Why is this Propeller Getting So Much Attention?
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- เผยแพร่เมื่อ 1 พ.ค. 2023
- Why is this Propeller Getting So Much Attention? Get an exclusive Surfshark deal! Enter promo code UNDECIDED for an extra 3 months free at surfshark.deals/undecided By changing the shape of a propeller design, we may have found a way to make drones (and a lot of other things that use propellers) not just quieter, but way more efficient. For some boating applications, the energy efficiency was boosted from 20% - 105%! Can this toroidal propeller really help everything from quieting tiny drones to helping boats sail further with less fossil fuels? And if just changing the propeller shape makes such a big impact, why haven’t we tried something like this sooner?
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Tedium of the constant injection of the "green" agenda misinformation forced into every video.
Toroidal shapes are found in nature, so it makes sense to make use of that blueprint.
I think they are good.
Matt,
The aerospace industry has been experimenting with "Open Rotor" designs for nearly 40 years now. The 20% fuel savings was known about in the 80's, but the noise and perception of passengers riding on a "propeller plane" instead of a "jet", along with fuel prices dropping prevented it from becoming mainstream.
My dad has patents on some of this tech dating back to the late 80's and early 90's. en.wikipedia.org/wiki/Propfan
I read about it some time ago. But PATENTS and this company can dictate the price, since no one else can make those.
I had this idea over 20 years ago after hearing about a plane with toroidal wing, but got told that "if it was any good, someone more educated would have done it already."
Thanks a lot, dad.
I understand that pain
To be fair, someone probably did do it already. Just because you're the first doesn't mean you'll get recognized for it.
That's not the mindset for any invention in human history...
Never, ever listen to someone who says things like that.
Yeah, that basically always means "that sounds hard and I'm too lazy" or "that sounds complicated and I'm not smart enough"
There’s no good reason why that toroidal propeller has to cost $5K. I’m all for making a profit on the design. Lower the price. Sell more props. Make more money. Bell curve.
Apparantly they are currently making the propellers by machining them from a solid block of stainless steel. If/when they move to casting or similar they will likely get much cheaper.
@@Anfros. It seems like a pretty good candidate for 3D printing if they are still gonna charge a ton for it.
Hehe tell that to the Eink patent holders .
It doesn't make sense
@@d3x0x Think they are moving to casting. 3D printing has pretty severe limits to material choice and properties that limits its usefulness for things like this.
It’s pretty weird to me that they aren’t cast. Most boat propellers are cast. With less noise at the same rpm, they should be even easier to cast durably.
its fascinating that the more advanced machines get, the more biological they start to look
@@rossimartiWhile Evolutionary optimization is a mathematical optimization method.
the term is bio-mimicry
@@untitled795 as a network engineer, I use principles in biomimicry 🦋 to optimimize networks and resources, to expedite fulfillment of requests, logistics 💫
to be fair nature did have a 3.7 billion year headstart in doing trial and error
I feel like "biological look" is subjective.
All this talk about the toroidal propellers and async propellers just has me excited that there's still so much potential for improving known working designs. It leaves you wondering or imagining if such a simple change like this yields 20% improvements across the board for multiple mediums... what's left on the table we haven't thought up yet to improve.
There are plenty of things that fit that description. The trick is to get the efficiency to sync up with the cost and existing manufacturing facilites. E.g. there are plenty of hyper-efficient airliner designs, but they mostly require non-standard manufacture and novel materials, which makes them unappealing to companies who have to protect their bottom line.
toilet paper, for example. just paper on a roll. george costanza thinks it cannot be improved. i think he is wrong.
Steam freely rises - condense to liquid power generator as it travels down power hot plate heat water make steam
@Paya So a bidet is what you are looking for, uses a small amount of water. You feel and are cleaner and you only need one small square of toilet paper to dry with. E
Very efficient
It would be extremely naive to say "such a simple change like this".
Because designing that kind of propeller requires a deep understanding of processes going on around spinning propeller, and these are quite complicated.
Manufacturing of such a complex shape requires precision computer controlled machines. It is not something that could easily be made in a garage.
So, we are producing propellers for almost two centuries, yet there is a room for improvement in that seemingly simple device.
I'm surprised by the absence of mention of the one word most engineers dread "turbulence", the design seems quite genius dealing with the turbulence and the fluid dynamics that come with the wing tip vortices. Dealing with the turbulent flow and harnessing it is definitely more than 2 birds in 1 stone. It's the entire flock :P
Definitely looking forward to the developments and applications. Thanks for the wonderful video covering topics like this as always.
And just imagine what we could achieve when we changed the traditional props on airplanes to these and changed those fan blades on turbofan jet engines to toroidial shapes. Now that would be interesting to see what sort of gains in power and fuel savings we would get there.
@@MrBrander Since turbofans pump directly into the engine's bypass/cooling duct, the outcome would likely be net negative.
If a toroidal prop dissipates wing tip vortices, I wonder if the same design can be applied to a stationary prop; a wing?
Maybe designing a stationary airfoil that incorporates such a design would improve flight capabilities of stationary wing aircraft?
@@ryanhungerford6448would the lower surface area of your new wing design also cut lift. Winglets already cut the leading edge vortices tip of most commercial passenger aircraft. It could definitely benefit current turboprop noise where these props already offer lower fuel consumption. Would it allow for a faster turboprop speed? I recall some speed limitations were due to leading edge tip damage as the local air nearby went supersonic
Nah, you do not need that- what you want to know is what will happen when you hit surface of the road, on your way down to a local lake...and how much $$ bills you will lose doing it.
Edit: There actually might be something more to it... I can't say more so make of that what you will.
I work for a marine propulsion engineering company. The props engineering team had a look into this and found the boosted efficiency claims to be wildly overstated, at least for the larger vessels we supply. As with most things, if it seems too good to be true, it usually is. They're a brilliant idea for drones though!
Maybe because large ships props run at lower RPM?
There's a boating channel on yt that tested the marine props. They seems to be tailor made to the specific engine setup. And the efficiency is mainly during half speed. Going full tilt removes any efficiency benefits and brings it on par with traditional props. But they have pretty fantastic stats when running them in their optimal conditions. Their price makes it somewhat infeasible right now however.
How it fairs on huge ships are yet to be evaluated I think.
@@brucec954 They also have CPP systems (Controllable Pitch Propeller) so they can keep their shafts spinning in one direction regardless of forward or reverse.
I had to imagine they were, 105%? If they claimed 15-30% it would seem more realistic
@@KoRntech The 105% was specifically at that 4000 RPM range. This why they only account for about a 20% fuel efficiency increase. If you operate outside that range there is not as much difference. That is usually how sales graphs work, they only grab the best case scenario.
For scenes where movement is important to illustrating something (i.e. I can't just pause the video and get enough information), like at 5:12 and 6:01, I would recommend making those clips longer (or putting them on a loop if they're short). I am repeatedly having to skip back, wait 7 seconds for the 3 second clip, try to see what is happening. I eventually just set playback speed really low on those parts, but it breaks up your narration and takes away from how well done everything else is.
The whole video is too fast to really take in most of the information. I get it that TH-camrs nowadays make their videos (incl. their voice recordings) a bit faster and usually I don't mind, but Ferrell overdoes it and his videos have become unwatchable to me on normal speed. It's a shame.
The reason people do that is so that you have to back the video up and re-watch the clip Again. TH-cam algorithm interprets that is a high-value engagement.
One relevant point that is getting little attention is that the benefits over traditional props are barely noticeable until the RPM's get relatively high (evidenced by the graph in this video). So instead of running these torroidal props at a high speed, the alternative is to run larger, traditional props at a slower speed, which most large commercial/military vessels do now. This will be a real game changer for drones and maybe light craft, but it will not reduce the carbon footprint of the shipping industry by half.
Why not both? If these are better even at low speed but making propellers bigger is better, why not use these but big?
RPM and prop size matters, despite small rpm the tip of prop is really fast due to how massive props are on cargo ships.
there's a limit to prop size that i think the shipping industry is already well aware of - ship draft. too big a prop would hit the bottom and break off. they really can't get any bigger safely.
But if this design works for them they could transport faster without increasing energy use. Faster transport means more profit for shipping.
I remember reading that the engines in cargo ships have a redline of only a few hundred RPM.
Those large ships you mention for the most part don't run on diesel (too expensive), they tend to run on bunker oil (cheap, energy-dense). They also tend to run at an engine rpm less than 400, which these props aren't designed for.
Turbulence/cavitation is still an issue in large ships and ducting the propellers would lead to significant energy savings. The problem with ducting propellers in ships is fowling and in drones, the extra mass is an issue. This propeller design avoids both those issues.
But engine rpm don't equal prop rpm which should be a lot more relevant for the prop design to be working or not, right? I'm no expert on boats or ships and would expect a cargo ship's prop to run slower than that of a boat but I can't make out why engine rpm should be a central argument
@@thilokm522 Actually in a big ship propeller rpm is probably the same as the engine rpm. However even propeller rpm is irrelevant, what is relevant is the speed of the tip of the propeller, which is a function of propeller rpm and propeller diameter. A big ship has a *much* larger propeller diameter, so the speed of the tip is still high enough that these sorts of propellers would be a significant improvement. If you can work out how to make them for large ships, then a 5% fuel saving means that next time the ship is in dry dock for maintenance if not before it is getting new propellers, even if they cost millions of dollars each.
@@jonathanbuzzard1376 More optimized prop shape is important, but a big issue with toroidal propellers in the open sea environment would be near continuous fowling with seaweed (not to mention other flotsam & jetsam). A fowled propeller vibrates violently and has significantly (40-70%) reduced efficiency. If a small inland or coastal boat prop gets fowled it is usually no big deal to stop & clear it-doing that with a huge freighter is another matter altogether. This is why self-clearing prop designs are such a big deal. (I should have added this to my original comment at the time I posted it.)
Some basic maths indicates that the tip speed of a 300mm diameter outboard engine at 4000 rpm is the same as that of a 10m diameter cargo ship prop doing 120 rpm
The conventional propeller shape also has a great benefit in its ability to allow for a mechanism to change the angle of attack of the blades. This is crucial for aircraft and some wind generators. It is a really interesting and challenging theme for engineers to develop an adaptable toroidal propeller.
Maybee it seems quite impossible at first, but to change the angle of attack, you can rotate the toroidal shape like a conventional propeller, at least to my understanding.
Turbulence=power loss. Same but different thought.. . Gasoline engines make a bunch of noise. Why are we not harnessing the energy that makes the loud pop. Obviously there's quite a bit of energy still coming out of the engine when the exhaust valves open. It just seems like technology would be better suited to harness this energy other than just a turbo to force the air back in.
@@brian6739 In F1 they use this thing called MGU-H to make the turbo more efficient and to harness some of the lost energy, it's almost like magic.
@@brian6739 it's called a turbo
I think variable props at best get around 75-80% more efficient over fixed props. But if there’s a baseline 200% more thrust and less turbulence of vortices (increasing overall lift with smoother air) is a easy upgrade as maintaining a fixed prop over a variable is drastic.
My first thought when I see this propeller applied to marine applications is thats what those covered submarine props have looked like for years and militaries wanted to keep secret. Crazy how something that has been around for so long and utilized so much is still undergoing improvements to design.
Yeah they had classified the tech that let them not produce bubbles in the water and eliminate the churning sound they would make, I think it might be how long it takes civilian markets to figure it out on their own, but it is pretty shitty they prolly knew the whole time
unlikely. pictures of american props have leaked before and they were not toroidal. i'm pretty sure this is an entirely new technology.
"marinetime" lol
Finally, a satisfying video! You answered all of your initial questions from beginning to end. Both micro- and macro-applications were considered and the mechanical aspect was fairly visible. Thanks!
The applications for wind energy could also be interesting. Smaller designs for consumer units for the same output is a game changer.
That was my first thought but I suspect the really big problem will be their weight.
I don't think that adding a toroidal propeller on a wind turbine is a good idea at all, at least not as a way to improve efficiency. Something might be said for noise reduction, but it probably would come at quite an efficiency loss. This is because in such a toroidal design, the two sides of the blade follow each other rather closely, meaning that the second blade gets more disturbed air. This is why a 4 bladed turbine is already inefficient, so 20 degrees or so separation with a toroidal shaped blade is certainly not efficient. Unlike the powerboat propeller where efficiency loss due to vortexes and cavitation at the wingtip are huge, the loss due to vortexes at the low rpm of a wind turbine are just not big enough. (This is also why this shape is not more efficient for drones even at their high rpm: wingtip vortexes in air are far less bad than in water)
That was my first thought as well
Many prototype small scale wind turbines do use a toroidal prop similar to these designs. They do this to optimize the design for very low wind speeds typically found near home roofs rather than the higher speeds of real wind turbine farms built much taller. You can find some of them in other videos Matt Farrell has done.
Not really. Not in the least. The video is extremely misleading on this. Wind turbines already use variable pitch props. Their RPMs generally do not produce significant sounds within this annoyance frequency. Accordingly, this technology basically offers zero to most market segments which require propellers.
"Save two birds with one stone"
Very exciting to live today! So much to look forward to. I hope we all can live long enough to see the future
This is fascinating! It might be interesting to see how this might work in combination with a Kort Nozzle in lower speed applications, as in towing vessels, how well it works in reverse, and the effects on vessel or aircraft maneuverability. I'd love to try one out! Propellers have come such a long way just in my lifetime, and I imagine there is a great deal more to learn. Many thanks!
I’d like to see some more independent real world testing on these. Seems like everybody is buying the efficiency gains without much skepticism
As always Matt, your videos are informative and interesting at the same time.
You deserve props
Thanks! Glad you enjoyed it.
@Undecided with Matt Ferrell Did I just slide a propeller joke by you unnoticed?
And full of wishful thinking
@@jopo7996 power to the punsters!
This has applications in many systems that propel things through fluids (air and liquids) and move the fluids themselves.
The thing you overlooked was that these propellers are indeed much more efficient, and as you showed especially at 3000-5000 rpm. Big container ships however do not have propellers operating at these speeds (because this is very inefficient!) and they run at about 100 rpm. So toroidal propellers probably don't help for this application. For drones, they are more quiet, but not more efficient.
Completely correct. Most of the information provided in the video is extremely inaccurate and misleading.
Why are they not more efficient for drones?
@@webdactic I think it has to be optimised for drones. It's hard to say
@@webdactic For tri/quad+ type drones with fixed pitched props, they likely are more efficient. But he also showed drone airplanes, which are likely to provide little benefit. Specially with larger drones where variable pitched props are already common. For things like boats and tri/quad+ drones, which have a large RPM window, constantly speeding up and slowing down, especially with a large transition period (such a boat coming onto plane), benefits are likely to be found. For others, where variable pitched props are already common (wind turbines, most airplanes), benefits are likely to be significantly reduced or all but absent.
@@justanothercomment416 The MIT page on this states that it ""achieves thrust comparable to that of a multirotor drone propeller" not more. Probably because the efficiency loss of wingtip vortexes in air is significantly less than in water where cavitation is a huge problem. There is an inherent inefficiency with dirty air in the toroidal design and even at the high RPMs a drone operates at, it seems this is still slightly more than the gains from the reduced vortex drag.
I've wondered how efficient this propeller design would be in a wind turbine.
It would make a more efficient blade no doubt.
(I used to work on wind turbine blades)
but the blades need to be actuated independently (optimize angle of attack during rotation). So this would be difficult, also the blades would require much more material. these blades are already massive(~13tons) , and non biodegradable (they just bury them) So I'm not sure the benefits would outweight the cost. no pun intended.
I guess one could reduce the size of the blade to compensate for material and justify it by the increase in efficiency. But the engineering required to manufacture something that large, transport, and repair it. Seem unfeasible/un-Scaleable
What if they were used in Darwin-style turbines, the ones with the fans bladed laying flat midway up a tower that channels wind from the top down a tube. Consistent power, only one angle, air always flowing the same direction regardless of wind. I've been thinking on the feasibility of 'power chimneys' on top of large buildings, with their air output being funnelled into the building's A/C system, the power running basic services like lights and elevators.@@daizhanennals1485
@@daizhanennals1485 As for the angle of attack, some aircraft have a propeller where the pitch of the blades can be changed. I don't see why a wind turbine can't do the same thing.
@@twistedyogert All wind turbines can adjust the angle of attack..
Wind turbine blades are already enormous. It would be impossible to make the blades like that.
all of these designs just remind me of the fluid dynamics explored by Viktor Schauberger. It's good to see it applied to a workable model. Also with the boat propeller, the major cost is with the fact that it's being machined from billet material, instead of being made from cast bronze. If it were cast, then it would be highly comparable to your average propeller as the volume of material isn't that much greater.
I’ve read the MAIN reason this hasn’t come sooner is that the inventors - particularly MIT - wanted to monetize it like everything else that comes out of there.
IMO, our Patent system is why we can't have nice things.
@@AmeriMutt76 it's why we have them
It's simpler than that and it was mentioned in the video. A high initial cost which in turn yields savings in the long term is simply antithetical to how capitalism works. If companies in capitalism were able to make solid long term decisions, climate change wouldn't be as big of an issue. But a system that will always value the quick buck over anything that's years down the line by design is adverse to changes like these.
@@ST-in7fo It's why so many nice things cost more in America than it does everywhere else.
They don't want their hard work stolen. I get that.
This is great, tnx for the info. It kinda sorta reminds me of the little winglets on the aircraft wings to reduce tip voratces. If you look at a jet landing in the rain you see the spirals coming off the wing tips.
Excellent report. What is astounding is how a propeller's design is really at the heart of the pollution problem. What is second on the list is how to get more power from fuel combustion.
8:17 "Surely someone must have been out there experimenting with non standard propeller shapes."
Militaries with modern submarines: *Nervous sweating*
Major Hardware did a couple episodes on the design. I am not a 3d modeler however I noticed that the drone propellers and all the PC fan designs did not have the depth that the boat prop had. A PC fan unlike a drone prop would need higher static pressure for efficiency as the weight is less of an issue compared to a drone application. More depth and less distance between the blades would greatly improve static pressure. It would be interesting to see someone create different designs between depth and possibly more blades to figure out the prop-er applications for this revolutionary concept. - @UndecidedMF I appreciate you letting this stew for a while to see what new comes up before making a video about it.
It would have been cool if this video included a quick reference to Major Hardware testing creative 3d printed designs based on user submissions. Even though it may not be drones or ships, their findings could foster other applications, like you noted this design was on a couple episodes. I like how he reports rpms, flow, sound, etc.
My physics game is weak, but in researching Sharrow (before I saw the price, more than my boat!) they made the point that in a ducted situation, the anti-cavitation and tip vortecise benifets reverse and are actually worse in most cases. They were testing for bow-thrusters. Probably not a magic bullet for Major Hardwares fan design test, but always cool to watch the tests
I like how they improved the propeller by splitting it in half making two propellers in one. They have done a similar thing with propeller engines for aircraft as well.
Amazing innovation that will go a long way across many sectors and Matt put it across with gusto. Nice
The nice things about noisy drones is when you can zip a drone in and park it a couple of feet above your friends head before they realize what you are doing and then increase the prop speed to make it shoot straight up.
Specially when you are far enough away that he can not catch up with you before he tires out and stops. Of course, that means you are going to have to be prepared and not get upset when he eventually does the same to you. Or he figures out a way to accurately drop water balloons on your head, in January, when it is 10 degrees.
Lots of fun.
I wanna take my time out to appreciate the intro of Matt's videos. I have watched so many and have always felt this excitement for his content. The intro is so well written, always creates a hype which is followed by the perfect beat drop and music!! Appreciation and kudos to Matt and his team
WTF?
Slurp
so else was worried when, in that one episode, the music had been changed to a more upbeat version? Glad they reverted that decision - it's just the most perfect opening music of any TH-cam channel 😄👏
The manufacturing issue is that one can't use existing injection molding techniques because the toroidal shape allows for no seam that let's you separate the piece from the mold. The part always traps itself by preventing the mold halves from separating from each other.
At a small scale, additive manufacturing (3d printing) gets around this, but with severe limitations in how strong/light/thin/smooth it can be.
For big metal propellers, the final casting isn't a problem as it simply breaks away, but the first step in casting requires creating a positive wax plug (which is then coated with layers of ceramic to make a shell, the wax is melted out, and replaced with molten metal, then ceramic shell is broken away). The wax plug is made using regular injection molding and for toroidal shapes has the same problem getting trapped inside the mold. Sharrow's propellers are $5000 each because each one is milled from a solid block of metal. Obviously that will not scale up. Fixing this will require some completely new molding techniques. (molds with more than two pieces hat separate in multiple directions)
The other issue with these props (at least for drones) is that they are heavier, which limits the performance and stability of the drone. Not an issue for a traditional flying tripod style drone, but for a race or cinequad chasing an extreme athlete through a race course it's a problem (and one where the style of drone is the most noisy and annoying to athletes and spectators alike).
I have a micro quad copter that I have been tinkering with various 3D printed toroidal propeller designs. It has a one button takeoff and land function that uses lidar to detect its position off the ground. The higher efficiency propellers throw off the algorithm for this function to a point that rather than coming a meter off the ground and just staying there, it shoots up to 2-3 meters, drops down to half a meter, and fluctuates up and down several times before settling in at one meter.
You'll get the same benefit more cheaply by simply ducting your propellers. In general though, physical characteristics change with scale so the benefit difference probably won't be much on your micro quad.
This video popped up in my feed, glad I watched it. This stuff is exciting
Nice video, great implementation of this topic!
Have you somehow come across approaches to use the toroidal concept for wind turbines? It would be exciting to develop a particularly quiet (small) wind turbine. Here, too, tip vorticies should be a cause of noise development!
Due to the aerodynamics, however, the design would of course have to be different. An optimal fan is after all, as we all know, a catastrophic wind turbine system.
There are many solutions to tip noise, through designs that we already have, that wouldn't require a completely new prop design.
Additionally, we look for a design that takes the least amount of material to produce. Weight and eol disposal are factors.
The Toroidal design takes a lot more material. This rules it out for most real world applications.
The first time I ever saw a torodial windturbine was a horizontal desing back in the late 70's on a green energy exposition. As i remember correctly it was mostly too complex to scale up. One of the most remarkable things was the flexible desing let it change height and diameter when (wind)speed variated.
Hi Matt, I discovered this propeller a few months ago; I contacted someone I know in the electric boat industry; they told me they already knew about Sharrow, had tested it extensively and found no noticeable difference in efficiency; such a shame as electric boats need all the efficiency gains they can get due to battery range restrictions.
Sounds like your friend needs to improve their testing methods.
Maybe they work best in sharrow water.
@@ernestdambach8925 it’s possible that the electric boat uses larger slower props due to electrics better torque at low speeds. ICE outboards basically use the water as a torque converter.
It might be that this toroidal prop is not going to make much of a difference for an electric powered boat on the basis that electric motors have very flat efficiency curves. If you consider an ICE the efficiency curve shows a dramatic reduction as you move from the peak torque (peak thermal efficiency) operating condition.
@@michaelharrison1093 Yes, that will have an impact however Sharrow also talks about the hydrodynamics which is separate from the engine/motor dynamics.
I watched a few videos on this subject, and it is amazing the savings that can be made!
Great topic! Thanks for updating us and sharing.
All the best.
I would love to see this design in computer fans and graphics card fans and even PSU fans to help reduce their noise. Just imagine how much quieter your computers would be...
What is fascinating is cavitation is actually from boiling water, yes the water boils due to the low pressure created from the boat prop. Love your videos!!
yes , by definition cavitation / boiling is when the pressure of the gas inside a liquid = atmospheric pressure above or around that liquid.... therefore if the propeller spins, it lowers the pressure inside the liquid to become more and more equal to the atmospheric pressure , then the bubbles pop. same physics in your kettle with heat doing the work, gas pressure in boiling water lowers to atmospheric pressure
I think the most fascinating part is that the water freezes after it boils! Maybe not behind a boat propeller, but just in laboratory conditions. (Vacuum chamber, etc.)
Thanks for all that information which is so useful and I appreciate and admire this channel
I saw some video about these propellers about a month ago. This is so cool. Industry has lots of money to invest in this kind of tech, which makes you wonder why this didn't happen sooner. I hope to see wide adoption of this propeller by many industries soon. Thank you.
Matt, this is what you do best - again and again. I've seen other videos on this, and kept an eye out of sincere interest, both as an engineer specializing in innovation and as a person concerned about our planet. You weighed in with a balanced summary of the current state of the development situation with clear technology. I've seen you do this multiple times as innovation moved forward for solar and batteries. I hope to see an update from you soon regarding the development of larger marine propellors and also toroidal drone propellors coming into use. And maybe an actual study of cost saving over time for boat owners who buy the more expensive toroidal propellors.
Great stuff.
Thanks for the heart, Matt.
Cavitation in water is an interesting subject that I've never seen explained very well. I used to hear that the cavities were air bubbles, but that is not true in all cases. You suggest steam. Even if true, I don't think heat is the key factor. I believe, at sufficient speed, a propellor literally breakds the water (as if the water were a solid) and there is an empty vacuum cavity. This would create steam even at low temperatures, as the boiling point of water is lower at low pressure near a vacuum.
Either way, the cavity would collapse quickly as the pressure of the surrounding water closed in. The steam, if any, would turn to water very quickly due to cooler temperatures and higher pressure.
I don't know if anyone has ever explored the details of whether cavities are empty vacuum, steam, or something else, and what the temperature is. Do you?
Relevant to your video, the toroidal propeller is more efficient because it puts more energy into moving water out at higher speeds and less energy creating vacuum cavities and noise and heat.
@@sidkemp4672 cavitation is formed from a vacuum, yes. Depending on the fluid it may fill with gases but it's mostly low pressure. The shock waves caused by this and their rapid collapse are what cause damage, at least that's my understanding.
Think of fluid in a vertical tube, sealed at one end, whether its Mercury or water, there is a length of tube where if the tube is made to rise out of the fluid, the top portion will always be a vacuum, like a Mercury pressure gauge. Same principle, if a little more complicated.
@@jdmjesus6103 Thanks JDM. This is what I thought. One difference between cavitation bubbles and glass tubes for mercury pressure gauges. As the walls of the cavitation near-vacuum space in water are liquid, the the cavitation space can disappear completely. This won't happen in the glass pressure gauge unless it breaks. Am I correct?
And thanks for mentioning damage - very relevant. I was focused in inefficiency.
Are you aware of any sources for articles I can read or videos I can view if I have an engineering background, but not hydralics, and I am interested in the measurement and dynamics of cavitation?
We looked Into this as well at our university. It seems most comparisons they Made were not with State of the art props en thus their efficiency gains are overestimated. Another slight issue is their inability for pitch control, limiting the use for windturbines and aircraft. Still a great video!
Just having less noise would be enough for some applications
Matt is just is a "NEATO" cheerleader ----he cries Go ,STUFFF! yea! now where are my blind followers, click- like my prettieszzz
I didn't need to look at it, "105%" efficiency told me everything I need to know.
Great show, thanks Matt!
Very exciting story! I hope you'll do an update when there are new developments in this area, such as commercial applications and cuts in production costs.
I am guessing that this is a prop suited for certain size vessels and is ideal to work in its specific field and application. If you work a prop that operates at an inefficent ratio for the majority of it's use, but that use is in the optimal performance for the toroidal prop, then it is likely best practice to use the toroidal prop in that application. Its not a one hat fits all situation, its a sun hat for a sunny day that you'd never wear in the rain
You had me at "donut shape". I knew I liked donuts for a good reason. D-OH.
Nice video on its history and potential- have heard of them over the last year, but no real details. Thanks for filling the gap.
Great video, thank you for making it.
5 years ago, there were those new torrodial formed carbon high profile wheels for cycling. For the lowest aero drag possible. At that time, they were more stable, efficient and stiffer. But they didn't get a lot of media traction
I find the beep a vehicle makes when backing up the most annoying sound on earth.
I work for Kongsberg, and I hadn't heard of that scandal😲. Reading up on it now. Thanks for a great video 😀.
I remember in 1970 I saw the same type of boat propeller used in Ocean City Maryland. This is not new but a cool idea Matt. Nive video.
Great content. I have subscribed to your channel for a while now, and I always find your production value high, and the quality of your content to be fantastic. I would gather that the cost of those propellers would have something to do with the precision needed to build them, as well as if there are any patents associated with their construction. But the whole technology sounds promising for many applications. Even wind turbines and other fluid dynamic applications. Thanks again as always.
This also shows the possibilities of innovation and imagination. Those that shut it down seem to suffer from a lack of those aforementioned qualities. I suggest that looking at this topic with vision towards the future, and the possibilities it can explore and uncover.
My first thought when I originally learned about these was if this sort of design would offer any benefits for something like the Mars drone... I'm curious how they would perform in a lower gravity, lower air pressure environment. And what kind of modifications would be necessary, if it is workable...
unloading the wing tips also
is very beneficial in reducing the drag of wings and propellers
I like the sound of drones, especially fast quads zooming around.
This is super interesting. I wonder if this “toroid” design can be translated into new props for GA aircraft.
Unlikely. Variable pitch propellers are already very efficent and, in the case of an engine failure, can be feathered to reduce drag which is not an insubstantial advantage. Without using some kind of super exotic material with a name like 'morph-o-metal' or something I can't see any advantages personally for using toroid. If you're using a fixed pitch prop it's because you can't afford a variable pitch, and if you can't afford a variable pitch...
Be interesting to see if the prop would make any difference in large cargo ships considering they only turn at a few hundred rpm. Based on the graph the smaller prop was good around cruising at 4000 rpm. But lower in the rpm it was barely more efficient.
Cargo ships run their props at slow speeds because that is where they are most efficient. If they could use this type of prop and be just as efficient at 10 times the RPM, they could cruise the seas at a much faster pace at the same MPH they get now.
Ships do have a much lower rpm, but they also have a much larger prop diameter, resulting in a similar tip speed when compared to stationary water. This tauroidal prop seems to gain efficiency based on tip speed, not rpm.
@@Shepshop1620, why not a smaller prop turning faster and generating the same thrust? Maybe a smaller power plant could be used?
Nothing is going to push one of those monsters beyond its hull speed, of course.
I would bet these would be fantastic for tug boats.
How about those high speed hydrofoil ferry boats?
Then there are the military applications...
This is pretty big news, I think.
@@MyName-tb9oz Faster rpm means much more wear and tear , needing to design entirely new engines and more emissions.
Not really, @@Wayoutthere. None of those, and particularly not more emissions. A new engine design seems fairly unlikely. Unless someone just wants to spend a lot of money rather than using something that is already available.
Thanks Matt, i finally understood cavitation.
Thank you for making your videos. They are addictive.
Would love to experience the boat propeller. that sound difference is crazy. Boats tend to be very inefficient due to all the drag. this propeller may pave the way to electric boats, where energy density has been a major concern
It's a six bladed propeller (three blades are swept forward, three are swept back, and they are joined where each set meet) that is being compared to a three bladed propeller that is horrifically overworked. The engine nearly needs to over-rev just to get the boat planing. If your boat isn't planing at 3000 rpm, something is horrifically wrong.
Ask yourself, why did they need to compare their prop to a terribly overworked and so will appear hyper inefficient standard prop of half the displacement? Because they're trying to disguise the fact that they've designed a six bladed prop, which will itself be fairly inefficient for most modern small boats. Hell, even nuclear submarines that don't need to care about efficiency at all, just noise, only go up to seven, and usually five.
More props means less efficiency, but they also mean lower loading per blade, which makes them feel and act like they're spinning than they really are. The lower loading means they cavitate at high RPM's, in this case high enough that the boat doesn't reach that limit. You can achieve the same with a conventional 6 bladed prop if you really want. You can also get a properly sized larger diameter three blade prop, or four if you really need it, to achieve the same lower loading without having to increase the blade count and cut efficiency.
Again, very serious question, why is the company that is trying to justify you buying their 5K propeller only showing comparisons to what is blatantly an undersized prop? Why are they not comparing a cheap, inefficient, and badly designed three blade prop most engines come with? Why did they go out of their way to undersize the test prop so badly?
Oh, because their prop doesn't create any savings or benefits when compared to a similar loaded and bladed prop, aside from being heavier and having higher form drag, which actually makes it slightly worse than a same sized six blade prop.
Do the math if you don't believe me, or buy it and run it yourself.
I think it would be cool to see some applications within jet turbines, like maybe toroidal compressor blades at the first stage to suck in higher volumes of air for higher fuel efficiencies?
Turbines don't have the same problems with tip turbulence. The blades run very close to the body of the compressor.
Great info as always!
The original units of this type from the beginning of engine power were 'screws' - that is air screws on heavy copter designs that never got off the ground and were laughed at, and screws that were on vessels in the water that produced excellent propulsion.
This current Toroidal concept picks up where that left off, getting rid of the entire mass of the large screw and still using the efficiency of the physical design structure.
I wonder if this design might improve PC fan efficiency and volume. I know that depending on your PC build you may be more interested in static pressure over airflow in general, but if this blade design can help either, I can think of at least two companies that would be interested (beQuiet! and Noctua).
Also, if this is capable of moving enough air, this could also improve HVAC sounds and efficiency. Out the game in your car that moves the vent air around. We benefit from more fans than you may think initially.
I would buy a toroidal pc fan just because they would look cool
I love these videos. They give me hope that humanity is researching and developing a better world. They also show us what are possible implications of each new tech instead of only talking about the new tech. Thank you for your work!
Humanity is not, the upper echelons are just finding new and faster ways to empty the pockets of the plebs, all in the name of the latest buzzword "environmentalism".
Thanks for giving credit to the very early (aprox 1900 ) similar designs .
7:46 'How to lie with statistics'
Graph starts at 5 instead of zero which skews perception for those who didn't notice this
Yes but it’s even worse than that. That graph is smoke and mirrors for sure but according to this data the boat managed 64 kts (!) at 6000 rpm with the conventional prop. Yeah well, that didn’t happen because according to Worldcat specifications their boat does 45 knots flat out. In other words, the graph is a fiction, easily debunked.
Another piece of BS here is that the so-called 3 blade Sharrow prop is actually a 6 blade. This alone significantly increases the advance ratio so comparing it with a 3 blade conventional prop is bogus.
This design hasn't been used in vessels before in part because of the expense of making them, and the savings in fuel haven't been as urgent in the past. In the case of aircraft, it may be materials technology; composites and materials such as carbon fiber and aramids allow us to make shapes requiring higher strength to weight ratios than before. I'm looking forward to these being used on electric aircraft capable of carrying passengers and cargo.
Electric plane? We aren't even close. 😂
The future of aviation are ornithopters not propellers
Would these types of designs have any impact on fans and fan blades? It would be cool to see this possibly impact standard home box fans or even computer fans!
I didn't even think about electric fans and other cooling fans. It's probably gonna take a while for the design to be that commercially available though. (Also hopefully it still allows one to make funny noises in front of the fan xD)
Great video, Matt.
I liked it.
Thank you
Thanks for your efforts; very interesting information.
They could make the boat propellers much easier with lost wax casting instead of machining them from a solid block. most large props are bronze based anyway which is perfect for the lost wax method.
The imperfections would make the propeller useless. Any surface imperfections add cavitation and cause degradation over time.
I've seen videos of large propellers being made; they still had to be machined at the end to get a good surface finish, then thoroughly examined. If the tips of a propeller can evaporate water, then imagine the forces that are experienced. Now imagine a hairline crack, or an imperfect casting where there is a 'cold shut', slag inclusions, or any other of the many possible defects from casting.
At those speeds, the flying metal chunk would punch a hole through the boat or its occupants, and leave behind a dangerously unbalanced, fast-spinning prop shaft.
TH-cam absolutely blew up with videos of these toroidal propellers on drones a couple of months ago when the news broke out, and in reality, the results seemed to be quite underwhelming. You get a less annoying noise frequency range, sure, but most people experimenting with them found out they had significantly less thrust in some cases, negating efficiency or noise benefits, and while the noise did have a lower pitch, they're still very loud. The MIT videos were also quite disingenuous in the way they played with the volume: standard propellers were turned up significantly while the toroidal ones... weren't even playing any sound at all because Sebastian is talking over it, lol.
That was due to the quality of their models vs the MIT variants.
A true refined one is much more efficient.
There was a lot of questions to MIT experiments so i had tested 3d printed toroidal propellers on a drone - they was in fact louder and kind of shaky and unstable. It may work underwater with a rotating speed that required underwater, and without much turbulence. But as propeller for a drones - it it debatable, i believe they need more development to be productive.
What do you think about the possible impacts to HVAC efficiency? Or even power plants? Or since those turbines are surrounded by tubes there is less impact?
I wonder if this is also a better design for, say, fans in a PC or other electronics for cooling while staying quiet. Perhaps for static pressure applications?
I think since PC fans already have a shroud/outer casing, the advantages of the toroidal prop wouldn't be substantial. I think there was an episode of the PC Fan Showdown from Major Hardware that had a toroidal prop fan that didn't do too well in comparison
@@j3rmyp4rkr but if they are as cheap to manufacture, any reduction in noise is good. I can still hear all the fans on my computers.
My alienware laptop has two fans, never hear them running.
@@dsloop3907 I guess I need to stop buying cheap shit
Very interesting! Perhaps 3-D computer modeling can tweak the designs for the greatest efficiency. It seems like anything with a fan or propeller could potentially benefit from this improvement. Maybe it can help as we transition away from fossil fuels.
Love these videos as an aspiring enviromental engineer
Genral question I have not seen you do a video about Bio-Gas production AKA anirobic digesters. and using the refined methane for home power use plus the heat that this process generates.
Hi Matt,
would these propellers work for wind farms? A similar improvement in efficiency / reduction in noise would be fantastic.
there are vertical axis turbines that already use a similar shape and some dynamic kite based wind energy farms are also looking into such novel applications :)
I'd wager not, since:
- bladed wind farms operate at _way_ lower RPMs where tip vortices are practically moot
- the fluid dynamics work a little differently in reverse - likely invalidating any efficiencies that aren't just side effects of noise reduction
- are _the propeller blades_ at wind farms even noisy, especially compared to the generators?
I would say yes and no. Windmill blades can now be adjusted for the best performance in different kinds of weather and i do not see how you could do that wit theas blades. That sead, because of the bigger range of affenciantie it might not have to.
Yes and no. The design should work the same for a wind turbine as it does for a propeller, but at those sizes increased material costs will make it unfeasible. It would likely also impact the efficiency of downwind turbines. The question is if the added material costs less than the profits you would gain with the added efficiency. You also need to figure out the engineering challenges that come with the added weight for the support structure and how that would affect possible height (which is corelated with higher wind speeds) and for the inertia of the system and how you would stop such wind turbine in dangerously high wind situation. My guess is that we could use this design with smaller home turbines
I'm curious to how this would perform in a wind turbine, if it takes power move a lot of air to provide that extra thrust I 'm left to think that it could work just as well in reverse.
I was thinking about this type of prop while watching Matt's last video about offshore wind. Cool that he's doing a video about them now, but I'd love to see an analysis of their potential in power generation.
This is the first time I've seen it mentioned anywhere :)
But did really no-one think of this before? or is it true that it only got developed because of modern tools? (simulations, 3d printing, what else?)
I would guess that some of these designs have probably been tried before, but due to their geometry they can be very expensive to manufacture, so it probably didn't make too much sense.
@@Anfros. yeah that's what I mean, because of modern tools, manufacture got cheaper, iteration got faster, planning&measurement more efficient..
At least 2, possibly 3 instances of similar developments have been brought to paper over the last century and a bit, at least one of them was patented. Unfortunately these designs never left the paper.
Question: Can this work for Computer fans too, or do those need different properties? These are so much quieter, it would be quite amazing for that setting, where you sit next to fans for potentially long times.
they have different properties. one of the main one is they arn't in an open air system, they need to push air hard through obstructions and such. also alot of the noise comes from the air inside and not just the fan but the turbulence of the air flow.
ps, you can get quiet fans.
@@mryellow6918 part of what these toroidal fans seem to do is to reduce turbulence, at least the turbulence created right at the fan itself. I'd imagine that'd still be possible to do in the cooling fan setting?
@@Kram1032 what I mean is you can't do anything about the turbulence inside the case. And you can't control what's obstructing stuff. For example your gpu fan blowing in all directions even against case fans
@@mryellow6918 certainly, but I guess I'm not sure that that's enough to dismiss the sound of turbulence happening at the fan blades.
There’s still so much to discover in material science, geometric shapes and how they interact in given circumstances or in natural environment
It’s amazing how such small word as physics can encompass Everything that exists or will exist even those that stopped exist but existed before,, how they act and react and influence and manipulate other materials changing it’s entire structure and properties
i work on boats for a living.
i'm definitely going to take a closer look at sharrow, for my own boat as well as something that my employer may want to start having available.
Actually that prop design can easily be cast even for larger ships, and the cores for the cast could be 3d printed. The high cost you see now is more then likely because its a new product and there is no competition at the moment.
And likely shrouded in patents.
One of the clips in this video did show a toriodal prop being made out of a solid cube of metal on a CNC machine, which seems extrodinarly inefficient, though easier to prototype. I would imagine the cost would drop dramatically once the design is perfected enough for castings to be made.
@@jpritchett42 Also not shown on the video is the requirement by Sharrow to define the engine in use, horsepower, type of boat and if I am not mistaken waterline length, and planing or displacement hull. As each prop is custom made for each application, hence machining from a solid block.
Probably get applied to windmills too, particularly the more consumer versions meant for rooftops and yards
I can't help but think about Morbo.
theres foil surfing but also foil boats. They also reduce the surface drag to a minimum. Plus theres also different coatings for the boats with lotus effect and even better than lotus (cant remember the of that plant.. something like sativa, silvana... something like that)
I love drones❤❤❤❤ and sound too. Such an amazing machine😊
I have been tinkering with propeller design for boats whose motors/engines have a "regen" capacity. I do not know if the toroidal dynamics work in reverse as well as forward. I love your channel. Thank you
Regen seems to be pretty useless in a boat, they don't continue on for very long once power is removed... The boat falls "off plane" and the water slows it down very fast. You couldn't recapture much energy, unlike a car.
Funny that drone designers never took a que from fan designers for custom computers.
For those of us who build our own, noise reduction is a key to a comfortable life behind a computer workstation.
Thanks for doing a video on this topic.
Those fans are usually spinning much much slower.
Great video, man!
+1.. Always the very best ... Very informative! .. Who needs a boat? .. Cheers, Vail, Colorado
105% efficient would mean what? At 8:12 this graph shows you reach max "efficiency" at 5000 RPM rather than 6000 RPM with the old propeller.
This graph really needs MPH rather than "efficiency". I 'm sure it is an improvement for mid range performance, but lets see MPH and MPG figures.
It's a 105% MORE efficient in the midrange than the regular propeller, not 105% efficient.
Sorry for the confusion there. I said the word "from" when I should have said "by." I'm making a correction to the edit now. This design boosted efficiency by 105% ... not to 105%.
@@UndecidedMF it is not an efficiency boost of 105% either. Efficiency is defined as power out over power in. Simply comparing advance per rpm is NOT an efficiency comparison. It is pointless enough to make the comparison at two different boat speeds. But when those two speeds are clearly hump speed vs a planing speed, as here, the comparison is, frankly, bogus. Why can you not see that?
I am imagining this being used for kitchen exhaust fans (aka the loudest part of cooking), wind mills (not sure about durability in hazardous conditions), and superchargers for vehicles (could potentially reduce size and power draw, and increase air pressure)
Brilliant, Love it.
I am fascinated by toroidal propeller technology and I brought it up and a Boat Drag Race at the Wild Horse Pass South of Phoenix. I spoke with racers and most had no clue what I was talking about. But, I ran across two guys that did know and had some unique input. The first was a big cargo ship captain. He said that the props that you use for thrust and that the toroidal props will be the future but it is NOT the best for speed. He said that boat speed is at the tip of the propeller so Drag Race Boats have a surprisingly small and not very broad blade. I got to talk to a long time boat drag racers and he kind of confirmed this and said that he used the toroidal prop does not work and he claimed that he tested in on his top fuel boats. He claimed the toroidal prop will not get the boat going from a dead stop to instantly high speed but in both cases boats are topped off at the same speed at the end. He also said that the drag race boat props are unique in that they have a very small pitch of about 6%.