Laddermill

I think it is just PITIFUL that we have thousands of supposed “AWE” people now, and yet after celebrating the genius of laddermill for years, the closest anyone can come to building one is to say it is to difficult. And people even in this discussion charcterize the nature of the performance as having off-the-top-of-their-heads-pre-defined limitations, without ever having seen even the most primitive version run. I’m not sure if “pitiful” is a strong enough word. How does anyone KNOW if it is “too difficult” if they never try? OMG how freakin’ helpless ARE people nowadays anyway? To me it is evidence that these people are not seriously serious or truly curious or inspired about AWE - it’s just “something to do:” Well they have to do something, right? So fly kites! Fun, fun, fun. The reason yo-yo kite-reeling was instead implemented while still using the name “laddermill” was because an existing kite could be ordered using a smartphone, between taking the group-selfies that are, so far, the main product of AWE “research”. How can anyone say they even HAVE a true “research” program if such an extremely simple configuration as a laddermill cannot even be TRIED, at any scale, no matter how much money and how many people are involved? OMG!?!?!?!??!?!?! I know people who build working aircraft out of soda straws and paper-plates from trash bins. You can build working wind energy devices for a near-zero budget! I think what is missing is the belief, knowledge, or understanding that “yes you CAN do things”.

“Auto-oriented Wind Harnessing Buoyant Aerial Tramway” was the invention called later Laddermill. Even the inventor has never built it, isn’t-it Doug?

Thanks for your perspective @derek.

Yes Pierre, after recording the buoyant aerial tramway (laddermill-type) invention, I quickly moved on (in my teenage mind) to a version that simply held its position relative to the wind, and spun, later called “SuperTurbine”, so-named for “the superposition of multiple rotors”. That does not mean “laddermill”-type wind energy devices should not be developed, built, tested, run, improved, etc. As far as I can see, as simple as it is, one will never be built unless I do it, because that is just how paralyzed and helpless most of the rest of the field are. It’s a good example of how placing your faith in “big-name” entities is often misplaced and without merit. It is amazing how any single individual can, in some cases, outperform the largest universities and corporations if they realize they “can do things”. It’s almost like the education process serves to convince people they are powerless to do much of anything. That is the case with so many things in this world - but I can only get to so many projects. With only two hands and half-a-brain, being only one person, there are only so many things I can do. Unlike my hundreds of other inventions, at least I had the foresight to understand way back in the 1970’s that someday, somewhere, someone would “invent” one of my inventions, and took the step to record the idea and have it witnessed and notarized. Otherwise, at least with regard to “laddermill”, I would be just one more idiot that nobody believes, spewing apparent self-glorifying nonsense on the internet! Like the people who popularized it then decided it was too hard to ever even try… WHAT???
My truth would have been indistinguishable from the rampant and almost universal lies that so far, define the field of AWE, starting with Magenn etc., and moving on through pretty-much the entire field. Show us a single big-name AWE “team” that has done what they said they would do!

Roddy asked: "please elucidate your understanding of how a laddermill will overcome it’s (sp) most obvious shortcomings.
High speed is an absolutely critical component in any kinetic energy harvesting system which needs to be lightweight and efficient. Laddermill doesn’t have high speed. Simplicity - another killer for laddermill, it is woefully overdependent on control devices on each wing. (and more…)
*** My (doug) answer is I do not necessarily agree with your points, but am not going to explain it further. I will instead go back to being dumbfounded, after reading for what seemed like years, how great the “laddemill” concept was, that out of that many people, nobody could be bothered to even try to build even the most rudimentary, feeble attempt before labeling it “too difficult”. I guess that was another way of saying “we were totally wrong so far, but now we’re suddenly right - laddermill is no longer a good idea at all, or even achievable! It was, but now it’s not.” Hmmm, really? So how does that work exactly?
My point is, if that many people are willing to spend that much time and energy promoting the idea, then refuse to even build a single attempt, I do not think people deserve to have anything more explained to them. If it is “too difficult”, then so be it:
Let’s just officially declare laddermill “too difficult”. Let someone with a sufficient level of skill to at least try it get to it, and maybe someday you may learn something. Pierre asked if I also had not built one. Well I did move on and build what I thought of as the next step in the progression “SuperTurbine”, but Pierre is right, I am one of the people who never built one. Here is the difference:

  1. I’m not affiliated with some major organization such as a famous university;
  2. I did not marshall a group of people together to develop the laddermill concept.
  3. I did not create websites indicating a serious development endeavor for laddermill.
  4. I never publicly stated (press-releases? articles?) that I was going to build one, let alone make such a big deal out of it.

But I sure was excited to (if the people had any credibility) see one! I was very happy someone was (supposedly) “going to” develop the concept, with all its huge possibilities.
Unfortunately, as we now know, in AWE, very few future predictions of peoples’ own future actions turn out to materialize. I think all the fanfare over laddermill, followed by nothingness, was the final straw in any remaining faith I had, that any of the most publicized “teams” in the AWE field could be taken even a little bit seriously. By this point, it is almost 100% certain that you could accurately categorize any statement of any future action by any AWE team or player, as not true, without even hearing what it is! And I would also say I see an inverse relationship between following through on one’s own statements, and the level of funding involved. Amazing the universal credibility in any field can have such low standard, which, in this case, seems to be near zero.
So don’t be like the rest so far. If you say you;re going to do something, do it. If you aren’t going to do it, don’t say you are. Hey, the only thing at stake is the most valuable thing you have: your own credibility and track record as trustworthy and believable.

Doug, you make some good points. It is amazing how little progress is being made by well financed AWE companies, and one individual can make a big difference, isn’t that what we’re all doing here.

This is lifted directly from the recent Airborne Wind Europe publication Policies for Airborne Wind Energy

start

Airborne Wind Energy is a promising technology. It can harness steadier and stronger wind energy in higher altitudes with significant material and potentially cost savings, it can be flexible and scalable and may thus be able to make an important contribution to the energy transition. However, the interviews, conversations and research carried out for this study revealed that there is still lot of scepticism on AWE technologies. The following quotes from DTU, ForWind, Fraunhofer IWES, Ocean Energy Europe, BMWi illustrate this finding:

 “… , the challenges facing the AWES industry are of such magnitude that it cannot be stated with certainty that this industry will be commercially viable.”
 “I doubt that we will see AWE making a dent in the energy universe any time soon or even midterm. Would I invest in such technology? Probably not …”
 “AWE still needs ten years, and this is what I have already said five years ago.”
 “The sector seems to be too optimistic. Wave & tidal were also too optimistic, then they could not deliver and interest got lost.”
 “So far I have not seen a convincing project proposal.”
 Jason Deign, GreenTech Media: “The likelihood of airborne wind energy becoming a commercial proposition any time before 2025 is remote.”

end

I believe the AWE Industry has lost it’s way, and doesn’t know how to compete with conventional wind, at any scale. Now is the time to look at other designs (not more YoYo and flygen).

Your laddermill design, using 2 fixed supports seems worth pursuing, linking two sides of a valley in a horizontal configuration. There is less snaking, and more homogeneous wind conditions will favour a steady power output. How difficult can it be to build and test that, surely a great university undergraduate project.

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Another advantage of a reel-out/in yoyo system over a laddermill system:
A yoyo reel can transmit far much torque and power than a laddermill wheel.

I disagree. Not another pivot! Makani and Kitepower B.V. have well developed systems and I hope they start producing those in numbers soon. One of the biggest advantages of awes is that they use less material, but material cost will only be relevant, when they are produced in larger numbers.
However for a hobbyist / aspiring inventor, the case might be different. What’s do you envision? Please post it in Engineering / System Design .

A guy goes to the local hardware store to buy a generator. There are 2 types, the old petrol one, and the new Yoyo model. The petrol one is rated for 5kW, and the YoYo for 5kW*. The guy is a bit confused so asks the sales assistent what the * means. The assistent says it’s exactly the same as the old one, but when you plug your power tools in, they’ll work for a few seconds then stop for a few seconds, then work for a few seconds and stop for maybe 30 seconds, and the cycle will repeat. The guy says he’d prefer it to be exactly the same as the old model, with power all the time, the assistent says, no problem you need to buy 3 YoYo generators and this big black box that synchronises them all together, voila. The guy says, is that the same price as the old model …

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Noone is building awes for that market. Wind energy to replace a 5kW generator is just a terrible idea.^^
Just imagine someone doing construction trying to work with an awes. He/She’d never know if there’d be any power. Just use batteries where possible and fill up the old generator with biofuel, where not.
The intermittency of yoyo is easily solvable however. There will be a conversion raw ac power -> dc -> ac anyway, so might as well put in some batteries there. Wind power generators generally aren’t synchronous so your black box synching device doesn’t make sense.

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Luke, we have different solutions for the output side of the generator, but the problem is on the input side. The YoYo design is only about 30% efficient.

A typical example can be found here : Fig 21 in “Flight control of tethered kites in autonomous pumping cycles for airborne wind energy” by Michael Erhard & Hans Strauch of SkySails.

It is a sawtooth production phase, followed by negative power for the retraction phase. The average power over the cycle is about 30% of the nameplate generator power. So a YoYo with a nameplate 5kW generator, will be rated at 1.5kW.

The guy in the hardware store will have to buy 3 YoYo generators, each producing approx 1.5kW to match a single old petrol generator rated at 5kW. Of course, the guy could buy a single YoYo generator that is 3 times bigger, 15kW of nameplate generator power, for a rated power output of approx 5kW.

The size of the generator is not important in the example, kW or MW, it’s the same whatever the size, it’s a design limitation.

The new generation of rigid wing YoYo will improve the efficiency a little.

I think that approach to naming the power of a Yoyo is so simpliatic to the extent that it is a pure lie. I would think 1/5 of the time used in return phase is practical, this reduces the average power loss to 20% for the return phase. Then you could argue about the Betz limit - call me when you have a flygen/rotating rig that uses more than 25% of the power swept…

No reason to talk down yoyo. We are all trying at the same thing here, just different approaches

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Because of crosswind flight requirement and efficiency a flygen like a Makani’s wing uses far more space than is needed in regard to Betz limit. So now yoyo (in spite of its 4/27 Betz limit) and flygen could have a similar output.

And in spite of some advantages rotating devices can be limited due to both lower swept area and efficiency per wing area.

All the AWE methods and materials should be pursued, comprising flygen and yoyo, rigid and soft wings, low and high technologies. A negative or positive knowledge progress for one will be a progress for the other in two ways: to do better, or not to do more.

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30% of what?

https://www.researchgate.net/publication/265554616_Flight_control_of_tethered_kites_and_winch_control_for_autonomous_airborne_wind_energy_generation_in_pumping_cycles

That’s a shit nameplate, then.
Does any awes company name their systems like that?

Nah, we’d make a new nameplate.^^

There will never be a guy in the hardware store being offered awes.

First we’ve got to agree on a meaningful metric, then we can start comparing systems. My all time favorite is economic viability.

Just had a video spoon-fed to me by youtube, called “The Laddermill Explained”


Rather than showing a laddermill, it instead shows a “yo-yo” kite-reeling rendering.
The video is dated 2010 - the time when the “laddermill” concept was being promoted, but it was easier to fly a kite than to build a laddermill, so they continued to use the name “laddermill”, but tried yo-yo kitereeling instead. I think they finally stopped calling it “laddermill” after some time went by.
I always thought the yo-you kitereeling looked questionable, but what weight does my opinion have in the company of so many highly-degreed engineers etc.?
So, since 2010, I’ve been hearing about the incredible amounts of power (such as “500 kW”) these yo-yo kitereeling systems were supposedly capable of. My take at that point was that, regardless of the efficiency, these people must be having better luck than I had theorized. But now, nine (9) years later, where is one yo-yo kite-reeling system in daily operation? We’ve certainly heard enough promises and press-releases. Now, rather than endless press-releases, we’re in an information drought. All we really know is that things are not panning out as promised. It would be great to have any real information to sink our collective teeth into, but I don’t know of any. Maybe someone associated with any of these projects will “leak” some information. But just saying that pretty much tells you all you need to know - not much happening with current AWE projects.
Remember “The Wizard of Oz” - whether its a piece of paper saying someone “has a brain”, or a little heart-shaped memento to wear over your chest, “Pay no attention to the man behind the curtain”.

There are some bits. https://forum.awesystems.info/c/news/l/latest

Was there a pivot somewhere already? Those are the original AWES concepts from the 1970’s … I for one am really looking for progress on those designs now. Why aren’t they more successful already? Pivot sounds Looooong overdue.

@Tom this is your AWES forum … You know AWES is about scalability… Making bigger wind power systems doesn’t mean they can only be huge. You must know there are realistic use cases for AWES ~5kW.
People exist in remote and rural (not in a city imagine) parts of the world with good wind resource and open space. Those same design classes can be scaled from small to >5MW >5TW

As for the term Hobbyist… Who in AWES is a hobbyist? Anybody?

Yes AWES is urgent and YES the most massive job is decarbonising the electricity power grid system… We need to decarbonise the whole of power infrastructure. Best we get on with it every which way we can please.

I believe a lot of yo-yo system nameplates were quoted in terms of the equivalent nameplate standard turbine device after an estimated improved capacity factor was considered…

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Stopping yoyo and flygen systems would be a mistake. Doing only them would be another mistake.

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I’m not aware of any changes in system architecture. But everyone’s still developing, still having things subject to change. I’d just like to see something nailed down and released commercially, even if it’s suboptimal. (Must be viable though)

That’s the big question.

Still disagree. Pivots would further delay commercialization. [citation needed]

Yepp. Maybe I misinterpreted what @derek said. The framing made me think of someone wanting to use an awes for a construction project. Connected to a storage system a 5kW generator is definitely useful. I’ve made this thread a month ago to discuss use cases for smaller awes:

:point_up:That would be me.

Honestly, I don’t think AWES will have a large impact in the medium term. Solar has become really cheap and saving energy is the easiest way to avoid emissions. Boring old insulation, not flying etc. We’ve had the discussion about the prospects of awes here The no market Hypothesis - #35 by PierreB and here AWE prognosis - #17 by tallakt .