building 17' machine need info and upgrades

[picmacmillan]

hi all...nice to be back...as stated above i started to build a 17' machine a couple 3 years ago..stator is done, rotors are done, magnets in place etc..going to assemble the thing this winter...was wondering how everyone made out that built one like it...if i remember right i went with danb's original design..i will check the facts tomorrow and repost, but i wondered how the machine stood the test of time etc..was the hub sufficient and the tail etc..also the tower..i beleive he used 10" thin walled pipe...if it works well i want to use it as my main power sorce this summer..thank you in advance for youre comments..if you have any diaries or links that i can do my homework on that would be appreciated....pickster

[dlenox]

pic,

I have recently made modifications to my 17'er.  Like you I initially built mine per OtherPower 'derived' specs.  I say derived cause they never really published all the dimensions/offsets/etc.

One recent change is the offset, from my initial calculations the turbine was offset 9.5" from the yaw bearing, I have increased mine to 12.5".  In addition I shifted the turbine as far forward as possible.

My turbine appeared to become wind-seeking at about 36mph winds and unfurled itself, creating a huge amount of output.  Eventually even though I was stall controlled the stator developed an internal short.

Other changes that I made was to lighten the tail vane, initially using 3/8" plywood the vane was 30#, using composite fiberglass I got the weight down to 10#.

This new stator I have wound the coils three in hand, #14 wire, 50 turns.

Here in WV it looks like winter is here to stay, so will not be able to put my turbine back into service until spring time.

Dan Lenox

[Timeless Turbines]

How did you move it more foward.

[dlenox]

Previously the turbine had very little forward offset with the back rotor only about an inch or so.

There were two things that I did to move it forward, easiest was that since I had to cut off the 4 x 6 tubing that connected it to the yaw bearing was that I adjusted the turbine 1" more forward.

The other thing that I did was to put a forward angle on the 4 x 6 tubing of about 8 degrees, this made the turbine about 3/4" more forward relative to the yaw bearing.

Here are a couple of pictures of the rough primed yaw bearing:

So now the rear rotor is about 3" forward of the yaw bearing.

Dan Lenox

[Dave B]

  Just to chime in here about my 16' machine and the changes I've made also. The 2 most important changes I've made and that corrected my late reacting furling is I lessened the furling hinge post angle by a few degrees (it does not have to climb as steep against gravity now) and the biggest change is the blade rotation with regards to the offset side of the hub mount.

 My blades now turn counter clockwise when looking at the blades from upwind and the hub offset is to the right. A bit of un-advertised research will show that the Dan's have changed this relationship and Hugh has actually posted that he is now building this relationship into his new machines also. (note: this can be reversed as clockwise rotation and offset to the left but the relationship is the same.)

 I have my own theory why to do this but the main thing is that for me and apparently now other's as well it assists the furling and helps to keep the blades out of the tower in radical yawing and high speed blade rpm as well. Take a look at Bergy, their offset vs. rotation direction uses this relationship as well and I have to admit I figured there just might be something to this. I call it precession other's may just call it blade seeking force when it works against and not with the furling action. For me, problem solved. Just some thoughts from many hours of changes and improvements.  Dave B.  

[dlenox]

Dave,

My rotation is also CCW, so I may have to consider this...  With us here in WV, in the throws of winter my turbine will not go back up until spring so I have some time to contemplate it and if necessary rework (again) my yaw bearing.

Thanks for the insight.

Dan Lenox

[picmacmillan]

thanks guys for the tips...if theres any more tips or comments.especially about tower design pipe used, height etc..would come in handy...fire when ready  pickster

[Dave B]

Hello,

  No guarantees that the direction of rotation as it relates to the offset side will make a difference in the furling response but for me it was night and day. I have put this link up many times, make of it what you will but it sure explains to me why it fixed my problem.  http://video.google.com/videosearch?hl=en&source=hp&q=precession+utube&um=1&ie=UTF-8
&ei=zUwhS57kB4np8Qaml62GAQ&sa=X&oi=video_result_group&ct=title&resnum=3&ved=
0CBgQqwQwAg#hl=en&source=hp&q=precession+utube&um=1&ie=UTF-8&ei=zUwhS57kB4np8Qam
l62GAQ&sa=X&oi=video_result_group&ct=title&resnum=3&ved=0CBgQqwQwAg&start=10
&view=2&qvid=precession+utube&vid=2327235859818348828   Dave B.

[Flux]

If you reverse the rotation it throws the bottom of the blades clear of the tower as it goes into yaw, This usually happens during a strong gust and this is the normal time for a blade strike.

If turbulence forces a yaw the other way then you might still be unlucky.

I think this is the reason why Bergey and Hugh have made the change.

My own experience is that direction of rotation doesn't affect the seeking force but there are so many things that influence this that it is foolish to be dogmatic. Certainly I would make the change on any new machine to reduce the risk of blade strike.

On a machine already built you have to make up your own mind. I have built machines both ways and if you get it right it furls correctly. Possibly one way gives more tolerance to insufficient offset, I don't know, I haven't direct evidence.

I will try to find pictures of a machine that did completely fail to furl due to insufficient offset just out of interest to see which way it furled. All my props rotate cw looking from the wind direction, I know it doesn't matter but it looks wrong to do it the other way to me.

Flux

[Roger Stafford]

Hi

I too have built a Dan's 17 ft and I am also having problems with furling. My gen is in AR. and I'm in FL. I just got back and only had 10 days to find and fix the problem.(luckly the weather worked out) First I adjusted the tail stop like someone here suggested, (easyest) didn't work. Then I adjusted the offset and now it's furling but still not soon enough,I think, don't know for sure because I don't know what the wind speed was for sure.(between 25 and 35mph)I am going to get the software from D lenox and install an annometer. Thanks to Dave B's post, I now have more ideas (tail post angle) which I'll try the next time I get to go out there. As for the tower, I used 10" tubing not pipe and it's 90ft to get at least 30 ft above the trees. The gin pole is 50ft. I mounted a 2" pipe set in concret at the end of the gin pole and added another clamp to help anchor the tower.I used 3/8ths cable from the end of the gin to the 4th anchor. Three sets of guides 3/8 cable at 80ft 5/16 at 60 and 40 ft.It works fine, 10 thousand lb whench. I figger the total weight is around 2400 lbs. (total weight of material) But I have to tell you it's only been up for 2 months. Make sure your side guides are level or you'll have problems raising and lowering the tower. Hope this helps have fun.

Roger