Wind Gen behaving strangely .

[ALLAN WARD]

My dated but very reliable AIRMARINE wind generator is behaving strangely lately in that at times it spins around and points its tail into the wind and continues making power albeit not as efficiently as when its facing the right way .
I have replaced the original noisy blades with Spreco's blue blades which has quietened the unit substantially .

Could this be what's causing it to run facing the wrong way ?

[Crew of Turning]

If it was an aeroplane I would guess the blades are pitched in reverse. I am pretty confidant that you can not install them on the hub backwards. Have you ever replaced the yaw bearing? Definately a mystery. By the way you can back up a turboprop aircraft by reversing the pitch. Vickers Vanguards did this often,

[ALLAN WARD]

The Spreco blades as with the original blades can only fit one way with recesses for the cap bolts that hold the blades .It behaves like this probably about 10% of it's run time .

The bearings are all good .

I changed the blades to please my neighbours where ever we are anchored but it is a lot noisier when it runs with it's tail facing the wind .

Fortunately it only happens every now and then .

[Jim Cate]

Our Air-X with original blades will sometimes spin about when there is a sudden change in wind velocity or when the regulator suddenly shuts it off. However, it has never run whilst facing backwards. I wonder if the blue blades have a different weight that might upset balance? Who knows?? Or maybe their overall aerodynamic drag is higher, and it overcomes the righting force of the tailfin when backwards.

So, you might try adding a bit of extra area to the tail fin... something simple, possibly held in place with liberal application of duct tape as an experiment. If it should work, you can make a more permanent fix.

Jim

[Whitebread117]

Anecdotal evidence- 2 neighbors have Air marine gens, another has a Rutland, and we have a Spreco Silentwind (and formerly a KiSS). The 2 air-x gens (one retrofit blue blades one came with blue OEM) do move about more frequently. Our two routine cruising friends both have air-x gens also, and they behave similar to our full time dock neighbors.

The Rutland tracks true to wind and is first to start, but is also first to shut down. The 2 air breeze gens (not sure of exact models or ages) start with low wind speed but hunt around quite a bit and do occasionally turn 180 degrees to prevailing wind.

Our Silentwind is slower to start but tracks prevailing wind better than the air x and produces a lot of power with low noise when the breeze goes north of 15knts. (Previous KISS was surprisingly similar to Silentwind).

The tailfin on the air x seems smaller than a lot of other gens- this might well contribute to yawing off the wind. If it's a concern, add a bit of weight to the tail fin or a bit more fin area (taping on cardboard would be good for a test) and see if it tracks straighter.

One of the big wind gen comparisons in recent years mentioned that the air x performs well even though it tends to veer off course regularly- if I can find a link I'll post it.

[OldBawley]

All of the modern styled windgens have to small tail fins. Just to sell more. People look at specifications before buying and a small short tail sells good. It also looks cool. It is however not efficient.


We use two windgens during winter. A modified Aerogen and self build big beast that I only mount up when anchored for longer than a day.

For commercial reasons the Aerogen has a short tail. That makes the forward part a lot heavier than the tail part witch results in waddling of the unit in light winds and some waves. Our Aerogen stands 7 meter high, increasing waddling. So I made a longer, heavier, balanced tail. Supported by two tubes in stead of one. Waddling over, increased efficiency.
In very high winds, the one tube tail starts vibrating. I noticed the vibration of the tail a few times in 90 knot winds, a dangerous situation. Inside it sounded like a truck was passing by at a few yards. The two tube tail will not vibrate.

As said before, increase the tail surface.

[GILow]

Hey OldBawley, I'd love to see photos of that Aerogen mod if you have them. We have the Aerogen 6 and it seems to track the wind very positively but what you say about weight is very interesting and makes good sense. I would not have called the tail fin small but I will look at it again with your comments in mind.

[OldBawley]

Our old Aerogen 4 was a gift as thanks for helping a stranded cat of the beach of Rhodes harbour. ( Greece )

The SS shaft of the gen was broken, I have a small lathe on board so I made a new shaft out of bronze. ( SS is a pain to turn on those toy lathes )

Worked fine for some years, then during a repaint job of the yawl mast I did some improvements.

First thing I rebuild the tail as seen in the photo. During real heavy weather the tail sometimes starts vibrating, the vibrating force is enormous. So I turned the tail upside down and made a second tailpipe. Also made the weight of the tail so that the weight of generator head plus fan is the same as the part behind the yawn axle.

That made the gen much more steady to the wind. Mounted up high for efficiency but small waves rock the boat, the swinging of the mast tended to make the genhead waddle, that is over now.

But, you need space, Aerogen could never sell a gen lake that.

http://s1155.photobucket.com/user/OldBawley/media/DSCF4066%202%20800x600_zpsanrngthr.jpg.html][/URL]

Second mod : inside the gen head is mounted against the back cover a bi metal switch. If the diodes get to hot that switch disconnect and lets the gen free-wheel. The fan turns as hell but no electricity is produced. That switch was preset faulty, I have adjusted multiple times so that the “off” occurs at a much later moment. Sure made the efficiency a lot higher. I can hear the gen switch on and of during hard winds, especially during summer. Humming is loading, no humming is free-wheeling.

Do not try this yourself, you could damage the gen.

As said our gen is old, maybe more modern aerogens have an other system to shut off.

As I have constructed a DIY windgen and in doing so learned a lot about blades I have also readjusted AND rebalanced the rotor. Small adjustments make big gains. I even polished the blades.

BTW : The DIY is a 1,7 m two blade and delivers about 4 times more as the Aerogen. Also delivers at low speeds because the gen is geared. From 12 knots of wind the Aerogen is sufficient to deliver anything we use AND is lot less dangerous.

[GILow]

Thanks for that, very interesting stuff.

Our Aerogen 6 is probably 30 years old, not sure how that compares with the age of your A4. Ours does not have a thermal cutout, and I don't remember seeing one in the A4 diagrams either. I might have missed it but I wonder if that was an original item?

I can see how the height of your installation would exacerbate the balance issue. Ours sits about 4 meters above the water so it does get some swing velocity in rough seas, but not as bad as you would get from 7 meters, that's a lot.

With luck I will get down to the boat tomorrow, and if so I will check and see how the overall balance of the A6 feels.

Matt

[OldBawley]

oops, ours is an Aerogen 3 ( Before WW1 )



De thermal switch is sen just above the rectifier.

So excuse, our big DIY whopper delivers 4 times more than an Aerogen 3
( diam. about 3 feet )

[OldBawley]

As an aside, those 7 m hight are good for the efficiency of the generator but bad for the sailing efficiency.

Since the sun is delivering all we need during summer, I have thought about taking off the fan during summer. Towing that fan against the wind augments the windage of the boat and I have been told I need 43 feet² of sail to bring that fan upwind.

The DIY has a two blade prop that can be easily stowed between two deck beams, the fan of the Aerogen is a big thing to stow.

[varkpilot]

Originally Posted by Crew of Turning

If it was an aeroplane I would guess the blades are pitched in reverse. I am pretty confidant that you can not install them on the hub backwards. Have you ever replaced the yaw bearing? Definately a mystery. By the way you can back up a turboprop aircraft by reversing the pitch. Vickers Vanguards did this often,

Interesting. I thought those wind gens had fixed pitch props. Didn't know they had Beta range. Maybe the vane portion is just not large enough to hold into the wind. It's easy to envision the wind catching the blades and turning the device around, especially a good gust. Oh, and you can back a King Air with Beta, too.

[ALLAN WARD]

Many thanks for all your replies .

New project on the list to mod the tail fin .

[GILow]

Originally Posted by ALLAN WARD

Many thanks for all your replies .

New project on the list to mod the tail fin .

Please let us all know how it works out.

Matt

[GILow]

Originally Posted by OldBawley

oops, ours is an Aerogen 3 ( Before WW1 )

....


So excuse, our big DIY whopper delivers 4 times more than an Aerogen 3
( diam. about 3 feet )

Geez, that took some searching. Seems the Aerogen 3 was a maximum 10 amps (or 120 watts) at 35 knots according to the only bit of data I could find from Google Books. But not as old as you'd think, I found an advert for one in the 1993 issue of Cruising World, so they must have still been in production then.