the superannuated meat skewers not up to it?
Hah! No. The only slightly positive thing about this event is that NONE of our work or fittings is to blame. Comedy 'skewers' holding fast thanks very much.... No loose bolts, slipped wire clamps etc...
We have carried out a fairly detailed investigation of the scene and shrapnel (one blade missing - presumed geosynchronous...) and are 100% sure the initial failure was one of two things.
Either - loss of one blade due to these two bolts snapping under full load furling....
Or - loss of any one blade due to fracture under high wind conditions leading to extreme vibration and doom.
The reason the beast is on the floor is that the blade which broke its bolts flipped around and the heavy end struck the wire and CUT it (!!!!!) We found the piece of edge which fits exactly around the shredded 10MM STEEL WIRE (
) Coyly modelled here by SpeccyAccidentInvestigatorBloke...
There are also some shreds of fibreglass embedded in the wire clamp just above the break if you look closely...
This is the 'cut' end of cable where it landed on the floor. I cannot imagine the force required to bend this really tough wire almost double and snap it - this was the windward side so would already have been taught as a really tight thing...
This is the blade that cut the wire.... we reckon the impact of the fat end hitting the wire caused the tip to shatter off - found in 2 or 3 tattered bits....
This 'shadow'on the ground is in fact a 20mm deep impact impression of the blade whacking the ground before it bounced away and broke a 25mm stake beside a new tree.....
That is some serious whackage!
The second blade ( seen in previous pic near strange wooden structure...) was found in the front garden of Frot Towers about 100 metres downwind. This one had flown directly over the house (at least 11 metres to ridge of roof..) and been stopped by a row of tall cypress trees. There is a small branch-shaped dent in its edge...
Third blade not yet discovered. Downwind farmer is looking out for it - we may go walkabout tomorrow to see if we can spot it. thinks... *if only Google Earth was in realtime...*
This pic shows the reason for thinking bolt snappage may have been to blame.... the ones on the right are innermost, visible face of blade facing out to wind. If the two innermost bolts gave way, the blade would have bent back away from the wind and pulled off the other bolts - hence deep gouges in the fibreglass. This is what happened to it even if it wasnt the primary failure. Nothing hit the mast. Bit flukey that the wire was hit really.... the welding all seems ok so if nothing had hit the wire we would just have a pole sticking up with amputated limbs....
B*gger......
I am hoping this is covered by guarantee...... ahem....
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