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Forum Index : Windmills : My special delivery from China
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5119 |
Hi guys. Well they have arived, my sample PVC blades. Cant wait for the weekend 
These will soon be available for purchase at a very good price compared to other options. They should be cheaper than those extruded fibreglass blades, and if your timber challenged like me, a lot easier to put together. Each lengh is 3 meters and weighs 4kg. Chord is 160mm Exciting stuff. Glenn 
The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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fillm Guru  Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Looks promising Glenn , has a price been set yet ? ...Will be interesting to see the hub arrangement you design and their performance , do you require your piclog back ? PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5119 |
Hey Phill. No price set yet, but the idea is they will be too cheap to not consider, even for the hard core timber blade fans. I forgot about the Piclog. Only if your finished with it, I can put another one together if I need to. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Janne Senior Member  Joined: 20/06/2008 Location: FinlandPosts: 121 |
Wow those pvc blades look scary be interesting to see how they will perform.If at first you don't succeed, try again. My projects |
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SparWeb Senior Member Joined: 17/04/2008 Location: CanadaPosts: 196 |
Those look really nice.  I almost want a set for myself! (No I'm too far away in Canada)
Do I see a closed cell in the trailing edge? That will help torsional stiffness. The biggest part of the torsional stiffness will still be the tube down the center and the end caps. Very ambitious, adding a "plate" to the tip's end cap. I hope you have lots of spares because it will take a lot of testing to prove what works and by how much. Here's some research on winglets and tip effects that I keep in my back pocket when this subject comes up: Martin Hepperle LTRS The second link is to the Langley flight research technical reports. It's an enormous resource - so you could quickly drown in numbers. Obviously it's a topic that's been analyzed to death. Here's one that's readable: KC-135 Winglet Tests So the graphs of interest are the CD versus CL which determine output power and Cp when embodied in a windmill. Steven T. Fahey |
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divemaster1963 Regular Member  Joined: 28/01/2009 Location: United StatesPosts: 46 |
wow they look good. hope they will be availbe in the us. if not hope you can look for a distributor. 
john |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5119 |
Hi John Yes they will be available in the USA, even cheaper with the low Australian dollar. I'm going to fit a set to my dual stator windmill this weekend, 2.6m diameter. Standard 1 inch exhaust tube will fit up the middle of these blades, and for the first 400mm from center ( most stressed part of the blade ) I'll slide in a length of 22mm steel rod. The 22mm rod is a neat fit inside the exhaust tube. I'll buy these today and post some pics as it comes together. Will keep an eye on the weight as I go. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| domwild Guru Joined: 16/12/2005 Location: AustraliaPosts: 873 |
Great, Glenn! Now forget your job, drinking and eating and leave your wife and children so you can do lots of testing of the new blades! Hub mounting of a formerly available extruded alu prop: The pipe of each prop was bolted via two U-bolts directly to the hub. This allowed altering of the angle-of-attack. Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up. Winston Churchill |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5119 |
Just what I was planning Dom. I'm going to use the hub I made for testing the Chinese fibreglass blades. 
Makes it easy to change angle, though I think I would prefer a 3rd U-bolt for each blade. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Glenn, keep an eye on the weight. Low inertia is hard to beat. My wooden blades weigh 600g each. The amount of steel and the adapters needed for the PVC ones will add up. UV protection with a decent thickness of UV block paint will add more again. I hope you can keep the weight below 1.5kg per blade. Gordon. PS edit : 3m for 4kg! you may be looking at up to 2kg per blade. become more energy aware |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5119 |
I agree a low inertia turbine with give a small gain in a gusty location, but thats not what I wanted. My timber blades weigh 1.2kg each, my PVC blades on the 2.6m turbine were 2.3kg each, and I had 6 of those! My Southern Cross windmill has a dozen steel blades, the whole turbine would be over 25kg. All these turbines worked perfectly well for me. I could replace all the steel blades on my Southern Cross windmill with hand made carbon fible blades, save 10 or more kg in weight, and maybe it would pump a few more liters per day, but does that mean I should abandon the Southern Cross windmill just because its got a heavy turbine? No, because what it has works perfectly well. Yes if I spend the time I could make a lightweight blade, but that is not what these blades were designed to do. Remember these blades were meant to be cheap, cut to length and easy to put together. We used the same profile the Windcharged turbines have used for many years, see http://www.royalfabrication.com/. The PVC used already has a good UV resistance ( I would need to contact Wes to check the exact ratings ), but yes your would still need to paint them, PVC white isn't a pretty colour. I could have a high performance lightweight blade made, using fibreglass or carbon fibre, in a range of lengths and TSR's. But it would cost you many times what these PVC blades are worth, and you couldn't experiment with them. These are blades for the people. If you want the best, then dont buy these, go and make your own. But if you just want a turbine thats a little heavier, a lot cheaper and easier to make, and has 80% or better of the performance, then these are a good choice. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
Glen, These blades seem to lend themselves to being perfect to experiment with the Jacobs pitch control... ready made for it in fact. The 1" exhaust with the 22mm down the middle for the root area, is just perfect for the beginnings of the Jacobs pitch system..... I'm starting to feel some pangs of experiment coming on 
........oztules something like this (stolen from Ronb's files) If you could con Trev into fabricating the triangle yolk, we may finally have a simple effective pitch control system for the man in the street. Village idiot...or... just another hack out of his depth |
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| SparWeb Senior Member Joined: 17/04/2008 Location: CanadaPosts: 196 |
Oztules, Here's a pitch control mechanism you might want to see: Laurie Forbes - Fieldlines posting I went to see it myself - it's remarkably simple. Steven T. Fahey |
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DaViD Senior Member Joined: 14/01/2009 Location: United StatesPosts: 120 |
That's some nice looking looking blades you have there Glenn. Hope they work as well as the look. If your not living on the edge your taking up to much space! |
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imsmooth Senior Member Joined: 07/02/2008 Location: United StatesPosts: 214 |
What are the size of your timber blades? Mine are 5' 2" and they are 10.5" wide at the root. They are 2.5" deep and coated with epoxy. They each weigh 3.5kg, which I thought was light until I saw you say yours are 1.2kg. |
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| oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
Thanks Sparweb. Given that the heart of both systems is the triangular synchronizing spider which has to twist and "rise" at the same time, then the only difference is how to generate the input/output variables. I think three big outside springs to pull the blades back in (jacobs) looks more reliable than the little single turn ones to rotate the blades back in. Using the blades for the weights is less bits, and these blades of Glens have the "line bored" holes up the center already... most of the problems solved at this point. Line boring wooden ones for any distance seems problematic for me. So with Glens blades, and the spider being required for both builds, the Jacobs wins hands down for simplicity... Spider, hollowed out blades to rotate around the center spar, and 3 big springs to return it and so by default be the safety part as well. So I think the Jacobs in this case.... purely because the blades seem to be made for this type of thing... and simplicity. I know it may be hard for some to visualize how the jacobs works....mainly the synchro spider part.. but once understood, it can be equated to trying to imagine the gravity furling on the normal mills... ikky till you actually see it in real life. ..........oztules Village idiot...or... just another hack out of his depth |
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| Jarbar Senior Member Joined: 03/02/2008 Location: AustraliaPosts: 225 |
It occurred to me that the blade could be allowed to rotate around the inserted shaft,with a limiting stop arrangement near the hub.At low rotational speeds the blade would rotate/twist back giving more torque maybe with a spring assist but as it gains rotational speed the blade would be self feathering.And find its optimal angle just by virtue of its own aerodynamics.Constantly self modulating relative to speed and wind pressure.If the PVC proved to be inadequate as a bearing surface against the shaft some glacier bushes could be inserted and the next shaft size down used preferably stainless steel diameter 22mm. Anthony "Creativity is detirmined by the way you hold your tounge".My Father "Your generation will have to correct the problems made by mine".My Grandfather. |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5119 |
The 1 inch exhaust pipe is a standard size and has an internal diameter of 22.2mm. The 22mm rod is a neat fit, with a little grease it should work fine as a bearing in this application. A grease nipple could be soldered to the outer pipe and pumped full of grease every couple of years. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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niall1 Senior Member Joined: 20/11/2008 Location: IrelandPosts: 331 |
mmmm... first there was f&p motors .... know interesting props for the masses....... maybe this is our last chance to beat the wallabies aNd the all blacks before it,s too late....... niall |
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| Janne Senior Member Joined: 20/06/2008 Location: FinlandPosts: 121 |
Glenn, I suspect that any kind of bearing that has any kind of play on it won't last long as a pitch control blade bearing, because of the constantly shifting loading. It would be interesting to know how that windmill with pillow blocks as blade bearings is doing.. I suspect it might have failed by now.. We used to have a pitch control in the larger mill with 80/140/35mm tapered rollers on blade shafts. They lasted a little over a year before they were worn to craters, and thus jammed into position. The trouble with using roller or ball bearings in the blades is that the blades spend most of the time in the same (full power) position making them prone to failing. If at first you don't succeed, try again. My projects |
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