you can find the stl files here www.thingivers... Don't forget to check out my companion channels TnT Onibus here / @tntomnibus and TnT Talk Time found here / @tnttalktime
Robert, when doing contra-rotation, I helps to have rotors that don't have the same number of blades so that they never all overlap each other all at once. If you use a five blade rotor in front and a six blade rotor in back, only one rotor at a time overlaps. This supposedly reduces noise and improves efficiency. Some of the most modern contra-rotating propeller planes do this.
apparently, the new RISE turbo prop use a static set of stators instead of a second contra-rotating prop to get most of the benefits of the 2nd prop without requiring any extra input
@@nimoadderI believe they are, otherwise the air would just spin round and round inside the turbine. The stationary blades make the air being pushed through. Actually, I know for a fact, that at least some Russian helicopter-turbines do have alternating rotating and stationary blades. I saw a guy on TH-cam tearing one apart and building it back up, so...
I did it robert. Rediscovered anxient egyptian mercury. Basically 3 years after starting my quest and one of my firsf people to watch was your videos. Thank you!
only because it is made from plastic with a lot of slack to make sure it turns mate - engineer this with bearings and the story would b completely different
I wouldnt confuse the two, contra rotaion is usually to eliminate a motion you dont need, say prop walk or other stuff. - I guess theres a reason the comon housefly dropped a pair of wings and replaced them by 2 adjustable counterweights.
I came up with a system consisting of a shoud & two contra-rotating blades, which were very close to each other, one idea was to have one blade being magnetic & the part of the shroud around it had conductors, whilst the other rotor was composed of conductors & the part of the shroud around it was composed of magnets, giving three areas where conductors are cutting through magnetic lines of force, hopefully maximising the energy being generated.
I think tge idea with contra rotating blades is the aerodynamics of the front blade should impart energy on the back blade. When the front blade rotates it creates a low pressure area behind itself, so when the blades pass by each other they're supposed to "pull" on each other due to the low pressure zone from the frontal blade. It'sbasically supposed to increasing effective wing span of the blades while minimizing the effect of drag. Proponents of this basically want an entire circle of thin blades staggered from each other in multiple layers. I think it's the same idea as jet engines, only without the front fan to suck in a large volume of air at high speeds. So you'd basically need an entirely new blade design for this hypothetical turbine.
I thought of this a few years ago. My thinking is that it would help systems that use an automotive alternator reach excitation RPM/speed at half of the wind speed. My thoughts were to rotate the body of the alternator and counter-rotate the shaft of the alternator.
This is a really nice video, and it raises a lot of questions. One such question is this: Does locking the axles together mean that the faster one (front) drives the other one (back) faster than the wind can turn it... and if that's so, won't that cause the back blade to add drag and resistance to the whole mechanism and negate whatever benefit you get from adding it in the first place? If the answer is "Yes", it seems that decoupling the blades and treating them as two separate wind turbines (designed for different wind speeds) should give better results. If the answer is "No", can someone please explain what actually happens, and the principles behind it? Thank you.
As a drone motor variation a contrarotating motor seems like a good idea. Should work for a generator but the extra weight of the extra blades may not be worth the gain.
For that set up I guess the real comparison should be if that harnesses any more energy than the normal double turbine given the extra inefficiencies in all the gearings and chain. My idea for contra rotating turbines is that one drives the magnets and the other drives the coil ( in opposite direction ) thereby increasing the relative speed to each other, although that will probably bring in the use of slip rings to get the energy out which adds a little extra maintenance.
with contra rotation maybe what you want is one coil and two sets of magnets, (one for each fan) but instead of having the magnets N S N S have one disc all north and the other all south sitting either side of the coils so you shouldn't have any north/south pairing, also the two fans don't necessarily have to be mechanically coupled, if the rear fan has to run slower then so will the front fan but decoupling them will let the leading fan run faster and the asynchronous rotation speed shouldn't be detrimental the the overall output. just some spur of the moment thoughts :)
The way you've arranged the gearing seems somewhat inefficient. If instead you took the output from the linking bevel gear with an output shaft running down the centre of the support to the generator. Not only will you have reduced the amount of redundant gearing, but it also becomes possible to turn the blades into the wind without moving the generator (no flexing of the connecting wires), as well as making the desired spacing between the two sets of blades easier (one each side of the supporting column).
@@jay90374 Not exactly if you did that the two fans would be independent and rotating in the same direction, also a more complex and therefore less efficient method. What I'm thinking of uses only 3 bevel gears (most car differentials use 6). Imagine the letter U made up of 3 bevel gears, the 2 uprights connect to the fans and the bottom gear connects to the output shaft.
An idea 💡 - not sure if you have done this.. but can't you have the one rotor mounted to the magnet plate and the other connected to the coil housing - this should result in a higher rate of flux change with the oposing rotation directions? :) a true contra rotating generator 😊 this does make the power connection a little trickier buuuut nothing you can't handle 😂
Problem with rotating the coils is that the coils then require slip rings for output which complicates the design a bit where as stationary coils don't and simplifies the design some what
I was thinking the same thing, I suspect a slip-ring would have less complexity (and certainly less losses) than the mechanical set up here. As for advantages, unless theres a noticeable output gain vs. the twin rotor design previously tried out, it could be useful in low wind speed applications, as would effectively double the generator speed without the need for gearing (and its losses).
All you need is a clever gearing system to have the counter-rotating blades power a single shat that turn a single plate of magnets. Don't certain WW2 bombers have counter-rotating propellers on a single engine?
Impressive Robert but why the extra chain drive? Surely the best position for the generator is on the intermediate bevel gear? At right angles to the wind and probably better cooling too.
you can change it as you wish mate - i put the chain in for others to be able to interface a variety of things easily - but it can just as easily be different if you want it to be
You're overcomplicating this design; Take your generator for a moment; we create two plates of magnets and two stator coils, one for the primary rotation and one for the counterrotation. Plate one and stater coil one are the larger diameter and used for the counterrotation blade, this will look like a ring frisbee or donut. In the donut hole of Plate one, is plate two, smaller in diameter for both the magnets and stater coil. Directly attach the drive shafts for both rotors to their respective generator disc setups. Now you have double the output of power without needing a ton of cogs and extra moving parts which can fail.
@@ThinkingandTinkering I understand the intent, that it's a test bed, but it is still overcomplicating the design. I'm not saying it isn't a cool design, or that I don't appreciate it for what it is, but it is an over complication. Perhaps consider an entirely different approach with the contra rotation, by using a vertical axis generator with two magnet plates and a central serpentine coil. The top magnet plate is driven by the counterclockwise front rotor while the bottom plate is directly driven by the clockwise rear rotor.
The benefits of contra-rotating blades on aircraft and boats is obvious, but for static wind turbines I can't see why they'd be better than non-contra-rotating blades. The problem with contra-rotating blades is that for part of the travel, the back blades are in the shadow of the fore blades, thus reducing efficiency. Aircraft and boats might be happy with that efficiency drop because of the benefits of balanced loads, but a static wind turbine can simply be made a tad sturdier to counteract the imbalance.
What about some vanes, don't they have a venturi effect? That is, make the wind travel twice the distance, first one way, then the other, and thereby speeding up the velocity of the wind? I think.
Thinking it would be interesting to compare output with a traditional 6 blade non-counter rotating setup. But as a twist, it would be interesting to also compare 6 blades in the same plane with 6 blades set on 2 planes, as in this experiment, but rotating in the same direction. Which in turn might lead to 6 blades on 6 planes.
Here is Lenz in turbulens and why we can ask! Can't force a square meter work like a cubic meter! And the diffrent will be 8 time's! Why I do not now but in test this come up and I just accept! So we can just get dubble effect in anti clockwise work but a higher speed! Now the questions is how much do we loose in gear looses? And this is why the simple solotions is the best! /Mikael
A couple of things strike me! 1. The first blade the wind hits will change the direction of the air moving immediately downwind of it. The amount of rotation (or vortex) created will depend on several factors not least the blade shape. So the optimal distance between would be dependent on those factors. Thinking further down the line it may be that you decide to incorporate FADEC into the prop. Having a variable pitch blade may complicate this too much though and would obviously affect the "sweet spot" needed for positioning the second blade set optimally! 2. These models are usually "proof of concept" (in your mind) but may well be commercially viable. By Commercially Viable I do not mean you would be purely in it for the money, but rather as an educational toy to teach these principals. Obviously self financing for that is a must! As a second angle on this it could also be an attractor to your channel, again allowing for the broadening of ideas and principles!
@@ThinkingandTinkering Yes I realise that. I was thinking of a kit of ready to assemble parts to form a toy for those without printers or the ability or knowledge to do it themselves. Or, dare I say it ... those who have not stumbled on the trove of knowledge on this channel! ;o) Maybe even a School thing (great for teaching principles with) but provided as a cheap kit that could also be a present for a kid and parent to have some quality time. To be honest it would be a good thing in higher education too. It would enable a deep knowledge of motors and generators and why they are the way they are!
Re your comment about contra rotating magnets. How about having a magnet sandwich, one coil then a magnet ring the above that another coin. So that both sides of the magnets are impinging on their own coils, double the output ?????? Steve
It would be interesting to see this design compared to the 6 bladed model you made a few weeks ago. Are you going to scale it up to the same swept area?
Do you really need all these gears and mechanical linkage? They all bring significant losses. Why not connect directly one set of blades to your serpentine coil and the other counter-rotating set to the ring of magnets? You will automatically get higher voltage. It will increase the rotation speed which is otherwise difficult to achieve without gears or making the generator prohibitively large.
Cost will be your biggest opponent here. I think it may cost as much as two windmills. And having two simple windmills will have a better uptime in the long run. And the added complexity with coaxial shafts and maybe gears will be a step back. Years ago they had gearboxes for matching the line frequency, but it had loses in heat and frequent breakdowns. Now they have direct drive to the generator, with a AC-DC-AC converter handling the line frequency. Less moving parts = more reliable. Even if you could engineer this with swiss precision, the up time will be lower. And noise will be higher. You will need 4 and 3 blades, to remove harmonic vibrations. On a standard windmill you have three swush sounds everytime it passes the tower. In this design with 4+3 blades, you have 12 swushes per rotation just between the blades plus 3 maybe 7 with the tower. That will be very noisy. You could counteract this by adding an angle to the blades, but that doesn't scale very well as you go bigger. The rotational forces will rip them of at some point. It is a lost cause, mate. 😊
it cost pennies mate - it's a test rig - it would help you work out the answer to the question you put -but it will cost you peanuts to find out - which is why the rig
I was working at mclaren automotive p16. I was watching a guy who was making development in wind dynamics. I said if there were 2 contra rotating crankshafts say like for a v 12the inertia would be equal. Like almost in a gearbox because the 2 shafts contra rotating. Like rubbish BMW motorcycles lop into a right hand turn but fight in left hand turns. Obviously someone liked that idea n I was sacked. Just sayin.
It looks great. Just keep it out of range of Ukrainian missiles. Sorry for the joke, but the world is crazy and making fun helps my sanity. Like the mechanical capacitor, I’m looking forward to your assistant coming back from uni to help with the measurements. Btw. I’m a sailor. Yachtie when I get a chance to leave Terra firma. As you probably know, all the wind turbines on yachts are single blades (and they are bloody noisy: so noisy that they are outlawed in many marinas because they drive people nuts). I’m intrigued by whether the contra rotation not only improves power generation but also allows the device to operate among polite company. Would love to see this proven.
@@ThinkingandTinkering This is a consequence of Betz's law. The first propeller takes about 59% of the wind's energy. This means the second one should be of a larger diameter and adapted to lower wind speeds (more blades).
Veljko Milkovic Pendulum water pump. Hi, Robert Murray Smith, please look at the pendulum water pump. You and Milkovic are geniuses. Thank you. (I just have to get to the right environment and finally I'll achieve something. I think I must become a shoemaker so that I can finally earn some money to support myself. I just don't have any money skills yet)
Only kinda sorta related... Why do they put the generators and gearboxes (literally tons of stuff) up on top of humongous poles instead of down at the base and running a shaft down?
Great video as always Rob very cool , a suggestion with serpentine generator have coil center with 2 opposed magnet disk each side , have magnets around each side Nth/sth , but matching nth/sth left to right with the wheel rotating vertically aswell , both sides magnet rigs locked together or 45° diagonal so not as hard to lock both sides together with magnets force.
True, but having the coils be stationary is advantageous because it makes the electrical power transmission easier by not requiring a wire coupling that can spin
@@Sebloe yep, they're pretty cheap too, but i think they wear over time, especially if they rotate a lot, and I'm not sure what the voltage or current limitations are for them
Interesting as an academic exercise but intuitively I don't think as efficient as twice the blades on a single axle. Friction of so many moving parts would decrease potential output.
If you say that one set of blades covers a usable area of 10%, would that leave 90% of the usable ariflow for the next set? You could then keep going until returns have diminished to a uneconomical point? It would add savings to the cost of setup. It would also be ideal for smaller scale turbines if you can gain the power of a much larger prop in. A smaller package.
This reminds me of a thought I once had... if each turbine follows Betz law, then how many turbines can we "stack" to harvest the remaining 40% or so energy left behind each turbine, and how close can we get to a 100% conversion of wind energy to whatever other form we choose?
Loads of questions , does this give a better output than a twin rotor , if you had a single 6 rotor propeller would it give the same output ,or better when you factor in less complexity and resistance... Obviously size difference,and spacing distance seen to be crucial ,
I can see this being applicable for catching the wind from multiple directions it would be interesting to see how it performs like in a vertical stack what's a propellers facing multiple directions or perhaps maybe that would cause too much turbulence and rip the whole thing apart. Just food for thought.
What if you had 2 sets of blades, one on each side of the mast, freely spinning, not connected to each other, one has the magnets and one has the coils both spinning roughly the same speed in opposite directions, would that not be like spinning a normal turbine twice the rpm? As you've said many times, moving the magnets over the coils quicker will generate more so spinning in opposite direction would be equivalent to increasing the rpm on a standard hawt?
How about using a planetary gearbox? Where you spin the ring gear one direction and the sun gear the other direction and your carrier for your planetary gears is your output and speed is determined by your tooth counts.
My apologies, but I am having trouble understanding the issue with rotating the magnetic plate. If you spin the coils in one direction and the magnetic plate in the opposite direction wouldn't they pass each other twice as fast as opposed to one being stationery?
Yes but generally you want either the coil or the magnetic plate rotating. From a strength of materials perspective there is less stress and strain and vibration on a lighter mass of rotation. So the trade off , what weighs less your coil or your magnets. Now another idea, contra rotating equal masses can reduce vibration by cancelling out rotational inertia. But the bearings must never go out or all of that material you saved because there is less stress/strain will be really stressed/strained out. Back to the magnets ,two magnetic fields rotating will add when they line up but they will subtract when they dont, the subtracted field strength will cost you half your energy.
As per comment above plus - how would you attach and balance the rotating body to the mechanism, including capturing the electricity off it if it is also moving?
it's spinning both plates in opposite directions mate while keeping the coil still - you can spin the magnets and coil if you want but it will mess up the wiring a lot
I agree the wiring would be fun to say the least if both were rotating, but I was attempting to ask about the part at the 55 second mark. I believe you said the magnets would end up north north and south south sometimes. Doesn't that happen anyway when only one is moving. This is the part I am not understanding. Thank you again for everything. I have learned a ton from you.
From the looks of it the front blades are forced to turn the rear blades at the same speed. To me this seems subtractive in speed but possibly additive in the torque of output. speed generally being the goal in a wind turbine generator would it make sense to reduce the gearing on the rear turbine blade set to maximize the speed of the output shaft?
I can udderstand contra rotating is useful in an hellicopter as it will make it more stable (it wont spin so you dont need a rotating blade on the tail. Im not sure the advantage in a windmil ie would it be better that two blades rotatiog in the same direction.
This is great, thank you. I'm curious what you do with all these energy devices. Do you have 100 wins turbines on your roof and an incredibly small power bill?
Lost me on contrarotating magnetic fields. Even tossed this at AI to double check my reasoning. Inertial frames of reference pretty clearly lays out that simply because we perceive one plate as stationary, it isn't. In reference to each other, they're both in motion either way. Ultimately what the advantage should be is running the contrarotation at a lower RPM to get the same output as the classic system. Even your example here shows this since you'd need a higher wind speed to get the same output in a 1 turbine system. The point is to eliminate the need for a gearbox and the losses associated with that.
your logic is wrong - AI doesn't help - AI is actually pretty stupid - it doesn't understand anything only what you put in - if you put error based logic in there you get error based answers out - sorry mate
@@ThinkingandTinkering Volta to my Galvani. One man's "nah" is another man's "eureka," so well have to agree to disagree. I'm well aware of the wikipedia-like pitfalls with AI, which is why I didn't stop reading there. I get ya and originally felt the same, but really should reconsider your bias against what's nothing more than a screwdriver also able to write above average poetry. If it truly was trash, it wouldn't have been able to help Ben from the channel Applied Science directly solve a chemistry problem caused by minute levels of dissolved CO2 he couldn't figure out.
In boats we call it duoprop, there's a lot of added complexity, but also something like 25% gain in output, what is happening is that you harvest the vortex from the tip of the blade, and as someone else already stated, keep one even, and one uneven number of blades, so they don't meet all at once, it prevents noise and vibration, they can still have the same "thrust" with different number of blades. Now imagine instead of gears, it had magnetic gearing instead, less los, and all the benefits, also easier to measure the difference, when testing. About the distance between rotors, obviously Volvo Penta and Mercury have done a lot of testing in water already, maybe someone else knows something about that.
So I am currently printing this after finding it on thingiverse. But I tried to scale it up to 140% but I cannot get the propeller with the longer shaft to push all the way through the other shorter propeller. Is one meant to be printed smaller ?
Robert, when doing contra-rotation, I helps to have rotors that don't have the same number of blades so that they never all overlap each other all at once. If you use a five blade rotor in front and a six blade rotor in back, only one rotor at a time overlaps. This supposedly reduces noise and improves efficiency. Some of the most modern contra-rotating propeller planes do this.
less noise = more efficient. Excellent response @berkana
have you tried making the rear set of blades bigger than the front?
I will t
@@TheAdeybob Yeah the blades should be 25% longer
Curved blades has the same effect and is simpler manufacture
apparently, the new RISE turbo prop use a static set of stators instead of a second contra-rotating prop to get most of the benefits of the 2nd prop without requiring any extra input
That's how turbine compressors work, alternating rotating and stationary blades
cheers mate
@@thekaxmax it isn't part of the compression, the stators are on the by-pass
@@nimoadderI believe they are, otherwise the air would just spin round and round inside the turbine. The stationary blades make the air being pushed through.
Actually, I know for a fact, that at least some Russian helicopter-turbines do have alternating rotating and stationary blades.
I saw a guy on TH-cam tearing one apart and building it back up, so...
@@TerrorTubbie666 search for the new RISE engine and you will see that the stators are acting as a contra rotating prop and arent insde the engine
It would be interesting to measure the RPM of the output cog with a single rotor vs double rotor (same orientation) vs double rotor (contrarotation).
I did it robert. Rediscovered anxient egyptian mercury. Basically 3 years after starting my quest and one of my firsf people to watch was your videos. Thank you!
Thanks for sharing!
Great video. I think the Contra-Rotating blade idea is great, but the mechanism seems to add more friction than the gain.
only because it is made from plastic with a lot of slack to make sure it turns mate - engineer this with bearings and the story would b completely different
I wouldnt confuse the two, contra rotaion is usually to eliminate a motion you dont need, say prop walk or other stuff. - I guess theres a reason the comon housefly dropped a pair of wings and replaced them by 2 adjustable counterweights.
cheers mate
To many moving parts = high losses. Thanks for another educational video. 👍
good point but it shows the principle and makes good frame work for others to test their own ideas
My uncle build one in 1976 patent it it was most effective but expensive.
cheers mate
I came up with a system consisting of a shoud & two contra-rotating blades, which were very close to each other, one idea was to have one blade being magnetic & the part of the shroud around it had conductors, whilst the other rotor was composed of conductors & the part of the shroud around it was composed of magnets, giving three areas where conductors are cutting through magnetic lines of force, hopefully maximising the energy being generated.
I think tge idea with contra rotating blades is the aerodynamics of the front blade should impart energy on the back blade. When the front blade rotates it creates a low pressure area behind itself, so when the blades pass by each other they're supposed to "pull" on each other due to the low pressure zone from the frontal blade.
It'sbasically supposed to increasing effective wing span of the blades while minimizing the effect of drag. Proponents of this basically want an entire circle of thin blades staggered from each other in multiple layers.
I think it's the same idea as jet engines, only without the front fan to suck in a large volume of air at high speeds. So you'd basically need an entirely new blade design for this hypothetical turbine.
Brill! I always wondered how contra rotating blades worked, thanks!!
cheers mate
I thought of this a few years ago. My thinking is that it would help systems that use an automotive alternator reach excitation RPM/speed at half of the wind speed. My thoughts were to rotate the body of the alternator and counter-rotate the shaft of the alternator.
if a larger space is needed between props have the back prop behind the mount this would also increase stability
good point mate
This is a really nice video, and it raises a lot of questions. One such question is this: Does locking the axles together mean that the faster one (front) drives the other one (back) faster than the wind can turn it... and if that's so, won't that cause the back blade to add drag and resistance to the whole mechanism and negate whatever benefit you get from adding it in the first place?
If the answer is "Yes", it seems that decoupling the blades and treating them as two separate wind turbines (designed for different wind speeds) should give better results.
If the answer is "No", can someone please explain what actually happens, and the principles behind it?
Thank you.
very good questions mate and this little rig would allow you to try it out and see
As a drone motor variation a contrarotating motor seems like a good idea. Should work for a generator but the extra weight of the extra blades may not be worth the gain.
For that set up I guess the real comparison should be if that harnesses any more energy than the normal double turbine given the extra inefficiencies in all the gearings and chain.
My idea for contra rotating turbines is that one drives the magnets and the other drives the coil ( in opposite direction ) thereby increasing the relative speed to each other, although that will probably bring in the use of slip rings to get the energy out which adds a little extra maintenance.
Would love to see which one produces more power - the doubled up single direction or the contra rotation double turbine blades.
Yes! Love the wind turbine videos❤🎉
cheers mate
It definitely seems like a good way to test the effectiveness of the primary blade set.
Excellent. I admire your honesty and generosity. Keep going strong.
cheers mate
I know that putting more blades on a common shaft reduces rpm but increases torque. Not sure about Contra rotating version.
The Past would have fits if it were introduced to this stuff.
with contra rotation maybe what you want is one coil and two sets of magnets, (one for each fan) but instead of having the magnets N S N S have one disc all north and the other all south sitting either side of the coils so you shouldn't have any north/south pairing, also the two fans don't necessarily have to be mechanically coupled, if the rear fan has to run slower then so will the front fan but decoupling them will let the leading fan run faster and the asynchronous rotation speed shouldn't be detrimental the the overall output. just some spur of the moment thoughts :)
This arrangement will couple them magnetically, which is OK for same direction of rotation but not for counter-rotation.
The way you've arranged the gearing seems somewhat inefficient.
If instead you took the output from the linking bevel gear with an output shaft running down the centre of the support to the generator.
Not only will you have reduced the amount of redundant gearing, but it also becomes possible to turn the blades into the wind without moving the generator (no flexing of the connecting wires), as well as making the desired spacing between the two sets of blades easier (one each side of the supporting column).
👍 cool, so basically you can take the differential off of a car and hang it with the drive shaft pointing down and blades where the wheels were?
@@jay90374 Not exactly if you did that the two fans would be independent and rotating in the same direction, also a more complex and therefore less efficient method.
What I'm thinking of uses only 3 bevel gears (most car differentials use 6).
Imagine the letter U made up of 3 bevel gears, the 2 uprights connect to the fans and the bottom gear connects to the output shaft.
lol - yes it is - but it doesn't make much difference mate this a frame work to test ideas - that is going to effect design
An idea 💡 - not sure if you have done this.. but can't you have the one rotor mounted to the magnet plate and the other connected to the coil housing - this should result in a higher rate of flux change with the oposing rotation directions? :) a true contra rotating generator 😊 this does make the power connection a little trickier buuuut nothing you can't handle 😂
Problem with rotating the coils is that the coils then require slip rings for output which complicates the design a bit where as stationary coils don't and simplifies the design some what
@@magapefarmshomestead6453oh agreed! Just a different way of going about it :)
that would make the wiring a bit of a pain mate but it could be done
I was thinking the same thing, I suspect a slip-ring would have less complexity (and certainly less losses) than the mechanical set up here. As for advantages, unless theres a noticeable output gain vs. the twin rotor design previously tried out, it could be useful in low wind speed applications, as would effectively double the generator speed without the need for gearing (and its losses).
All you need is a clever gearing system to have the counter-rotating blades power a single shat that turn a single plate of magnets.
Don't certain WW2 bombers have counter-rotating propellers on a single engine?
Impressive Robert but why the extra chain drive?
Surely the best position for the generator is on the intermediate bevel gear? At right angles to the wind and probably better cooling too.
you can change it as you wish mate - i put the chain in for others to be able to interface a variety of things easily - but it can just as easily be different if you want it to be
You're overcomplicating this design; Take your generator for a moment; we create two plates of magnets and two stator coils, one for the primary rotation and one for the counterrotation. Plate one and stater coil one are the larger diameter and used for the counterrotation blade, this will look like a ring frisbee or donut. In the donut hole of Plate one, is plate two, smaller in diameter for both the magnets and stater coil. Directly attach the drive shafts for both rotors to their respective generator disc setups. Now you have double the output of power without needing a ton of cogs and extra moving parts which can fail.
yes - but it is mean to be a test bed for others and that is going to influence the design
@@ThinkingandTinkering I understand the intent, that it's a test bed, but it is still overcomplicating the design. I'm not saying it isn't a cool design, or that I don't appreciate it for what it is, but it is an over complication.
Perhaps consider an entirely different approach with the contra rotation, by using a vertical axis generator with two magnet plates and a central serpentine coil. The top magnet plate is driven by the counterclockwise front rotor while the bottom plate is directly driven by the clockwise rear rotor.
@@ThinkingandTinkering I'll try to do a mockup in Blender and link you to it to demonstrate what I mean.
The benefits of contra-rotating blades on aircraft and boats is obvious, but for static wind turbines I can't see why they'd be better than non-contra-rotating blades. The problem with contra-rotating blades is that for part of the travel, the back blades are in the shadow of the fore blades, thus reducing efficiency. Aircraft and boats might be happy with that efficiency drop because of the benefits of balanced loads, but a static wind turbine can simply be made a tad sturdier to counteract the imbalance.
have a quick read at the research papers mate - this is a hot topic
What about some vanes, don't they have a venturi effect? That is, make the wind travel twice the distance, first one way, then the other, and thereby speeding up the velocity of the wind? I think.
i don't know
How about wimshurst generator windmill?
well this a good frame work to test ideas - so go for it mate
Thinking it would be interesting to compare output with a traditional 6 blade non-counter rotating setup. But as a twist, it would be interesting to also compare 6 blades in the same plane with 6 blades set on 2 planes, as in this experiment, but rotating in the same direction. Which in turn might lead to 6 blades on 6 planes.
well this a good frame work to test ideas - so go for it mate
Hi! What if the magnets rotated to one side and the coils to the other? (I understand that we would add to the complexity of using brushes)
So the Idea is to get more out of the same diameter? Possibly quite stupid idea but if thats the case why not use 4, 6 or more sets of blades?
Here is Lenz in turbulens and why we can ask! Can't force a square meter work like a cubic meter! And the diffrent will be 8 time's! Why I do not now but in test this come up and I just accept! So we can just get dubble effect in anti clockwise work but a higher speed! Now the questions is how much do we loose in gear looses? And this is why the simple solotions is the best! /Mikael
well this a good frame work to test ideas - so go for it mate give it a go and see
supercajifragilisticexpihalitosis!
A couple of things strike me!
1. The first blade the wind hits will change the direction of the air moving immediately downwind of it. The amount of rotation (or vortex) created will depend on several factors not least the blade shape. So the optimal distance between would be dependent on those factors. Thinking further down the line it may be that you decide to incorporate FADEC into the prop. Having a variable pitch blade may complicate this too much though and would obviously affect the "sweet spot" needed for positioning the second blade set optimally!
2. These models are usually "proof of concept" (in your mind) but may well be commercially viable. By Commercially Viable I do not mean you would be purely in it for the money, but rather as an educational toy to teach these principals. Obviously self financing for that is a must!
As a second angle on this it could also be an attractor to your channel, again allowing for the broadening of ideas and principles!
I agree with your points mate and they are interesting - on the second point I do provide all the models via thingiverse and they are open source
@@ThinkingandTinkering Yes I realise that. I was thinking of a kit of ready to assemble parts to form a toy for those without printers or the ability or knowledge to do it themselves. Or, dare I say it ... those who have not stumbled on the trove of knowledge on this channel! ;o)
Maybe even a School thing (great for teaching principles with) but provided as a cheap kit that could also be a present for a kid and parent to have some quality time.
To be honest it would be a good thing in higher education too. It would enable a deep knowledge of motors and generators and why they are the way they are!
Re your comment about contra rotating magnets. How about having a magnet sandwich, one coil then a magnet ring the above that another coin. So that both sides of the magnets are impinging on their own coils, double the output ?????? Steve
i wouldn't think so mate - but tbh the best answer is to give it a go and see
It would be interesting to see this design compared to the 6 bladed model you made a few weeks ago. Are you going to scale it up to the same swept area?
i May well do mate but the main point is to provide a frame work for others to test their ideas
Do you really need all these gears and mechanical linkage? They all bring significant losses. Why not connect directly one set of blades to your serpentine coil and the other counter-rotating set to the ring of magnets? You will automatically get higher voltage. It will increase the rotation speed which is otherwise difficult to achieve without gears or making the generator prohibitively large.
Cost will be your biggest opponent here. I think it may cost as much as two windmills. And having two simple windmills will have a better uptime in the long run.
And the added complexity with coaxial shafts and maybe gears will be a step back. Years ago they had gearboxes for matching the line frequency, but it had loses in heat and frequent breakdowns. Now they have direct drive to the generator, with a AC-DC-AC converter handling the line frequency. Less moving parts = more reliable.
Even if you could engineer this with swiss precision, the up time will be lower.
And noise will be higher. You will need 4 and 3 blades, to remove harmonic vibrations. On a standard windmill you have three swush sounds everytime it passes the tower. In this design with 4+3 blades, you have 12 swushes per rotation just between the blades plus 3 maybe 7 with the tower. That will be very noisy. You could counteract this by adding an angle to the blades, but that doesn't scale very well as you go bigger. The rotational forces will rip them of at some point.
It is a lost cause, mate. 😊
it cost pennies mate - it's a test rig - it would help you work out the answer to the question you put -but it will cost you peanuts to find out - which is why the rig
@@ThinkingandTinkering
Go big or go home. A windmill that size is useless.
I would also be interested to find out how much less power can be had if we were to remove one set of blades. I bet the loss would be 25-35%, NOT 50%.
well this a good frame work to test ideas - so go for it mate
Hi sir good morning sir, I am Kalyan from Guntakal, two wheeler bike frente suspension how to attach two wheeler pls send me video sir 🙏
I wonder how more better it would be with mars blades.
well this a good frame work to test ideas - so go for it mate
I was working at mclaren automotive p16.
I was watching a guy who was making development in wind dynamics.
I said if there were 2 contra rotating crankshafts say like for a v 12the inertia would be equal. Like almost in a gearbox because the 2 shafts contra rotating.
Like rubbish BMW motorcycles lop into a right hand turn but fight in left hand turns.
Obviously someone liked that idea n I was sacked. Just sayin.
Robert discovered the chain-link and overuses it 🙂
of course what else is it for lol
It looks great. Just keep it out of range of Ukrainian missiles. Sorry for the joke, but the world is crazy and making fun helps my sanity.
Like the mechanical capacitor, I’m looking forward to your assistant coming back from uni to help with the measurements.
Btw. I’m a sailor. Yachtie when I get a chance to leave Terra firma. As you probably know, all the wind turbines on yachts are single blades (and they are bloody noisy: so noisy that they are outlawed in many marinas because they drive people nuts). I’m intrigued by whether the contra rotation not only improves power generation but also allows the device to operate among polite company.
Would love to see this proven.
well you have a frame work mate - give it a go and see
very cool!😄😲
cheers mate
What is the efficiency of it?
no idea
Large bird “grinders?” Not to diminish innovations, rather to encourage similar thinking being applied to the world’s ecosystems in deployment.
Birds have to attend wind farm safety training, or else its their fault really.
😅
Cool.
cheers mate
The second propeller should be larger in diameter and have 5 blades
well this a good frame work to test ideas - so go for it mate - try it and see - doesn't sound like it would do much to me but I don't really know
@@ThinkingandTinkering This is a consequence of Betz's law. The first propeller takes about 59% of the wind's energy. This means the second one should be of a larger diameter and adapted to lower wind speeds (more blades).
:)
cheers mate
Veljko Milkovic
Pendulum water pump.
Hi, Robert Murray Smith, please look at the pendulum water pump.
You and Milkovic are geniuses.
Thank you.
(I just have to get to the right environment and finally I'll achieve something. I think I must become a shoemaker so that I can finally earn some money to support myself. I just don't have any money skills yet)
or you could just put a second stator on the other side of the magnets, now you could do both!
well this a good frame work to test ideas - so go for it mate
Only kinda sorta related...
Why do they put the generators and gearboxes (literally tons of stuff) up on top of humongous poles instead of down at the base and running a shaft down?
Great video as always Rob very cool , a suggestion with serpentine generator have coil center with 2 opposed magnet disk each side , have magnets around each side Nth/sth , but matching nth/sth left to right with the wheel rotating vertically aswell , both sides magnet rigs locked together or 45° diagonal so not as hard to lock both sides together with magnets force.
you could also have contra rotation where one set of blades drives the magnets and the other drives the coils the opposite way, doubling the speed.
True, but having the coils be stationary is advantageous because it makes the electrical power transmission easier by not requiring a wire coupling that can spin
It's a bugger to wire up, though
@@wikedawsomis that possible? Can you get wire coupling that spins?
@@thekaxmaxbut is it possible?
@@Sebloe yep, they're pretty cheap too, but i think they wear over time, especially if they rotate a lot, and I'm not sure what the voltage or current limitations are for them
@2:20 I guffawed .
awesome lol
Interesting as an academic exercise but intuitively I don't think as efficient as twice the blades on a single axle. Friction of so many moving parts would decrease potential output.
well this a good frame work to test ideas - so go for it mate give it a test for real
Awesome 👍 it's like doubling the size of your props with a smaller package
cheers mate
Love it! Well done man!
Thanks a ton!
If you say that one set of blades covers a usable area of 10%, would that leave 90% of the usable ariflow for the next set? You could then keep going until returns have diminished to a uneconomical point?
It would add savings to the cost of setup.
It would also be ideal for smaller scale turbines if you can gain the power of a much larger prop in. A smaller package.
This reminds me of a thought I once had... if each turbine follows Betz law, then how many turbines can we "stack" to harvest the remaining 40% or so energy left behind each turbine, and how close can we get to a 100% conversion of wind energy to whatever other form we choose?
Loads of questions , does this give a better output than a twin rotor , if you had a single 6 rotor propeller would it give the same output ,or better when you factor in less complexity and resistance...
Obviously size difference,and spacing distance seen to be crucial ,
I can see this being applicable for catching the wind from multiple directions it would be interesting to see how it performs like in a vertical stack what's a propellers facing multiple directions or perhaps maybe that would cause too much turbulence and rip the whole thing apart. Just food for thought.
What if you had 2 sets of blades, one on each side of the mast, freely spinning, not connected to each other, one has the magnets and one has the coils both spinning roughly the same speed in opposite directions, would that not be like spinning a normal turbine twice the rpm? As you've said many times, moving the magnets over the coils quicker will generate more so spinning in opposite direction would be equivalent to increasing the rpm on a standard hawt?
So I was thinking about this today. If it was good for energy generation they would have built windmills with two generators back to back.
How about using a planetary gearbox? Where you spin the ring gear one direction and the sun gear the other direction and your carrier for your planetary gears is your output and speed is determined by your tooth counts.
I will take EVERY engineering class this man has to offer lol
Do gyroscopes and pendulums not work well together, can they be made to?
propwash could maybe an issue?
Couldn't you jus squirt a little wd40
Would another coil on the other side of magnets yield more power?
My apologies, but I am having trouble understanding the issue with rotating the magnetic plate. If you spin the coils in one direction and the magnetic plate in the opposite direction wouldn't they pass each other twice as fast as opposed to one being stationery?
Yes but generally you want either the coil or the magnetic plate rotating. From a strength of materials perspective there is less stress and strain and vibration on a lighter mass of rotation. So the trade off , what weighs less your coil or your magnets. Now another idea, contra rotating equal masses can reduce vibration by cancelling out rotational inertia. But the bearings must never go out or all of that material you saved because there is less stress/strain will be really stressed/strained out. Back to the magnets ,two magnetic fields rotating will add when they line up but they will subtract when they dont, the subtracted field strength will cost you half your energy.
As per comment above plus - how would you attach and balance the rotating body to the mechanism, including capturing the electricity off it if it is also moving?
it's spinning both plates in opposite directions mate while keeping the coil still - you can spin the magnets and coil if you want but it will mess up the wiring a lot
I agree the wiring would be fun to say the least if both were rotating, but I was attempting to ask about the part at the 55 second mark. I believe you said the magnets would end up north north and south south sometimes. Doesn't that happen anyway when only one is moving. This is the part I am not understanding. Thank you again for everything. I have learned a ton from you.
Is "sticky out bit" a technical term?
From the looks of it the front blades are forced to turn the rear blades at the same speed. To me this seems subtractive in speed but possibly additive in the torque of output. speed generally being the goal in a wind turbine generator would it make sense to reduce the gearing on the rear turbine blade set to maximize the speed of the output shaft?
no mate - I showed them free running and independent right at the start of the video
I can udderstand contra rotating is useful in an hellicopter as it will make it more stable (it wont spin so you dont need a rotating blade on the tail. Im not sure the advantage in a windmil ie would it be better that two blades rotatiog in the same direction.
read around a bit on this mate - you will find it is a hot topic
Yay! Now I can complete my martian lander!
awesome lol
This is great, thank you. I'm curious what you do with all these energy devices. Do you have 100 wins turbines on your roof and an incredibly small power bill?
harmonics are used in jet engines I have been toiled
oh right
Great little machine. Always fun 😊 thank you 🤝
You do read the comments!! 😆✌️
I do! lol
Lost me on contrarotating magnetic fields. Even tossed this at AI to double check my reasoning. Inertial frames of reference pretty clearly lays out that simply because we perceive one plate as stationary, it isn't. In reference to each other, they're both in motion either way. Ultimately what the advantage should be is running the contrarotation at a lower RPM to get the same output as the classic system. Even your example here shows this since you'd need a higher wind speed to get the same output in a 1 turbine system. The point is to eliminate the need for a gearbox and the losses associated with that.
your logic is wrong - AI doesn't help - AI is actually pretty stupid - it doesn't understand anything only what you put in - if you put error based logic in there you get error based answers out - sorry mate
@@ThinkingandTinkering Volta to my Galvani. One man's "nah" is another man's "eureka," so well have to agree to disagree. I'm well aware of the wikipedia-like pitfalls with AI, which is why I didn't stop reading there. I get ya and originally felt the same, but really should reconsider your bias against what's nothing more than a screwdriver also able to write above average poetry. If it truly was trash, it wouldn't have been able to help Ben from the channel Applied Science directly solve a chemistry problem caused by minute levels of dissolved CO2 he couldn't figure out.
In boats we call it duoprop, there's a lot of added complexity, but also something like 25% gain in output, what is happening is that you harvest the vortex from the tip of the blade, and as someone else already stated, keep one even, and one uneven number of blades, so they don't meet all at once, it prevents noise and vibration, they can still have the same "thrust" with different number of blades.
Now imagine instead of gears, it had magnetic gearing instead, less los, and all the benefits, also easier to measure the difference, when testing.
About the distance between rotors, obviously Volvo Penta and Mercury have done a lot of testing in water already, maybe someone else knows something about that.
that is interesting mate - thanks for posting
This is the way forward, when it comes to maximising area and taking advantage of turbulence.
cheers mate
So I am currently printing this after finding it on thingiverse. But I tried to scale it up to 140% but I cannot get the propeller with the longer shaft to push all the way through the other shorter propeller. Is one meant to be printed smaller ?
You are so awesome!!!! Your vieos are fascinating!!!
Thank you so much!