 Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me. |
Forum Index : Windmills : VAWT vs HAWT Comparison
| Author | Message | ||||
MacGyver Guru  Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Boy, it's been a while since I've been here. I know there are a lot of mixed emotions on the VAWT versus HAWT subject, so I whipped up one of each and shot a little video. Turns out, my movie is of the wrong file type. Figures. Any idea how to show it on here? I took it on my iPhone. Anyway: I'm torn between the greater power, but more stress of a HAWT versus the simplicity, but lower power of the VAWT. At low wind speeds, they seem to turn comparably, although I know the HAWT takes more advantage, due to both its orientation into the wind and its swept area. Still, the simplicity of the VAWT has me captivated. One moving part and no slip rings to get electricity from the tower to the ground. That's a big deal in my book. If nothing else, they are fun to watch spin. Neither of these do any work; yard art if you will, but I thought it might be fun to compare apparent wind speed and RPM. I have yet to build my promised GINORMOUS VAWT, which has an enclosed single, flat blade, but I'll get around to it if the cancer doesn't beat me to the punch. . . . . . 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 |
||||
| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
I suppose if worse comes to worse, I could post the .mov file to my Facebook account and you could see it there. Nial and I post there all the time. I'll set a link here to my Facebook page. Edit: Crap! That didn't work either. Not sure where to go from here. Oh, oh -- I figured it out. Movie . . . . . 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 |
||||
| Pete Locke Senior Member  Joined: 26/06/2013 Location: New ZealandPosts: 181 |
Quite simple. Get a YouTube account going (it's free) and assuming your video is on your computer, it's a click away to up load it to wonders of YouTube. Then post the link here and all the fraternity to admire. ......And after this I spotted the link. Well I'm old which is my excuse  |
||||
Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
The VAWT's appear easy on paper, but once you start to build them you realise why everyone says build a HAWT instead. The biggest factor is area facing the wind. The power of any windmill is dictated by the area facing the wind, and its much easier to achive big numbers with a HAWT than a VAWT. A typical build of say 4 square meters would need blades of just under 1.2 meters long. But for a VAWT, you need something like 2 meters diameter and 2 meters high, which is a much more difficult build. The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
||||
rustyrod Senior Member Joined: 08/11/2014 Location: AustraliaPosts: 121 |
Correct me if I am wrong A VAWT with the blades mounted in the full S shape spins slower but develops more torque (A) than (B) A VAWT with the blades overlapped spins faster with less torque (B) than (A) Will a VAWT with the blades separated by the width or twice the width of the blades turn more slowly but develop more torque,(C) than either (A) or (B) Purpose:- Diaphragm pump. Slow powerful turns to reduce hammering/wear of valves The fact that the blades are further from the central point must produce more leverage, yes? Could this be called a greater swept area? I accept more difficulty in construction I have drawn the blades for clockwise rotation when viewed from above as to suit the direction of whirly winds and cyclones in this southern hemisphere Always Thinking |
||||
| govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383 |
Vawt video Hi, this is a silly video I made a few years ago, It may give you some ideas. Basically I found I had better results with more blades. What size is your project? What is your average wind speed? I can only suggest make it as large and as low cost as possible. Bigger VAWT I look forward toward your results. just because your a GURU or forum administer does not mean your always correct :) |
||||
mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412 |
Hello everybody; It has been so long since I have been on this great forum. Very glad to be back. I agree with Gismo...and keeping it balanced is a real trick. Unless a guy - or girl, has access to manufactured and balanced blades it will be difficult to keep the thing together. The fair sized ones like mine do ok, but you will need a REAL GOOD Break system to stop it in higher winds. Just unbelievable how much torque this thing has in a 25 plus mph wind. I'm just a farmer |
||||
| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Crew Okay, here's my deal. I live on the Texas plains now days. The wind is a constant 15 to 30 mph daily and WAY HIGHER if your luck is running low. I got hit with (read that bull's-eyed by) an EF-2 down-burst tornado 3 years ago, which screwed up everything. That being said, my HAWT "screams" most of the time. For that reason, I have it a fairly lightweight "furling" tail feather (see video posted above). The VAWT was just for fun. I like to watch stuff twirl in the wind. The HAWT can and used to make electricity, but I was lazy and merely ran the wires down the tower, therefore it would entangle itself about said tower almost daily and force me to yank it down to fix it. Hence, no more generator! If I ever take the time to build my "ginormous" VAWT, it will be thus and so: I will build a circle of vertical fins between two large, round surfaces. The fins will all cock one direction, thus accepting wind from any direction BUT here's the catch: The "blade" as it were, will be a flat piece of either aluminum or sheet plastic. It will be balanced somewhat, but not dynamically. This is for three reasons. First and foremost, I don't care! Secondly, it shouldn't go fast enough to make things wobble and thirdly, it will be short and stout, sticking up into the wind just about 7 to 12 feet high. It will be about 3 to 4 feet from fin tip to fin tip. Think about one of those wind turbine thingies, which ventilate attics, but it doesn't spin. Instead, it "spins" the air inside and that flat blade is merely immersed in the flow. I've already built a tiny one, so I know it works. To the underside of the contraption, I'll fit a pulley and build a step-up transmission and so on. Next, I'll add either a generator or an air pump (remember me? I'm the guy with the air engine fetish) or maybe just let it spin with a couple of bicycle rims attached to give the appearance they are "wobbling" in place -- Yard Art! Anyway, that's where this is going. I have two awnings to finish (welded steel) and one deck, then all the "homework" as it were here, will be done and I can play again. I've been battling cancer for years, so that takes up some of my time, but I've got a good foot-hold on that for now, so I'm, for the most part, ignoring it. I figure, either it will go away or I will go away, which in turn will mean it will go away as well. See? Sooner or latter, it WILL go away! . . . . . Mac Edits: typos 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 |
||||
| Adriaan Kragten Newbie  Joined: 14/10/2015 Location: NetherlandsPosts: 9 |
I have written two public reports about vertical axis windturbines, KD 215 about Darrieus rotors and KD 416 about drag machines. I advice to study these reports first if you have plans to build a VAWT. These reports can be copied for free from my website: www.kdwindturbines.nl |
||||
 Print this page |
