1
L1
2 L1
T
2
3
Point of contact
between blade and
scales
4
L24
L2T
This figure shows the method for locating the point of contact of the blade on
the plate.
b) Where H1 = the height of the plate at 1, etc. Find the height of the
point of contact using the following equation:
H = ((H1 × L1T ) + (H 2 × (L12 − L1T )))× (L24 − L2T ) + ((H 3 × L1T ) + (H 4 × (L12 − L1T )))× L2T
L12 × L24
The results should provide a straight line when force is plotted against
deflection; this testing procedure gives a good comparison between the
strengths of different blades but does not give an indication of the forces or
wind speed that a blade can withstand.
20
18
16
14
12
10 Instrom (Wooden)
Simple Test
8
6
4
2
0
0 2 4 6 8 10
Force (N)
The figure above shows the results of the simple test on a wooden blade
compared to the same test carried out on an Instron machine. The error
between the line plotted for the simple test and results from the Instron test
was -0.30mm (2.04%) at 10N. If the point at 8N is regarded as an outlier the
error is -0.065mm (0.36%)
42