These wind turbines are Hugh Piggott design and were built from his 'Wind Turbine recipe book'. see https://scoraigwind.co.uk/all-of-the-books-by-hugh-how-to-get-them/

They are 3.7m, 12 footers, and have our especially made fiberglass blades from our own moulds, and these 3 have been flying for nearly 12 years. 

We have wound the 3 phase coils for DC battery charging at between 46v and 61v and are directly clamped/connected to the 48v battery. Any excess electricity is diverted by controllers to dump load heaters. .

The design of the blade and the PMG permanent magnet generator, are very well matched together for optimal output.  The tail design has the ability to pull the wind turbine out of the wind direction if the wind increases to dangerous and excessive levels.