Something to remember for anyone looking at VAWTs: The spiral shape does not actually matter for generating power. They'd work if you untwisted them. The twisting part is for noise and vibration reduction - it means the horizontal force on the turbine remains roughly fixed throughout the spin, rather than pulsing as the cross-sectional area changes and making the whole turbine wobble.
The twisting is also supposed to reduce the torque pulses and help with starting as there is always some part of one blade that is optimally aligned with the wind.
Putting those tubercles on a spiral shape seems like a challenging task to me, but would that work too or is it important for the tubercles to be across the straight axis?
I'm sure that you have many viewers, like me, who wonder what difference things like tubercles make when we come across them. I expect the vast majority of those people, also like me, don't take it any further, let alone far enough to be able to draw any meaningful conclusions. So, on behalf of all those people, thank you! Curiosity satisfied, knowledge increased and entertained to boot!
Do you remember air fix models these 3D printed wind turbines would make great working models could come flat packed in a box for those who don't have printers. Yet again nice design.
You can download all of his designs, and scale and experiment with materials. He invited us to play with his designs. I really dont think that he minds.
Another application that comes to mind with the addition of tubercles would be for turbines. Specifically with the compressor side of turbocharger, because you mentioned increased capture in turbulent airflow, I wonder if that would provide better energy scavenging and efficiency on existing internal combustion engines. Great stuff as always!
BullsEyePower makes a 'BatMoWheel" compressor that uses something similar as a drop-in replacement for stock diesel turbos. It does make more power, but it's also a billet wheel, and in general billet wheels make more power than cast ones because of better tolerances. Notably though neither Turbonetics nor Garret were interested in the technology and they make most of the highest-end racing turbocharger compressors.
@@IFRYRCE Very interesting piece of info, thanks for sharing! After having a look at the design, it seems a bit different, but could functionally provide several of the same benefits. But thinking of it now, it's probably quite hard to make and maintain balance, especially as that wheel gets up to 80k-200k RPM. So I understand some of those potential challenges and hesitations as to why they wouldn't jump on the band wagon unless it shows massive performance improvements. I suppose I'll just leave that to the pros to experiment lol
Very impressive 49% increase in efficiency Rob.. I did notice the reflective tape was seriously putting the rotor out of balance which will have sapped some energy. Nice work.
@@rayg436 It would certainly be possible, and it would certainly make a difference, but one challenge when creating a helical blace is how the tubecle shape is adjusted to fit into the swept leading edge of the blade. There are a few ways in which this can be done, and it seems likely that each method would have a slightly different result to the other methods, so some testing might be required. The alternative to testing in a lab, is to look to nature to find a mammal that uses a swept blade. The whales features in the video clearly have a swept fin, but their fin moves fore and aft as well as up and down, and also rotaties at the 'shoulder', so the tubercles that evolution has tested for the hump-backed whales are optimised for the range of movements and time spent in each position. For a VAWT, the blade doesn't move (althouhg it should), so a different arrangement of tubercles on the leading edge might be optimal.
The increase from ~100 to ~149 rpm is very impressive. The only question I have is were the tubercles additively applied (fan blade width slightly longer on avg) or subtractively applied (fan blade width slightly smaller on avg) or were they applied sort of mid way so that no overall change to the mass and width of the blade occurred? If the overall width of the unchanged blade was shorter, it would be similar to say slightly increasing the diameter of a fan blade and calling it better... but everyone know that a larger diameter blade generally will have better performance... which is why I am "hoping" that the tubercles were either subtractively applied or applied in such a way as to average the change so some parts of the blade were smaller and some larger.
mate this is a rough and ready test of a principle - I wouldn't worry too much about it tbh - but you might want to have a read on the subject as it looks - roughly - as if it is worth delving into deeper - and to be honest that is about ll you can get from a rough and ready experiment like this - having said that i added a bit on and cut a bit off to maintain width length and breadth the same
@@ThinkingandTinkering Well, that is perfect, thank you... it sounds like this technique can seriously improve airflow. I will definitely look into it!
The hit bird brings me to the point here in Germany was brought as an argument against wind turbines. Until some veterinerians said that actually a thousands of birds every year are killed by cats which are a real threat to some species. Then no one continued in that matter..
Unfortunately on practical terms the public concern matters more than that actual implications, in the same way the political implications of innovation don't necessarily translate to political perceptions
@@philip5940 They kill even eagles, the young ones while unattended. In Germany over 90% of bird kills are caused by cats. I even saw them here on my property killing them in their nests. When European Ships got ashore on unexplored islands during the last hundred years whole populations were killed by cats brought with them. Anywhere they were unwillingly introduced, they reached to survive in great numbers , in Australia as well as in in the far north regions where they killed almost all of the ground brewding populations. Cats are by far the biggest thread to any birds worldwide.
Nature inspired designs are such a great starting point for any project. Hm...the self starting issue is well a big issue. I would think that a little curvature on the thin blade side would probably help take care of that, though you would lose a bit on the air drag. In any case, turbines and batteries, and engines are what I am always curious about(especially those that seem lost to time, ie..historical yet odd designs). Thanks Rob for the video! It really gives me some food for thought. Keep doing what you are doing! Thanks again.
I just watched a documentary on Y.T. 2 days ago about the inventors of tubercles. I thought it was fascinating! I immediately thought " Robert Murray Smith would love this technology!" Ha, you're already on it!😎👍
That is a pretty remarkable difference . Like I said before they should be on all propellers. On wings as well but, I was thinking that these were designed after a whales so for water. That in my mind makes me think that using them for air the bumps should be ten times smaller since the decrease in density from water to air🤙🏻
- 10x, 100x or 1000x ?? (Density difference of air vs water is huge). - "Reynolds number" is a nondimensional metric used in fluid dynamics... (Point of research). Don't forget of course air speeds are usually 10x faster than water speeds(100x comes with compression issues mostly- high speed aircraft).
i am not sure it is that simple mate - lift is a product of fluid density and fluid velocity - so - though water is more dense it also moves more slowly - however, size, shape and distribution is a very active area of the research when it comes to tubercles - so good point
@@ThinkingandTinkering I think that it is worth testing. The results are already outstading but, I think that this will make a drastic difference still.
Would be really interesting to see if there is any difference between this smooth type and a very sharp one. Maybe the sharp tip would cut through turbulence even better.
Sorry for my english, but hope you will understand my idea. If you put a 25% diameter size shield on north-west side (from 9 to 12 o'clock) of construction - it will protect your generator of negative wind pressure and theoreticaly blades will go faster.
This is amazing!!! Now we have a VAWT that is 1.5 times more efficient than a conventional Darrieus turbine, at 45%. This will very well compete with conventional wind power in generation efficiency, which is 50-55%. Let's now add Tubercles to more efficient designs like Gorlov and Ugrinsky and see if they increase efficiency!!!
I like to see a comparison with and without tubercles on a model aircraft. I think for an aircraft type like the Fairchild Republic A-10 Thunderbolt it may very useful. Could even increase agility.
I watched a video of a Rutan E-Z airplane recently. On low airspeed it was quite wobbly with a canard in front and the wing at mid-fuselate. Maybe this kind of "improvement" to the canard would let it work better without increasing size.
2 things Robert; the balance won't let it start but it would if it was balanced and 3-7 degrees of to the outside of the leading edge depending on the symmetrical wing used will increase the torque and starting abilities as well as increasing power all through the range of rpm/tsr, try it, you'll be surprised
7:28 the little start need could be solved with the addition of a small windmill with a one directional gear. it could be just 3 square panels as it only has to get it started.
Nice work. Better if you had added a load to test the output difference. VAWT are great for yachts, as much safer, not swinging around, and easier to stop in high wind. If quieter even better, noise is the big drawback for turbines on yachts.
Bob is struggling with the cheapo tachometer 🙂 You should add a tachometer to the axle and/or device , one based on a hall effect would be nice. I always feel pain when you're struggling measuring RPM or other physical quantities.
Your next step is to outfit each type it with an identical generator and LEDs; then stand them both vertically to see the improvement portion difference in that which is more akin to a real world implementation. I'll download your files and follow this as well.
The orientation should make no difference (but its an easy test to do), but I was keen to see the impact of the tubercles on power generation (how much more power do the tubercles allow to be collected). Also, to make it a fair test, we need to consider whether adding tubercles is increasing the area of the blade or keeping this constant. 3D Printing provides the opportunity to design alternative blades that use the same mass of plastic, so we can be sure that each blade isn't slightly bigger and therefore gaining an advantage from its size rather than its shape.
That modification is very intersting. Robert, if you were to connect each turbine to a generator (Each turbine would need to use the same generator to keep things equal), with the same wind speed, and connect to a stable load. The speed of rotation of each turbine, under the same load, should determine if the modification also increases in torque, from the original. Just a thought🤔💭
Two issues with your test: 1. Having the blades close to the tabletop really screws up your results. It needs to be away from surfaces etc. 2. Skater bearings are not good, as the shield on the race inhibits free movement. Open race bearings are superior to shielded race bearings.
i am sorry mate neither of those are issues with the test as both were tested in the same conditions - they are issues with performance of a stand alone version that is true but that isn't what is being looked at
Another interesting similar idea is shark skin to blades, & wings instead of swimsuits, and adapt them for air? Which I imagine will cause micro Tubercel effect over the entire wing???
to me they (Tubercles) look like diffusers, so it's interesting that increases performance in that in some case they are meant to reduce drag and others they seem to increase vehicle stability implying a downward force
They might also be compared to Vortex Generators, and a comparison of VGs vs. Tubercles would be interesting. It would be easy for Robert to print a set of blades with VGs and run a comparative test. I think the testing also needs to look at different wind speeds to see whether the VGs or Tubercles are better at different speeds.
Hello my Friend, I have not commented in a while. I have always thought these tubiclals to be what large ships are missing from their design. If a boat or a ship were to have “wings” for underwater lift, keeping the ship more buoyant and more stable, along with the “infinity props” for propulsion, I bet shipping would move faster and also save on fuel. I really like the way you think. And your input helps me to think more, and in a different way. Who knows? Maybe a small personal submarine with a depth limiter could be in the future of recreational vehicles?
We also need a barrel spring ratchet winding to store the winds power to a capacity so that we may have some power stored enough energy to 3d print one more wind turbine
Very funny, even " just " the energy input to heat the hotend, may never be recovered. - a solwr panel will get that sorted in the interim, just have to recapture that embedded energy now... Lol.. it never ends.
So biomimicry, making the turbine more and more like a wing. Will a later video feature an entire chicken attached to a generator? Every video is highly entertaining. Cheers!
I was recently driving through West Texas, looking at all of the wind turbines that all look the same and the same as they did 10 years ago. I was thinking that surely there has to be a better way. I think legislation may have gotten in the way of inovation.
Hi Rob This reminds me of research the US navy did to understand why dolphins swim faster than their form should. They discovered that to go faster than their body shape allowed dolphins rippled their skin. I don’t know fluid dynamics but you might be able to incorporate this to increase speed of blades. André
I don't know how focused your airstream is, there, in your bench test, but if you look at the video I think you'll see that the two test mills would probably work a lot better if you raised the fan about 8-10cm.
@Robert Murry-Smith Could you try this on an Archemedes setup? It would good to see if it makes an improvement upon and already highly efficient wind turbine.
I think vertical turbines are far more appealing to the eye, and there are so many design options that could work, and we do need smaller scale solutions that can work in urban areas, vertical designs are showing some promise on that whereas horizontal designs are a no-go for urban areas. Still, we need to see some read world evidence of these new designs working well in urban areas like on a house, if it doesn't produce any meaningful energy then it's pointless, and so far, every time I see these new designs being tested, they always test them in ideal conditions where there are a lot of wins, if they really want to convince us, they really need to show them working in urban areas like on houses and show us the numbers it's generating, until then, solar is a better option.
Do you think the leading edge of a wing on a light aircraft with tubercles would generate more lift thus reducing take off and landing distance, power required, and can be done at lower (safer) speeds?
The Mexican Patent MX/a/2023/006829 Vertical Axis Wind and/or Hydraulic Turbine, Foldable, Multi Configurable and Synchronized Mixed Blades, does not harm birds
I'm wondering if those "tubercules" are going to be appearing on the next generation of airliner wings from Boeing and Airbus. It might be worth it even if they only give a tenth of the efficiency boost as in your demonstration.
I wonder why they think they have to raise the generator and everything up to the blades on a HAWT? Why not run a drive-shaft off a 90 degree gear behind the blades and the driveshaft will encourage a nice flywheel effect and the gensets being on the ground will have easier and safer access for maintenance.
Hmmmm, a thought... obviously one could test tubercles on the leading edge of the blades of the spinning turbine in a Darwin wind collector... but I wonder if they would also show significant benefit when applied to the leading edges of the collector itself, whether they be simple flat plates at 35degrees or parabolic cones.
Interesting it opens up several lines of enquiry, more smaller tubicles, or fewer larger tubicles, whether even sized tubicles or irregular sized ones works better?
absolutely mate - my choices on position, spacing, size etc where really pretty random - you are spot on i think - there are loads of things to be looking at
I forget what you call the air collector thing you were talking about a while ago, the one that's like a vertical tube, kind of, but with blades all around collecting the wind and pushing it downward.. Anyway, would the tubercles have a positive effect on that?
(how does your latest deal compare with a shading device to reduce drag experienced by the upwind blade - no longer truly "omni" but that's the deal with some designs) A voith schneider type of mechanism for VARIABLE AoA, will allow an improvement in "thrust"- torque- output throughout the cycle, at the "cost of complexity"... Nothing is free of course.
I'll predict right now that within 5 years we will see these on the front of commercial jet wings. Very similar to when commercial aviation added the upswept tips on the wings.
- then 10 years later they will disapear in whole or part, just like blended wingtips... Something trendier comes along (sometimes it works better too, wh just have to see)
The Rutan brothers were working on the wild-looking curved wing tips. But, I think it was more like 20 years before they were taken up by commercial aircraft. The airplane industry is very slow to adjust because they test things and they're just hesitant to change.
The first test your arm was a lot lower partly blocking the air from the model. 2nd test your arm was up out of the way of the airflow. Not a equal test. In any case HAWT will always be more efficient as the blades don’t have drag going back against the wind.
Have you tried dimples like on golf balls over the surface of the blade or maybe just along the trailing edge? Don't know if that would make a difference or not just a thought cheers
You could check out the owlet fan, commercialized by ziehl-abegg, which mimics the wing tips of owls, to reduce noise. There is a SciAm article, I think from the late 70s, which discusses why owl wing beats are most silent.
Seems a vawt on large scale would be better for wild life and longevity. Use a blade with a roughly 30°-45°'V' shape with 3 on a vertical axel. Stacking another offset by about 45°-60° , the repeat. With a 100'-150' diameter. Using a smallish 'V' scoop connecting the tips. At a angle with the v-scoop blades spiraling around the tips. With about 4-6 blade sets high seems it would be a decent turbine. If I had a 3D printer, and a hair drier, a British accent, I'd try it myself! *",* also; possibly have the top 'V' scoops at a different angle , possibly 60° , 70° , 80° maybe as much as 90° with tubicals on both the leading and trailing edges. See how goes it! ✌️
I did a whole bunch of research on vawt's. The slightest change in chord length can have dramatic results. Traditional turbines win hands down in so many ways. The main problem is sail area Vs materials used. Vawt's are like F1 cars. All speed and no pulling power. Fixing this torque problem comes at the expense of complexity. I have a complex solution to address the vawt issues but have never built it. You are welcome to try if your machining skills are up to it. The mechanical concept has dumbfounded everyone so far but I'm sure you are smart enough to get to grips with the drawings. Let me know.
@@ThinkingandTinkering I love all of them and tinkering. (Trying to resist topic drift) If adding the bumps on the trailing edge of the wing alters the overall chord length, it can have a really big effect. So your results (increase in rpm) could actually be better than you realize.
Well, in the US they are tearing down perfectly good smoke stacks. They could be retrofitted with wind turbines, and take advantage of the natural updraft
@@VinceSamios , not on the outside, have them inside, and the internal updraft would be controllable with dampers where air inlets such as removed breeching ducts are. Also, wouldn't have to be as heavy duty as vertical independent windmills
@@dash-4150 there's a concept called solar towers, which uses massive greenhouses and a very very tall tower. Like 1km tall. I don't think a smoke stack scale would make any sense whatsoever.
@@ThinkingandTinkering Yes. I'm attempting an STL for this after I figure out how to do this in CAD - easy to make a screw, but, not sure how to make it with the tubercles. At least not yet. I'll post something when I get something worked out. This is brilliant biomimicry tech! Love It!
Good one but the outer surface has to be more curved than the inner one to create a lift like on an airplane wing, here both sides looks pretty much the same
Was not expecting such a dramatic difference. Someone recently said to me that VAWTs are limited by size, by which I think he meant the distance from blade to axis. Is this true? I really feel like this is an under-developed and poorly researched option.
I am sorry mate but that doesn't mean anything to me - what did he mean limited by size? Did he mean there is only a certain size you can go to? Or did he mean size limits output? Either way that's true of everything - so a bit meaningless really
Legit question. If tubercules help with the efficiency in airfoils, how come airplanes have straight leading edges? Not trolling, I assure you. Thanks for any response.
it's a relatively new discovery mate and the airline industry s very conservative - for good reason - aircraft with tubercles are being investigated right now
You could if that paint would also be resistive enough to make heat. But this paint would aso need to be flexible enough, so your socks wouldn't turn into stiff rain boots. And painting them all would not be a good idea, instead just make a zig-zac line on the sole. You could use a conductive silicone. But i had such idea where you buy carbon fiber heating tape. First you can sew it gently on the sole, then add some silicone to bind it with material and protect from wear, connect a battery... But i bet you could find a heating socks cheaper. Unless ofcourse it is for tinkering and fun 😊
@@ThinkingandTinkering I watched it. It's a good video. It's easier to demo it in a cradle, I agree. It's also funny that it's on a horizontal axis is all. Funny to me anyway 🤷♂️
@@ThinkingandTinkering I watched it. It's a good video. It's easier to demo it in a cradle, I agree. It's also funny that it's on a horizontal axis is all. Funny to me anyway 🤷♂️
They already do it. There is a whole section of VAWTs designed for rooftops. I'm thinking about putting those on my rooftop for a while now. You can't see that from the ground level, so noone will be whining it is ruining the view. It's also not much visible from the top, it's accessible - whole construction is on it's side, so you can check it whenever you want. Very serviceable. 🙃
