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Forum Index : Windmills : Ebay Gullwing Blades.
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paul_mac1 Regular Member  Joined: 17/05/2010 Location: AustraliaPosts: 74 |
Has anyone bought any of these bladesfrom the UK? Just wondering if these are any good, as every company says theirs are the best 
These eliminate cascade failure at high speed apparently, but was wondering if they have the torque to get a fairly large motor going, the video in the ad shows a small motor spinning in light winds. What are your thoughts? Regards, Paul |
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| VK4AYQ Guru  Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Paul I haven't tried these blade so a suck it and see approach is in order, however looking at the flat plate construction and the small diameter of the blades makes me question the efficiency of the blades to pull a heavy load also the flat plate construction isn't the most efficient aerodynamic blade and tends to concentrate stresses in the blade at the mounting bolts and may cause fatigue, I have been trialing a few types of high speed blades and found that they don't match their advertised specifications. If you are in a high average wind area above 19 ms small diameter blade may be OK but in my experience they will start up OK but hit a wall when the alternator comes on line, not enough torque. I have tried from 56 inch to 124 inch blades on my test alternator and so far have found that big is best. All the best Bob Foolin Around |
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| paul_mac1 Regular Member Joined: 17/05/2010 Location: AustraliaPosts: 74 |
Thanks Bob. I think I'll go with my original plan. Regards, Paul |
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| dwyer Guru Joined: 19/09/2005 Location: AustraliaPosts: 574 |
HI Paul I have see this before and thinking making some for myself as Tev's Blades which l have got now is very hard to start with medium wind blowing but the higher wind blowing is good and keep spinning at low speed until wind die and same over again as l also thinking by add something like gull wing on tip of blades might help to start at low speed easier  what you think if l go ahead with this modification. ??? 
regard Dwyer |
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| paul_mac1 Regular Member Joined: 17/05/2010 Location: AustraliaPosts: 74 |
Hi Dwyer, I have no experience with these blades, sorry, thats why I put a question on here. Im sure someone will give you some guidance on this issue tho, don't despair. Regards, Paul |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5124 |
Hi Paul I dont like the look of them, I would be afraid of them failing in high wind and throwing a blade. Sheet aluminium is weak and they will fail at the bolt holes. Sheet metal blades can also be noisy. But, you dont know until you try. They could perform as well as the seller is advertising. You might want to look at their previous sales and see if you can contact a buyer for some feedback. Dont expect much over 100 watts from that diameter. I have no idea what a CASCADE FAILURE is? Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| paul_mac1 Regular Member Joined: 17/05/2010 Location: AustraliaPosts: 74 |
Hi Glenn, From what Ive read, a cascade failure is when the blades lose power when the wind is too strong, with these blades, they just keep getting faster, as fast as the wind can make them go......if that makes sense to you, sorry, its the best I can explain it
Regards, Paul |
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| paul_mac1 Regular Member Joined: 17/05/2010 Location: AustraliaPosts: 74 |
Ok, Ive gone with the Windy Nation 5 Blade Hyperspin System. Regards, Paul |
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| dwyer Guru Joined: 19/09/2005 Location: AustraliaPosts: 574 |
Hi Glen As your say "I don’t like the look of them, I would be afraid of them failing in high wind and throwing a blade" As I don’t think so look at older motor vehicle metal fan use for radiator cooling, industrial fans, windmill ,wind turbine, grain silo are all mostly made of metal and lot of them use aluminium as blades as they rareing fail and look at feedback as seller have sold many blades over couple of years without withdrawing if complaining is lodge by the buyer is made then he have to pull out of the market because safety reason 
dwyer |
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Perry Senior Member  Joined: 19/11/2009 Location: Posts: 190 |
When I hear the term cascade failure I think of one blade failing then hitting the next and so on ad so forth. It's a term they probably shouldn't use if they mean it in other terms. By the looks of them the winglet portions looks to be cosmetic in nature. I thiunk people will try to bend up an interesting shape and claim it works better without pointing an eye towards test data. No mention of Cp or TSR.etc. all the things you really need to know about a blade to estimate it's performance. Basically they are just angles slats so I wouldn't expect much in the high speed catagory. Perry |
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| dwyer Guru Joined: 19/09/2005 Location: AustraliaPosts: 574 |
Hi Perry l think you are correct as many are try selling cosmetic blades with out mention of Cp or TSR including performance data  and many of hobby windmill don’t do the math or understanding the math or theory is the problem but it not always their faults but trying enjoy their wind mills toys by encourage themselves to have some fun by learning and making the mill these days “That life “
Dwyer |
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