Preparation
Fibreglass
The woven cloth (WC - 200gsm) fibreglass needs to be cut to shape before
lay-up can begin. 16 layers are required, but not all layers stretch all the way
along the blade (the blade needs to be stronger at the root). As shown below,
each half blade is made from 4 layers which reach from root to tip, 4 layers
which reach ¾ of the way from the root, 4 layers which reach halfway from the
root and 4 layers which are just ¼ of the blade length from the root. This is to
ensure that the root is strong as this is where the bending moment from the
force of the wind, and the tension from the gyroscopic effect, will be greatest.
4x
4x
4x
4x
25%
50%
75%
100% = Full Length
MOULD
The layers must be cut to the correct size and with the correct weave
orientation. The weave of the woven strands must rotate by 45 º between
each layer, therefore careful attention must be paid when cutting the layers
(see below).
90º Weave
Cut shape with strands
up/down and left/right.
This weave runs parallel
to the length of the blade
(from root to tip).
45º Weave
Cut shape with strands
at 45 degrees to the
90 degree pieces.
14