Airloom’s Whacky Wind Clothesline Turbine Idea

What if you don’t put airfoils on a central, spinning axis, but instead have them careen around a circular track? If you’re a company called Airloom, you’d say that it’s a very cheap, very efficient and highly desirable way to install wind-based generators that can do away with those unsightly and massive 100+ meter tall wind turbines, whether on- or offshore. Although grand claims are made, and venture capital firms have poured in some money, hard data is tough to find on their exact design, or the operating details of their one and only claimed kW-level prototype.

Transpower's 'flying clothesline' wind turbine setup.
Transpower’s ‘flying clothesline’ wind turbine setup.

Despite the claims made by Airloom, they’re not the first to have this idea, with Transpower in the 1980s making itself famous with their ‘flying clothesline’ that featured a continuous loop of sails tensioned between two ropes. These ran around a pole on either end with each having a generator for a claimed total of 200 kW. Ultimately Transpower seems to have gone under along with many other wind power pioneers of the era as they couldn’t make their idea economically feasible. Something which is a definite trend in the field.

Some parts about Airloom’s design are definitely concerning, with the available images showing each airfoil running along a central rail on a number of wheels and with their ‘Power Takeoff’ (i.e. generator) not defined in any meaningful manner. Here is where [Robert Murray-Smith] had a bit of fun in a recent video, creating his own dual-chain version that somewhat resembles a mixture between the Transpower and Airloom designs. He also put the design up on Thingiverse for others to 3D print and tinker with, requiring a handful of bearings for smooth running.

For the power takeoff, [Robert] suggests that in his design the cogs around which the chain moves could be attached to a generator (like in the Transpower design), but he could see no indication of how Airloom intends to do this. Feel free to put your own speculations in the comments. And if you’re from Airloom, show us the details!

53 thoughts on “Airloom’s Whacky Wind Clothesline Turbine Idea

          1. To be fair I’ve met an alarming number of engineers with little to no understanding of thermodynamics. It was one of the few classes they scrapped by in. And yet they go on to work in places like the aerospace industry.

          2. “Every free-born American citizen considers it among his inalienable rights and privileges to invent a patent medicine and a waterwheel, and he usually does both with usual ignorance of, and indifference to, the laws of both hygiene and hydraulics.” — Samuel Webber, “Ancient and Modern Waterwheels,” Engineering Magazine (1891), p. 329.

  1. “Ultimately Transpower seems to have gone under along with many other wind power pioneers of the era as they couldn’t make their idea economically feasible. Something which is a definite trend in the field.”

    Added complexity/cost with no real benefits tends to do that.

    1. Not if I understand the design, they are not drag sails, they fly across the wind, the only power loss sections are as it rotates them (short edges of the loop).
      Still seems like a design invented by people who have never been away from a desk in the cold, gritty, wet, unforgiving reality of outside.

      1. Absolutely – the airfoils rotate to present a minimal cross-section to the wind as they are brought back up into position.
        Still, this is an energy expenditure that robs from the total output.

  2. What if—hear me out—you attached a turbine blade to a bowling ball, then had it roll down a series of switchback ramps and hit a bowling pin, which was tied to a string, which pulled the switch on a fan, which blows another turbine blade past a series of dominoes, which knocks an egg into a frying pan, the smell of which eventually wakes up a bird who squawks at that wakes up a nuclear engineer

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    1. Did you not read the article? It pretty much says we don’t have many details but is likely to be in the kW range as that is what their prototype is (although it could be scaled up) and previous attempts have also only been around 200 kW.

  3. When I first read about this and that Bill Gates was an investor, I tried to find a video (including on their website) which made the design more clear, but couldn’t find it, and thought it was just “me.” Glad to know it wasn’t just me, that the design is not clearly laid out.

    JimTerr

  4. This is very similar to the (very old) Savonius rotor design, but with added complexity with the chains instead of a simple rotating rotor. Maybe the rectangular form can give more boost then you loose with the extra complexity, but it also becomes dependent on wind direction. Maybe it’s usable in areas where the wind always blows in the same direction?

    1. The problem is , you cannot make the standard designs more simple. Someone said “If nothing change the result stays the same. Try to use more of the wind energy in the swept area . It is possible but it will be more complex

      1. No, it isn’t possible to extract more wind energy in the same swept area. Look up the Betz limit – it’s only been well understood science and widely documented for a mere 100 years.
        Modern three blade turbines achieve about 80% of the theoretical maximum.

        You are proposing an approach where we just change things at random just to see if we get a better outcome. Sure, if you’ve got a few million years for a better design to evolve by natural selection. Alternatively you could read a textbook and use a brain.

        This concept is very obviously extremely stupid:
        – huge mechanical complexity
        – lots of wearing interfaces
        – energy collection at ground level where there is basically no wind
        – clearly more infrastructure and actual structure for a give swept area, despite their crazy unsubstantiated marketing claims

        Anyone who has had any real engineering training can see these things at a glance. Anyone who has read even a basic primer on the design of wind turbines will KNOW that. The people behind this are either idiots or crooks. The people who invested in them are definitely idiots.
        It makes me so angry to see stuff like this get airtime. Why do real companies who have something genuinely useful to save the planet have to compete for investment from morons against junk like this?

        1. Yeah, you can’t get much better than modern wind turbines. They are quite simple mechanically too. This idea seems to be the opposite to what you want for a wind turbine.

          Wind turbines are tall to have stronger and more reliable wind, this is on the ground. Wind turbines spin in one direction continuously, meaning they don’t have to push against the wind, this has a whole return stroke pretty much where they have to push the blades against the wind. Wind turbines are more robust and resistant to mechanical damage or dust and dirt, partly because of their height but also their relative simplicity, these wind turbines either have ropes or chains and tracks and are close to the ground and only work in windy areas and wind and the ground tends to mean dust. Wind turbines only need a few rotating parts, this needs many moving parts hence leading to more maintenance.

          Overall it just isn’t a good design, I bet it is just another startup there to get VC money and then disappear.

          1. I’m not defending the concept and I’m really not sure about the details of the design. But I just need to comment about the assumption that the sails on the back side of the track would be pushing against the wind. To solve this problem, it is only necessary to rotate each sail 90 degrees about its own axis as it rounds the corner of the track. This will permit sails on the back side of the track to continue to push around the track in the same angular direction as the sails on the front of the track. And I could see a relatively simple mechanism at each corner of the track providing the 90 degree flipping motion.

            As to the other comments about mechanical complexity, numerous bearing surfaces, and poor wind velocity near the ground, I think these are valid concerns.

          2. For Rick Sink
            To rotate the blades like that would be dependent on wind direction. Could rotate the whole apparatus into the wind at this point just to keep it simple…

  5. As an original TRANSPOWER electrical engineer I have fond memories of the first article in Tehacahpi CA (and this one pictured outside Palm Springs) preferring to call it the “Sail boat race” Turbine. Had some 250 on order before the prototypes sailed. An excellent team of men truly trying to prove concept (and get some money back) but it proved to have multiple catastrophic engineering issues electrical and mechanical. But it helped propel multiple careers in the now 45 year old industry, and volumes of stories throughout.

    1. Needs some liquid pistons or magnetic. Although it might not be as bad as one think it is, after all gondolas are able to keep on spinning for years, problem is efficiency, but scale might mitigate some if the draw backs .

  6. I guess you can cut out the central space of a circular turbine, but I can’t help but think even for vertical axis, it’d be easier to have several small regular ones side by side. Maybe also figure out an easy efficient way to make all the blades face the right way at all times, since usually no-one bothers but I don’t think it’s been proven impossible. Variable-pitch horizontal axis arrays still seem like their numbers work out better though, except in specific situations.

    The flying clothesline looks fun though. Especially if I could securely hang my clothes from it, for laughs. But as the link says, it looks like it was a bit of dirty laundry behind the scenes.

    1. These type theories must maintain a very precise upper and lower vertical line. On a 400 foot circle 1/10 of an inch length differential upper to lower rail/rope length will very quickly become inches, then feet of lost vertical and history shows all hell “breaks” loose. Controllable….but why add that engineering cost to an already lost concept? Been there, done that.

  7. A few years ago I worked with a German company with a better approach. They used kites flying at an optimal altitude (higher usually means more wind but you don’t want to be a flight safety problem). The kites were attached to electric train bogies used as generators. These ran on an oval track like the system in the article, pulling the bogies around the track. The kites tacked at the end of the track and the bogies could be powered to keep them moving when tacking or when there was a lull in the wind. The kites could be quickly hauled in during heavy winds or when flight safety required. Cheap to build using existing equipment. They built a full scale prototype but, at the time, couldn’t get funded partially due to the huge sunk investment in wind turbines.

    1. Thank you. I remember it being a kite that the angle of attack could be controlled. It worked off a generator on a winch. It would fly up into faster wind generating, then drop into lighter wind and get reeled back in.

  8. So far the best option is still nuclear. It is more reliable and probably more environmentally friendly than most of the green energy options. If fuel reprocessing was used then even just with nuclear waste we would have enough to power us for a relatively long time and hopefully by then fusion would be viable.

  9. Pretty hard to innovate without trying something new. What a bunch of negative-Nellies.

    The design definitely seems to have a lot of hurdles to overcome but there is plenty of space in the world for alternative designs. These images we are seeing could just proof of concept demo machines. Lower maintenance and construction costs seem to be the the target of this approach.

    1. I was fortunate to participate is several “modern” wind turbine design programs, inside and consult, from 1980-2021 and find that ALL have some merit. The BIG however is whether to spend TAX PAYER DOLLARS on something that is long over tested and not in line with wind engineering standards of known parameters and known desirable requirement, such as space allocation/MW, cost per MW, application intended, height of wind resource of application and sometimes “REALITY CHECK”. Darrius had weak point in blade curvature fatigue, TRANSPOWER was bi-directional vs omni, too-low to ground, non-pitch cannot stop quickly so needs short blades, Ferris-wheel turbines. 1-lade, 4 and 5-Blade turbines have harmonics that kill the mechanical and electrical systems. 3-blade VAWTs just seems TODAY as negotiable through all the modern pitfalls and experience.

  10. I’m glad to see Paul Gipe’s website, wind-works.org, referenced in the article. His experience with and documentation of the history of wind, including crazy ideas that don’t work, is incredibly valuable.

    Anyone reviewing “alternative” wind energy systems absolutely needs to check out his website.

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