Blade joining
When set, the two halves of the blade need to be joined to form a single unit.
To do this they need to be accurately cut so that the two pieces fit together.
The join should be made with minimal impact on the blades aerodynamic
shape. The final piece should appear as close to the original wooden mould
as possible.
Also additional strength and rigidity is added to the blade through the use of a
‘stringer’ from the root to the tip. A wooden core is inserted at the root. This is
so the screws used to hold the blades to the wind turbine have something to
‘bite’ into. It also stops the blade root collapsing when the front blade
assembly is bolted onto the generator on the wind turbine.
Blade trimming
Warning: The dust from cutting fibre glass is TOXIC. A dust mask must be
worn during this operation - ensure others around the blade do not inhale the
dust.
Firstly the excess (over lap from the mould) must be cut off. This was done
with a circular cutting saw. A jigsaw or a mini-cutter could also be used. A line
should be visible at the edge of the part, distinctly showing the smooth section
from the mould and the excess overlap. Take care not to remove any of the
final blade part.
Then grind down the inside edges at approximately 45 degrees. This is to
allow the two blade halves to fit just inside each other to make a full blade.
The two halves can be placed together for comparison to check they fit well.
This can be a long process and usually requires a few attempts (additional
grinding) until the two halves fit perfectly.
This image shows the blade cross section
Grind these edges
so that the two halves
fit together
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