Furling a Windmill Question

[JBarker]

A friend texted me last night about his A702 windmill and thought the wheel was spinning too often in the wind with the brake set. I told him mine does the same and the manufacturer had engineered it to relieve some of the pressure of the wind while furled.

My question is when is it spinning too much with the brake set? Is there a set standard when it should or shouldnt? Thanks for your advice.

Jerry

[CTXmiller]

Mine will spin a little in heavy winds of 35+Mph. The experts on here can provide sound advise, but I keep my brake fairly tight by lowering my brake handle, keeping the brake line tight. My angle iron corner brake...I’ll loosen the bolts a hair and push it a inch or so further down and then retighten the bolts taking any slack out of the line.

[Ron Stauffer]

Jerry
You will get lots of varying advice on this.

If it is a pumper and you are in freezing climates, then it should not turn at all or the pump pole needs disconnected in winter. If it is furled and still turns slow, this is a recipe for freezing.

If it is non pumper, I like the brake to work to some degree as it makes servicing easier. Most new 802s we have put up will hold the wheel solid and I think that was the intent for the brake. They seem like they hold solid for around 10 plus years and then there is enough wear on all the parts to allow some slippage. A welded nut on the brake arm is the easiest cure and there also is the longer button arms available for the furl ring.

Ron Stauffer
Montrose CO

[billcobb]

If it's truly "furled". (My F & Ws operate the same way), the fan is perpendicular to the tail van and the brake band is tight. On my A602 (same as A702) the brake band tension is controlled by a spring adjuster. I could see a sudden cross wind putting a momentary force on the wheel which might overcome the brake, but if it's turned out of a constant wind, the fan should be just about stationary even without the brake applied.

We had some 60 mph winds last week (Polar Vortex) and all my mills were stationary, even 2 where the brake mechanism is INOP. BTW: does anybody glue brake material to the steel band on a windmill brake ? Mine are just steel on steel. I like them tight when I'm up there. No need to go out for a spin.

[Ron Stauffer]

Bill
FWIW, I have two D602 cases in the bone yard that very nicely installed riveted brake lining. One came out of CA and the other AZ. Both suffered hub failures but dont know if the brake lining was the reason. They are so similar looking that it makes me wonder

Ron

[Bryon]

The brake should slip in gusts from varying directions. If the mill just sits and turns when it is off, then you should turn the mill on, draw a line on the top side of the "V" shaped bracket for reference, loosen the bolts a bit that hold the handle, slide the handle down about 1/2 inch and re-tighten the bolts, then turn the mill off. The tail should be pulled into the parallel to the blades position about 3/4 of the travel of the cut-off handle to the tower leg. The rest of the travel should be to "set" the brake. If it already does this, then there may be an issue with the brake or oil leaking onto the surface of the hub between the brake and the hub.

I hope this helps,
Bryon

[windybob]

Where's Randy when you need him..... He would say that brakes ruined more windmills than anything else, so toss them in the trash. In fact he did on more than one occasion.
I don't agree. Lots of good advice here, a bit of turn in a gust is fine, but I think a lot depends on the size of the mill also. A 6 footer turns on the tower much easier and faster than say a 10 or 12 footer, so on a larger mill a little slip may be better to ease up on the pressure. Most of what we work on are 6 footers, and a snug brake is good. Of course, we are lucky to get it because half the stuff we work on is worn. We have a truck full of tricks for most mills.

[Wayne]

There's Windy with his Windmill tricks again!

[LoTec]

If I have an Aermotor mill in the shop to rebuild, I rebuild the 609 furl lever (AKA brake harness). I disassemble, then make new vertical straps or, often, weld a stack of grade 8 washers on each end of the strap to re-establish the original length between the pivot holes and make the strap a bit thicker and less likely to wear. I knock out the original shoulder rivets and thread the holes in the top casting, then install the straps with screwed-in hardened bolts and a jam nut inside to lock it, with a good dose of red lock-tite. I also use hardened bolts at the bottom of the strap. For an on-the-tower brake adjustment, yeah, like Ron Stauffer said, I usually swap the 786 brake lever for one with a nut welded on the push arm part. I also have had very good results with putting several coats of spray-on rubber truck bed liner on both the brake band and the hub braking surface.

[Rockabye74]

I would like to see a picture of the modifications that you just discussed.