My Number 2, 3.7m diameter, (12 footer) fails.

[kitestrings]

Wow, those look good... that's a BIG cedar.  Around here if they get that big they often have rot in the first four feet or more (and ours are white cedar).  Are you planning to cut them from these blanks; one piece, or will they be re-sawed and laminated.

Seems like it would take more than a few weeks of air-drying, no?

[clockmanFRA]

Bruce S.   Yes that knot is there but its at 1.8m, so that end will be the tip and as you know the tips are very small so it will be on the other side to the knot.

I have spent a couple of hours with Dimitri checking and double checking that i can get a blade from each piece with out the knots.  Awkward when its quarter sawn as its not easy to see where a knot will be.   

Besides i have 2 sets, so one will be a spare set.

Normally i stack other timbers on top with small pieces of wood between to allow air flow.

But its good to have 2 sets ready to carve.  yyiippppeeee.

[clockmanFRA]

Yes KS, they might need a bit more time to really dry, just depends on our summer here.

That tree was felled about 9 years ago.  A French main Town parks Arboretum department had declared the 4 mature cedars as dangerous and were condemned, Dimitri picked up the job and the timber was free.  When they were cut today there was still some damp in the wood so it may take longer, but i can wait, as masses of other capital projects need getting on with.

If you look in the Photo of Dimitri cutting, the log he is cutting is the next section up.  Mine came from the main trunk, in the photo you can see my blanks just behind and sort of stacked.

KS, the smell is so heavenly, we should bottle it and start a perfume company, 'La Cedar de toilet'. haha

[Bruce S]

KS, the smell is so heavenly, we should bottle it and start a perfume company, 'La Cedar de toilet'. haha

That smell is even better than Saddle Leather!

[SparWeb]

Looking forward to it, too!

[acme12]

Nice planks of cedar you have clockman. Have you ever tried this three common European species:

European larch (Larix decidua), i think best price/performance ratio, good fungal resistant.

Sybirian larch (Larix sibirica), less warp, higher price since it is imported from Russia or...

Red pine (Pinus sylvestris), bit softer, less / good fungal performance.

[topspeed]

Hi Guys,

Many thanks for your understandings.

'KS', Not down yet as the weather is very cold and snow everywhere but very wet/damp and my field is waterlogged.  The coil stator mounting 12mm /1/2 inch thick bolts have bent, and that means that its likely that the Resin encapsulated coils stator has fractured/broken as it is fragile.   So that might need replacing.
The 2 magnet discs might be okay, but there holding bolts also hold the blades and they are well twisted, so they are probably damaged.   I will just have to wait till she is fully down.       I have a saying,   "I expect nothing, so will not be disappointed"

Yes 'Sparweb', cedar is lovely to work with, but having trouble getting my hands on good cedar.

Yes 'Scruff' they normally stand high winds and the auto furling that Hugh Piggott designed works well.      My No 1 actually survived officially recorded Hurricane winds, but the top section of that 4 inch thick wall tube mast bent slightly.
OHHH Real Marine ply, and you can get it, thats luxury.     
As you are in the EU and i live in the EU, France i might start trading with Ireland a lot more, as at present all my normal sources in the UK are off limits for the time being as Europe and the idiots officials in the UK sort out the customs paperwork.       My local French Post office head woman took me to one side and said,   "Please don't send anything to the England at this time as we are no sure what the required paperwork is, as England seem to want more documentation than other countries outside the EU".
I put it like this Scruff, I try to keep stuff simple, Hugh Piggott's design is very simple and it works, "but just remember there is a WILD HORSE (1kW to 2kW)  on top of a mast kicking the crap out of it".

Hi, BigRockCM,
Yes those blade clamping discs might be made of a different material but No 1 and No 3 have no issues.  I also think its weight, those fiberglass blades are 3 times as heavy as Cedar ones, then the fiberglass gets wet inside, the plywood gets wet the blade core wood gets wet and something is going to give.    Its always a balance between strength and weight.

Yes i will miss all working this winter, as the three of them really do charge up my batteries when day after day there is very little Sun and little power from the PV.

I found the missing blade, yeps 10kg /22lbs in weight in the ditch of our local road 100 meters/300ft away. Sshh dont tell anyone.

(Attachment Link)

I think a fiberclass clothing on top of a wood surface is a must. It can also be sanded really smooth.

The aviation grade plywood is what I am after, but I can only use normal hardware store ply as a filler or such. I had to reinforce the last tower with pouring epoxy 1 cm thick inside the 4 walls of it.


Before....



....and after.




Altogether after 6 alterations it sorta started to rotate "normally" showing that it has too small area for the stiff generator....and solidity was too big. I am doing these 3 new mods now...as the foil was also not adequate.

This kicks like a pony with 300 watts top output.

[clockmanFRA]

I wish you well Topspeed with your endevours.

After flying my HAWT Turbines for over 12 years, one big thing i have learned is the issues with material that is subject to water impregnation, and water ingress causing balance issues with the blades.

Yes My No3 turbine fiberglass blades were coated with Fiberglass resin on all the plywood interior blocks at the mounting hub, but how long will they last, we will see.

My No 1. blades was coated with fiberglass resin and over paint, but 12 years later the water still got inside the wood blades at the hub mounting and seeped down the blades internal cedar wood.

Folk will say to me, seal this, paint that, mastic here, mastic there, but obviously climate conditions are a real big factor.

[MattM]

I wonder how fast 'impregnated' lumber loses its waterproofing as she spins?  Physics certainly should come into play and force all that good stuff to the outer tips through raw certrifugal forces and capillary action through a path of least resistance.

[topspeed]

I wonder how fast 'impregnated' lumber loses its waterproofing as she spins?  Physics certainly should come into play and force all that good stuff to the outer tips through raw certrifugal forces and capillary action through a path of least resistance.

I figure the centrifugal forces are not to blame...the weather and elements just take a toll. One ought to refurbish the wooden structure every 2-3 years.

[DanG]

Look into MDO (medium density overlay) sign painters plywood // concrete form plywood - the stuff tested 36 months in the Everglades… Used it as floor panels in my Airstream ever since it’s my first choice for everything.

Also they’ve been perfecting porch paint for 100’s of years - 2 or 3 coats of oil based exterior primer with 2 or 3 exterior oil based top coats - then refresh topcoat after a few seasons…

[clockmanFRA]

Hi DanG,

Like topspeed says, "the weather and elements just take a toll"

The thing is that plywood on that failed Turbine had been used for 7 years, and yes it got re-painted every year or so, with an Industrial Oil based primer and oil based top coat.

The wind turbine is a dynamic structure with every bit of it handling stress, flex, gravitational forces and centrifugal forces.

I sealed every screw hole and overpainted, i also mastic sealed around the 5off 12mm/1/2 inch main blade to hub bolts, but still the water got in.

I see it like this, ..... There is a fine line between getting it working and producing Power, and making it stand the elements of the weather.  ie, I could make it and seal it and re-design everything so not a drop of water ingress, I hope. But then the cost the weight and the work involved just makes wind power at this scale absolutely not cost effective.

Hugh Piggotts design is fantastic. Its the blades and the hub that are stressed and at the rotational speed of a 12 footer/3.7m diameter, any imbalance is soon seen and causes the issues.

Well that's my opinion with 3off, after nearly 14 years flying.

Remember that my No2, has My design and made fiberglass blades, has only a little vibration after 5 years of flying, so by No3 i think i got it about correct. I hope?

[mbouwer]

Hi ClockmanFRA,

Have you seen the operation of Sparwebs Duplicator in the test run?
Shaping blades that way also seems like something for you.

Regards Rinus

[kitestrings]

I'd say you've done really well to keep'em up and going this long...and made refinements that are improving the longevity.

I've said this repeatedly here, it is not unique to this turbine, but I think plywood is simply not the best choice for the hub.  I think thin metal plate, or AL if it doesn't interfere with other things is better.  Sencenbaugh used a round metal hub plate, then three thin square blade plates to sandwich the blades.  He then tied them with another thin plate that went over just the outer pairs of blade bolts.  A threaded stud through the center of this plate was used to fasten a spinner.  I've never seen one fail.