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Forum Index : Windmills : Tail Positioning

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Bryan1

Guru

Joined: 22/02/2006
Location: Australia
Posts: 1448

Posted: 02:48am 01 Apr 2007

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Hiya Glenn,
Eh mate I'm on doing some research on wind generator tails and your page on furling is a great explanation, however, I'm abit unsure whether the tail mount say angled @20 degrees should be inline with the tower centreline or as you show on the furling page offset to the opposite side of the turbine centreline offset by the same amount. I have noticed the Dan's have their tail mount inline with the tower centreline. It could be this wont make any difference but it's a gray area I hope to get answered.

Cheers Bryan

Gill

Senior Member

Joined: 11/11/2006
Location: Australia
Posts: 669

Posted: 12:19pm 01 Apr 2007

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G'day Bryan,
I hope Glenn doesn't mind me jumping in on this one.

It doesn't matter where the tail extends from.
Most offset to the opposite side of the yaw bearing to the genny because of genny size and the need to extend the tail past it.
Yet you could just as effectively furl with a tail in line with the prop axis.

It's the counter clockwise moment (the winds thrust against the prop * its offset) against the clockwise moment (tail resistance(weight) * tail length ) about the yaw bearing.

Clear as mud. ay!

Further to this, you queried the alignment of the 20deg tail pivot.

For Glenn's design the tail pivots 20deg off vertical, is 45deg to the front/back axis in the plan view.
The calculations are based on this.

Personally, I think better furling could be achieved with a different positioning and i have built this into my duel rotor mill currently under construction.

I'm using 70deg.
so the calculation changes to:

Furl resistance = Tail Weight * Sin ( Pivot angle in degrees) * Cos 70deg
Furl resistance = XXXKg * Sin 20 * Cos 70 = YYYKg

Still the proof is in the pudding, So have to get it up and running before I mouth off to much.

Well, hope that's helped.

was working fine... til the smoke got out.
Cheers Gill _Cairns, FNQ

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