We heard you loud and clear in the UA-cam comments-you all wanted to catch the pure sound of our latest Whisper plane, without the extra tunes added. Well, guess what? We're all ears! Here it is, straight-up Whisper audio goodness, no distractions included! Let's dive into the sound of soaring together! 🎵✈ ua-cam.com/users/shortsMeLD_w3ZNwU?feature=share
When will we see Tubeculs on the leading edge, Shark skin on all surfaces , and zig zag owl trailing edge? Just Tubeculs give 20% extra lift and efficiency imagine the rest?
Yes, we will put out a video with this data. But it is important to recognize that this journey has been about improving the sound 'quality', so that the sound is more pleasing to the human ear. And of course, we get a decibel decrease in the process that is substantial.
A lot of good feelings about the success of the prop but very few facts to support that. How many decibels quieter? What was the speed difference? Climb difference? How much does it weigh? I think the NR prop has better static trust with an 80hp. Maybe altitude? The prop looks amazing, it would be nice to know if outperforms other props. Thank you for the video.
Right now we are showing 20% increase in static thrust, which is amazing. And, we will do much more controlled decibel tests in the future. The sound was noticeably smoother and quieter. It recorded quite a few decibels lower. Climb rate and speed better with the 20% increase in thrust. When you make a prop more efficient it produces more thrust with less noise. Win-win. Now if it could do it for a lower price then it truly would be magic ;-)
I've been looking into quieter drone propellers. There are some interesting designs out there that move the blade tip vortex out of phase between the blades.
I am VINDICATED by this new propeller !! Some 20 years ago or so I designed a simple wooden prop with bent inward tips of about 15 degrees, it was about 9 or ten inches and I meant to buy the electric motors to test between it and a straight planar prop but I never got around to it, I believe I left it with my dad because I made a smaller one for me. I hope he still has it because MY house burned down and I lost almost everything I owned. I would have been happy with ten to fifteen percent improvement in thrust with a given amount of power, but your tests show about 25% more thrust and that makes me very happy. I am glad someone perfected this design and now it can be used with electric planes also to extend their range.... and I don't have to use my time to manufacture them because Mr. Catto is doing it better than I could have imagined and with a much larger knowledge base in the physics behind it.
I always like to see new tech, but with a prop... there is a lot more than just static thrust. Did the climbout change? Did the cruise speed change? Did the fuel consumption change? And, since the vid is about a "Quiet" prop.... you should have had a Db meter inside, and outside the plane.
@@stevemitz4740 Sure, claim it as the design of your deity of your choice. There's enough to choose from. Maybe go flat earth as well as creationist and wear a tin hat too.
Dear Mr. Fluid on the brain NZ boy! Your slam on God/ "Our Creator" (as our USA's founding fathers put it, at risk of life!) is Ludacris, You silly people who have been trained to scoff God/ Our Creator, have your own silly, faith based religion, that posits, all complex symbiotic & dependent life forms all just evolved like magic, just in time to feed other hungery life form, all without a Creator! Duh, and silly boy You, dare mention Tin Foil hat & Flat earthers? How silly of you-people “think”, soaring birds airfoils/ wings just evolved, [without a Creator]? Why couldn't Ludwig Prandtl's airfoil prop just evolve, without a creator? I.e. questions’ God loathing Leftist people can't answer, only ridicule! Hopefully you wise up, before your time is up! Hell is not a nice place to spend eternity! Jesus suffered & died to pay your way, to glorious eternal Heaven! So wise up Suka!
@@fluiditynz Of course Ludwick's new stick had to have a designer,!...But NOT a simple sea gull, that just evolved like magic, I.e. no Creator involved! Right? ... Now tell me, you are not “faith based!”
When will we see Tubeculs on the leading edge, Shark skin on all surfaces , and zig zag owl trailing edge? Just Tubeculs give 20% extra lift and efficiency imagine the rest?
Please for the love of god and everything that is good in the world.... can you just leave the music out. Its cheap, its for teenagers, and its distracting.
@@SlingPilotAcademy Your content is excellent please 🙏 only use music for transitions. It is too distracting the entire time. Your content is very good and is lessened by the continuous background Sincerely a very informative and well done video. The details teach a lot
It's great to see you guys encouraging sound reduction. There are industry-standard sound tests you can run - that would be very helpful to share as well.
Ground testing is fun to see, but the airflow during flight is obviously very different. Optimal pitch increases with air speed. With the same throttle position, 5500rpm on the ground is going to result in much higher rpm in flight.
Well done Craig. It looks logical to me, and that reduction in noise with increase thrust is a huge benefit. I love the simplicity of the fine adjustment mechanism for all three blades at once. Cheers from Sydney, AU.
When voluntary procedures become involuntary.... and we are grateful for it. Our situation has forced us to work on becoming the quietest flight school in the world.
Love that prop. Finally someone improving prop design. Not being an engineer I have always wondered why the exhaust of an airplane is dumped right in front of the cockpit? Why not add 5 or 10 lbs of exhaust pipe past the cockpit to lower the cockpit noise level. The 1 negative that I do see is the parasite drag. The rubber hangers used in the automotive field could work for support. Also the exhaust pipe could be designed to help scavenge the exhaust gases vs creating back pressure so that could help increase the power. IMHO. I'm sure this has been tried but I have never seen it, not that I have seen everything.
Wonderful ! All about performance and if noise goes down that is a rediculous byproduct ! Cool little aircraft - Have fun and as always , be xtra safe - because it’s more fun ! 😊 We do this because it’s fun and serves the people ! See ya - DeBary , Florida .
Noticed that on the first test with the DUC prop, the prop spinner was on. I think for a valid test, the spinner must be on in ALL tests and the winds must be documented to be the same
Like most have said use a decibel meter and it would be nice if you added charts to visually show the differences in thrust, sound, speed, and rpm. I wonder what would happen in a contra-rotating setup with these blades?
Have you guys considered testing toroidal props? They seem to be outstanding. You should've had a decibel meter to determine the amount of the sound difference.
(youtube) hobbyists usually fail to replicate it. because most people do not understand how to measure it anyway and do not understand that it has a sweet spot at a certain rpm. if you just make a kind of visual copy and don't know how to measure it, then nothing fits. in the end of the video they had about 15% more thrust at max. rpm. but the boss said to increase pitch a tiny notch more. that might even lower maximum output. but it is irrelevant because it is about the maximum efficiency at cruising rpm, not rpm max. same goes for the toroidal prop from MIT or the sharrow propeller.
Amazing! The Catto Blade reminds me of the similar design used in new airline industry engine like the GE-E90 that has and provides all the properties the catto blade has efficiency, power, fuel savings and noise reduction!
I'm so glad to see other people leave comments about horrible music being edited into videos. I can't figure out why so many UA-camrs think that they need the music. 99% of the time it is annoying, distracting and makes me not want to watch the video.
You really need to try the Eprop super smooth and super quite and 2.5kg in weight...better on the gearbox and will produce the best performance for a Rotax as it has been totally designed for the Rotax engines. Everyone with a Eprop is super happy. Try one..if you dont like it they give you a full refund
Reckon if the leading edge had nodules on it leading into V patterns similar to what is on the bypass cowling in newer jet engines coupled with a winglet on the tip will give the ultimate in quietness. The challenge is there is nothing like that available to my knowledge. So now is the time to get one developed, built and tested.
I wish you would have used one of your other Slings to give us a real time comparison! One during run up and one on the fly over test. But amazing technology and video, thanks
Variable pitch propellers went out with the B. of Britain, Dowty-Rotol constant speed props were found to be better. Your tests are conducted at ground level, but Spits and Mustangs achieved their fastest speeds at about 15,000 - 20,000 ft. Would this new prop perform well at altitude?
Inspection of Blackhawk helicopter blade tip uses the same idea. The blade has a dog tooth about one blade cord inboard. Generates a vortex rotating opposite the tip vortex. I can understand the noise reduction, but can’t understand why doubling the vortexes increases efficiency.
Would be nice of you to at least mention astonishing Paul Lipps propeller that Catto made for Lipps as an inspiration for the "new" propeller that resembles propellers used on little photography drones for more than a decade. Now if you can rmake similar 1909 Olmsted propeller that I think inspired Paul Lipps, that would be nice.
Hey, you asked for a suggestion of what to make quieter on your plane? I dunno if this is reasonable, but.... what if you somehow measured your exhaust manifold pressure, since straight off the block, your exhaust gasses are basically some sort of percussive phenomenon. Then, armed with that recording of the status quo, you somehow enlist the CFT expertise of Catto and his staff. Then iterate over some sort of exhaust design that in no way restricts the exhaust gas outflow, but somehow does a secret sauce to the exhaust gasses, so that by the time they exit, they have become no more than a smooth, laminar flow, and just happen to be at the ambient air pressure, whilst having a velocity matching your IAS? 🤣 As a suggestion, I intend for it to come across as ridiculous. I would think that meeting those criteria would make your exhaust inaudible, and your crew of inventors who made it that way, would suddenly be defense contractors, never having applied for the job! Whether this is good news or bad news, I don't see that happening, but you can certainly say that my suggested goals are "aspirational." Meaning you can aim for that perfect result, and, should you attain 3-5% toward that goal, you would have a decent result. Get halfway there and, boy howdy, you might forget to shut the engine down due to not hearing it, anymore. 🤣 Here are a couple of thoughts that might help: look into how "shotgun" style directional microphones are designed. Although the lateral arrays of holes seem like baffles, their purpose is actually to allow off-beam sound (i.e., sound from sources to the sides) to enter the microphone in a pattern that causes it to destructive interfere with itself. Maybe the corresponding method of handling exhaust gas is to do something like divert it into a few channels, then cause it to travel slightly different lengths in the channels, until you merge those channels back together in a large-bore outflow channel. The hope there being that the percussive wavefront (the "p's in pow" in the "pah-pah-pah-pah-" rhythmic exhaust sound) could be delayed by different amounts, so that the pressure peak of some channel will be mixing with the low-pressure valley of some other. If, at any given time, every "pow" is mixed with every "ah" then instead of "pah-pah-pah-pah-" it might sound like "------" instead! The tricky bit might turn out to be: figuring out how to adjust the destructive interference, to match your RPMs, as you transition through the flight regimes. Maybe the "channels" would need to be made similar to the inner workings of an accordion, with a mechanism that changes musical keys to keep it harmonious. I suggest this as an example only because I have no idea what is inside an accordion! In other words, it's food for thought, if you consider Twinkies food. Here's another completely unverified spatially for you: Exhaust gas is hot, and takes up more volume than the ambient air. If you can cool it somehow, it would, of course, shrink back a bit closer to ambient density. Considering that it was the expansion of hot gasses that made the piston move, and then was exhausted as the "p in pow" sound, causing the exhaust gas to have cooled at some point after the cylinder, and before it is finished being exhausted, should get you a little bit closer to the "b in bow" or the "v in vow." Set your sights on the "m in mao," and... uh, let's just say we Americans are still dreamers. So a thought might be to 3d print a new exhaust manifold. Don't change anything much, except add internal and external "heat sink" fins. Or, go really to an unproven, and possibly dangerous extreme, by flowing your avgas through narrow "coolant loops" in the exhaust manifold. Transferring exhaust gas heat to the pre-ignition fuel, just immediately prior to compression and the spark could have beneficial results! You might get more efficiency, more power, quieter exhaust, and radiant skin. You would want to watch out for: dieseling, pre-ignition, premature detonation, chunks of motor getting blown out, engine bursting into flames, shutdown procedure now includes fire department step, and in-flight stalling due to fuel lines now all coked up and congested from it. So, this is an idea I emphasize might be terrible. On the other hand, it might be great. I have no idea. Maybe those ideas are most useful for triggering you to have better ideas that supplant them. If so, my work here is done! Good luck, guys! I will be looking forward to your progress toward silence in propeller-driven aircraft.
Yes, we will put out a video with this data. But it is important to recognize that this journey has been about improving the sound 'quality', so that the sound is more pleasing to the human ear. And of course, we get a decibel decrease in the process that is substantial.
Propellers have one purpose ONLY and that is to keep the pilot cool , you would notice the pilot overheating and sweating a lot when the propellers stop spinning
Beautiful prop. Mr Catto knows his stuff. Outstanding results. Decibel count would have been nice. Lose the music. It contributed nothing in fact it was a distraction.
The wonderful thing about a quieter prop, is that it is only quieter because if it is more efficient, and therefore higher-performing. It is the turbulent air/inefficiency that creates a lot of the noise. So, this is a great case where we don't have to give up performance to get a decrease in sound level. We showed a 20% higher static thrust in these tests, and quieter prop
@@SlingPilotAcademy That sounds awesome! As someone who will likely purchase a Tsi kit in the near future but hasn't yet done so, will there be an approximate timeline for the changeover published at some point once all the data are in?
What regulatory regime are you operating under which allows you to test fly like that? Where I am everything would be bogged down in paperwork for months!
The military could use this technology on there tail rotors to cut the noise. That's where the most prop noise comes from on a standard design helicopter.
I snapped 2 motorcycle tie-downs when lifting an elk out of my truck with a forklift. I’d worry about that strap recoiling into the prop if the hook bends. I have no idea how much elasticity there might be in that strap, but this would be an expensive way to find out.
What is the story with the music?! This is not a gym workout session... why is there no sound dB measurement (even with the phone)?? One frame with summary charts comparison before and after
My guess is the spinner back-plate was probably unique to the Duc hub adapter. Plus it's just more hassle to remove each time while you're still making adjustments. Flying without it won't make much difference, perhaps a few knots of top speed lost. I get the impression the priority here was testing quietness/efficiency.
When will we see Tubeculs on the leading edge, Shark skin on all surfaces , and zig zag owl trailing edge? Just Tubeculs give 20% extra lift and efficiency imagine the rest?
We heard you loud and clear in the UA-cam comments-you all wanted to catch the pure sound of our latest Whisper plane, without the extra tunes added. Well, guess what? We're all ears! Here it is, straight-up Whisper audio goodness, no distractions included! Let's dive into the sound of soaring together! 🎵✈ ua-cam.com/users/shortsMeLD_w3ZNwU?feature=share
It was a very well done video. I learned a lot. It seems your fans prefer less music because the content really is that appealing 👍🏼
Please always know that music will never be wanted in these videos. Music is the worst thing ever in aviation related videos. Thanks 👍🏻
Awesome - just the regular audio is best . Thanks
When will we see Tubeculs on the leading edge, Shark skin on all surfaces , and zig zag owl trailing edge? Just Tubeculs give 20% extra lift and efficiency imagine the rest?
I was about to complain lol sounds well tuned!
Decibel meter would have been nice
Yes, we will put out a video with this data. But it is important to recognize that this journey has been about improving the sound 'quality', so that the sound is more pleasing to the human ear. And of course, we get a decibel decrease in the process that is substantial.
No Meter? Glad I didn't watch the whole thing! wtf, zero results from a bunch of over caffeinated excited spazes
@@ZacLowing that are trying to sell their products with zero data
A lot of good feelings about the success of the prop but very few facts to support that. How many decibels quieter? What was the speed difference? Climb difference? How much does it weigh? I think the NR prop has better static trust with an 80hp. Maybe altitude? The prop looks amazing, it would be nice to know if outperforms other props. Thank you for the video.
I’d order one if I knew it was better than my WW
Right now we are showing 20% increase in static thrust, which is amazing. And, we will do much more controlled decibel tests in the future. The sound was noticeably smoother and quieter. It recorded quite a few decibels lower. Climb rate and speed better with the 20% increase in thrust.
When you make a prop more efficient it produces more thrust with less noise. Win-win. Now if it could do it for a lower price then it truly would be magic ;-)
@@SlingPilotAcademy what did ft per min go up to? 20% as well at same speed?
We will get numbers... but no, not that much
Hanging by my fingernails waiting for the numbers - decibels, feet per minute & cruise mph changes in an apple for apples comparison!!!???
Cut the music
ua-cam.com/users/shortsMeLD_w3ZNwU?feature=share
I suggest a decibel meter in the cockpit, with old prop, and new.
I've been looking into quieter drone propellers. There are some interesting designs out there that move the blade tip vortex out of phase between the blades.
Yea, technology and advancement (and CFD) are amazing
I am VINDICATED by this new propeller !! Some 20 years ago or so I designed a simple wooden prop with bent inward tips of about 15 degrees, it was about 9 or ten inches and I meant to buy the electric motors to test between it and a straight planar prop but I never got around to it, I believe I left it with my dad because I made a smaller one for me. I hope he still has it because MY house burned down and I lost almost everything I owned. I would have been happy with ten to fifteen percent improvement in thrust with a given amount of power, but your tests show about 25% more thrust and that makes me very happy. I am glad someone perfected this design and now it can be used with electric planes also to extend their range.... and I don't have to use my time to manufacture them because Mr. Catto is doing it better than I could have imagined and with a much larger knowledge base in the physics behind it.
I always like to see new tech, but with a prop... there is a lot more than just static thrust. Did the climbout change? Did the cruise speed change? Did the fuel consumption change? And, since the vid is about a "Quiet" prop.... you should have had a Db meter inside, and outside the plane.
Wow. Those blades are so clearly inspired by Ludwig Prandtl's second formulae and the bell curve lift distribution. All to reduce tip vorticies.
To me, it looks looked like Ludwick just plagiarized/ copied God's bird wing design!
@@stevemitz4740 Sure, claim it as the design of your deity of your choice. There's enough to choose from. Maybe go flat earth as well as creationist and wear a tin hat too.
Dear Mr. Fluid on the brain NZ boy! Your slam on God/ "Our Creator" (as our USA's founding fathers put it, at risk of life!) is Ludacris, You silly people who have been trained to scoff God/ Our Creator, have your own silly, faith based religion, that posits, all complex symbiotic & dependent life forms all just evolved like magic, just in time to feed other hungery life form, all without a Creator! Duh, and silly boy You, dare mention Tin Foil hat & Flat earthers? How silly of you-people “think”, soaring birds airfoils/ wings just evolved, [without a Creator]? Why couldn't Ludwig Prandtl's airfoil prop just evolve, without a creator? I.e. questions’ God loathing Leftist people can't answer, only ridicule! Hopefully you wise up, before your time is up! Hell is not a nice place to spend eternity! Jesus suffered & died to pay your way, to glorious eternal Heaven! So wise up Suka!
@@fluiditynz Of course Ludwick's new stick had to have a designer,!...But NOT a simple sea gull, that just evolved like magic, I.e. no Creator involved! Right? ... Now tell me, you are not “faith based!”
When will we see Tubeculs on the leading edge, Shark skin on all surfaces , and zig zag owl trailing edge? Just Tubeculs give 20% extra lift and efficiency imagine the rest?
My god. Came to hear the prop but all I hear is MUSIC!!!!
LOL under rated comment. CHEERS
ua-cam.com/users/shortsMeLD_w3ZNwU?feature=share
I've been commenting the same, but it has been IGNORED. The music is always as loud - and often louder - than the commentary.
By your request, here is a clean video of the sound ua-cam.com/users/shortsMeLD_w3ZNwU
@@SlingPilotAcademy The loud music issue is not just this one video. It's pretty-much ALL of your videos. Go back and watch them.
Please for the love of god and everything that is good in the world.... can you just leave the music out. Its cheap, its for teenagers, and its distracting.
Thanks for the feedback. We will post a raw video with just the sounds from the aircraft
ua-cam.com/users/shortsMeLD_w3ZNwU
He means for the entire video...@@SlingPilotAcademy
@@SlingPilotAcademy
Your content is excellent please 🙏 only use music for transitions. It is too distracting the entire time. Your content is very good and is lessened by the continuous background
Sincerely a very informative and well done video. The details teach a lot
It's funny, I would maybe have never noticed until you said so. Now it's all I hear. Thanks for ruining youtube for me :)
We've been wiating for a Prandtl based prop for years now - glad to see/hear one flying! Now I need one in a constant speed hub for our C182A!
Prandtl, is that the name of this design?
Also I want to make a propeller. Could i make it for you? I want to get into the bisiness.
I would like to have heard a low flyover with the old prop and then with the new prop. Cool design...wish you much success.
We will do this in an upcoming video
It's great to see you guys encouraging sound reduction. There are industry-standard sound tests you can run - that would be very helpful to share as well.
Don’t do the music
ua-cam.com/users/shortsMeLD_w3ZNwU?si=5wPZiqh-O9u2WYB4
Maybe just when no one is talking and so we can hear the prop noise change.
That is a very quiet propeller! Well done to Mr. Catto.
Is that music comming from the prop ? ?
I look forward to when we can order the upgraded blades for the Tsi airmaster prop!
Ground testing is fun to see, but the airflow during flight is obviously very different. Optimal pitch increases with air speed. With the same throttle position, 5500rpm on the ground is going to result in much higher rpm in flight.
Well done Craig. It looks logical to me, and that reduction in noise with increase thrust is a huge benefit. I love the simplicity of the fine adjustment mechanism for all three blades at once. Cheers from Sydney, AU.
Im glad to see yall are finding uunique solutions to the Torrance problems
When voluntary procedures become involuntary.... and we are grateful for it. Our situation has forced us to work on becoming the quietest flight school in the world.
Love that prop. Finally someone improving prop design.
Not being an engineer I have always wondered why the exhaust of an airplane is dumped right in front of the cockpit?
Why not add 5 or 10 lbs of exhaust pipe past the cockpit to lower the cockpit noise level.
The 1 negative that I do see is the parasite drag.
The rubber hangers used in the automotive field could work for support.
Also the exhaust pipe could be designed to help scavenge the exhaust gases vs creating back pressure so that could help increase the power. IMHO.
I'm sure this has been tried but I have never seen it, not that I have seen everything.
Great points! Exactly
In a video that is promoting noise reduction, the music is not helpful🤷🏼♂️
ua-cam.com/users/shortsMeLD_w3ZNwU?feature=share
Cool! Can you scale the down to drones?
Awesome. I'm almost ready to order my TSI kit, and I'm excited for when this prop is available.
Us too!
How does it perform in climb and cruise? Those are the two most important parameters.
Wonderful ! All about performance and if noise goes down that is a rediculous byproduct !
Cool little aircraft - Have fun and as always , be xtra safe - because it’s more fun ! 😊
We do this because it’s fun and serves the people ! See ya - DeBary , Florida .
Craig Catto is a wizard! A legendary prop designer and great guy all-around!
Daniel Raymer and Craig Catto .... Two legends there
:-)
Would love to see that on a turbine otter or radial beaver. Cool stuff you guys. Love it.
Cheers from little Nakina Ontario 🇨🇦
Perfect. Finishing up the Vans and I'm buying this.
Awsome to see as a pilot my self.
This prop is in mew bourn stage to.
2024 and out it will get so damn much better ❤❤❤
Noticed that on the first test with the DUC prop, the prop spinner was on. I think for a valid test, the spinner must be on in ALL tests and the winds must be documented to be the same
WOW that's amazing
Totally awesome 🎉
Excellent! You're only a step away from having a plane that's so quiet, some people will suspect -- and complain -- that it's a UN spy plane.
does an unspy plane spill the beans, or let the cat out of the bag at every opportunity ??
The shape of this Catto prop just looks right
you guys should invite the Torrance city council to come see your guys's quieter airplane
We will. We hope they will show up! ;-)
Like most have said use a decibel meter and it would be nice if you added charts to visually show the differences in thrust, sound, speed, and rpm. I wonder what would happen in a contra-rotating setup with these blades?
Have you guys considered testing toroidal props? They seem to be outstanding.
You should've had a decibel meter to determine the amount of the sound difference.
(youtube) hobbyists usually fail to replicate it. because most people do not understand how to measure it anyway and do not understand that it has a sweet spot at a certain rpm.
if you just make a kind of visual copy and don't know how to measure it, then nothing fits.
in the end of the video they had about 15% more thrust at max. rpm.
but the boss said to increase pitch a tiny notch more. that might even lower maximum output. but it is irrelevant because it is about the maximum efficiency at cruising rpm, not rpm max.
same goes for the toroidal prop from MIT or the sharrow propeller.
They are a joke. Not efficient for aircraft.
Time to update the POH limitations😂
Amazing! The Catto Blade reminds me of the similar design used in new airline industry engine like the GE-E90 that has and provides all the properties the catto blade has efficiency, power, fuel savings and noise reduction!
Awesome video guys.
Thanks so much!
I'm so glad to see other people leave comments about horrible music being edited into videos. I can't figure out why so many UA-camrs think that they need the music. 99% of the time it is annoying, distracting and makes me not want to watch the video.
make sure that when you install an experimental prop to have all your friends and hangers on stand in line with it during testing run up
Haha - good point. ;-)
Glad I'm not only one wincing at that. Wow. All standing directly inline. Yikes.
Ja, if the prop pops y'all can have a braaivleis 😮
I had intended to watch a bit at the start and skip to the end but I watched the whole video 😃😃
there you go, even more efficiency
Hello Jean aka "Dassie" ! Greetings from Corrie Snr here in the RSA!👌👌👍👍
You really need to try the Eprop super smooth and super quite and 2.5kg in weight...better on the gearbox and will produce the best performance for a Rotax as it has been totally designed for the Rotax engines. Everyone with a Eprop is super happy. Try one..if you dont like it they give you a full refund
Reckon if the leading edge had nodules on it leading into V patterns similar to what is on the bypass cowling in newer jet engines coupled with a winglet on the tip will give the ultimate in quietness. The challenge is there is nothing like that available to my knowledge. So now is the time to get one developed, built and tested.
Can't hear anything with that music. Keep it out!
That was an improvement. Now to see how durable it is.
Hi, is the test complete and what is the result?????
I wish you would have used one of your other Slings to give us a real time comparison! One during run up and one on the fly over test.
But amazing technology and video, thanks
Great work/engineering Catto
Does Sling Pilot Academy have any plans to test a CS prop on a HW or TSI with gthe 916 engine?
Catto nails it again. Great company, don't blame the FBO's music on him!
Seeing Torrance airfield makes me so homesick...
Great prop design!
Frequency response graph as well as dB level?
old school here. do you not safety wire prop bolts anymore?
The prop on the Joby electric has a similar tip shape.Hopefully it'll work even better at higher Mach numbers
Variable pitch propellers went out with the B. of Britain, Dowty-Rotol constant speed props were found to be better. Your tests are conducted at ground level, but Spits and Mustangs achieved their fastest speeds at about 15,000 - 20,000 ft. Would this new prop perform well at altitude?
This class of aircraft flies low.
Mis más sinceras felicitaciones a los que desarrollan mejoras tecnológicas para la aviación.
Even I could hear the difference, sweet.
Yes, it is all in the ear of the beholder
What tools should i use to design my propeller? 360 ? Or just foam or wood models?
I wonder if you could redesign the rotor on an autogyro to make the gyro use less gas at a faster flight
Inspection of Blackhawk helicopter blade tip uses the same idea. The blade has a dog tooth about one blade cord inboard. Generates a vortex rotating opposite the tip vortex.
I can understand the noise reduction, but can’t understand why doubling the vortexes increases efficiency.
Would be nice of you to at least mention astonishing Paul Lipps propeller that Catto made for Lipps as an inspiration for the "new" propeller that resembles propellers used on little photography drones for more than a decade. Now if you can rmake similar 1909 Olmsted propeller that I think inspired Paul Lipps, that would be nice.
It would have been nice to have db readings using a "conventional" prop vs the new prop...
Hey, you asked for a suggestion of what to make quieter on your plane?
I dunno if this is reasonable, but.... what if you somehow measured your exhaust manifold pressure, since straight off the block, your exhaust gasses are basically some sort of percussive phenomenon. Then, armed with that recording of the status quo, you somehow enlist the CFT expertise of Catto and his staff. Then iterate over some sort of exhaust design that in no way restricts the exhaust gas outflow, but somehow does a secret sauce to the exhaust gasses, so that by the time they exit, they have become no more than a smooth, laminar flow, and just happen to be at the ambient air pressure, whilst having a velocity matching your IAS? 🤣
As a suggestion, I intend for it to come across as ridiculous. I would think that meeting those criteria would make your exhaust inaudible, and your crew of inventors who made it that way, would suddenly be defense contractors, never having applied for the job! Whether this is good news or bad news, I don't see that happening, but you can certainly say that my suggested goals are "aspirational." Meaning you can aim for that perfect result, and, should you attain 3-5% toward that goal, you would have a decent result. Get halfway there and, boy howdy, you might forget to shut the engine down due to not hearing it, anymore. 🤣
Here are a couple of thoughts that might help: look into how "shotgun" style directional microphones are designed. Although the lateral arrays of holes seem like baffles, their purpose is actually to allow off-beam sound (i.e., sound from sources to the sides) to enter the microphone in a pattern that causes it to destructive interfere with itself.
Maybe the corresponding method of handling exhaust gas is to do something like divert it into a few channels, then cause it to travel slightly different lengths in the channels, until you merge those channels back together in a large-bore outflow channel. The hope there being that the percussive wavefront (the "p's in pow" in the "pah-pah-pah-pah-" rhythmic exhaust sound) could be delayed by different amounts, so that the pressure peak of some channel will be mixing with the low-pressure valley of some other. If, at any given time, every "pow" is mixed with every "ah" then instead of "pah-pah-pah-pah-" it might sound like "------" instead!
The tricky bit might turn out to be: figuring out how to adjust the destructive interference, to match your RPMs, as you transition through the flight regimes. Maybe the "channels" would need to be made similar to the inner workings of an accordion, with a mechanism that changes musical keys to keep it harmonious. I suggest this as an example only because I have no idea what is inside an accordion! In other words, it's food for thought, if you consider Twinkies food.
Here's another completely unverified spatially for you:
Exhaust gas is hot, and takes up more volume than the ambient air. If you can cool it somehow, it would, of course, shrink back a bit closer to ambient density. Considering that it was the expansion of hot gasses that made the piston move, and then was exhausted as the "p in pow" sound, causing the exhaust gas to have cooled at some point after the cylinder, and before it is finished being exhausted, should get you a little bit closer to the "b in bow" or the "v in vow." Set your sights on the "m in mao," and... uh, let's just say we Americans are still dreamers.
So a thought might be to 3d print a new exhaust manifold. Don't change anything much, except add internal and external "heat sink" fins.
Or, go really to an unproven, and possibly dangerous extreme, by flowing your avgas through narrow "coolant loops" in the exhaust manifold. Transferring exhaust gas heat to the pre-ignition fuel, just immediately prior to compression and the spark could have beneficial results! You might get more efficiency, more power, quieter exhaust, and radiant skin. You would want to watch out for: dieseling, pre-ignition, premature detonation, chunks of motor getting blown out, engine bursting into flames, shutdown procedure now includes fire department step, and in-flight stalling due to fuel lines now all coked up and congested from it. So, this is an idea I emphasize might be terrible. On the other hand, it might be great. I have no idea.
Maybe those ideas are most useful for triggering you to have better ideas that supplant them. If so, my work here is done!
Good luck, guys! I will be looking forward to your progress toward silence in propeller-driven aircraft.
It would be nice to measure the difference in the cruise speed and fuel consumption, also the noise level can be measured using any mic
Is there a way to use 'Noise Cancellation' (like military helicopters)?
What is the net efficiency improvement?
It would be interesting to see the performance difference of a prop change on a WW2 fighter.
Before and after comparison would be nice. Maybe two planes following each other. And as others suggested, decimal meters.
Yes, we will put out a video with this data. But it is important to recognize that this journey has been about improving the sound 'quality', so that the sound is more pleasing to the human ear. And of course, we get a decibel decrease in the process that is substantial.
For you! ua-cam.com/users/shortsMeLD_w3ZNwU
Propellers have one purpose ONLY and that is to keep the pilot cool , you would notice the pilot overheating and sweating a lot when the propellers stop spinning
Now you have to redesign the exhaust , Get the noise level down to match a Honda Gold wing Touring Bike.
Beautiful prop. Mr Catto knows his stuff. Outstanding results. Decibel count would have been nice.
Lose the music. It contributed nothing in fact it was a distraction.
So was the only benefit a quieter plane? Please let me know so I can see if I want one of these vs my Whirlwind.
The wonderful thing about a quieter prop, is that it is only quieter because if it is more efficient, and therefore higher-performing. It is the turbulent air/inefficiency that creates a lot of the noise. So, this is a great case where we don't have to give up performance to get a decrease in sound level. We showed a 20% higher static thrust in these tests, and quieter prop
@@SlingPilotAcademy awesome. Wonder how it’ll do on 150hp or more as well. Will you be switching the entire fleet to these over time?
Once we have finalized everything we will convert our entire fleet over time
@@SlingPilotAcademy That sounds awesome! As someone who will likely purchase a Tsi kit in the near future but hasn't yet done so, will there be an approximate timeline for the changeover published at some point once all the data are in?
How would a propeller designed from a Sycamore seed work?
Safety wire on the prop bolts???
A toroidal fan blade. Manufacturing a toroidal blade and the certification by the FAA is the difficult part.
A set of numbers at the end would be nice.
What regulatory regime are you operating under which allows you to test fly like that? Where I am everything would be bogged down in paperwork for months!
The military could use this technology on there tail rotors to cut the noise. That's where the most prop noise comes from on a standard design helicopter.
They already do
How about the prop's performance at cruise speed? There is more to a prop than pulling a truck and noise.
Sounds reasonable, zero lift at the tip, less noise. Where is the decibels meter? Where is the summary chart? Noise, Static Thrust, Climb Rate...
I snapped 2 motorcycle tie-downs when lifting an elk out of my truck with a forklift.
I’d worry about that strap recoiling into the prop if the hook bends.
I have no idea how much elasticity there might be in that strap, but this would be an
expensive way to find out.
It’s 300lbs dude. Relax lol
Must have been A REALLY BIG ELK !
What is the story with the music?! This is not a gym workout session... why is there no sound dB measurement (even with the phone)??
One frame with summary charts comparison before and after
ua-cam.com/users/shortsMeLD_w3ZNwU?si=gYFActUAuLyvWa-k
So what's the speed difference??
It was several knots faster in cruise. We haven't done completely controlled testing, but it was about 4 kts faster in cruise and climbed better
Comparison results could be done using a Toroidal Propeller ???!!!
Reminds me of the Prandtl wing.
Music needs to be louder! ;) :D
The aircraft flew without the prop hub cover? Why? (forgot what it's called. -"spinner?")
My guess is the spinner back-plate was probably unique to the Duc hub adapter. Plus it's just more hassle to remove each time while you're still making adjustments. Flying without it won't make much difference, perhaps a few knots of top speed lost. I get the impression the priority here was testing quietness/efficiency.
@@boydw1 Thanks.
Yes, we didn't have a custom spinner made for this prop yet, and it was not necessary for the tests we were doing
@@SlingPilotAcademy Thanks.
Now that the exhaust is the remaining sound, that should be easy to redirect upwards away from the ground, rather than a muffler.
Yes, our "Swiss muffler" silencer kicks up behind the wing upwards
How can I buy one for my Rotax 914 ? 😊
Will these be adaptable to evtols that have multiple propellers
If you look at the blades used by Archer and BETA and others you will see that they look similar
we need these on drones!
Some drones have utilized a similar design!
When will we see Tubeculs on the leading edge, Shark skin on all surfaces , and zig zag owl trailing edge? Just Tubeculs give 20% extra lift and efficiency imagine the rest?
Please leave the music off.
ua-cam.com/users/shortsMeLD_w3ZNwU?si=-mbp287cjSMmlzn3
If there is no lift at the tip then why is there a tip vortex?
Angle of attack is very close to zero, but not always at exactly zero, and the prop has a shape and termination at that point that causes disruption.
Insane result so is the music