Darrieus Windmill Flying
Recently we saw it flying so we took some video of it. I-25, Jackson Creek, and Gleneagle are in the valley below in these videos and we’re just about 1 mile north of the northern border of the Air Force Academy.
I don’t know much about this particular windmill such as how much power it puts out, but it’s a massive dynamic structure as you can see in the video. The scale is evident because the windmill is positioned to the east of the house in the video by about 75 yards and the tall garage door you can see on the house in the video is for storing an RV.
It’s a beautiful sight, I think, but Darrieus windmills are all but extinct due to design flaws and better VAWT designs now available. After the video below, I’ve included more information on Darrieus designs if you’re interested.
Here’s a slightly different zoom of it:
[Updated 4/26/2010 - windmill was flying again. This time I got some closer footage and also you can hear the significant sound and vibration it emits when it’s flying]
According to Paul Gipe, Wind Power, the Darrieus designs are:
“bedeviled by poor performance and poor reliability. The aluminum blades often fatigued and sometimes failed catastrophically. This was in part because the lift forces, which propel the blades, reverse direction every revolution, flexing their attachment to the torque tube or central mast. Another source of frequent flexing of the blades is inherent in the rotor’s eggbeater shape. When the rotor is at rest, the blades sag due to their own weight, stressing the connection to the torque tube. Moreover, the presumed advantage of housing the drive train at the ground level was offset by the large bearings and guy cables at the top of the rotor. ...“Nor are Darrieus turbines reliably self-starting. Their fixed-pitch blades can’t drive the rotor up to operating speed from a stand-still unless the blades are parked in just the right position relative to the wind. While this isn’t necessarily a serious limitation, it does require motoring the rotor up to speed.” ... “Work on [Darrieus] technology has practically ceased.”
There’s a good article on Darrieus in Wikipedia also.
[update 3/20/09: Here’s an article on how Darrieus windmills work.]
