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Forum Index : Windmills : Vane Weight

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Bobden
Newbie

Joined: 11/05/2009
Location: United Kingdom
Posts: 5
Posted: 07:49pm 05 Feb 2011
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Hi all I am building a self furling wind turbine all going well. Have tried to calculate the weight for the vane to furl at 10 ms ( 22 mph ). The answers I get are ridiculous and obviously wrong. Can you help me out, the info for my turbine are

Blade diam .62mm

Head off set .05mm

tail length .6mm

Furling speed 10ms (22mph)

Vain area .1134 sq m

Pivot angle 20 deg

Any help would be great full as it driving me mad. I must be doing the same mistake each time.
Regards Bob
 
Greenbelt

Guru

Joined: 11/01/2009
Location: United States
Posts: 566
Posted: 05:52am 06 Feb 2011
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Have some confidence, It'l come to ya.
Time has proven that I am blind to the Obvious, some of the above may be True?
 
fillm

Guru

Joined: 10/02/2007
Location: Australia
Posts: 730
Posted: 09:24am 06 Feb 2011
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Bob,

By the dimensions you have quoted, this turbine would almost fit onto a match head .
Hope you are not expecting a lot of power from it .
PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits
 
Bobden
Newbie

Joined: 11/05/2009
Location: United Kingdom
Posts: 5
Posted: 10:34am 06 Feb 2011
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Phill
Thanks already I have quoted the blade radius, the blade diameter should be 1.24m.
Bob
 
Greenbelt

Guru

Joined: 11/01/2009
Location: United States
Posts: 566
Posted: 07:10pm 06 Feb 2011
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Hi Bob;

You have several mistakes on your post or it may be a joke in poor taste.
I will assume that you do not have the (Metrics)and decimals figgered out. I have a
Neighbor friend who is a good mechanic but he has a problem (Dyslectic from birth) keeping his numbers in order.

Review of your post.
Item # 1, Blade diameter .62mm. (when reading this, It says dia. is slightly more than one half of one millimeter. This is the size of a sewing needle, rather small for a turbine. On your second post you have given a diameter of 1.24 meter which is reasonable to discuss but still a bit small for the average. There is 1000 Millimeters in 1 meter, So your blade has a diameter of one thousand two hundred and forty mm.

Item#2
Head offset,.05 mm. This is smaller than the bearing clearance in an engine, even
(.5 mm) one half a millimeter is way too little for an offset. But .05 meter would probably be a working number, 50 mm., Philm could tell you better than I.
Item # 3
Tail Length, .6mm. again very small, .6 meter, (.6m )not mm. is close to the size you would need for your small turbine. .6 meter is 600mm.

Item # 4
Furling speed you have spot on numbers.




Time has proven that I am blind to the Obvious, some of the above may be True?
 
Bobden
Newbie

Joined: 11/05/2009
Location: United Kingdom
Posts: 5
Posted: 08:09pm 06 Feb 2011
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Hi Greenbelt thanks for the input, first its a joke then I am dyslectic. Yes I made a mistake but it is plainly obvious I meant meters or part of a meter. Just to let you know I have figured it out without your help, but then my turbine is small on average so not worth bothering with. Still thanks for making up my mind that I will never ask for help again, thanks to sanctimonious armchair experts like you!!!

Bob
 
Greenbelt

Guru

Joined: 11/01/2009
Location: United States
Posts: 566
Posted: 10:12pm 06 Feb 2011
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Hi bob,
OK.Edited by Greenbelt 2011-02-08
Time has proven that I am blind to the Obvious, some of the above may be True?
 
brucedownunder2
Guru

Joined: 14/09/2005
Location: Australia
Posts: 1548
Posted: 10:22pm 06 Feb 2011
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You'll be OK ,Bobden. Just hang in there ..

We are a strange mob over this way ,sort of take the mickey out of anything..

keep talking and asking questions

Bruce
Bushboy
 
Greenbelt

Guru

Joined: 11/01/2009
Location: United States
Posts: 566
Posted: 08:06pm 07 Feb 2011
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Hi Bob
I must apologize for the remarks in my previous post, After reading it over it does have a snotty sounding attitude.It was not intentional. the intent was to point out the importance of posting correct information so that a meaningful answer can be provided. I admit to being suspicious of whether your post was a real request for assistance or a prank. There are many people who get their cookies by logging on a web site and post something to generate friction.
Good luck on your project. Regards, Roe
Time has proven that I am blind to the Obvious, some of the above may be True?
 
VK4AYQ
Guru

Joined: 02/12/2009
Location: Australia
Posts: 2539
Posted: 01:32pm 08 Feb 2011
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Hi All

Confusion caused by an extra m.

Hi Bobden

We all should laugh at our mistakes, I have a similar problem with metric, being brought up on the imperial system, remember if we can't laugh at ourselves then somebody else will do it for us.

All the best

BobEdited by VK4AYQ 2011-02-09
Foolin Around
 
MacGyver

Guru

Joined: 12/05/2009
Location: United States
Posts: 1329
Posted: 05:36pm 08 Feb 2011
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Bobden

Assuming you're still around, I too build "toys" (read that "rather small stuff") and I as well have taken a lot of "pot shots" from the crew here; it happens. Just grin and bear it.

I plugged your diameter of 1.24 meters into Alton's Calculator and you can expect nearly 100 watts at an rpm of around 800 or 900 if your windmill is coupled to a working generator. At that rpm, furling is not so much a problem, but if you wish to make it do so, simply build a post at around 45* opposite to the side the alternator (generator) is mounted, so they are each on a side opposite the yaw point. That means the generator is on one side and the tail is on the opposite side.

The tail will "hinge" about the post; just make it a few feet (a meter) long and try it out. Be sure to put a "stop" so if the thing furls it doesn't wipe out your blades altogether. The tail should furl towards the side the generator is mounted. I saw a post on Youtube where the guy made the post angle so steep, the tail actually furls "above" the blade path, so he didn't need a stop, but most folks use a stop and let the tail furl within the region of the blade plane.

I've found that trial and error is a very valuable tool. Try it for yourself and when you come up with a winner, post your results on the 4m for others who will surely follow.


. . . . . Mac
Nothing difficult is ever easy!
Perhaps better stated in the words of Morgan Freeman,
"Where there is no struggle, there is no progress!"
Copeville, Texas
 
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