Author Topic: counter clockwise turning blades  (Read 3421 times)

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gww

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counter clockwise turning blades
« on: September 02, 2014, 06:12:19 PM »
Started to make anouther set of blades today.  Of course I screwed up the first blade.  It doesn't matter if I screwed up the same way while making my last set, I have to mess at least one up every time I make them.

To my question.  Facing my turbine head on, my blades turn clockwise and my tail furls to the right.  I am making sopme 9 foot blades to replace some 8 foot ones.  I am not changing the 5 inch offset or the 48 inch tail length. 

Will the turbine furl easier with counter rotating blades?
Thanks
gww

hiker

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Re: counter clockwise turning blades
« Reply #1 on: September 02, 2014, 07:09:58 PM »
only problem i had with ccw blades were on a motor conversion--they unscrewed the holding nut on the shaft--heard the blades going supersonic--jumped out of  the motorhome--tried to turn the gen away from the wind--about then they came loose-flew over my head and landed in a tree aways off....just one out of a few mishapes....not sure on the furling ?
WILD in ALASKA

gww

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Re: counter clockwise turning blades
« Reply #2 on: September 02, 2014, 07:31:14 PM »
Hiker
I have had numerous mishaps myself.  Still experiancing some now.  Have one turbine that is shorted out at the top of the tower and did ruin the blade today.  Dropped one while raising,  had two bend the towers double, lightning took out an inverter last week etc etc.. 

This turbine is a hugh piggott design but I will try to remember when and if I ever get to the fisher pykel build.

I don't have to worry about tower/blade contact as I tilted the turbine head slightly but was wondering about furling. 
gww

gww

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Re: counter clockwise turning blades
« Reply #3 on: September 02, 2014, 07:31:38 PM »
double post
sorry
gww

just-doug

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Re: counter clockwise turning blades
« Reply #4 on: September 02, 2014, 08:25:46 PM »
in my opion,the rotation should put the top of the rotor pushing into the wind when fully furled to control speed better.the lower edge of the rotor is in the turbulence of the tower,the top of the rotor in straight air.if the rotor top turns with the wind it will be more inclined to increase speed.like a over shot water wheel.top of rotor turning into wind should prevent runaway.

gww

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Re: counter clockwise turning blades
« Reply #5 on: September 02, 2014, 08:38:06 PM »
just=doug

I am not sure I know what you are saying.  Currently, facing my turbine blades, the blades turn right and the blade offset to the tail is to the right causing the blades to turn right to the wind.  This is opposit to what you like, or am I mixed up?
Thanks
gww

gizmo

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Re: counter clockwise turning blades
« Reply #6 on: September 02, 2014, 11:52:25 PM »
I will say if you have more than one windmill side by side, keep them all rotating in the same direction. Turbines rotating in different directions looks real weird!

frackers

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Re: counter clockwise turning blades
« Reply #7 on: September 03, 2014, 12:30:22 AM »
Beware gyroscopic precession http://en.wikipedia.org/wiki/Precession or at least use it to your advantage.

Using the naming convention in the wiki article, make sure your spinning direction (blades) and rotation (yaw of the generator head when it pushes out of the wind) doesn't result in pitching that lifts the whole generator off the yaw bearing.

That happened to me about 3-4 years ago and for the new blades I reversed the pitch to reverse the direction and no problems even in extreme conditions (a few weeks ago the mill, 10 footer, hit 560+rpm which puts the tip speed at about 320km/hr - call it 200mph!!).



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Frank S

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Re: counter clockwise turning blades
« Reply #8 on: September 03, 2014, 12:31:43 AM »
I will say if you have more than one windmill side by side, keep them all rotating in the same direction. Turbines rotating in different directions looks real weird!

Just don't look up let em confuse the neighbors
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jarbar

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Re: counter clockwise turning blades
« Reply #9 on: September 03, 2014, 02:04:08 AM »
Precession of blades can be demonstrated by spinning up a bicycle wheel between two hands and then supporting one end of the axle.Gyroscopic force will hold it upright and it will precess either to the left or right depending on direction of rotation.This will give a better indication of forces involved on your windmill.Trying to change it's plane of rotation is difficult, I attempted to to simulate vertical furling which has wheel flaring up and to one side in a figure eight pattern. ;D

Jarbar

gww

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Re: counter clockwise turning blades
« Reply #10 on: September 03, 2014, 08:15:23 AM »
Ok
I have survived some really hard winds wirh the eight foot blades, as they are, so I am going to try the nine foot ones the same way, ie; clock wise.  Thanks for all the responces.
gww.