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Forum Index : Windmills : Furling
| Author | Message | ||||
| Ringo99 Newbie  Joined: 11/11/2013 Location: IrelandPosts: 3 |
Hi I need help understanding furling, Where does 20KG come from and is the offset always 100 mm Ringo99 |
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MacGyver Guru  Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Ringo99 Welcome to the 4m. For starters, a little more background information might be needed here to answer your specific question. Here's a link on Furling, which may be a good place to start your understanding of the topic. Back in the day, I thought I knew how it worked, but after reading this link, I found there is much, much more to it than one might think. Best wishes on your projects. . . . . . 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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| Ringo99 Newbie Joined: 11/11/2013 Location: IrelandPosts: 3 |
Thanks Mac. I am working on the Furling equation and it states mast offset = 100 mm, Is it always 100 mm, Furl resistance = tail weight X sin20 X sin 45 tail weight = 20Kg X sin20 x sin 45 Where does the 20kg come from, Has it got to do with 20 meters per second. Help much appreciated. Regards Ringo99 |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Ringo99 Wish I could help you out there, but I'm a 'trial-and-error' type of backshedsman. I just try stuff and if it works, it's a feather in my cap. If it doesn't work, it was a fun project and I'm on to the next one. Many of us here do this stuff for fun; merely a hobby. Others are dead serious and they would be better able to help you out with the maths. Downwind, VK4AYQ or Gizmo would be your best bet here, if they have the time and understand your question; I specifically, do not (understand that is). . . . . . 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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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Furling is one of the hardest area's of DIY windmill construction to get right without on site trial and error testing. Fact is you can apply all the maths and science, and still end up with a result totally unexpected. There are two options. Either use a design that's been built by others and proven itself, or build some adjustment into your windmill so you can make adjustments to get it working correctly. Pre-existing designs, like those of Hugh Piggott ( http://www.scoraigwind.com/ work well, but I bet took lots of trial and error to get right in the first place. If you follow his design, it should furl as expected. For a new design, your best bet is to include ways to adjust the pivot angle, both back and to the side, and include ways to change the weight of the tail. Sorry, but there is no simple answer to furling. You can use the page on furling as a guide, but don't rely on it. No the 100mm is not set, its just an example. The 20kg was the weight of the tail and boom, again, an example only. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Ringo99 Newbie Joined: 11/11/2013 Location: IrelandPosts: 3 |
Thanks Mac , I too am in it for the challenge and fun but trying to get my head around furling. Regards Ringo99 |
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| Air Bender Senior Member  Joined: 25/01/2011 Location: AustraliaPosts: 206 |
Hi Ringo99 I built a small furling mill a while back, I scaled down Hugh's offset. I done this by taking the diameter of his blades and working out the fraction difference between his and mine, and then altered the offset by this fraction. The same thing was done with the tail weight, but I built my tail a bit lighter, easy to add weight later. The pivot angles I did not alter from Hugh's design. My mill furled spot on first time. I think it is a good idea to build the tail light so it should furl sooner than later, it is easy to add weight if it furls too soon. All the best Dean. |
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