10 Footer update

[bzrqmy]

My ten footer has been up since earth day.  Time to take it down and do some inspections and finish packing my electronics into a steel control panel.

One of the first problems I knew I had is that my side anchors are messed up on my tilt up tower.  Let me try to describe in words as I have to pictures.  My tilt-up tower when in the down position points east.  Side anchors would be North and South.  My pulleys are hooked to the West anchor and I pull in the direction of West.  I released the tension of the turnbuckles on my side anchors about as loose as I could.  While lowering the tower, I had to loosen the cable clamps twice as the tension was extremely tight as I lowered.  Upon investigation, my side anchors are too far west of a centerline running through the North-South plane of the tower.

Idealy, in a flat world, the side anchors would be on this centrline plane.  I am considering actually putting new anchors offset to the east of this centerline so while lowering the tower, the only thing that can happen is the cables would go slack.

Anybody see a problem with this?

As for the blades, two of the three are in good shape, the third has a crack about 12" from the tip and must be replaced.  After reading the article Dan B posted on maintenance, which I can't find anywhere on this board, I checked my blade tracking and discovered I have one blade tracking out 1" and one blade tracking in 1", making a 2" offset.  Blades were 2 x 8 pine.  

I have been observing weird tail tracking in good wind.  After inspecting on my test stand, my tail has got to be at an angle of 30 degrees to the centerline of the hu shaft.  I know it's supposed to be 10 degrees, but I am way off.  I am thinking about welding a piece of keystock as a stop to get this back in the neighborhood of 10 degrees.

I knew my air gap was wide.  I wanted to be on the conservative side.  I will lower the gap on the back rotor.  When I do this, I have a large gap on the front rotor.  The only way I can thik of to reduce the gap is to grind some off the jam nuts.  My stator ended up being a bit shy of 1/2".  I think I used some of that funky undersized 1/2" plywood for the stator mold.

All in all, I have been pretty happy with the performance of the last two months,  I figure a little tweaking will just make things better.

Any suggestions?

[Flux]

"I have been observing weird tail tracking in good wind.  After inspecting on my test stand, my tail has got to be at an angle of 30 degrees to the centerline of the hu shaft.  I know it's supposed to be 10 degrees, but I am way off.  I am thinking about welding a piece of keystock as a stop to get this back in the neighborhood of 10 degrees."

Your observations are similar to mine. With my machines even 30 deg is not really enough to keep them directly into the wind, but an error of 30 deg to the wind when running doesn't seem to have much effect on performance.

I think the 10 deg is a dream. These things run at a much larger angle to the wind than most people imagine. Try building one as a mirror image with offset on the other size and run the two together and you will really see how far they do run off wind.

Stick with your 30 deg.

"I knew my air gap was wide.  I wanted to be on the conservative side.  I will lower the gap on the back rotor.  When I do this, I have a large gap on the front rotor.  The only way I can thik of to reduce the gap is to grind some off the jam nuts."

Yes if you want to reduce the air gap you will have to do that. Just moving the stator back in the same gap will do nothing, it is the distance between magnets that is the air gap.

Flux

[Adam T]

Is the base for your tower pretty permenant, or more so than your guy anchors?  Would it be any easier to move your tower base to the west, than to move your two guys (north and south) to the east.  Hopefully you have an easy solution.  If you have substantial amounts of concrete options either get fewer, or more expensive.

Best of luck.

[SparWeb]

...I am considering actually putting new anchors offset to the east of this centerline so while lowering the tower...

That sounds like a solution.  Bear in mind that it's not a "mandatory" change, only one that makes raising and lowering the tower easier.  I lived with this situation for 2 years before fixing it.

Did you use screw-in anchors?  Did you embed them with a vertical concrete hole?  If you haven't concreted them in yet, you could try screwing the North and South anchors down a little more, closer to the ground (if possible).  The N&S guy wires will be longer, but they will not be much farther away from the top of the tower when it is lowered.  Whether this is enough to make them slacken or just become "less" tight depends on your particular situation.

Having a tower that can be raised easily for maintenance and "tweaking" makes the hobby a lot more fun.

Did you laminate pieces of wood together to make the blades?

Tracking misalignment isn't as bad as mass imbalance.  Once you've made a new third blade, see if you can shim the blade in its root mounts with a few thin sheets of metal to get the tips to turn true.

[bzrqmy]

Base of the tower is fixed.  I have screw in anchors, but they are not used as such.  I welded extra rebar perpendicular to the anchor and embedded in concrete.