Introduction
This is a guide to the manufacture of fibre-glass wind turbine blades. These
are for use with the wind turbine design produced by Hugh Piggott and
described in detail in his ‘How to build a wind turbine: the axial flux windmill
plans’ guide, available from http://www.scoraigwind.com/
An earlier version of Hugh Piggott’s guide, focussing on the electrical
generator is available from the Practical Action website at:
http://practicalaction.org/docs/energy/pmg_manual.pdf
This is a practical guide which is designed to show the process of producing
a wind turbine blade from fibre-glass. This guide stemmed from work trying to
produce a 1.8m blade for a 1kW version of Hugh’s design for use in the
Philippines.
The blades are made from fibre glass, rather than wood as Hugh Piggott
suggests, for a number of reasons:
• The time for manufacture will be much lower and a number of blades
can be produced in one batch. This will also reduce costs.
• The use of moulds allows good repeatability and hence well balanced
blades
• Good quality, straight grained wood was difficult and expensive to find
in the Philippines. Also, due to lack of control over the logging industry,
using some of the local hard woods would not be very sustainable.
A fibre glass blade construction guide has been produced by Practical Action
and is available from:
http://practicalaction.org/docs/energy/blades_manual.pdf
Such blades have been manufactured in Sri Lanka and in Peru, for smaller
machines up to 500W. This is a guide to producing larger blades for a 1kW
machine, along with more details on the production process.
This guide is exactly that – a guide. There are numerous other (probably
better) techniques to use. This is documentation of the author’s experience.
The authors would be very interested to hear other people’s experience and
ideas.
It is presumed that the original blade has been correctly designed from an
aerodynamic point of view. This is not a guide to the aerodynamic design of
wind turbine blades.
Overview of the production process
The production process is as follows:
1. Produce an original blade from which to make copies. This would
usually be carved from wood.
2. A fibre-glass female mould is then taken from the original. This mould
is in two halves. This mould can be used a number of times.
3. The two halves of the blade are then made separately using a number
of layers of glass fibre mat and resin.
2