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Forum Index : Windmills : Vawt...going in a big way
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KarlJ Guru  Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
I took one look at that pic at the top of the page and said to myself "this guy is an aeromodeller" F1 Pylon racing models 
Here is an engine I used to run, quite a piece of kit, the inlet and exhaust ports you could fit a finger into. It had 2 speeds (flat out and stopped). It would barely get on the pipe on the ground at 20,000rpm and needed to "unwind" in the air, apparently in the "world class", guys hands to 35,000rpm+ The wing was 60" so about 4 feet tip to tip. you could place each tip on a milk crate and stand on it, jumping up and down if you liked, but it didn't move at all as far as I could tell. But in the turns the wings would visibly bend 
Now I liked that thought so much, I thought I'd take a look at what the boys are up to these days. Completely insane model FAST And if you want almost unbelievable 399mph Yes folks 642KM/hr fast then you need to do it without the drag caused by the prop ....Yep with a glider 399mph model I had a 3m Eclipse which was fast but this stuff is just amazing. Carbon fibre mate! Looks like a Hijack but I'm praising your skills... honest! Luck favours the well prepared |
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Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566 |
mac46, Just a note, Please accept as candy rather than sour grapes. When a red line shows up under a word you have typed in your Post, Put your pointer/Cursor on the word and click the right side button on your mouse. I'll say again I'm very impressed with the work you have shown here. Cheers---Roe Time has proven that I am blind to the Obvious, some of the above may be True? |
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mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412 |
Hello every one, VK4AYQ, Green Belt, Karl J, I feel like a buck private standing in a room full of generals...and everyone is looking my direction...I'm not out to break any new ground or to prove a point here, just need to understand the vawt and why it does the strange things it does. Thank you all for you'r kind words and thoughts, suggestions noted about the condies crystals...that vid is insane, 230 mph-impressive to say the least. Most farmers around here are good people with kind hearts, willing to lend a helping hand in an instant without being asked,as are most people I suppose,just trying to do right by the world. I would be assured that many places in the world have people like this, gives us hope and a free spirit. I jus want to say thank you "all" again for the interest, suggestions, and yes...the vidios too! That set me up in my seat, wow. I'm awake now!!! .....Mac46 I'm just a farmer |
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| mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412 |
Here is a picture of the winglet, at least thats what I call it. I've discovered that its better to have it on the bottom of the wing...at least with this wing profile anyway. .....Mac46 I'm just a farmer |
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fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Hi Mac, Nice work , its good to see someone do such a profesional job and not afraid to build big. What is the Airfiol , it looks like a GOE222 scaled up . I have sold quite a few of the ALU GOE222 extruded blades to poeple building VAWT generators , and with some of the pics and movies they have sent the section works very well, even I am considering having a go one day. Hope you can set up some type of logging on it when it gets going, and you can stream it live to the piclog page here . PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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| mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412 |
In this picture you find out how I managed to get that stuff up there in the air. The old crain does'nt look as sweet as it used to, but it can still do a hard days work. The white tank is approx. 5 1/2feet in diameter x 13 1/2 feet, and is bolted down to some very substantial concrete...it goes 4 feet into the ground not including the exrtra large footings, all crossed with 1/2" rebar,12 inches on centers. There is also 6" steel I-beam submerged at the floor surface in a "H" pattern, it was a 4000# mix and all poured as one piece. (not going anywhere in my life time). The steel tubeing is 2"x4" 10 ga. side wall and will undoughtedly need futher refinement before the project is finished. Welded with 6010 DC rod for the root pass, 7018 DC for the next 2 cover passes. (Welders do it in all positions) That black mat is rubberized padding, I mostly use it in front of my shop benches, but it comes in handy when I'm outside welding in the mudd too. .....Mac46 I'm just a farmer |
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| mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412 |
Hello Fillm, Thank you for you'r interest in my project. Yes the wing profile is based on the GOE 222...I have changed the leading and trailing eddges slightly,I've added winglets on each end and added a 1/2* negative tahedreal from the center trailing edge, but other than that its a true GOE222. Yes, that profile is a winner through and through, I've only tested it in detail in scaled down sizes...hopefully it will not disappoint me. I did test a larger size once...did'nt take long at all to see that it was to much, had a 3' cord as I remember. As far as getting the on line logger goes, well It may come to pass...but getting this thing running and not flying away may take some time. You right about centrfical forces...I've seen some incredable damage from steam turbines and compressors when they fly apart. .....Mac46 I'm just a farmer |
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| mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412 |
Hi fillm, you were asking about the GOE222 wig profile and I was talking about the different changes I've made. Here is a picture of the winglet...but this was taken before I thinned it's profile down. I've serched my pictures and can't locate any more recent ones, or any of the leading and trailing edges. When I have a chance I'll take some pictures of these areas and post them for you. I blunted the leading edge somewhat, makes it have a wider angle of attack, Dos'nt take very much to make a noticable differance. I added the 1/2 degree of dahedreal to the trailing edge because it helped form the vortex's in the wing tips...this helps creat lift for the next wing in procession. (at least this is what my testing has shown). Something like what geese create when they fly...thats why they always fly in a "V' formation...more lift in this region. I hope this helpes answer you'r questions. .....Mac46 I'm just a farmer |
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| mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412 |
Mac46, I completely misstated the vortext findings in my last post, I pulled my data and it shows an increase of lift...especially near the wing tips, and reduced drag also at lower speeds, the winglets helped to REDUCE not increase the voetex's on each end of the wing. It shows more laminar flow in these areas as well. Very hard for me to say by how much, but it was enough That I noticed it without any fancy vaccume guages and such. By reduceing the vortex you in as much reduce the induced drag whitch increases the wings renolds number for a given wind speed. Whew...I'm getting a headack form all this again. Its been alittle while since The data was recorded and I need to get it fresh in my mind. ....Mac46 I'm just a farmer |
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MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Mac46 You talk like my son, the Aeronautical Engineer; are you one too? My son is always spouting off $5 words at me that go in one ear and come out the other; they're wasted on me. I don't know what the heck he's talking about most of the time. I just try stuff and if it works great. If it doesn't, I try it another way. I'm in this for its entertainment value, by the way, in case you haven't guessed by now. I know that some of the larger wind turbines actually put little "vortex generators" on the leading edges of the blades. These little guys redirect the wind flow so as to increase the boundary layer, I think. That's another one of those $5 words! I can tell you from flying experience (R/C) that winglets put the skids to tip vortex and hold a plane in the "groove" better than anything except a dihedral, but they're much, much easier to build and install than modifying the entire wing. As we speak, I'm building a "plank" glider. It's nothing but an asymmetrical-section wing (Clark Y) with vertical stabilizers at each wing tip, much the same as what you've done with your VAWT blades. This one has an electric motor, so I can fly it anywhere. When it's finished & flying, I'll do a YouTube video and post the link somewhere in "Other Stuff". By the way, I make my planes' wings out of the same stuff I make my turbine blades out of, namely Coroflute plastic. . . . . . 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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| fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Hi Mac46, Im a bit embarrased, I should have gone back to page 1 where in the first line you say it is based on a GOE222 airfoil , my appoligies. It happens when threads start getting a few pages long. This reminds me a bit of a movie I watched recently "The Astronaut Farmer" It was a good watch. Looks like you have done some serious home work with testing , I suppose you just knocked up a quick "Wind Tunnel" in the back shed. All in all the GOE222 profile is an incredible profile for the wind turbine, whether it is VAWT or HAWT , the low down power is incrediable and its not short on RPMs when the wind gets up . I suppose the big question is what are you going to load it up with, with that much power you would have a lot of options? PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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Oscar4u Regular Member  Joined: 23/02/2011 Location: New ZealandPosts: 42 |
Hello Mac46 any chance of borrowing your crane? Makes me feel inferior when I look at my poxy elec forklift! Love your foundation as well. Cheers Oscar Oscar4u - for all your rotary cowshed repairs |
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| mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412 |
Hello Oscar4u, fillm, MacGyver, and everyone, Oscar4u, The crain is not for sale, sorry...I can loan it to you for a spell if you want. This old girl has been with me for alot of years, shes a real sweetheart. Its been walking the walk for many a year now. fillm, first, I have'nt taken any pictures again...yet, but I will, and I'll get'em posted for you. "The wind tunnel", if one can call it that, was fastioned out of scrap ply board, an old furnace motor and squrrel cage, also had a BBQ tank at one end for makeing smoke, and 2 electronic scales to help with measurements.As I remember I had a few strob lights as well, and plexiglass here and there to see whats going on in there. It was on the end of what I call "very crude", but it did the job. In my area the average wind speed is about 10 mph, alittle more during the winter mounths, and so I need the "larger" turbine to help extract the power of slower wind, and a vawt because of constant changes in wind direction caused from being on a bluff overlooking the river. As far as what am I going to couple it to, I'm planning on an air compressor, note the 500 gallon tank in one of the previous pictures, and a electric gennerator/alternator. I have'nt given that part of the project to much thought as yet...well thats not true, I have, but have'nt made any final plans. Need to find out if this thing will "walk the walk" or not first. MacGyver, No I'm certainly not one of those engineeres, and sorry for the $5 dollar words and such...seat of the pants reserch is all, finding out what works and suttle changes to "tweek things" to make them work even better. Have fun with you'r new project, I'll be looking it over once its posted. I'm not aware of any thread on "wing tip" flutes ,or tips ,or winglets,..what ever there called, but I do know that there is more to them than most people think or realize. Prehaps some discussion on this site is merrited. I'd estimate atleast 10% gain by adding winglets...I'll let it rest there.(for now) .....Mac46 I'm just a farmer |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi Mac46 Great post, love the pictures. I agree about the winglets. I fitted a set to a Lenz2 vertical I built a few years ago and it made a definite improvement, and reduced the noise slightly as a bonus. 
I also had a set on some GEO222 blades on a HAWT windmill. 
The science today is they do help, which is why many new aircraft have then as part of the main wing, and I've seen some big wind turbines with them too. I figure, they cant hurt, and a profile like the GEO222 has enough width at the tip to let you fit winglets securely. I was wondering Mac if you have thought about braking? Some way to bring it under control if it gets away from you. I do remember hearing stories of the early Darrius and H wing verticals suffering over heated brake discs when trying to control the turbines in strong winds. With something the size of yours I would be looking at a car disk brake set up, or a big old drum brake. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412 |
Glenn, oh hey, good morning, (morning here anyway,) a Quick answer is yes, I've fitted a disc break to th main shaft, also planning on a direct coupler arm to phically pin the turbine in a stationary mode, during storms, but have'nt fabed this yet...but deffinately planning to do it. Thank you for the response and the pictures, do you have any data or guess as to how much the wing tips improved preformance? I'm currious because I have'nt tried any full size applications. I am also wondering if clockwise vrs counterclockwise rotation on vawt makes a differance??? My data here in my area shows a slight improvement in ccws rotation??? This might be from changeing wind direction, or from northern hemisphere location, don't know what creats the differance. I know that tornados spin ccw here, must be a reason. I also wanted to ask about the low pressure area created inside the swept area of a vawt, this may have a effect on final speed reached, wind pouring in below and from above the turbine, I've noticed all these things, but I'm baffeled by it all. I have lots of "head scraching" ahead of me. Any comments or ideas from anyone on this? .....Mac46 I'm just a farmer |
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| mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412 |
fillm, and everyone, Here is a picture of the trailing edge. You'll have to enlarge it to see the slight neg.* of tahedreal (sp), its probably not even a 1/2 degree.(ever so slight.) More pictures to come, .....Mac46 I'm just a farmer |
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| mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412 |
Here is another view of the trailing edge,(bottom side), I think you can see the slight down turn in the last few inches...well upturn in this picture, the wing is hanging upside down. Hard to make everything coop. when I'm trying to get a specific camera shot. .....Mac46 I'm just a farmer |
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| mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412 |
This is the leading edge profile, ever so slightly blunted from the GEO222 profile. I hope the blue tape will help you see the profile better. .....Mac46 I'm just a farmer |
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| mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412 |
Here is a rear view showing the attack angle of the winglet, I set it up next to the window to try to keep it from being so shinney and reflective. My thoughts are that an angled and downward protudeing winglet is more efficient with this wing profile. I hope this helps explain what I'm up too, and what my finding are. I could be way wrong with all of this, the real test wil come when I put this thing to work. .....Mac46 I'm just a farmer |
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| mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412 |
I was talking about the skin of the wing earlyer, here is picture of a section where you can see the skin being sanded down to profile, and a few small sections of this that have just been glued on. Notice the thickness differance, and how much will be taken away with the sanding process. The color variation in the shin is from different ply's of the skin as they are exposed from sanding. I keep an eye on this because it helps me guage how deep I'm going with the sander. The final debth/ height, is even and/or flush with the profile of the ribs. The ribs were all clamped together as a group, evened out as best I could and then gang sanded to ensure they all had the same profile. (this was ofcourse prior to assembly). .....Mac46 I'm just a farmer |
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