[a-w-h] Air403 and flutter stall
- Ken talks about wind turbine noise, when the turbine idles just before
cutting in and when the wind changes direction. For most turbines I
quite agree that you can easily learn to live with these noises, in fact
you can start missing them, when they are not there anymore. These
noises are very different from the noise of flutter stall, which for
instance characterizes the Air models.
Flutter stall appears at high wind speeds making the blade move rapidly
back and forth around the center line.
Flutter stall is VERY noisy. Dave talks about nervous horses, Graham
about unhappy neighbors and I can tell about one of my old Windflower
prototypes getting into a runaway resulting in blade flutter stall. The
windows in a cow stable a couple of hundred meters away started to
vibrate at high frequency, making the cows afraid and very hard to
control. Angry farmer.
Flutter stall reduces revolutions of the rotor, and I assume the Air
turbines uses this method for speed control in order to get the price
down. Flutter stall gives you speed control for free being already built
into the construction. You do not have to add extra technology in order
to provide speed control by a furling tail, blade pitch or rotor tilt.
I know flutter stall very well, and it is most painful to the ear. In
fact I consider it unhealthy. I am against too many regulations, but
this should be prohibited. A real wind turbine should always operate
below non-hazardous dB levels, and as such I can I can only see the Air
as a low cost compromise. Sorry Andy. I do recognize your work for
building an industry, and I expect you are working on solving this
problem in future models. No more on this subject from me.
- --- In firstname.lastname@example.org, Claus Nybroe <windmission@v...>
> Flutter stall is VERY noisy. ...Nah, he only listens to his engineers, and they swear they can't hear
> I expect you are working on solving this problem in future models...
a thing anymore:)