Welcome to the Zennor Phoenix project

This video was for our crowdfunding campaign. We are grateful to our backers for their support in making it a success. The project is under way, watch this to see what we are aiming to do.

Work is still in progress and we have a long way to go to make a really excellent wood-chip fuelled engine. If you missed the crowdfunding and want to help, please donate here:

This update shows progress by May 2015.

This is our update – early July 2015.

This video is – Sept 2015.

Sept 2015 – Sept 2016: Lots has happened in the last year. We have a working system but not working well enough yet. We’ve built a test rig to assess motor performance, this has identified a valve problem that has lead to improvements with a newly machined part. We are also working on developing tube technology to improve performance – this work continues. We have modified burner airflow paths to increase heat output. We have tried different boiler winding configurations for more steam.  With data logging and various modifications we are optimising steam control:

Experiments have shown we had not maximised airflow rates so Graham has built larger bellows:


We have had a PhD proposal accepted for funding, see here for details:

Dec 2016 more steam stability tests (working in the dark because the generator has broken):



Work is still in progress. We think we may be close to having a good wood-chip fuelled engine. If you missed the crowdfunding and want to help, please donate here:

This site aims to give a summary of information in support of our successful crowd-funding bid. It contains rare film and photos, lesser known engine examples and historical facts, plus an overview of our research and practical work so far.

Firstly, we should explain that the ‘Zennor Phoenix’ itself will be an experimental power-assisted recumbent trike built to trial a new concept of biomass fuelled engine. If successful, we hope it will enable the development of range of sustainably fuelled engines for a broad range of potential applications; a carbon-neutral alternative to fossil-fuelled engines. This site also aims to give some background on the use of sustainably grown wood as an engine fuel, in both practical and ecological terms. We believe this to be a neglected area of research that could be of significant importance in the future.

Based in a rural workshop situated high on the moors above Zennor in West Cornwall, we have been exploring and developing the primary components of a new engine concept, which could exist in several variants. What is fundamentally different about our work is that our engine is designed for use with biomass (e.g. wood chips). We are not attempting to adapt existing fossil-fuelled engine technology to run on a bio-fuel, but rather designing an entirely new engine specifically for use with the most environmentally benign energy crop possible; wood.

In the wake of technology-led over dependence on fossil-fuels, the cultivation of wood as an energy source has fallen into decline. Coppiced and managed woodlands have suffered neglect, or have been lost entirely, and forestry brash/scrap wood has become almost valueless, yet could be a potentially excellent engine fuel. We feel strongly that this is an ecological problem that needs to be addressed, and perhaps a paradox that needs to be exposed. By launching this website we hope to accelerate the development of our ideas for wood fuelled engines. Through this we aim to provide new incentive for tree planting, to both increase wildlife habitat and ensure future source of clean energy.

For the purpose of early trialling we will focus on the simplest engine variant, this being the Rankine cycle or ‘closed-loop’ condensing steam engine. This is particularly appropriate for us given our locality; the historical birthplace of steam power. We hope that in building and testing this engine we will gain useful knowledge to inform the development of other more advanced types. We are, for example, interested in the use of a Brayton cycle, which uses air as the heat-expansive working fluid.

Thank you to all who supported our Crowdfunder: