The MIT study that resulted in this “groundbreaking” propeller design is actually more than a few years old. When it first came out, the Navy tested the props and found that there was not enough benefit to them for them to be adopted. The reason is this: being a fixed blade, while they give a slight efficiency boost, by design they are also limited in the rpm they can be turned at before that efficiency is lost. This might not be a big deal for large ships where the conditions they operate in are relatively stable, but when applied to aircraft, it introduces an additional issue: the pitch can’t be altered in emergencies or for descent, which can cause damage to the engine by overspeeding the prop. This was a common issue that led to a lot of crashes before the constant speed prop was invented. With a constant speed prop, you can feather the prop blades in the event of a loss of power, or reduce prop rpm while descending to help control airspeed. A toroidal prop being incapable of doing this would be a technological step backwards in aviation technology and is the reason why it’s not been widely adopted. It’s a novel design that will forever be limited to speed boats and recreational craft that can actually utilize its benefits.
You explained it so much better than I ever could. When they mentioned using it in aircraft, the first thing I thought of was the inability to vary the pitch. Forget about reverse pitch to slow down after landing. Not being able to feather a failed engine is a recipe for disaster.
@@martinuribe4722 I mean there are still a large number of planes that have fixed pitch props - the piper cub comes to mind off the top of my head. But then, the cub isn’t designed for high speed flight either, although a lot of them have been modified for constant speed props, especially the ones operating in austere environments, where a reversible prop is kind of a necessity, such as what bush pilots fly. It’s not so much that not being able to feather a prop is a disaster waiting to happen so much as it makes dead stick landings trickier due to the additional drag, especially when you’re already getting close to the ground
The same issue applies to naval vessels. In the Coast Guard, and I surmise the Navy also, the engines are not 'reversed', but the screws are reversed in pitch. We took a 378 foot cutter at flank speed to a dead stop in her own length by just reversing the screws. (Back in '73, if I remember accurately)
@@toddcrookham515 no, but cavitation stops below 400 ft anyway, so no benefit to using a toroidal unless you’re above 400 ft and going fast, which only happens when you’re getting shot at. The rest of the time (when you’re on station) you’re doing 5 kts to nowhere just listening for contacts. Plus on nuclear subs, efficiency isn’t as much of a concern, because when you’re fuel won’t run out for 15 years and the rest of the sub is already as streamlined as it can be, the little bit of reduced drag from the prop doesn’t really make a difference. The Russians made a sub during the Cold War that could do 44 knots submerged, and that kind of speed made it loud. Subs are all about staying hidden and quieter than the background noise to avoid detection
Good point. That’s what I want to actually hear. I live in a tranquil Mountain environment, but there are noise pollution annoyances. First there are internal combustion engine cars and those are going to go away mostly within about a decade or so with electric cars Then there is a general aviation airport not so many miles away, and there is nothing, not even a Harley Davidson, more annoying than the sound of light aircraft Engine, such as a Beechcraft bonanza. I absolutely hate the sound, and it goes on for a couple of minutes in the middle of the day, or whenever. Just awful
One of the reasons there are fixed pitch propellers and variable pitch propellers is efficiency at differing speeds. Fixed pitch props are efficient only at a specific speed/performance range, which is why we have different fixed pitch props. Make one of those toroidal props able to be set for different speeds and you might have something.
It is pretty much limited to motor vessels .. motor sailors often use regen ..reversed pitch to normal or folding blade propellors to reduce drag under sail. However it undoubtedly does have a role to play...and can help with retractable electric motor propulsion. Ultimately 3 d printing of small and medium sized props would probably be more economic than machining from billets.
@@Dakwiinn True and that's a good trial area but the added rotational mass might prove a bit of a balancing problem. For high speeds and greater safety the rim driven electric fan water jet might outperform even the sharrow design but almost anything is better than what most motor boats use.. The other issue remains the safety problems exposed props cause to Marine mammals and other humans in the water.
@@Dakwiinn True but those are the few, cheap and inefficient aircraft. The market is just too small to make them for that class of aircraft. Those propellers are extremely expensive. Cost outweighs the benefits.
Been seeing these video's for ages. I guess they got bored of the airless tires that will change the world, or was it the hubless wheels that will change the world, or was it the hydrogen cell that will change the world, or maybe it was the ionic thrusters that will change the world, or maybe it was the aerospike rocket that will change the world, or maybe it was..... Just like all those other concepts, these have proven to be impractical. The efficiency advantage comes at a steep cost. Real world testing has shown that they are just marginally better in one aspect, but require sacrificing far too much in other ways. The focus should be on finding applications that they are suited to and not pipe-dreams about changing things that they are obviously not.
Were toroidal propellers developed to reduce cavitation noise in submarines? How can I change pitch with these propellers? Suppose I was flying a twin egine arcraft and one engine failed. How would I feather a toridal propeller?
@@robertcarveth8722 You can't, it adds to the drag. In a twin engine aircraft it will add to a severe yaw which could make it uncontrollable. In any aircraft it reduces the ground distance you can fly as you descend, limiting your landing options in an emergency.
I ask the same thing. Here is what I ask. @mrmikes4553 1 minute ago Have a question. This is a huge national security question on submarines and warships. We all know when propellers turns in the water they create millions of bubbles per minute. What the tech guys call this is called cavitation. The bubbles creates noise that sonars can track the sub or ship. The bad guys can launch the torpedos at our warships. Can this new design propellar stop the cavitation that the old style propellers does? I have no clue what type of propeller the navy use. That is a top secret clasified information that Donald Trump might have given away to that billionaire and his wife at Mar-A-Logo while they were eating thier dinner. That open mic most likely from a phone caught the whole converation.
I agree with the clickbait as he doesn't prove their new design on an airplane. However I know competitive drone racers and they've all switched to the new design
It's clickbait and horse crap. These people shouldn't make info on subjects they do not understand. Don't talk about vortices if you can't even draw a schematic of it. Btw you can calculate "efficiency" any number of ways. These dumb toroidal props have lousy blade loading: if you use the same amount of material to make A LARGER conventional propeller, the larger convention design will out perform the toroidal!
You 3-D print the first one then you make a high temp silicone mold, allowing you to pour aluminum into the mold. You will still have some polishing and machine work, but this should bring the cost way down. If not, can you take those silicone molds you fill them with carbon fiber And you’ll have some tooling and polishing but not much and with any aluminum tape substructure built into the carbon fiber working like rebar to Steffen it’s still will cost a whole lot less
One problem I’d like to see addressed, a lot of plans don’t have fixed propellers. They have blades that rotate to allow better efficiency at higher altitudes. I can see it working with ships for sure, but unless you have a fixed prop aircraft it won’t really help out for commercial aircraft who the vast majority of have variable pitch propellers
If a normal VP prop had a 15 % efficiency to that of a fixed prop and a toroidal prop was 27% more efficient : that would blow a hole in your argument!
Multi-engine aircraft must have variable pitch propellers for feathering in case of an engine failure. It is also good for aerodynamic breaking and better performance.
I would be interesting to see a windmill application. Noise is a major problem. The only problem I see is swept area. Present windmill blades sweep large areas. To make a torodial blade with a larges sweep area might be too costly.
as someone who has personally printed and used a LOT of these toroidal props on my drones, yes it is true that they drastically cut down on the “buzzing bee” noise however, they create their own much more annoying lower sound.
@@skulldgry1215 There is a lot of talk about "Archimedes wind turbines" and there seems to be a number of start-ups. Also, if you do a RUclips search for "Fibonnaci Turbines" you get an expanded discussion. Of interest is enhanced blade design for larger wind turbine blades.
The toroidal propeller looks like two propellers bent at their ends and joined, so you get four times the surface area. There is a connection to the Archimedean screw too, I think.
As a pilot I'd think that one limitation with this type of design is they could not make a variable pitch one. It would probably have to be a fixed pitch. Limiting efficiency at high altitude. They make planes that have constant speed props for a reason.
I've been flying with a Prince P-Tip 2 blade prop on my LSA plane for the last 12 years, it's quieter by a fair bit than other props used on the Rotax 912S, not just quieter overal, but it has a deeper tone, it almost sounds radial engine like. We will have to see how these turn out, but I'd suggest they could best be experiemented with on light and simple planes first, if nothing else there'd be less "help" (interference) from the FAA.
Sub props don't cavitate at depth due to the enormous pressure and if the sub is bookin' it , it's gonna make some noise regardless. Subs that don't move are detectable from Space by their heat plumes. These subs are just tooling around at 8 Kts and 600 feet depth.
Major drawback: Toroidal propellers *cannot* be used for any application that currently uses a continuous rate proportional pitch propeller. These systems rely on an external control (automatic or manual input) to change the pitch of the blades to achieve differing amounts of thrust or reverse the direction of the flow. You find these proportional pitch systems on ships and aircraft.
You can't make a constant speed toroidal propeller so this won't be widely used in general aviation. Drones will be vastly improved if made quieter though so they will see the most use from this.
The problem is most propellers are not "constant pitch". You can't adjust a toroidal propeller for cruise or climb, thus in practice it will be more inefficient.
Thanks for the video. I don't see this change making a big difference in passenger or freight aviation. There's a comment below mine that covers part of the issue. I don't know whether it's true, but it makes sense. Maybe these propellers will be good for drones, but I don't know whether drones are ever going to be that important to real aviation. Maybe they will become valuable in surveillance, but that may never be a huge energy usage. If these could work on big ships, that could be a major change in the world. If they can only work on smaller watercraft, the innovation will be useful but probably not revolutionary. Saving a bit of fuel is always good, and reduced vibration and cavitation will lead to longer propeller and shaft life. These improvements are worthwhile, but they aren't really revolutionary.
So far the uses have been in applications where the RPM is adjusted for greater or lower speed, like on a boat. Most planes, beyond the basic models, don't adjust their speed by just increasing engine RPMs, but by adjusting blade pitch. More angle into the air for greater thrust, less angle for less thrust. This allow the pilot to maintain the most efficient engine RPM for any given airspeed. The MIT design would be a fixed pitch prop, so the engine would have to increase RPM for more thrust. Higher desired airspeed, higher RPMs, higher the fuel flow.
I'm wondering when we'll see these toroidal propellers for RC model boats, RC aircraft and other aerial drones. I have a pair of 4' boats that would love these, a small RC sub, and an RC jetski that would rock with these (all being twin-prop, so I'd need left and right-hand props)
Drones and their variants would benefit regarding the lower noise. Not likely for passenger aviation beyond small fixed pitch aircraft. All the same, a useful development.
This would be great for flying drones in / over the forest. Sasquatch would be less likely to hear it. What can it do at higher altitudes, such as 17,000ft elevations?
Right now they are CNC machined 1 at a time out of a solid billet of stainless. Very inefficient way of making them. Cost could come way down if widely adopted and mass produced. Right now they only make sense for charter boats where the fuel savings can pay for the expense rather quickly.
@@wally7856 finishing it out of cast steel billet should improve cost massively, should repay with about 400 pce at least our 250€ part are now cheaper then the previous cnc machined fom gnereic steel billet.
As far as I know 1mm loss within 12 Years in Panama. So no issue here. Cast steel machined to fine surface lasts long enough. Propeller damage due other means is a far bigger issue.
No. This MIT propeller is *_NOT_* going to change aviation in any way! Sorry to break it to you, but that's complete bullshit. Why? Show me how to feather this propeller, I dare you....
You do realise there are tens of thousands of light aircraft flying out there that have fixed pitch propellers that can’t be feathered! In saying that, this propeller would have been adopted already if there was a real performance benefit at a reasonable cost!
Yes boats, and yes drones. But how about for vacuum cleaners? More efficient, quieter vacuum cleaners would be welcomed by everyone. How about leaf blowers? Quieter leaf blowers? Oh God yes!
A forged casting for boat propellers would mitigate the mass production expenses, with the advancement in metallurgy this design this is entirely achievable.
Given the mass of the prop it could be a night mare for CG. Also, rapid maneuvering torque loads and rotational inertia could lead to bent prop shafts, incredible vibration and catastrophic failure. As pictured, it just doesn’t look ready for prime time.
Never going to replace conventional props on aircraft. 20 years from now, you'll see aircraft will still be using the same sort of props fitted today. This is all nonsense and pure clickbait.
I kept looking for some example using a toroidal propeller on a private plane or similar and don't see anything like that in this video, so it looks like there is no breakthrough. AFAIK toroidal propellers won't work of any full sized aircraft, it'll only work in marine environments because of the density of water or tiny toys like hobby quadcopters which are well known to be aerodynamically different than very large aircraft, large enough to transport at least one human. This video glosses over the simple fact that the toroidal shape has to be designed for an optimal rpm and that rpm has to be relatively slow or like any propeller cavitation happens. This video suggests that there is a benefit to lower rpm but that's only half true because there is an enormous penalty to trying to spin faster than the shape's optimized value. Additionally, the development of toroidal propellers has probably been stunted by the ease of simply designing a ducted or shrouded propeller which resolves the tip turbulence problem. There is no need for the very high cost of manufacturing a toroidal propeller to gain that benefit. So, bottom line is that there are some theoretical benefits for marine use but AFAIK is a dead impossibility as an airplane propeller.
If we had a toroid propeller, driven by a turbine and covered with a cowl, we would have a world beater. It could probably be "scaled upwards" to very impressive sizes.
Why not just curve the tips some, instead of a complete loop, so they are like the ends of newer airplane wings.. Should reduce the turbulence at the tips.
I may be stupid but How do propeller cone tips generate anything like speed of sound vortices? As he says. The infinitely small centre of anything that is rotating, nomatter what the RPM, is effectively Stationary. So the closer to the centre of a propeller = the slower the relative airflow. Visa v, the longer the prop blade length the higher is the relative tip speed. So obviously, minimising the prop diameter will minimise air noise but atainable thrust also. So the answer is simple, fold the prop blade back towards the centre and increase its chord or pitch to recover the power. A smaller diameter prop will reduce any inbalance factors so enabling use of higher RPM's resulting in more power.
Lets not kid ourselves, even if there was a 20% decrease in fuel for container ships...., there is NO WAY those companies are going to pass it on (especially to their clients who aren't going to pass it on to us), instead just making more profit. 😕
A traditional aircraft propeller sacrifices Efficiency for Performance over an available Power Sources' Operating Range (the engine) for Airframe = X (the plane). What part of Efficiency is directly disproportional to Performance are you having a hard time with?
I googled boat companies using "toroidal propellers" and got nothing. You doubled engine efficiency with this propeller. Why aren't boat companies featuring it to increase boat interest?
Fixed-pitch propellers will not be more effective than high aspect-ratio propellers with adjustable pitch. Noise is just a part of the problem, as usual!
The problem with our boats is that it has more drag and we performance boaters want top speed… It also costs 8X more. Not practical. In aircraft we need to be able to change pitch going into feather. Also, not practical.
Have a question. This is a huge national security question on submarines and warships. We all know when propellers turns in the water they create millions of bubbles per minute. What the tech guys call this is called cavitation. The bubbles creates noise that sonars can track the sub or ship. The bad guys can launch the torpedos at our warships. Can this new design propellar stop the cavitation that the old style propellers does? I have no clue what type of propeller the navy use. That is a top secret clasified information that Donald Trump might have given away to that billionaire and his wife at Mar-A-Logo while they were eating thier dinner. That open mic most likely from a phone caught the whole converation.
I know the navy uses big propellers on submarines because they can turn slower and will not cavitate in the water. Thats all I know about this top secret propeller.
As the only effect proven, Sharrow props increase efficiency in a mid-load situation of glider boats. That however is caused by a design flaw, intrinsic to all classical v-shaped glider hull boats. Their immense resistance when just enetering plaining prevents from running a top-speed-optimized prop as efficient in the mid-speed range. Sharrows propellers do have significant advantages in water flow directivity in that mid-speed regime. All other attempts to bring toroidal props to the hobby market so far did not succeed. Guess why. There is no such thing other than a stated advantage from MIT.
This is very misleading. They do not double efficiency. If they did you would see them everywhere. Manufacturing cost has nothing to do with it. The design is not suitable for fixed wing aircraft. Absolute nonsense video
The MIT study that resulted in this “groundbreaking” propeller design is actually more than a few years old. When it first came out, the Navy tested the props and found that there was not enough benefit to them for them to be adopted. The reason is this: being a fixed blade, while they give a slight efficiency boost, by design they are also limited in the rpm they can be turned at before that efficiency is lost. This might not be a big deal for large ships where the conditions they operate in are relatively stable, but when applied to aircraft, it introduces an additional issue: the pitch can’t be altered in emergencies or for descent, which can cause damage to the engine by overspeeding the prop. This was a common issue that led to a lot of crashes before the constant speed prop was invented. With a constant speed prop, you can feather the prop blades in the event of a loss of power, or reduce prop rpm while descending to help control airspeed. A toroidal prop being incapable of doing this would be a technological step backwards in aviation technology and is the reason why it’s not been widely adopted. It’s a novel design that will forever be limited to speed boats and recreational craft that can actually utilize its benefits.
You explained it so much better than I ever could. When they mentioned using it in aircraft, the first thing I thought of was the inability to vary the pitch. Forget about reverse pitch to slow down after landing. Not being able to feather a failed engine is a recipe for disaster.
@@martinuribe4722 I mean there are still a large number of planes that have fixed pitch props - the piper cub comes to mind off the top of my head. But then, the cub isn’t designed for high speed flight either, although a lot of them have been modified for constant speed props, especially the ones operating in austere environments, where a reversible prop is kind of a necessity, such as what bush pilots fly. It’s not so much that not being able to feather a prop is a disaster waiting to happen so much as it makes dead stick landings trickier due to the additional drag, especially when you’re already getting close to the ground
The same issue applies to naval vessels. In the Coast Guard, and I surmise the Navy also, the engines are not 'reversed', but the screws are reversed in pitch. We took a 378 foot cutter at flank speed to a dead stop in her own length by just reversing the screws. (Back in '73, if I remember accurately)
Submarines are probably a great fit. Noise is the enemy in Submarines, you definitely don't want cavitation!
@@toddcrookham515 no, but cavitation stops below 400 ft anyway, so no benefit to using a toroidal unless you’re above 400 ft and going fast, which only happens when you’re getting shot at. The rest of the time (when you’re on station) you’re doing 5 kts to nowhere just listening for contacts. Plus on nuclear subs, efficiency isn’t as much of a concern, because when you’re fuel won’t run out for 15 years and the rest of the sub is already as streamlined as it can be, the little bit of reduced drag from the prop doesn’t really make a difference. The Russians made a sub during the Cold War that could do 44 knots submerged, and that kind of speed made it loud. Subs are all about staying hidden and quieter than the background noise to avoid detection
It’s totally Clickbait, because this is a story that keeps being re-released year after year after year as “new“. It’s not a new MIT design.
Thank you.
I’m out..
Thank you for saving me the time!
And the AI voice track 🤮
Why isn't there a single noise/sound sample from those new propellers in the video??
ruclips.net/video/DfeWKGEtMx0/видео.htmlsi=YQa0nen_Nxs8lHeG
Not the same scale, but an example.
The video creators have nil rights to any of the stuff!
Good point. That’s what I want to actually hear. I live in a tranquil Mountain environment, but there are noise pollution annoyances.
First there are internal combustion engine cars and those are going to go away mostly within about a decade or so with electric cars
Then there is a general aviation airport not so many miles away, and there is nothing, not even a Harley Davidson, more annoying than the sound of light aircraft Engine, such as a Beechcraft bonanza. I absolutely hate the sound, and it goes on for a couple of minutes in the middle of the day, or whenever. Just awful
@@steveperreira5850 so, they built the airport after you moved there?
I wonder more about an efficiency way over 100%!
My milkshake mixer has a similar blade. I bought it in 1984. 😂
litterally 1984
One of the reasons there are fixed pitch propellers and variable pitch propellers is efficiency at differing speeds. Fixed pitch props are efficient only at a specific speed/performance range, which is why we have different fixed pitch props. Make one of those toroidal props able to be set for different speeds and you might have something.
This will NOT change passenger aviation due to the static position of the prop blades. However drones and boats may see this in use
It is pretty much limited to motor vessels .. motor sailors often use regen ..reversed pitch to normal or folding blade propellors to reduce drag under sail. However it undoubtedly does have a role to play...and can help with retractable electric motor propulsion.
Ultimately 3 d printing of small and medium sized props would probably be more economic than machining from billets.
A lot of light aircraft have fixed pitch props…
@@Dakwiinn
True and that's a good trial area but the added rotational mass might prove a bit of a balancing problem. For high speeds and greater safety the rim driven electric fan water jet might outperform even the sharrow design but almost anything is better than what most motor boats use..
The other issue remains the safety problems exposed props cause to Marine mammals and other humans in the water.
@@Dakwiinn True but those are the few, cheap and inefficient aircraft. The market is just too small to make them for that class of aircraft. Those propellers are extremely expensive. Cost outweighs the benefits.
Been seeing these video's for ages.
I guess they got bored of the airless tires that will change the world, or was it the hubless wheels that will change the world, or was it the hydrogen cell that will change the world, or maybe it was the ionic thrusters that will change the world, or maybe it was the aerospike rocket that will change the world, or maybe it was.....
Just like all those other concepts, these have proven to be impractical. The efficiency advantage comes at a steep cost. Real world testing has shown that they are just marginally better in one aspect, but require sacrificing far too much in other ways. The focus should be on finding applications that they are suited to and not pipe-dreams about changing things that they are obviously not.
"Never let the truth get in the way of posting a clickbait video."
Were toroidal propellers developed to reduce cavitation noise in submarines?
How can I change pitch with these propellers? Suppose I was flying a twin egine arcraft and one engine failed. How would I feather a toridal propeller?
These will always be fixed pitch. I expect they'll have a bigger impact in shipping than in aviation.
How do you feather a prop in a fixed pitch prop aircraft?
@@robertcarveth8722 You don't Most small GA aircraft are not able to do that. Constant speed props are a high-performance item in GA.
@@robertcarveth8722
You can't, it adds to the drag. In a twin engine aircraft it will add to a severe yaw which could make it uncontrollable. In any aircraft it reduces the ground distance you can fly as you descend, limiting your landing options in an emergency.
I ask the same thing. Here is what I ask.
@mrmikes4553
1 minute ago
Have a question. This is a huge national security question on submarines and warships. We all know when propellers turns in the water they create millions of bubbles per minute. What the tech guys call this is called cavitation. The bubbles creates noise that sonars can track the sub or ship. The bad guys can launch the torpedos at our warships. Can this new design propellar stop the cavitation that the old style propellers does? I have no clue what type of propeller the navy use. That is a top secret clasified information that Donald Trump might have given away to that billionaire and his wife at Mar-A-Logo while they were eating thier dinner. That open mic most likely from a phone caught the whole converation.
Largest blade possible moving as slowly as possible, is the secret to efficiency.
Correct.
Boat propellers are a totally different animal than airplane propellers, its apples and oranges. Nice click bate though.
Actually there not both are considered fluids.
I agree with the clickbait as he doesn't prove their new design on an airplane. However I know competitive drone racers and they've all switched to the new design
It's clickbait and horse crap. These people shouldn't make info on subjects they do not understand. Don't talk about vortices if you can't even draw a schematic of it. Btw you can calculate "efficiency" any number of ways. These dumb toroidal props have lousy blade loading: if you use the same amount of material to make A LARGER conventional propeller, the larger convention design will out perform the toroidal!
Says the man who doesn't own a boat, plane or a positive comment.
yes I do own an airplane and am a pilot.@@monomarino5349
Best of luck with the variable pitch control mechanism fellows...
I'll check back with you guys in 20 years time. See how your getting along..
Awesome! Let's get them on the Mooney airplanes! Mooney aircraft are so loud with their high performance engines and props!
You 3-D print the first one then you make a high temp silicone mold, allowing you to pour aluminum into the mold. You will still have some polishing and machine work, but this should bring the cost way down. If not, can you take those silicone molds you fill them with carbon fiber And you’ll have some tooling and polishing but not much and with any aluminum tape substructure built into the carbon fiber working like rebar to Steffen it’s still will cost a whole lot less
Thank you, Jet Boat,& ski's !
One problem I’d like to see addressed, a lot of plans don’t have fixed propellers. They have blades that rotate to allow better efficiency at higher altitudes. I can see it working with ships for sure, but unless you have a fixed prop aircraft it won’t really help out for commercial aircraft who the vast majority of have variable pitch propellers
If a normal VP prop had a 15 % efficiency to that of a fixed prop and a toroidal prop was 27% more efficient : that would blow a hole in your argument!
Multi-engine aircraft must have variable pitch propellers for feathering in case of an engine failure. It is also good for aerodynamic breaking and better performance.
Be careful, looks like your tip toeing into classified information here with submarine propulsion
I would be interesting to see a windmill application. Noise is a major problem. The only problem I see is swept area. Present windmill blades sweep large areas. To make a torodial blade with a larges sweep area might be too costly.
maybe the drag of toridal prop my be much less , we need to wait for the research to be extended into the aircraft industry.
as someone who has personally printed and used a LOT of these toroidal props on my drones, yes it is true that they drastically cut down on the “buzzing bee” noise however, they create their own much more annoying lower sound.
@@skulldgry1215 There is a lot of talk about "Archimedes wind turbines" and there seems to be a number of start-ups. Also, if you do a RUclips search for "Fibonnaci Turbines" you get an expanded discussion. Of interest is enhanced blade design for larger wind turbine blades.
So how do you change the pitch of the propellers in flight, so you can feather them if need be?
The toroidal propeller looks like two propellers bent at their ends and joined, so you get four times the surface area. There is a connection to the Archimedean screw too, I think.
So how do you change the pitch?
For aircraft?
How do you feather the propellor?
As a pilot I'd think that one limitation with this type of design is they could not make a variable pitch one. It would probably have to be a fixed pitch. Limiting efficiency at high altitude. They make planes that have constant speed props for a reason.
I've been flying with a Prince P-Tip 2 blade prop on my LSA plane for the last 12 years, it's quieter by a fair bit than other props used on the Rotax 912S, not just quieter overal, but it has a deeper tone, it almost sounds radial engine like. We will have to see how these turn out, but I'd suggest they could best be experiemented with on light and simple planes first, if nothing else there'd be less "help" (interference) from the FAA.
The mitigation of cavitation in U.S. Navy submarines is extremely important to facilitate non-detection. Any thoughts on this unique application?
Sub props don't cavitate at depth due to the enormous pressure and if the sub is bookin' it , it's gonna make some noise regardless. Subs that don't move are detectable from Space by their heat plumes.
These subs are just tooling around at 8 Kts and 600 feet depth.
Major drawback: Toroidal propellers *cannot* be used for any application that currently uses a continuous rate proportional pitch propeller. These systems rely on an external control (automatic or manual input) to change the pitch of the blades to achieve differing amounts of thrust or reverse the direction of the flow. You find these proportional pitch systems on ships and aircraft.
You can't make a constant speed toroidal propeller so this won't be widely used in general aviation. Drones will be vastly improved if made quieter though so they will see the most use from this.
The problem is most propellers are not "constant pitch". You can't adjust a toroidal propeller for cruise or climb, thus in practice it will be more inefficient.
I've seen many videos about this "new" toroidal propeller and we're still waiting.
How would you feather the prop it if were a solid component?
May have limited use in certain situations, but unless the blade angles can be adjusted economically, it's a dead end for airplanes
Thanks for the video.
I don't see this change making a big difference in passenger or freight aviation. There's a comment below mine that covers part of the issue. I don't know whether it's true, but it makes sense. Maybe these propellers will be good for drones, but I don't know whether drones are ever going to be that important to real aviation. Maybe they will become valuable in surveillance, but that may never be a huge energy usage. If these could work on big ships, that could be a major change in the world. If they can only work on smaller watercraft, the innovation will be useful but probably not revolutionary. Saving a bit of fuel is always good, and reduced vibration and cavitation will lead to longer propeller and shaft life. These improvements are worthwhile, but they aren't really revolutionary.
So far the uses have been in applications where the RPM is adjusted for greater or lower speed, like on a boat. Most planes, beyond the basic models, don't adjust their speed by just increasing engine RPMs, but by adjusting blade pitch. More angle into the air for greater thrust, less angle for less thrust. This allow the pilot to maintain the most efficient engine RPM for any given airspeed. The MIT design would be a fixed pitch prop, so the engine would have to increase RPM for more thrust. Higher desired airspeed, higher RPMs, higher the fuel flow.
How do you feather the rotor blades?
I'm wondering when we'll see these toroidal propellers for RC model boats, RC aircraft and other aerial drones. I have a pair of 4' boats that would love these, a small RC sub, and an RC jetski that would rock with these (all being twin-prop, so I'd need left and right-hand props)
Could this be used in ceiling fans to produce more air flow with less energy and size?
Drones and their variants would benefit regarding the lower noise. Not likely for passenger aviation beyond small fixed pitch aircraft. All the same, a useful development.
So, does all that efficiency make a big difference in the torque curve?
This would be great for flying drones in / over the forest. Sasquatch would be less likely to hear it. What can it do at higher altitudes, such as 17,000ft elevations?
sounds great or rather sounds lesser but good results ,good luck on sales
A tiny prop like this costs $8k to $10k each for boat outboard motors. How much for a plane?
Right now they are CNC machined 1 at a time out of a solid billet of stainless. Very inefficient way of making them. Cost could come way down if widely adopted and mass produced. Right now they only make sense for charter boats where the fuel savings can pay for the expense rather quickly.
@@wally7856 That is often promised for various products that prove they really suck when put into mass production!
@@wally7856 finishing it out of cast steel billet should improve cost massively, should repay with about 400 pce at least our 250€ part are now cheaper then the previous cnc machined fom gnereic steel billet.
@@oliverherzog7702 Cast steel in the Ocean? Wouldn't last a week.
As far as I know 1mm loss within 12 Years in Panama. So no issue here. Cast steel machined to fine surface lasts long enough. Propeller damage due other means is a far bigger issue.
Can it deice or vary pitch?
Interesting. Let’s see how long it takes to perfect it!
No. This MIT propeller is *_NOT_* going to change aviation in any way!
Sorry to break it to you, but that's complete bullshit.
Why? Show me how to feather this propeller, I dare you....
You do realise there are tens of thousands of light aircraft flying out there that have fixed pitch propellers that can’t be feathered! In saying that, this propeller would have been adopted already if there was a real performance benefit at a reasonable cost!
How do you adjust pitch?
this is the biggest issue
How do you feather a toroidal prop, in the evening of engine failure?
Or even changing the pitch?
Anyone else remember the scify series about ancient flying craft in India? Wasn't there a ceramic disc that looked similar to this?
Cool.
It's a seaplane now.
Yay MIT!
Part of the appeal of airplanes is the noise. You know, like muscle cars.
I wonder where we’ll see them first on large ships? Military or civilian?
And classic propeller with a propellerring is less noisy and perform better than propeller without the ring.
Yes boats, and yes drones. But how about for vacuum cleaners? More efficient, quieter vacuum cleaners would be welcomed by everyone. How about leaf blowers? Quieter leaf blowers? Oh God yes!
A forged casting for boat propellers would mitigate the mass production expenses, with the advancement in metallurgy this design this is entirely achievable.
Big ships need these asap
Given the mass of the prop it could be a night mare for CG. Also, rapid maneuvering torque loads and rotational inertia could lead to bent prop shafts, incredible vibration and catastrophic failure. As pictured, it just doesn’t look ready for prime time.
Never going to replace conventional props on aircraft. 20 years from now, you'll see aircraft will still be using the same sort of props fitted today. This is all nonsense and pure clickbait.
"Never" or in "20 years" ?
What about variable pitch for airplanes?
Two things:
1) This is not new technology/it’s old news
2) USE A POPPER-STOPPER.
I kept looking for some example using a toroidal propeller on a private plane or similar and don't see anything like that in this video, so it looks like there is no breakthrough. AFAIK toroidal propellers won't work of any full sized aircraft, it'll only work in marine environments because of the density of water or tiny toys like hobby quadcopters which are well known to be aerodynamically different than very large aircraft, large enough to transport at least one human.
This video glosses over the simple fact that the toroidal shape has to be designed for an optimal rpm and that rpm has to be relatively slow or like any propeller cavitation happens. This video suggests that there is a benefit to lower rpm but that's only half true because there is an enormous penalty to trying to spin faster than the shape's optimized value.
Additionally, the development of toroidal propellers has probably been stunted by the ease of simply designing a ducted or shrouded propeller which resolves the tip turbulence problem. There is no need for the very high cost of manufacturing a toroidal propeller to gain that benefit.
So, bottom line is that there are some theoretical benefits for marine use but AFAIK is a dead impossibility as an airplane propeller.
i wonder if this shape could make my boilers less noisy. or my pumps moving more water at less motor amp draw.
If we had a toroid propeller, driven by a turbine and covered with a cowl, we would have a world beater. It could probably be "scaled upwards" to very impressive sizes.
If you have a cowl (duct), the problem is already solved
You dont need high end milling machines to make these.
They can easily be 3D printed.
Viktor Schauberger has entered the chat
He had organic "based on nature" impellers and such designed years ago.
You can't make toroidal props variable pitch which severely limits their use.
I wonder how well that would work on a pusher with a shroud?
I was just thinking the exact thing 😂
What about mass inertia?
CLICK BAIT!
Seems the boat propellers need a tail cone to eliminate that last bit of cavitation.
Have they ever used a mobius strip to form the toroids?🤔
Thank you for using the feminine singular suffix for one who aviates.
Why not just curve the tips some, instead of a complete loop, so they are like the ends of newer airplane wings.. Should reduce the turbulence at the tips.
How would it work in a low-pressure atmosphere like Mars?
This changes everything! Again! Hooray.
Or it doesn't.
I see a military application! Naval submarines are always looking for a quiet propeller design and they can definitely afford the cost!
If they're so great, put them in household fans.
Boat propellers will change aviation forever?!?
Not that getting hit by a propeller is fun, but might this design also be a bit safer for animals like manatees?
I may be stupid but How do propeller cone tips generate anything like speed of sound vortices? As he says.
The infinitely small centre of anything that is rotating, nomatter what the RPM, is effectively Stationary.
So the closer to the centre of a propeller = the slower the relative airflow.
Visa v, the longer the prop blade length the higher is the relative tip speed.
So obviously, minimising the prop diameter will minimise air noise but atainable thrust also.
So the answer is simple, fold the prop blade back towards the centre and increase its chord or pitch to recover the power.
A smaller diameter prop will reduce any inbalance factors so enabling use of higher RPM's resulting in more power.
for a vid about Aviation a lot of the time was taken up by nautical applications
This silly thing keeps popping up. It's best ignored until we see an example running on an actual full sized aircraft (not a drone).
200% increase........Holy cow. MIT is gunna be trillionaires
Lets not kid ourselves, even if there was a 20% decrease in fuel for container ships...., there is NO WAY those companies are going to pass it on (especially to their clients who aren't going to pass it on to us), instead just making more profit. 😕
Cheap transportation costs will never trickle down to consumers always have double talk on cost.
Makes one wonder how such propellers would improve aircraft carrier speed and efficiency.
Why has there been no attempt to test toroidal propeller on an aircraft?
A traditional aircraft propeller sacrifices Efficiency for Performance over an available Power Sources' Operating Range (the engine) for Airframe = X (the plane). What part of Efficiency is directly disproportional to Performance are you having a hard time with?
I googled boat companies
using "toroidal propellers"
and got nothing.
You doubled engine efficiency with this propeller.
Why aren't boat companies featuring it to increase boat interest?
Fixed-pitch propellers will not be more effective than high aspect-ratio propellers with adjustable pitch. Noise is just a part of the problem, as usual!
Straight up clickbait look at your picture you used.
You don't show one video of a new airplane blade working. Just boats and drones
What to do: The name of this channel is "Aviatrix." Just don't click on videos from this channel, or block the channel altogether.
What about, for helicopters? It would have to be somehow variable.
Your Volumes on this Video need increasing
The problem with our boats is that it has more drag and we performance boaters want top speed… It also costs 8X more. Not practical. In aircraft we need to be able to change pitch going into feather. Also, not practical.
Plane props twist to increase decrease torque at will. I don’t see how a toroidal prop can do that
Be ideal for stealthy submarines, no cavitation noises.
No, it won’t. Hydrodynamics is completely different from aerodynamics. This prop won’t work on aircraft.
It's basically a ducted fan but done with the tips.....
I want to see a 15 meter model for a container ship
"10 fold something is not the same as 10x something,, it's doubling 10 times.
Ducted Toroidal...?
Can you see through the propellor? Then, no.
Have a question. This is a huge national security question on submarines and warships. We all know when propellers turns in the water they create millions of bubbles per minute. What the tech guys call this is called cavitation. The bubbles creates noise that sonars can track the sub or ship. The bad guys can launch the torpedos at our warships. Can this new design propellar stop the cavitation that the old style propellers does? I have no clue what type of propeller the navy use. That is a top secret clasified information that Donald Trump might have given away to that billionaire and his wife at Mar-A-Logo while they were eating thier dinner. That open mic most likely from a phone caught the whole converation.
I know the navy uses big propellers on submarines because they can turn slower and will not cavitate in the water. Thats all I know about this top secret propeller.
As the only effect proven, Sharrow props increase efficiency in a mid-load situation of glider boats. That however is caused by a design flaw, intrinsic to all classical v-shaped glider hull boats. Their immense resistance when just enetering plaining prevents from running a top-speed-optimized prop as efficient in the mid-speed range. Sharrows propellers do have significant advantages in water flow directivity in that mid-speed regime.
All other attempts to bring toroidal props to the hobby market so far did not succeed. Guess why.
There is no such thing other than a stated advantage from MIT.
This is very misleading. They do not double efficiency. If they did you would see them everywhere. Manufacturing cost has nothing to do with it.
The design is not suitable for fixed wing aircraft. Absolute nonsense video