Another reason for my choice is that the Air-X’s suffer, in my estimation,
from too short of a tail. They sing and dance comically in the wind and
are very, very active. Perhaps more than they need be. I love to watch
them, the music is wonderful, I enjoy the performance immensely. I enjoy
their output too. Hardly a night goes by that I don’t fall to sleep
lullabied by their song.
The Air-X’s do sing louder than the Mallard.
But very often, in the midst of a perfect tune, the Air-X’s spin
themselves right out of the wind stream, they stall, and then fire up once
again as they rotate back into the wind. Fun to watch, pleasant to listen
to, but the fact remains, there’s a lot of wind that gets past the rotors
without generating electricity. It also has got to be hard on the
bearings, yet none have complained nor required maintenance. Like an
argumentative friend, these units fight the wind much more than they
probably need to, most often they win, but occasionally they lose out and
spin down. On occasion, in the higher winds, the foils will enter a
flutter stage, here, blade tips are literally ripping and tearing through
the wind, vibrating mercilessly, and scaring the bejesus out of the
animals or anything else that is in or around the house, just as if Santa
Claus fell out of his sleigh and landed on a hot metal roof in the middle
of the night ... with ice skates on. Whoa! It makes food fall out
of my mouth when it happens at dinner.
The
Mallard, it seems, is much more tolerant of wind instability. It stays
focused in the wind, it has a job to do and it does it well, does it with
less noise, less stress, and more confidence. It gives me the feeling that it
will outlast the wall it is mounted on. It will probably be there when I
am gone, just like the old Jacobs or Windchargers in the dust-bowled
’30s.
The
Air-X’s are indeed robust as well, and I wholeheartedly recommend them,
but on a rooftop, they seem to work harder than they need to in order to
get the job done, i.e. to get those little electrons inside the battery
bank. I suspect that a clear mounting of the Air-X’s on a tower
would eliminate the turbulence, but an old buzzard like me is not about to
climb a tower or lay one down when the time comes. Because sooner or
later, there will be a time for real maintenance. It just hasn’t
happened yet and a tower is just not in the plan for me. I will
consider another Air-X for the 5th wind generator perhaps next year but
that will be measured against the performance I see from the upcoming
Mallard unit.
Each genny has its own comfort zone. Like a race car with a hot camshaft,
each unit seems to have a sweet spot at which it prefers to run. At the
sweet spot, the rotors seem to turn effortlessly, the music is steady,
unstressed, comfortable. The Air-X’s enjoy the wind at 20-30 mph, the
Mallard likes a stronger dose. Much stronger. Scarily stronger!
The
Mallard is content in a wind speed around 30-40 mph, even higher, although
it works well at lower wind speeds, too. It is smooth, deep-voiced,
even-keeled. There’s little wasted motion, no unsureness or burden, just
a willingness to move and capture the wind. It faces the wind
continuously, almost effortlessly, even though it does not possess a slip
bearing that would allow it to continually rotate to follow the wind 360
degrees around like the Air-X’s do. Oh yes, it rotates to face the wind
in any direction, but a special clamp is used that allows the wires to
twist inside the mast as it does. I thought this concept, initially revolting to
me, would be problematic. But not so, not so at all.
Wind just doesn’t behave in such a manner to corkscrew the unit round and
round its axis on the pole continuously like a merry-go-round. It
blows from one direction, moves to another, and then again to another.
On a rooftop, even more turbulent is its behavior, the wind will buffet
the tail vane left and right, but it rarely gets it to completely spin in
circles more than once or twice before it can unwind itself. In
between gusts, the Mallard leisurely unwinds itself when the wires become
taut.
I
use a highly flexible and tough rubber coated wire like welding cable at
least for the wires that run down the mast. Nevertheless, to ease my
concern, in addition to using the more flexible wire, I fabricated a
connector on the wires at the bottom of the mast and installed it in a
bird house (see the accompanying pictures), so that I could easily break
the connection, like unplugging an
extension cord, to allow the twisted
wire inside mast to unwind periodically. I’ve allowed it to unwind on a
couple of occasions and was almost disappointed that there wasn’t any
serious twist in the wire to unwind. I’ll do the same for the next unit I
install.
The
Mallard is not afraid of the wind. It keeps putting out more and more
power as the wind increases in intensity. The Air-X’s, while steady and
reliable, will shut down and preserve themselves for another fight later
on when the wind is more respectful. They do a great job at the moderate
wind speeds, even better than the Mallard, but when the air gets tense
and you can feel the trouble in the air, the Mallard 800 seems to fill
itself with an intolerable brightness; I see war in the eyes of my big
green friend. It doesn’t stop putting out power. It would rather start a
fire than to quit producing. Scary, in and of itself, it’s willingness to
output power that is endearing to me! And now that I have confidence in
it, I let it fly and do what it is born to do.
Last winter, when the winds blew strong out of the northwest night after
night, I let it do its thing, all winter long. Rarely did I have to shut
it down due to overproducing winds. I have installed a dump load
controller to handle this kind of contingency and it has worked well. On
the other hand, there were a handful of occasions during the winter months
where I ran low on power and had to fire up the gas generator. The winter
sun, low in the sky as it usually is here in the northland, could not
carry the burden like it does in the summer and the wind generators have
to work for me. Between the steady output of the Air-X’s and the less
frequent, but mighty outbursts from the Mallard responding to the winter
wind howls, my meager power needs were substantially satisfied... without stress, without repairs, without a monthly bill. I’m up for the
next wind generator.
So
that’s the plan. Decision is made, parts purchased... stay tuned,
we’ll add the next wind generator together over the course of this
summer. Stage 1: Circuit Design and Parts Acquisition coming up next.
Now, where the heck are my tools?
