In January 2018 the blades were blown off the turbine yet again!!! for photos see here
After a long search I found some Aluminium Blades from the USA which I put on in September 2018. These lasted longer than the Wooden Blades, but only two and a half years. John-Joe Bowen at Bowen's Forge, just up the road, is a magic Blacksmith who made some new blades for me from 4mm Aluminium Sheet. These are 1mm thicker than he previous one. I decided it would be interesting to compare the performance of these three types of blade, so below are graphs of RPM and Output in Watts for the three blade types.