.

The nose of the programme aircraft opened up: electric motor, radiator, coolant hoses and wiring inside the engine mount.
Drive and cooling on the demonstrator

The integration problem

Four constraints decide whether it flies.

Mass and volume

Storage, stack, battery and cooling all compete for a budget that was fixed before the power system was chosen. Every kilogram spent on one subsystem is taken from another.

The thermal path

Heat has to leave the system somewhere, on a platform with little room for a radiator and a duty cycle that does not pause. Thermal design is usually what limits continuous power, not the stack.

Two dissimilar sources

A fuel cell and a battery on one bus behave differently under load. Deciding how they share demand, and what happens when one is lost, is a control problem before it is a hardware problem.

Demonstrable safety

Whatever the architecture, it has to be shown to behave correctly when something fails. That evidence is produced on the ground, against requirements written before the build.

Current programme

A hydrogen fuel-cell and battery power system in a light aircraft.

Our central project brings all five capability areas onto a single platform: a fuel-cell power source with battery support, electric propulsion, the power electronics between them, and the control systems that supervise the whole.

Every constraint above is met in practice on it. Mass and volume are the most visible: the hydrogen has to be stored inside a wing that was already full of structure.

The aviation project
Hydrogen pressure tanks strapped between the ribs of an open aircraft wing in the workshop.
Hydrogen tanks in the wing

Method

Proven in practice before it is scaled.

The work follows what Martin Seng calls a grassroots development approach: start at a manageable scale with commercially available technology, integrate it into a complete real system, test it extensively, and improve from what the tests show.

  1. 01Start at a manageable scale
  2. 02Use what is available
  3. 03Integrate a complete system
  4. 04Test extensively
  5. 05Scale what proves itself
The approach in detail

Scope

Where our work stops.

We work on the power and control system and its interfaces to the platform. We do not design airframes, and we do not certify them. Where a programme needs approvals, we work to the customer’s requirements and to the organisations that hold them.

Saying so plainly is part of the specification. An integration partner who is vague about the boundary tends to be vague about the interface as well.