Rod,

I used to work in a lab where we studied breakdown of turbines under extreme rotational stresses. It was a lab run by Dan Lathrop, http://complex.umd.edu/ who is trying to replicate, in a lab setting, the geodynamo of the earth's magnetic molten core - which generates the earth's magnetic field due purely to the tremendously turbulent rotation of said molten core. As we made bigger models and spun them faster and faster, we had to be VERY careful to engineer the things to be able to withstand the centripetal forces required to not explode.

I got to take a tour of Calvert Cliffs, MD's nuclear power generation facility when one of the two turbines was shut down for repair - got to check out the blades, shaft, and most especially, the specs on the housing that the actual reactor is located in. While generally the several-feet-thick-concrete, clad-in-eight-different-kinds-of-steel is advertised as being able to withstand a such-and-such earthquake, a tsunami, AND a jetliner crash all simultaneously, the actual most dangerous thing that could possibly happen is that a blade on the turbine break down and go flying. Take a 20-foot-radius solid metal turbine blade, spin it up to 3600 RPM, and you've got a tip velocity around 5,100 MPH.

The reason the blades didn't fly far in the video is because they're constructed for maximum turbulence and minimal mass. Hollow formed fiberglass seemed to be the tower construction, and to make good blades you just need something that won't explode outward violently with centripetal force - "light" is your best bet. As soon as they cracked off near the hub, they tumbled on their long axes, and performed their other job really well - catching turbulence - thus slowing themselves down a bunch.

As for the control systems failure - I dunno. if that's really 300 feet across , the amount of braking power needed to slow it down more would be immense. Could have been a hardware limit, not just M$ bloatware. The hub sure slowed down fat once the props were no longer forcing it, so the generator sucks up mechanical energy and turns it into current pretty well. i'm impressed as well - that was doing phenominally well for a good long while. I'd love to see high-speed video, and know what was the first to go.... a gust knocking the tri-prop off-axis, one blade torquing a tiny bit too much and coming off... the resulting imbalance immediately cracking off the other two, and one taking out the tower in the process. Hooray for destruction.

the original poster of the thread I saw the video was answered by someone from Denmark who knew a little
about it. Said the technicians were working until noon of that day and were pulled out as the wind was
rising and they could not solve the problem. http://www.komotv.com/news/local/9383316.html
Here is the link of some pictures of the one that fell out west. Oregon, not Washington, my mistake this time.
Was the same story, the software system failed and they were unable to feather the blades to prevent the
overspeed. Guy that was killed rode it down was the story. The picture on the bottom I was told doesn't show
how hard it hit. The rest of the turbine is supposed to be shoved 6 feet down into solid rock.

The turbines in my area have towers made of metal and the blades are fiberglass. Structural integrity must be
very high. When transporting the pieces some the trailers are a short front trailer attached to the semi-tractor
and the back is just a dolly chained onto the rear of the tower or blade.

And I was thinking about applying for a windmill maintenance job... :-(

Do those things have elevators to the top or do you have to clime a 200 ft ladder...

http://www.youtube.com/watch?v=eyrBj1USOXQ