I did not want to wait with an update until also the last blade frame was fully tensioned as we are already in twilight.
I have been able to make the central column stiffer by first, and yes I told earlier that I would not try it, using rigid foam to fill up the column.
That helped ever so slightly so not a complete waste of time and material.
Then I went for the body armor. That helps as well but what it also enables me to see is that the problem of flex manifests even on short distances.
it is the part between the arms and the column retainer block where we still can see flex. Sure less now it is filled with rigid foam but not nearly as much as I think one should need.
This basically also makes the plan I had next to shorten the central column by 1 meter, leaving 1 meter a dead end so I will not even go there with this current column as it would probably make no difference as that is not the weak spot.
So I will be going for the 100mm diam alu after all.
But I will let this version still spin for a while with 1 maybe 2 wind panels per blade as long as the wind is manageable. Just to see more things happen where I should focus on.
![VAWT backyard experiements 15786-0](https://www.fieldlines.com/index.php?PHPSESSID=dbf247e9bbfb1aa6b8bb9077de7ea947&action=dlattach;topic=150846.0;attach=15786;image)
{1}upcoming improvements are to replace the 8mm ropes (that have a max tensile strength of 90kg) with 4mm stainless steel wires. I am hoping it will increase the tensile strength while reducing the vibration likeliness.
@MattM, this is one of the reasons I did not fancy yet the idea of fortifying the structure with yet another structure because as far as I am able to tell by now is that adding surface area for the wind to catch on or to bang to it will make a lot of difference.
So this is why I am not fully confident in using slimmed down versions of formulas to calculate wind load even though I have been asking for them. Nah let field tests speak for them selfs as I am simply not able to wrap my mind around even the most basic formulas as soon as they start becoming in a form or containing components I am not yet familiar with
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