i guess Im asking randomly but does someone know a trick to log back into an instagram account?? I was dumb forgot my password. I love any assistance you can offer me.
@Ahmir Samson thanks so much for your reply. I got to the site on google and im in the hacking process now. Seems to take quite some time so I will reply here later when my account password hopefully is recovered.
In World War II it was the sound of the German Stuka that struck fear into the hearts of soldiers. In World War III, it will be the sound of 5-inch bi-blades at 65,000 RPM.
According to a propeller tip speed calculator, at 65,000 rpm the tips of a 5 inch prop would be supersonic, traveling at 966.8mph. That explains why those powerful race drones are so loud, but I still don’t quite think those props can handle the drag that occurs when the tips go supersonic…although when I compared the prop design of a race quad to the prop designs of planes that have supersonic propellers, the quad’s props look like they’re gonna handle it WAY better. Just wonder if it’s possible to make a race drone with supersonic propellers to make it super loud and fast
@@sulawesi-steve No not I'm not scared of flying when I am in the middle of nowhere I am fine. I have major social anxiety and just scared of upsetting someone and getting in a confrontation
@@RobertCondonSunnyTurtle ah ok, that's fair enough, thanks for being honest. Are you in the position to get a cheap spare set of goggles? I kept my first box set I got with my wizard, I take them with me if I'm flying somewhere that I know people walk there dogs. I keep an eye out obviously, plus I've got a spotter 100% of the time 🧐...... I find this helps to show how fun it is to 'fly like a stunt bird' and that I'm just enjoying my free time, not spying on people or practicing dropping of drugs ha.
@@sulawesi-steve Yep got a spare set of Goggles and a little hand held display. I almost always have good experience with people just been curious. It's mostly just in my head. Someday I am good and really enjoyed flying others I just can't get out of my head and can't barely fly. Thanks for the advice though. I've been flying for fpv over 8 years now and have only had a few bad interactions but many many great ones. I had some bad times where I just stopped flying but have always come back because this hobby is so good for me.
Corrected and I loved watching it then... Haven't watched a RR it well over a year.... I believe since the drones vs car windows ep I believe is the last one....
Qualitatively speaking, for the same diameter, number of blades: 2 8 RPM needed for certain thrust: high low noise: loud quiet top speed (high-speed efficiency): high low low-speed (hovering) efficiency: low high
8 sounded really nice! I think the higher pitch also made it not as shrill sounding. The biggest thing I noticed was with the 8 blade, there was almost no echo compared to the other louder blades. So it's definitely a lot quieter overall.
there is lot of aerodynamic physics behind this experiment, which could explain why is proper diameter, number of blades and rpm does it's job... The main idea is that only diameter increase flow(volume of fluid per minute) which increases thrust, and explains why bigger drones fly more efficient. Number of blades increases pressure, but decreases flow, that really helps to increase "grip" of the drone. The most efficient setup in theory of hydro and aero dynamics is to have only 1 blade, but you'll have unbalanced motor that makes it inefficient in terms of tribology of bearings, that's why the most efficient drones use 2 blades. As for high rpms(which highly increase pressure, and flow a little bit) which you have to use in that case because you don't have enough flow because of small diameter of props shows bad effect because you have something like cavitation in water at pump input because of low pressure when sucking, in the air you have vacuum at the edges of props which also could be said that you are running props with a speed higher than speed of sound. So when you are running 8 blades you have less flow and less air goes at speed of sound, that's why they are much quite than 2 bladed which have much higher flow
I'd love to see those 8-blade props tested with ducts. I'd expect more power (better efficiency due to tip vortices being prevented) and maybe even quieter.
I love the feel of torque on a 2 blade quad, but as for flying, I enjoy 3 blade with an aggressive pitch the most. They always feel locked in, faster and are soooo quiet!
two things. First, have you tried to put them on a 3-4 inch frame? Second, I wonder if they might come out with a 4 inch 8 blade prop? The first option might save some weight. The second option would reduce rotations and the pitch a little.
Dude! Everything you do makes me want to try whatever the thing is you're experimenting with. Your videos are inspiring, even when you're trying crazy ideas.
We played around with 8 blade props years ago. Back in the CC3D days and the bite is insane. Super locked in, 2 and 3 blade props felt sloppy back them compared to them. The are faster at mid, throttle for sure but really caused mega sag if you went above about 70% throttle. This was on BH 2205 2522kv motors and 4s 1300. They felt amazing but they pulled so much amps that it literally was unflyable even on a totally fresh pack... After a, min of flight if you got on the throttle at all for any length of time it would cook a esc or sag so badly you would have to back off... The 6 blade 5 inch props was halarious... What's fun is to take 3in props on a high KV 4s 5 inch build and run 6s. The motors have so much torque with that little prop that it literally man handles them and response is so quick and clean and at hover it's making some noise lol... Wot on a unloaded 3 inch prop on 6s on a 2900kv really screams.
I just did the mathematics. It's obvious when you think about it. If you halve the blade diameter and quadruple the number of blades (of the same angle), then you get the same lift at the same RPM, so it's a straight swap on your current rig, without changing motors, ESCs or batteries. It would be interesting to see what impact such a change has on noise level, air speed and agility.
So, a little math here. The circumference of a a 5 inch prop is 15.710 inches. That means a 5 inch prop tip at a potential RPM of 65,000 would be traveling at 1,021,150 inches per minute, or 16.1 miles per minute, or 966 miles per hour. That means that weird sound hat you are hearing is the prop blade is likely breaking the sound barrier, and becoming much less efficient. The eight blade props would be doing 677 mph at 65000, which under load will not reach that rpm, and is staying under that sound barrier.
This was fascinating! So is there a reason NOT to just use 8 blades all the time? I’ve been looking for quieter props for a long time, so I’m considering trying these 🤔 What’s the reason for 3 inch on a 5 inch though?
Interesting to see you starting to do "appetizer" bits at the beginning - its really valuable for Facebook retention, especially considering their ad rates are way better than youtube.
HQProps also make 5x4x6 that could get you a nice balance. Would be interesting to see how different the flight time would be with 8-blade props on a light 5" race build.
The smaller prop being quiet does make sense. The 5 inch could be breaking the sound barrier while the 3 inch is not. Another way of looking at it, is that all the noise your hearing from the 5 inch is the sonic boom of the propeller tips.
I bet and to prove it, I calculated the tip speed of the 5 inch propellers at 65,000 RPM and sure enough, it is supersonic at 966.8mph. Another thing is how it sounds at 11:26. It had a very distinct “buzzsaw” kinda noise. I heard a 4 inch quad before and it sounded mainly like a “whoop” or “zip” instead of that kind of intense shredding kinda sound. It was still the LOUDEST drone I’ve ever heard tho! I would love to get one with supersonic props and basically destroy ppl’s eardrums lmfao. That is why I love race drones
@@NiNo9 There is a lot of drag that slows down the props and maximum rpm is also limited by the ecs (mosfets don't switch instantly). It would be nice to see real rpm in osd.
In what seem like the old days, I used to run 5S on 2600 kv F40 Pro V2 motors. This was in the days before Betaflight had a motor output limit. Tuning was difficult and never perfect, and the best I could really do was put a throttle cap on the radio to keep from pushing the props too hard. When I'd flip the switch to bring disable the throttle cap on the Taranis, the Racekraft 5051 props would scream like a banshee. The sound was just ridiculous. On any 5" prop.
That honestly makes sense, more blades make more thrust at a lower RPM, more blades cutting the air is less turbulent, so less noise...??! Maybe I’m crazy I dunno, but it’s crazy how quiet that is
Sooo. In aerospace engineering this is an entire field of study. Basically, what it comes down to, is more blades == less efficiency. At those speeds, a two bladed prop will probably save you some battery power and handle about roughly the same as the 8 blade, however, the two blade prop experiences less drag to spin up to speed, so it uses less power to spin up to the same speeds as the 8 blade. when you start to get to super sonic speeds, thats when a propeller starts to warrant a fan shaped design. Like in a turbojet engine. I'm not an engineer, but I from what i understand, thats where the science of blade numbers comes in. More blades = more more juice to power it with marginal or negligible increases in performance. You can look to WW2 to see why they chose to keep planes with 2 or 3 blade props :p But i guess its a decent trade off to make your drone quieter O:
You can take inspiration from the aerospace industry. GE's GE9X has similar design in blades. For a few reasons. 1. Way more effective in power to fuel consumption 2. Noise levels dropped dramatically. You're seeing and testing GE's theories and might even realize it :)
Extra blades means you are pushing more air at the same RPM as with the other props but the 8 blades are smaller in diameter to lower turbulence between the blades. A 5 inch version of the 8-blade with more powerful motors would be awesome to see.
Ong fr lmfao that would be me bc I love doing punchouts. It already sounds and feels epic on a tiny whoop. Can’t imagine how epic it would be on a 3-5 inch quad
I just bought my first drone. Zero Features. Just a basic all piloting all the time drone. Loving it. Just the fact that I can get so much practice piloting. My buddy smirks when I am flying, because I just fly out a ways, circle back, establish hover and land accurately.. I was doing it with a store bought drone in the wind. I did my first attempt at a flip with it a few minutes later and lost control though. This is what happens when you let your friends bait you into showing off. Drone is fine. Flown a Phantom before. It was almost too easy to fly. I started out years ago in helicopters. So it seems to transfer well.
Im late to the party, but I’m assuming the 8 blades just add to the disc surface, obviously, and just acts like more of a “wind brake” so to speak, making the snaps more precise and snappier. This is really cool!
The motor KV rating is unloaded RPM per volt, not the loaded RPM per volt. The actual rpm of the motor will vary depend on the load you place on the motor. The props will be spinning no where near 65 thousand RPM
Um I bet the 2 blades ones will spin at at least 64,000 rpm bc of their low pitch angle. Those blade tips sound like their going either close to or slightly over the speed of sound bc like listen to how loud it is. Most 2 blade quads aren’t that loud but ofc it can be the camera’s mic and stuff
i am using same propellers on a simple DIY cinewhoop with 3s battery. major difference is the sound it generates. it is quiter and thrust is more than 3 blades. good thing isthe load on ESC is not much different. 26 amps in total vs 24. but very fragile when used out of a duct, and acetone warps them FYI.
Sounds like the octoblade pushes the sound energy up to higher frequencies, possibly in to ultra sonic region, so the noise is still there, but above human hearing range. At what number of blades does it stop being a prop and become a fan? Are there any swept-blade versions? The five blade sound is like the F1 V10 of the quad world. Now wondering about octobladed phantom, if quiet enough to record dialog while getting drone shots.
I suspect the frequency of the noise made by the 8 blade props is above that of human hearing capability and all we hear is the air turbulence from the props. what is cool is you can easily make a standard 5 inch 4s high kv drone that you can alternatively put a 6s pack on and these little props on for quiet flying.
Holy crap. Am I making this up, or is the combo of the high rpm 8 blade props along with the lack of active braking (being a 3” prop vs 5” prop) allow this to fling harder than a 5”? You were shooting past that tree pretty hard!
Hey Nurk I'm wondering about prop down force? blade tilt in degrees, helicopters increase tilt to the blades to achieve takeoff, such as five degrees compared to ten degrees I'm just guessing. I know it would probably decrease battery consumption but increase speed right?
I love it! Very quiet for a beginner would be excellent! Sound too loud is sometimes scary for many people and neighbors! You guys should produce the quite and new 64 blades by Nurk FPV.
I personally don’t like quiet race drones. To me, they should be like mini fighter jets which is loud, fast, and highly maneuverable. In fact I wanna find out if it’s possible to have a drone with props that go supersonic which would give u extra thrust, and a LOT more noise lol. If it is I would love to get an fpv quad and install more powerful motors on it with a very specific propeller design that can handle the drag when creating shockwaves on the tips due to going supersonic
Ordered 20 sets for my 5". I've always hated the sound because it draws so much attention - this is major for me, and is well worth whatever drawbacks might not have made it into the video. Question is - which motors to buy?
Would love to have some of those for my DJI mini two. Same diameter as stock. Would be awesome to see how they perform on the mini two especially at high altitudes.
can you put the largest blades like make the arms on the top so they won't hit anything on the top and try to get the blades as close to each other that you can
I think the real winning factor on biblade props is that the motors can start and stop faster compared to heavier props giving you more authority and precision.
I remember old pylon racers using a single blade counter balanced as multi blades would one cause more surface area and two also hit dirty air from the previous blade.... could be worth a try?
Thats why submarines also been using props with many blades for decades because it makes them quieter underwater. For submarines this is very important. Just a little side-info :)
Just a question from an outsider... Physics whise, aren't the 8 bladers more efficient because less energy is converted into sound? I mean, we heard it echoing back, it was really loud.
I doubt those were reaching 65k rpm. The RPM you calculated would be with no load on the motor (props off). Remove the props, Plug the quad into betaflight, in the motors tab, enable bi directional D-shot. Enable the motor sliders and spin up your motors, you will be able to see the actual RPM reported by the ESC. Now put the props on and (very carefully) try the test again. I can assure you the RPM will not be 65,000.
I'm the " that's not right" guy today. I'm just so excited $gme blew up again today. Get on the shuttle to the moon at market open tomorrow!!!!!!! 65k unloaded with no battery sag. As prop rpm increases the drag increases by square. The motor can produce x amount of torque regardless of rpm. 2000kv 6s = 15krpm at half throttle and 20k at full throttle. Current consumption 5a and 20a respectively. 2600kv 6s = 20krpm at half throttle and 20k at full throttle. Current consumption 20a and 80a respectively. Battery on fire huh? Lets say this motor can produce 2 ft/lbs of torque and the prop requires 2ft/lbs to spin them at 20k. A perfect match of kv to the prop would be the prop requires 2ft/lb at the max rpm the motor can produce, say 20k rpm. The motor can't magically pick up stator volume to quadruple the torque output to 4ft/lbs and pick up twice the rpm. Now lets say the same setup with double the kv. The motor will only spin the motor to 25k with 2ft/lb of torque. Above that the motor will not spin faster however it will pull more current effectively turning the wasted wattage to heat. At the end of the day we would like like the system to be scaled where max throttle is 5% bellow max rpm of the motor/prop combo for decreased angle of attack when the prop unloads. I suppose we could do an 8s battery on 2600kv and cut the throttle scale in half to produce a sharper bell curve in rpm up to half throttle.
Question: What's the best 5" prop?
Answer: 3" 8-blade.
Rofl
There are now HQ props, 8 bladed 3.5inch, and 6 bladed 4 inch that should work better in a 5ª quad than the extreme 3" props.
i guess Im asking randomly but does someone know a trick to log back into an instagram account??
I was dumb forgot my password. I love any assistance you can offer me.
@Holden Milo Instablaster =)
@Ahmir Samson thanks so much for your reply. I got to the site on google and im in the hacking process now.
Seems to take quite some time so I will reply here later when my account password hopefully is recovered.
7:35 LTT Was here
Rofl
More like LDT 🤣
In World War II it was the sound of the German Stuka that struck fear into the hearts of soldiers. In World War III, it will be the sound of 5-inch bi-blades at 65,000 RPM.
i have 6-inch bi-blades, but only can fly them far away from civilisation. it eaven scares the crap out of me. hehehe
Not far off now eh
You didn’t know how correct you were when you wrote this.
@@Flumphinatoryeah 😢
This aged like fine wine
imma hold out for 16 blade.
I’m waiting for the 69
420
Do dual motor mounts with 8 blade.. there u go, 16 per arm
Low turbulence
Half blades.
Would be cool to see a 5” 8 bladed prop fly in this set up.
According to a propeller tip speed calculator, at 65,000 rpm the tips of a 5 inch prop would be supersonic, traveling at 966.8mph. That explains why those powerful race drones are so loud, but I still don’t quite think those props can handle the drag that occurs when the tips go supersonic…although when I compared the prop design of a race quad to the prop designs of planes that have supersonic propellers, the quad’s props look like they’re gonna handle it WAY better. Just wonder if it’s possible to make a race drone with supersonic propellers to make it super loud and fast
11:26
I'm loving how happy and excited NURK is at the beginning. Seriously, how many awesome drones has he flown and this still happens for him.
Nurk: shows us that 8 bladed props exists
Me: Buys 5 sets before even seeing the comparison
Same 4 sets haha
now they are backordered!!! damn.. Im late to the party
@@timm1065 try RDQ?
found them on Pyrodrone; luckily. now I'm just trying to decide on a frame and set of motors to get that free shipping... lol
HQprops recently released 8 blade 3.5inch and 6 blade 4 inch that should be a better match for a 5" quad, I think (and also look gorgeous)
I often have anxiety about the noise of my drones this might be worth trying for me.
Can I ask why??
Are you scared of your own flying ? Or just not like the sound?
@@sulawesi-steve No not I'm not scared of flying when I am in the middle of nowhere I am fine. I have major social anxiety and just scared of upsetting someone and getting in a confrontation
or even just being noticed.
@@RobertCondonSunnyTurtle ah ok, that's fair enough, thanks for being honest.
Are you in the position to get a cheap spare set of goggles? I kept my first box set I got with my wizard, I take them with me if I'm flying somewhere that I know people walk there dogs. I keep an eye out obviously, plus I've got a spotter 100% of the time 🧐......
I find this helps to show how fun it is to 'fly like a stunt bird' and that I'm just enjoying my free time, not spying on people or practicing dropping of drugs ha.
@@sulawesi-steve Yep got a spare set of Goggles and a little hand held display. I almost always have good experience with people just been curious. It's mostly just in my head. Someday I am good and really enjoyed flying others I just can't get out of my head and can't barely fly. Thanks for the advice though. I've been flying for fpv over 8 years now and have only had a few bad interactions but many many great ones. I had some bad times where I just stopped flying but have always come back because this hobby is so good for me.
This is how rotor riot episodes used to be before they started shilling equipment.
Corrected and I loved watching it then... Haven't watched a RR it well over a year.... I believe since the drones vs car windows ep I believe is the last one....
Qualitatively speaking, for the same diameter,
number of blades: 2 8
RPM needed for certain thrust: high low
noise: loud quiet
top speed (high-speed efficiency): high low
low-speed (hovering) efficiency: low high
I really like that sound. Not being able to hear as much of the speed change from acro flying makes them a whole lot more stealthy
Very interesting and unexpected for me just how much softer the sound was with the octo-blades.
8 sounded really nice! I think the higher pitch also made it not as shrill sounding.
The biggest thing I noticed was with the 8 blade, there was almost no echo compared to the other louder blades. So it's definitely a lot quieter overall.
👍👍 This is the sound that was etched into my brain several years back of how a 5 inch drone should sound snap flipped and rolled. 8:52
there is lot of aerodynamic physics behind this experiment, which could explain why is proper diameter, number of blades and rpm does it's job... The main idea is that only diameter increase flow(volume of fluid per minute) which increases thrust, and explains why bigger drones fly more efficient. Number of blades increases pressure, but decreases flow, that really helps to increase "grip" of the drone. The most efficient setup in theory of hydro and aero dynamics is to have only 1 blade, but you'll have unbalanced motor that makes it inefficient in terms of tribology of bearings, that's why the most efficient drones use 2 blades. As for high rpms(which highly increase pressure, and flow a little bit) which you have to use in that case because you don't have enough flow because of small diameter of props shows bad effect because you have something like cavitation in water at pump input because of low pressure when sucking, in the air you have vacuum at the edges of props which also could be said that you are running props with a speed higher than speed of sound. So when you are running 8 blades you have less flow and less air goes at speed of sound, that's why they are much quite than 2 bladed which have much higher flow
Don't know why, but the quick transition at 1:21 with the full blown back hair cracked me up. Great video Nurk
I'd love to see those 8-blade props tested with ducts. I'd expect more power (better efficiency due to tip vortices being prevented) and maybe even quieter.
I love the feel of torque on a 2 blade quad, but as for flying, I enjoy 3 blade with an aggressive pitch the most. They always feel locked in, faster and are soooo quiet!
I might get a set of these to try on my long range build to see how much it effects efficiency.
poor efficiency
Affects*
two things. First, have you tried to put them on a 3-4 inch frame? Second, I wonder if they might come out with a 4 inch 8 blade prop?
The first option might save some weight. The second option would reduce rotations and the pitch a little.
I like the way you can come up with stuff and have a good reason... wild life filming!
That's always the goal!
Snap roll sounds extactly like when my cat sneezes 4:06
Dude! Everything you do makes me want to try whatever the thing is you're experimenting with. Your videos are inspiring, even when you're trying crazy ideas.
Those 8 blade props sound SO GOOD!
We played around with 8 blade props years ago. Back in the CC3D days and the bite is insane. Super locked in, 2 and 3 blade props felt sloppy back them compared to them.
The are faster at mid, throttle for sure but really caused mega sag if you went above about 70% throttle.
This was on BH 2205 2522kv motors and 4s 1300. They felt amazing but they pulled so much amps that it literally was unflyable even on a totally fresh pack... After a, min of flight if you got on the throttle at all for any length of time it would cook a esc or sag so badly you would have to back off...
The 6 blade 5 inch props was halarious...
What's fun is to take 3in props on a high KV 4s 5 inch build and run 6s. The motors have so much torque with that little prop that it literally man handles them and response is so quick and clean and at hover it's making some noise lol... Wot on a unloaded 3 inch prop on 6s on a 2900kv really screams.
I just did the mathematics. It's obvious when you think about it. If you halve the blade diameter and quadruple the number of blades (of the same angle), then you get the same lift at the same RPM, so it's a straight swap on your current rig, without changing motors, ESCs or batteries. It would be interesting to see what impact such a change has on noise level, air speed and agility.
So, a little math here. The circumference of a a 5 inch prop is 15.710 inches. That means a 5 inch prop tip at a potential RPM of 65,000 would be traveling at 1,021,150 inches per minute, or 16.1 miles per minute, or 966 miles per hour. That means that weird sound hat you are hearing is the prop blade is likely breaking the sound barrier, and becoming much less efficient. The eight blade props would be doing 677 mph at 65000, which under load will not reach that rpm, and is staying under that sound barrier.
1,416.8 fps if people are looking for that measurement
966 is superso at Mach 1.2. So yeah, I bet the prop is supersonic
This was fascinating! So is there a reason NOT to just use 8 blades all the time? I’ve been looking for quieter props for a long time, so I’m considering trying these 🤔 What’s the reason for 3 inch on a 5 inch though?
8:45 I think you can hear the PID fighting top and bottom right there. The motors almost sound like their chirping.
Dang just missed it. I do love my hq 6 blades on my cinewhoop.
I use the same on my cinego.. they're great..
Just got some for my protek25, hope it works
Interesting to see you starting to do "appetizer" bits at the beginning - its really valuable for Facebook retention, especially considering their ad rates are way better than youtube.
HQProps also make 5x4x6 that could get you a nice balance. Would be interesting to see how different the flight time would be with 8-blade props on a light 5" race build.
Who would even try those thing? And still get some nice performance results. Keep tinkering, you're onto something.
The smaller prop being quiet does make sense.
The 5 inch could be breaking the sound barrier while the 3 inch is not. Another way of looking at it, is that all the noise your hearing from the 5 inch is the sonic boom of the propeller tips.
I bet and to prove it, I calculated the tip speed of the 5 inch propellers at 65,000 RPM and sure enough, it is supersonic at 966.8mph. Another thing is how it sounds at 11:26. It had a very distinct “buzzsaw” kinda noise. I heard a 4 inch quad before and it sounded mainly like a “whoop” or “zip” instead of that kind of intense shredding kinda sound. It was still the LOUDEST drone I’ve ever heard tho! I would love to get one with supersonic props and basically destroy ppl’s eardrums lmfao. That is why I love race drones
65,000 rpm is over 1,000 rotations per second. Try to wrap your head around that!!!
Soo... what is the 5inch tip speed??? Over 1400kmh. What is the forces on the prop? Around 200kg... This is not possible without exploding the prop.
@@NiNo9 its a 3 inch prop
@@NiNo9 There is a lot of drag that slows down the props and maximum rpm is also limited by the ecs (mosfets don't switch instantly). It would be nice to see real rpm in osd.
the guy in video just did some simple math and thought that's it. 65K. But it's 65k without resistance (no prop). with prop is way less
In what seem like the old days, I used to run 5S on 2600 kv F40 Pro V2 motors. This was in the days before Betaflight had a motor output limit. Tuning was difficult and never perfect, and the best I could really do was put a throttle cap on the radio to keep from pushing the props too hard.
When I'd flip the switch to bring disable the throttle cap on the Taranis, the Racekraft 5051 props would scream like a banshee. The sound was just ridiculous. On any 5" prop.
That honestly makes sense, more blades make more thrust at a lower RPM, more blades cutting the air is less turbulent, so less noise...??! Maybe I’m crazy I dunno, but it’s crazy how quiet that is
Sooo. In aerospace engineering this is an entire field of study. Basically, what it comes down to, is more blades == less efficiency. At those speeds, a two bladed prop will probably save you some battery power and handle about roughly the same as the 8 blade, however, the two blade prop experiences less drag to spin up to speed, so it uses less power to spin up to the same speeds as the 8 blade. when you start to get to super sonic speeds, thats when a propeller starts to warrant a fan shaped design. Like in a turbojet engine.
I'm not an engineer, but I from what i understand, thats where the science of blade numbers comes in.
More blades = more more juice to power it with marginal or negligible increases in performance. You can look to WW2 to see why they chose to keep planes with 2 or 3 blade props :p
But i guess its a decent trade off to make your drone quieter O:
Of all that stuff in the video the thing that got me most excited was the proper use of the word "maths"
Your analog camera gives me strong nostalgic vibes of 90s
You can take inspiration from the aerospace industry. GE's GE9X has similar design in blades. For a few reasons.
1. Way more effective in power to fuel consumption
2. Noise levels dropped dramatically.
You're seeing and testing GE's theories and might even realize it :)
I wonder if a 3.5 in 7 or 8 blade prop would be a replacement for a 5 inch blade?
Extra blades means you are pushing more air at the same RPM as with the other props but the 8 blades are smaller in diameter to lower turbulence between the blades. A 5 inch version of the 8-blade with more powerful motors would be awesome to see.
At 12:00mins. The way you laughed bro is nothing short of happiness. I can't wait to get into this
The "FPV-Nerd-After-Punchout-Giggle" at @10:39 😂🤣😂🤣😂🤣
Ong fr lmfao that would be me bc I love doing punchouts. It already sounds and feels epic on a tiny whoop. Can’t imagine how epic it would be on a 3-5 inch quad
So 8 blades in the ducts on the Cinelifter? How much quieter would it make that beast?
I want 5 inch version of those 8 blades
Same thought.
I'll reach out.
When changing prop blade #’s do you have to tune the drone differently to keep the motors from heating up? Or is that usually not an issue?
Dude I love my octoprops on my cinewhoop super grippy efficient surprisingly and quiet!
I just bought my first drone. Zero Features. Just a basic all piloting all the time drone. Loving it.
Just the fact that I can get so much practice piloting. My buddy smirks when I am flying, because I just fly out a ways, circle back, establish hover and land accurately.. I was doing it with a store bought drone in the wind. I did my first attempt at a flip with it a few minutes later and lost control though. This is what happens when you let your friends bait you into showing off. Drone is fine.
Flown a Phantom before. It was almost too easy to fly. I started out years ago in helicopters. So it seems to transfer well.
I expected it to have lame punch out on the 8 blades but what the hell🤣🤘
So sick!
Im late to the party, but I’m assuming the 8 blades just add to the disc surface, obviously, and just acts like more of a “wind brake” so to speak, making the snaps more precise and snappier. This is really cool!
I’ve been obsessed with quiet quads for ages now I’ve found the bigger the prop with lower kv is best great video though
Amazing discovery, keep trying more blades.
The motor KV rating is unloaded RPM per volt, not the loaded RPM per volt. The actual rpm of the motor will vary depend on the load you place on the motor. The props will be spinning no where near 65 thousand RPM
Um I bet the 2 blades ones will spin at at least 64,000 rpm bc of their low pitch angle. Those blade tips sound like their going either close to or slightly over the speed of sound bc like listen to how loud it is. Most 2 blade quads aren’t that loud but ofc it can be the camera’s mic and stuff
i am using same propellers on a simple DIY cinewhoop with 3s battery. major difference is the sound it generates. it is quiter and thrust is more than 3 blades. good thing isthe load on ESC is not much different. 26 amps in total vs 24. but very fragile when used out of a duct, and acetone warps them FYI.
Almost reminds me of EDFs with the sound.... time for an EDF quad
Sounds like the octoblade pushes the sound energy up to higher frequencies, possibly in to ultra sonic region, so the noise is still there, but above human hearing range.
At what number of blades does it stop being a prop and become a fan? Are there any swept-blade versions?
The five blade sound is like the F1 V10 of the quad world.
Now wondering about octobladed phantom, if quiet enough to record dialog while getting drone shots.
what you have is no longer a propeller but a UDF - unducted fan also called propfan
I suspect the frequency of the noise made by the 8 blade props is above that of human hearing capability and all we hear is the air turbulence from the props.
what is cool is you can easily make a standard 5 inch 4s high kv drone that you can alternatively put a 6s pack on and these little props on for quiet flying.
Exactly!
that 8 blade setup sounds really good! and i's noticeably quieter !!!!
I'd like to see 7-8 inch running 8 blade 5 inch props if they even still exist.
after watching this video i can safely say "I Studied the Blade"
I feel sorry for the batteries! Very cool to see and hear the 8-blace props.
Holy crap. Am I making this up, or is the combo of the high rpm 8 blade props along with the lack of active braking (being a 3” prop vs 5” prop) allow this to fling harder than a 5”? You were shooting past that tree pretty hard!
Hey Nurk
I'm wondering about prop down force? blade tilt in degrees, helicopters increase tilt to the blades to achieve takeoff, such as five degrees compared to ten degrees I'm just guessing.
I know it would probably decrease battery consumption but increase speed right?
Seems like this is what your ducted thick needs. Will need some beefy motors for 7 inch octoblades though.
I love it! Very quiet for a beginner would be excellent! Sound too loud is sometimes scary for many people and neighbors! You guys should produce the quite and new 64 blades by Nurk FPV.
I personally don’t like quiet race drones. To me, they should be like mini fighter jets which is loud, fast, and highly maneuverable. In fact I wanna find out if it’s possible to have a drone with props that go supersonic which would give u extra thrust, and a LOT more noise lol. If it is I would love to get an fpv quad and install more powerful motors on it with a very specific propeller design that can handle the drag when creating shockwaves on the tips due to going supersonic
Ordered 20 sets for my 5". I've always hated the sound because it draws so much attention - this is major for me, and is well worth whatever drawbacks might not have made it into the video. Question is - which motors to buy?
I would just get any kind of large displacement 2500kv or so motors for it. Something like.. 2207 or 2306.
@@NURKFPV appreciate the reply, thank you!
Fantastic flying, Paul! 😃
Thanks for all the tests and sounds!
Stay safe there with your family! 🖖😊
At the..... end ..do you use (a fish eye lens .? )........and how expensive is ?
Very interesting what would you say has more lifting power less blades or more blades?
Hey Nurk, Wondering what patch/antennas are being used with your rapidfire?
Nice test,, but can you please tell me what size of motors do I need to have so I can put all this kind of propellers....!!!!
Would it destroy the Sendrone Squirt whoop flying, or will it make it alot less screamisch?!
Would love to have some of those for my DJI mini two. Same diameter as stock. Would be awesome to see how they perform on the mini two especially at high altitudes.
I thought there was burn in on my phone for a second... You got something on your lens there lol
Its his Camera Sensor probably
can you put the largest blades like make the arms on the top so they won't hit anything on the top and try to get the blades as close to each other that you can
Correction apparently the ones that I just named, are the ones that I was asking for years ago. They're of a "Durable" nature.
It would be interesting to see the 8 bladed props on 8 motors. Did you consider trying them on the big baby?
Please do a video with 4x modern EDF units (like those fancy CNC'ed aluminum ones) :)
this is the coolest hobby how do i get into this as a beginner?
I wonder about a higher blade-count 5" prop on a lower kv motor. Maybe 1000kv motor with a 6 blade 5" prop.?
Wow I love how quiet that is 😊
That's insane how much quieter the eight blade is
I think the real winning factor on biblade props is that the motors can start and stop faster compared to heavier props giving you more authority and precision.
omg that thing is so cool with 8 blade props!
can i just put 8 bladed 3 inch props on my 5 inch quad to fly some stealth fpv?
8 blades sounds sick , what a beast.
Look up air zipline drone propeller. It's a propeller that uses technology in nature to reduce noise. Cool looking tho.
I remember old pylon racers using a single blade counter balanced as multi blades would one cause more surface area and two also hit dirty air from the previous blade.... could be worth a try?
Love these videos! Your video on the 160mph with Josh was my favorite, but now time to get some props.
THanks again-
Thats why submarines also been using props with many blades for decades because it makes them quieter underwater. For submarines this is very important. Just a little side-info :)
Just a question from an outsider... Physics whise, aren't the 8 bladers more efficient because less energy is converted into sound? I mean, we heard it echoing back, it was really loud.
"That sounds horrifying!"
It's just a little banshee shrieking for souls.
Nothing to worry about.
(Someone make a horror dub of this, please.)
Would be interesting to see the same with a track setup, would the same "grip" hold out?
I doubt those were reaching 65k rpm. The RPM you calculated would be with no load on the motor (props off). Remove the props, Plug the quad into betaflight, in the motors tab, enable bi directional D-shot. Enable the motor sliders and spin up your motors, you will be able to see the actual RPM reported by the ESC. Now put the props on and (very carefully) try the test again. I can assure you the RPM will not be 65,000.
Now try putting two of these propellers on the same shaft, as if it had 16 blades. 👍👍
I'm the " that's not right" guy today. I'm just so excited $gme blew up again today. Get on the shuttle to the moon at market open tomorrow!!!!!!!
65k unloaded with no battery sag.
As prop rpm increases the drag increases by square. The motor can produce x amount of torque regardless of rpm.
2000kv 6s = 15krpm at half throttle and 20k at full throttle. Current consumption 5a and 20a respectively.
2600kv 6s = 20krpm at half throttle and 20k at full throttle. Current consumption 20a and 80a respectively.
Battery on fire huh?
Lets say this motor can produce 2 ft/lbs of torque and the prop requires 2ft/lbs to spin them at 20k. A perfect match of kv to the prop would be the prop requires 2ft/lb at the max rpm the motor can produce, say 20k rpm. The motor can't magically pick up stator volume to quadruple the torque output to 4ft/lbs and pick up twice the rpm.
Now lets say the same setup with double the kv. The motor will only spin the motor to 25k with 2ft/lb of torque. Above that the motor will not spin faster however it will pull more current effectively turning the wasted wattage to heat.
At the end of the day we would like like the system to be scaled where max throttle is 5% bellow max rpm of the motor/prop combo for decreased angle of attack when the prop unloads. I suppose we could do an 8s battery on 2600kv and cut the throttle scale in half to produce a sharper bell curve in rpm up to half throttle.