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Forum Index : Windmills : Blade angles
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JimBo911 Senior Member  Joined: 26/03/2009 Location: United StatesPosts: 262 |
I would definitly have to agree with Shawn. Build something smaller/cheaper let the wind beat it up for awhile keep a close eye on it make the necessary design changes then watch again in time your design will evolve and that will put in a much better place when it's time to go full size. As far as furling goes with the ALU blades that Phill sells here I have my system working just fine it furls when and how I want it to. I slow and made changes untill I found the sweet spot. It's a matter of matching all the components. Most importantly make sure you can stop or control your mill when storms move it or it will just be a matter of time before mother nature rips your mill off it prich. Jim |
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Rastus Guru  Joined: 29/10/2010 Location: AustraliaPosts: 301 |
Hi Shawn, Until recently I hadn't considered timber blades,not because they are old fashioned,more out of convenience.Buying alluminium blades of the shelf is pretty straight forward.However I'll learn more about timber blades before I fully commit myself,they could have advantages that outweigh convenience.Seeing as you advise to start small,(and "Jim" agrees)would a dual F&P with 3mt swept area fit into that category?Or do you consider small by the hieght the mill is raised as well?I've purchased the motors,and I'm progressively selecting options to include in final plans!!! before I start/complete the project.One definate feature is I'm going to exstend the spline along the shaft and not drill out or bore the rotor centre.I'll post pics of that when done and I'll try following the pic post thread.Another definate is I'll copy your mill set up to safely adjust furling.There aren't a lot of definates so far, but a lot of learning has happened along the way,and plenty more ahead I'm sure!Thanks to you and Jim for the latest post. cheers Rastus see Rastus graduate advise generously |
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fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Hi Shawn & Rastus, Firstly with regards to blades , it can depend on the wind resource you have available , I would think in Shawns location you could put 3 cricket bats onto a generator and it would make power. But if you live in a location that has light wind with the occasional storm and a few wind events per year, then 95% of the time you are chasing every watt you can get . Shawn, you have linked the Alu blades with the fact that they burn out stators because they are to powerfull. I would think that this is a strong point in their favour that they can, and the design must be respected for the power that they can deliver. If you do not get your furling right or do not have other controlls in place, then of course you can extract to much power from the wind, which, pretty well can be said about most blades in 15m/s+ if your alternator can be overdriven by the swept area. In my opinion having a set of proven well designed proper airfoils up in the wind from 2 - 5m/s that are making power for the 95% then that is a winner. Jimbo and myself have had our share of failures at the hands of mother nature, gaining controll for the other 5% and finding your furling sweet spot is where it is all at, to date I have no confidence in any mathmatical equasion for furling as the variables of RPM , Blade size, Blade Weight, blade protrusion from yaw , tail pivot from yaw ,Pivot friction, Tail design, and probably a few others, all come into play and tweeking your furling by trial and error is the only way. I would also think that you would point out that timber blades have troubles as well, on Hugh Piggot type Ax Fx mills such as the one you are building, have also suffered the same fate with over heating stators and catching on fire in big storms, as well as breaking and throwing blades, which obviously comes back to controll, as with any type of blade, be it, Wood , Aluminium, Steel, PVC etc. The other thing to consider is the maintainence on timber but all in all I think they do look good when you have a well built varnished set. I would also think that getting 3 matched blades is difficult as would getting a proper airfoil, is flat one side and curved the other an efficient airfoil or just easy to build? Rastus, If you go back over some of my early F&P Dual build pictures from a few years back you will see the variable offset arm mounting the dual head that I developed and others have copied over the years. It does work OK but you also need to get your furl angles right . If you think you need a spline on the front stator so the rotor will not slip, it is an over kill. The 250w ~ 350W max of torque force is nothing that the front stator will deliver, basicly a firm fit and loctite 608 is all you need, the spline will weaken the shaft considerably and if you are going to mount a 3m rotor on it I would recomend leave it at 25mm . But apart from all that if your blades do not transfer wind energy to power through lift and drag then you will be at a loss like I was with all the time I spent on my ABS pipe blades, watching a windmill sit still in winds under 4m/s, hence my counter rotating bump start blade hub from the early days. LINK HERE if you would like to have a look , the yaw and all the stuff is laying arround if you are interested PM or email me . Centrifugal Force is your Enemy, Strength & Balance is your friend. PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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shawn Senior Member Joined: 30/03/2010 Location: New ZealandPosts: 210 |
Rastus buld the best and highest tower you can afford/get away with as this will be a keeper!! As for the blades your choice to make the wind you have, the money you have, the time you have, will help you decide. F&p duals in my mind make a great first mill. But the furling will be your (only) control you canot shut them down in a good wind unless you take the tail off or tilt the tower down both i do not recomend in any sort of wind!! It is a fun journey good luck. |
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| udsn Newbie  Joined: 15/12/2010 Location: JordanPosts: 9 |
Dear All , thank you - Rastus & Oscar4u Dear Fillm where did you get the industrial fan hub -head? As some one has advised me to start a thread just for 5 to 10 Kwatt windmill system I will. But for now I will share pics of a feathering system since this thread is about blade angles general idea, welcome notes. I hope its ok to post so many pics Best regards 
want real scince |
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| Rastus Guru Joined: 29/10/2010 Location: AustraliaPosts: 301 |
Hi Pill M, Both you and Shawn tend to agree that the power of the GEO blades can be a blessing and a curse,they can start in low wind speed and potentially do damage in hiegher winds.Your head design is a great innovation,setting furling right seems way out there?I'm not particularly happy with the balance of F&P heads and feel an additional bearing between the hub and rotor will improve it,Providing any blades additional support.Apparently smart drive rotors aren't balanced,but does't become a problem until 600+rpm.To minnimise runout it's easier for me to exstend the spline.Using a brake is still on the drawing board.Thankyou for these and other valid points you raised. Hi Shawn, I realised to late the swept area isn't 3mt,rather diameter of swept circumference is.I agree with you about the tower and have settled on engineered plans for a 19mt lattice tower due to site factors.While the tower is both climable and raise/lowerable I dont want to do either vary often.A well made,set-up mill from the get-go would be ideal but seems more and more unlikely with current norms.So I'm posting threads to evaluate other possible options eg pitch angles,brakes and multiple mill location.Thanks again for exspanding the possibilities. Hi udsn, The pictures are great and right on the subject that has been raised.Also the quality and details they provide are first rate.Each of the feathering methods you have illustrated seem to require a horizontal (forward/reverse) movement to operate.Do you propose to supply this with a governor, an electric solonoid or other device?Thankyou for your efforts, Best wishes to all,Rastus see Rastus graduate advise generously |
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| udsn Newbie Joined: 15/12/2010 Location: JordanPosts: 9 |
Well thank you all again. I preferred the horizontal system as you have noticed because 1- I won’t have to worry about wiring going into and out of the Rotor/hub. 2- One thrust bearing at the tip of the controlling rod that goes through the inside of the main Axel Tube to control the Main blade pitch controller micro hub , I can put any system I want electrical or mechanical to push pull the control rod. 3- Also seen this very nice pitch control system which I thought is fast. And I can sense it if I wanted. And I don’t have to do the calculations of centrifugal forces,also if the RPM goes too high micro controler stops the main rotor , ues i do intend to put a braking system, not to mention the small extra weight of teh balls, also one can do an optimal angle verses RPM control along side wind speed via the controller chip via algorithms. windmill blade pitch control Even though Rutus or Oscar pointed out for me that mechanical is NOT high maintenance as electrical or stepper motor control. What do you all think? I tend to agree with them both. My first intention is small electrical motor just like the video, which some one nice has donated three hand held Drills that are geared and clutched and work on 18Votls. All I need is an enclosed sensor/potentiometer (we dont have them here) and some one nice or crazy enough to do the PIC for me for FREE. 
That doesn’t mean I will not use pure mechanical I keep my options open. Hope to hear from you all. want real scince |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi All I am using the 222 blades from phill and have nothing but praise for them, they generate torque from 2 MS up and using a boost module I have been able to harness this low speed energy. It's my my firm conviction that it is better to get the furling set up right rather than trying a feathering hub for your first wind turbine. The design of the blades causes them to become less efficient at high speeds and this is an advantage as they are less inclined to run away in high winds, my mill survived a unloaded event in 40 + MS winds last week when a cheap amp meter couldn't take the overload, it was pegged out and I think that the mill delivered around 100 amps for a bit until the composite shunt blew to bits. No damage to the mill as the furling saved its bacon. If you must go for feathering then forget the electronics and little drill motors because they will not be reliable in the longer term and to try and control with a microprocessor in a thunder storm isn't going to last long unless it is put together with a fool proof failsafe redundant feather mode. You can use a centrifical weight system to actuate the feathering, it is easier to do with simple tools. You will spend more time trying to keep the electronics going than its worth, wind turbines live in a harsh environment. I had a look at the u tube video and to be honest the action is far to slow he was saying 8 seconds, in that time a mill can run away in gusts as 8 seconds is a long time in some circumstances. All the best Bob Foolin Around |
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Oscar4u Regular Member  Joined: 23/02/2011 Location: New ZealandPosts: 42 |
Hello Everybody if one puts stops on the mechanical govenor it should make it easier to get it right. I think that design of UDSN needs a slide because the linkages will jam I suspect. In the last week through reading this site I learnt about self furling tails. If I do mine like that it will have a rope or lever to pull it square to the blades. Someone was mentioning a 19m tower. My waterpumping mill is a 6m high A frame tower. The top of it has a bit of 50mm pipe on it vertical in which I slip a 40mm pipe with a bend. From this I hang a rope four to one block so that I can pull the head and blades up. Works really well. Cheers Oscar Oscar4u - for all your rotary cowshed repairs |
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| Rastus Guru Joined: 29/10/2010 Location: AustraliaPosts: 301 |
Hi Bob, Your post has practical value for those of us with little or no mill exsperience,and adventurous ideas.The details of the gail/storm survival of your mill are impressive!Are the angles and tail calculations on the home page for F&P mills reliable, or has exsperience lead you to other considerations to get furling right?From a practicle position I totally agree with your estimation of the drives and controls udsn is proposing,they will prove inadequate in service,and the destructive "window" comes down to milli seconds when criticle pionts are reached. Hi udsn, With your limited resources its only logical to use as much as you have readily available.Sadly though a mechanical govenor coud prove cheaper and more reliable in your application.I'm not familiar with large storm events in Jordan.Do you exsperience more thunder/flood storms, dryer/dust storms or mainly gail force winds?Knowing this will influence replies to be more specific to your needs. Hi Oscar4U, You are spot on, a jib or lifting attachment at the top of structures can be put to many uses.Thanks Best wishes to all Rastus see Rastus graduate advise generously |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi All Furling is a mill specific type operation, if you build a mill that is exactly the same as the one the figures where calculated on you could be in the ball park, however we seldom follow the leader and tend to incorporate our own ideas into our personal mill. Blade type has a lot to do with it as different blades react differently at speed and power loading, not to mention the diameter of the blades and the weight of the blade hub assembly. Lots of variabilities. My new mill was a store bought mill from Phillm, so was already set up for its configuration, but me in all my wisdom Dooh, decided to increase blade diameter for my average low wind conditions, and that was the end of the furling. Phill suggested a modification of furl angles to 5 deg lay back and 10 degrees to the side, this I did and after cut and weld of the mounting I ended up with 5 and 9 degrees, I also put a larger tale vane on to stop the will wandering around so much in turbulent conditions. all in all it has made a usable furl action, however the mill can still put out double the proposed amps in short bursts as it goes in and out of furl, resulting in blowing the amp meter the boost module and the GTI, all easily replaceable thank goodness and the mill sustained no structural or electrical damage. I have not used a F&P mill myself, but if you follow the lead to the letter of those that have I am sure that the furling as presented will be somewhere near the mark. The center line offset for rotation is critical as is the weight of the blades with its corresponding dynamic gyroscopic forces, also the tail vane size is important as to small tail vane cant generate the forces to furl properly on the small moment arm of the furling mechanism Also the hight of the vane is important to get the vans out of the dead air at the center of rotation. I am making a adjustable furling pivot to make it easier to modify furling, rather than the cut and shut method I have been using, when the heat drops off a bit so I can work in the workshop, I will post details on the forum for all. All the best Bob Foolin Around |
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| udsn Newbie Joined: 15/12/2010 Location: JordanPosts: 9 |
Dear all thank you for the reply. I truly appreciate the input. Oscar I think that design of UDSN needs a slide because the linkages will jam I suspect I will draw the slid to see if we are talking about the same thing slide wise. Rastus With your limited resources its only logical to use as much as you have readily available. Well I want to make the windmill any where from 5 to 10 kwatts if I can , The gen set is around 300 US dollars.(they tell me) and it’s a normal gasoline gen set - to take apart. The inverters is around 2k dollars for 5 kwatts and arroun 4 to 5 k dollars for a 10kwatts. if not more. So the price for the PIC is nothing including the programmers work compared to those numbers. Rastus Sadly though a mechanical governor could prove cheaper and more reliable in your application. I agree, totally. The problem I face with governor is I don’t know how to make it, (will draw from Oscars pics and psot ) and most importantly how to calculate it especially that I am un able to estate the wind speed or the final RPM of the windmill rotor. so no way to even get a ball park figur if the size or the length of the rods for the governer. Rastus I'm not familiar with large storm events in Jordan. There are none, maybe some very rare occasions mostly sunny. Rasus Do you experience more thunder/flood storms, dryer/dust storms or mainly Gail force winds? Knowing this will influence replies to be more specific to your needs. I would say mostly calm slow rarely Gail winds. I would consider building the gen set with magnets and stuff , but not enough numbers and i dont think the magnets are sold here. I just want to get rid off those blades invested a lot of money for something that is not selling. I will tray to post the pics of governer and the slding arm . have to get back to work hope to hear from you soon want real scince |
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| Rastus Guru Joined: 29/10/2010 Location: AustraliaPosts: 301 |
Hi Bob, Thankyou for the additional account of your mill and the successfull changes you made.Your summary of how individual furling is for each mill enlightened me further.I'll be keenly interested in your future developements and posts. Hi udsn, My comment about available resources was directed more at things that can easily be obtained locally,sorry for the wrong impression!The gen set being suitable for a fuel engine can provide an operating RPM range to produce 5-10kwatts of power.The horse power or KW's of the engine will provide a guide to the wind power needed to drive it.Details about the wind conditions in your area may be on the internet.Using info on this sites home page, and including the previously obtained statistics ,you will have a general estimation of your project.Due to the outlay for your project and to safeguard these costly components,I would ask for help with the design of a mechanical governor once you have some or the above info.It is possible that a commercial product will prove suitable and save you the troudle of making it.I hope these suggestions are helpfull.The amount of available wind in your desciption is of concern.It is the sole driving factor for a mill!!! All the best Bob and udsn,Rastus see Rastus graduate advise generously |
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| Rastus Guru Joined: 29/10/2010 Location: AustraliaPosts: 301 |
Hi to all, I feel I've overlooked some important details from VK4AYQ/Bob,the 222 blade performance.They aren't as efficient in high wind conditions and don't easily run away!These blades may not have a profile that suites feathering at all,putting there performance into unknown territory?"Please advise" The reason for feathering is to limit mill rpm which the 222 blade seems to inherintly do,although that limit has been outside of some F&P DIY builds,leaving furling as a necessary "evil/good". cheers Rastus see Rastus graduate advise generously |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Rastus The 222 blades run slower in a given high speed wind event compared to the high speed airfoil section I have on my other mill but they also produce much more torque at speed, and can still run away if not loaded sufficiently, mine will produce 3 KW from the little alternator, this has resulted in a burn up of some of the elictricals in the system, my point is that on a F&P single it wouldn't load them as much due to saturation of its core and therefore run away more easily, even a dual rotor wouldn't be enough load. Neo magnets would help but still not be enough load on the blades. As for the furling, all airfoil's will furl but there are different total angle of blade rotation to get a neutral power point. With the 222 blades my calculations suggest a rotation of approx 100 degrees, this gets them to where their TSR is around 1, in high wind they are still producing power but tip speed is equal to wind speed. To go past this point and apply electronic breaking could stop the blades, but then they would loose centrifugal force in the disk that helps stabilize the disk in its rotational plane. If you observe a aircraft propeller in fully furled position the blades are streamlined to the airflow, They can do this because their construction is much stronger than our blades and the propeller is much smaller in diameter resulting in less loading rear wood on the hub and furling device. Turning the blades flat on to the airflow would stop lift and rotation by stalling the blades but would result in the wind energy being spread right along the flat surface and having enough force by leverage to bend the blades back and damage the hub, and or resulting in a tower strike. All the best Bob Foolin Around |
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| Rastus Guru Joined: 29/10/2010 Location: AustraliaPosts: 301 |
Hi Bob, Thanks for your promt reply!It becomes safer for me to "just fool around"with the knowledge you and others share.No doubt the feathering calculations/results you have provided will prove very usefull to anyone planning to feather the 222 blades.Using the 100deg rotation to match wind speed,would a 3mt dia. blade be turning 140rpm aprox in 80kmhr winds?Your summary of completely stalled blades with 0deg rotation is a deterrant and should be considered with due care.While in my case,I'll rely on furling to control the mill,idividual projects vary and governing speed by feathering might prove viable,depending on the scale of the mill.Your advise is exspanding my grasp of mill components and there function.All the best Rastus. see Rastus graduate advise generously |
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| Midwoud1 Newbie Joined: 25/12/2012 Location: NetherlandsPosts: 23 |
Hi I'm new on the Forum. Living in the Netherlands.Average windspeed 5,5 m/sec. Build an active pitch-controlled wingenerator 2,9m dia. prop. PMG.Axial generator 24 volt. Actuator : Cordless drill. Rpm.switch , microcontroller (Arduino) Auto- feathering. Running 2 years very good. Very low maintenance. http://www.youtube.com/watch?v=RiQiqi5jzVs http://www.youtube.com/watch?v=9jaz3soqXLo There are 2 more projects in The Netherlands, 1 in Turkey, 1 in Spain. Best wishes , Rgds : Frans |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Welcome to the forum. Some nice work there, and works very well. Was the gears something you made or are the an off the shelf item. Pete. Sometimes it just works |
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| fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Hi Frans, Nice work , I remember following your thread on fieldlines a year or so back , there has been some good disscussion with active and flyweight pitch control , here is the link to that thread if anyone wants to have a read ACTIVE PITCH CONTROL I am in the process of building a 4Mtr Dia pitch controlled Axial mill myself but have doubts about totally relying on a micro processor without a redundancy, so I am trying to go down a different path of flyweight with an actuated safety system that can park the blades when needed . I will be getting back to that as soon as the AX I am rebuilding goes into the air in the next few days, after burning out the 3rd stator I have completly scraped that and gone with a new design and have incorporated a manual furl option which I have used on smaller mills . IMHO, Axials are so prone to burn out they need ultimate protection in strong winds. A link to the Blog on that , HERE PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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| Rastus Guru Joined: 29/10/2010 Location: AustraliaPosts: 301 |
Hi Frans, Watched the videous.Impressive! You have a good range of control with quick and smooth responce.With the movement inside the nose cone it's not noticeably different to other mills,almost the secret weapon.With 2yrs of service under your belt your should be "proud" of your achievements.You mentioned low maintenance,what has that included?If you have developement pictures or further details you'd like to share we'd love to see them.Kind regards Rastus see Rastus graduate advise generously |
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