Does more propeller blades mean more quieter drones?
ฝัง
- เผยแพร่เมื่อ 28 ก.ย. 2024
- I recently built the loudest drone I've ever experienced, and I wanted to take it the other direction and see what I could do to make the drone a little more quiet.
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Do you mean 'penta' instead of hepta? The link goes to a five blade prop, not seven.. Love the content as always. Keep em coming Nurk.
Gemfan D76-5 5blade are the quietest, by far... Beats all the ones you tested! And the noise difference, BTW, between Gemfan and HQ is huge!
Any updates on silencing drones?
Might be worth analyzing the frequencies present in each (FFT would help) and how they affect perceived loudness from a person's point of view
I do this for my job (FFT analysis) and I second this!
I feel happy watching your videos 😊
That's The goal!
I think the smaller the prop the lower the frequency and higher decibel, however the apparent loudness with a higher frequency or "shrill" as you mentioned has a perceptible loudness more than the mere 5db you save on the meter. Also, I think dogs hear it easier with the higher frequencies, as I notice animals further away howling more when I fly higher bladed props around my neighborhood. I think a good trade off for everything is 5 blades.
I think the Thicc seems louder because of the extra props, it sounds like a whole cloud of drones coming at you (2 at least). A Conventional airplane rule is more blades is quieter, same as more cylinders is quieter for engines, they produce a more even pulsation pattern which seems quieter. I'm not sure why multiple props don't seem to abide the rule, maybe because they are independent sources and not in sync. Just thinking out loud here, don't know if it's any help. Good luck in getting the Thicc muffled, I'll be watching, and hopefully learning how to quiet my fleet down a bit. It never hurts to leave a smaller impression on the public and less scary sounding is a good thing.
lower rpm ive found really helps sound.... my 7" is quieter than any of my 5"s, also more blades = less rpm to create thrust and usually quieter
I think you missing a few points here, less props give less noise. a plane would onley get more blades when ground or fuselage clearanse give problems given the avaiable power. more cylinders makes a piston engine more in balance (becouse instead of 1 big bang to make a full rev its spread over multiple cylinders) while a good prop already is balanced. less rev is less drag and better pull force. bigger prop/blade is always less db than small high rpm props/blades. problem is to drop rpm you need longer blades. becouse everything needs to get smaller we neet more blades to deliver power hench higher rpm+drag= more noise
6:34 that is the worst sound ever when you get that partial Betaflight start up chime. Great video Nurk!
@NURK FPV have you seen Albert Kim's light cinewhoop build? It was only about 58dB in noise level.
Happy New Year - Remember that dB scale is logarithmic and every 3 dB is a halving or doubling of the volume.. If I'm not mistaken if the noise level in a factory is above 85 dB(A) then hearing protection is required.
3db is not at all halving or doubling. 10dba is perceived as that doubling number to the average human ear. 6db is gained or loss when voltage is doubled in audio circuitry. 3db is a typical number for 1 click on a volume dial since it is easy to 1/4 voltages.
Every 10db increase is double the perceived volume, for reference.
and they try to measure it with a normalized microphone of the phone... real db meter is needed here
You should do another comparison without the ducts and with.
Or a no duct/half duct/full duct.
The one thing that the added blades will 100% do is reduce the overall flight time.
Over the years, I've designed and build dozens of Ducts for multi-rotors and can 100% say that they are not worth the time or effort. Rather a propeller-guard or non aero-lip'd Duct is the way to go.
Specifically:
A) Duct lift gains are rubbish: Sure the Duct Aero-Lip does provide "some" added lift in level flight but usually only enough to make up for the increased mass. However this does not take into consideration things like the added drag nor the fact that the Aero-Lip's lift will attempt to re-level the copter as soon as your orientation isn't balanced. For those not understanding what this means, only the leading edge of the Duct will provide any lift in fwd / rwd flight. The end result is that the Ducts added lift is moot in any situation other than level flight and that the FC will fight against the Ducts lift to maintain the copters current orientation. Thus you'll burn thru the LiPo faster (lower flight times) and often have poor handling.
B) Adding Ducts make the Copter sound much much louder and the reason being is two fold: 1) The Shape / Taper of the Duct acts like a flying public alert system as your neighbors know realize.. 2) The Duct oscillates as the propeller rotates internally due to the pressure wave coming off the tip of the propeller coming in contact with the Duct-Wall. The effect is just like a wine-glass that oscillates as you rub your finger around the top. However the Propeller shape, speed and distance from the wall directly contributes to the frequency and amplitude of the sound being emitted.
(All that noise being created = thrust being lost)
C) Any build that uses a Duct would be better off with just a prop-guard: Think of the first two issue above (A & B) and realize that a pure propeller guard consisting of just a circular wall is superior. If in doubt consider the following... Less mass, less drag and less noise and the thing is its very simple to build as its just a tube that the prop sits in, nothing more. No Aero-Lip, no taper and doesn't need to extend more than 1-2 mm beyond the rotational area the prop will exist in. (Above and below the propeller to compensate for possible prop flex)
D) Spacing and Speed is important: What I mean by Spacing is that the Propeller tip should be no further than 1% of the total Duct width (from the ducts wall) to best reduce prop-tip vortices. This reduction in turbulence will help reduce noise while also boosting the overall thrust of the propeller. Normally for a 5" propeller or smaller, It's best to aim for 1 mm separation as any smaller is likely to result in the prop striking the wall at some point. Ok and finally Speed... If it isn't already obvious, a slower moving propeller has lower losses and generates less noise. Thus a tiny Whoop with 10k motors will be really loud for its size.
IMO best way to reduce the noise is to use a non-tampered Duct / Guard (without a aero-lip) and long (Stiff) 2-bladed props. The prop tips need to be within 1 mm of the duct wall to reduce prop tip vertices and boost the overall lift efficiency. Ideally, you'd want a low KV motor to keep the propeller speeds low, while still being able to maintain a good TWR.
Here's a few things I've played with and shared but its by no means everything: www.thingiverse.com/1smug_bastard/designs
Cheers!
Happy New Year Paul. That huge drone strapped to your back looked like a Ghostbuster Proton Pack 😂
Happy new year, Paul!!! 😃
Great testing there!
Stay safe there with your family! 🖖😊
The Big one sounds like an aerial Hyena family in an argument........
Nice... I'll probably go w/ 5 blade. Thanks for doing this man!
Get a good meter in a quiet place and do a stealth 250 dji build
Thanks, Nurk!
coudnt it be that the whining of the engines is just louder then the sound being produced by the props?
Hell no
Awesome video. I love the tutorial videos (I'm a better pilot because of them (even though I'm not that good yet)), but sometimes you just wanna break out the quad and do something not regular. I like the videos like this one and the 3-mile power loop; just some guys out with a drone doing some stuff. Not sure I'm making sense, but keep it up. :)
I just got done watching your last video! Guess I can watch Moutain biking videos later
Hope you enjoy!
Hey nurk! What is the purpose of the tests? Are you trying to achieve the quietest for general use or on-set? It seems like an interesting problem. Would any kind of rifling in the duct reduce this? Make the airflow less turbulent, thus driving down noise levels? Also, is it just the props, or is it possibly also the ducts "ringing" with motor vibrations? Possibly a piece of felt between the ducts and frame as a test?
Thanks! I'm always concerned about the noise of my quads bothering other people in parks and such. Switching to toothpicks helped a lot to reduce noise, but I guess I could try some other props to make it even quieter. Someone knows some silent 65mm props?
the avan rush props made my toothpick sound more like a whistling turbo than a quad...
@@DanRichmondFPV Yeah those are the least noisy I've tried yet, at least at lower rpm.
Phones have automatic gain control on the microphone. Also I highly doubt the base level was 65dB. 65dB is a lot of background noise.
You can buy a real sound meter for like 30 bucks on Amazon. You should have considered that for real precise measurements.
Yep noise level is a funny thing. When I dj a larger venue I always have to break the phone and apps out to check and verify sound. And at the same vol depending on where the speakers sit the overall volume and tone totally changes. The more coroners a room has the quieter it gets at same volume. I guess that would kinda be like more blades on a cinewhoop. 👍. BTW Happy new Year! 🎊🎆🎈🥳
‘the more coroners a room has the quieter it gets’ 🤣 That is some classic internet comedy right there!
@@axm2689 what I was getting at is if a room is say 100x100 square the sound at for example 50% volume is louder than a room that’s the same 100x100 but has a ton of angles depending on where you set up the sound.
@@archer4922 I understood what you meant but since you misspelled ‘corners’, it made it funny is all. No harm, no foul.
@@axm2689 🤣🤣🤣 I just caught that. Hah!
*5 flexible blades but larger in both ways with low rotation wil help keeping some silent and quiet noises 🤫*
Awesome video.
Keep on living your dreams.
Thank you! Will do!
@@NURKFPV
Happy new year.
Hope it doesn't bother you that I comment the same on every video.
My daughter Odette will be born on 24-05-2021.
Regards from south Africa.
the first CIA "quiet" helos doubled the number of blades on the tail rotor to dramatically cut noise. dark docs rulz.
I just started running four blade props and my drone is significantly quieter now these are only my first set but I have got like six packs on them and I'm really starting to like them give me a month and I'll let you know how good they turn out
so how did it turn out?
What motors/kv and what battery were you using for the tests?
I wonder if lower kv motors are quieter than higher kv.
Lighter Motors need less RPM so they are quieter.
Happy new year everyone. 🤓
Great videos man. Your a machine. Lol " more quieter " 😁
87dbi really is still fairly quiet I thought the big one would be louder than that
More quieter?
tesla mask is dope!
yes, im grammar police: it’s quieter, not “more quieter”
I think he was using the improper grammar on purpose.
That app doesn't look very accurate.
As long as the scale that is being used doesn't change it at least shows the difference between things accurately.
Not sure which one he’s using but I know decibel x is pretty accurate when compared to my stand alone sound meter. But I can see and kinda hear where that one may be a tad off but not much I wouldn’t think.
You can't use "more" and "-er" together.
thanks for your insight.
BTW avada0, have you become a flat earther yet? If not I suggest viewing the 13 part series _what on earth happened_ in my about to learn how the earth is not a globe
it was a good video. doesn't have to be totally scientific to get some results and understanding about the subject.
It might be worth shutting the f up whilst you're trying to measure how quiet your drones are. How on earth are you supposed to tell the difference between them when you're constantly talking and don't even shut up long enough for there to be enough silence to measure?
The higher pitch is much more annoying to me even though it reads lower on your meter.
I went from 3 to 2 blades on my 5 inch and bi blades were way quieter
I had the opposite effect. They seemed louder to me.
Always thought higher number of blades was louder must just be the higher pitch
Yoooooo
yo yo
I like this test but it's kinda stupid :"D everything around you is made of concrete that amplifies the sound.. not to mention your measuring device
So, a great real-world test. As long as placement is the same reflections shouldn't matter when judging them against each other.
Bro purchased a decibel meter 😭 must be scammy indians
First
YEET
that phone app seems lame. it updates super slow like theres alot of averaging or something. i have a free sound meter app that is much more responsive also if you paid for that app why does it show ads? try a different one!
love the video!
Happy new year Paul! Hope you had a good one! Are your Squirts running 4S or 6S?
they’re running 4s
I wonder how much the weight and pitch of the prop makes a difference 🤔 or even the length. If someone could invent quiet props it would transform people’s perception of our hobby!
Mini 2
Nurk.. mabye because you use different props on the top and bottom of the big drone some air magic is happening.. if one prop is pushing more (different pitch) than the other you wont have optimal airflow.. Mabye try just the top ones and then just the bottom ones.. Would be interesting to see.
more quiet/quieter
Not the most quieterest shizzle. Thanks for the research! Take care
you need an open field where the noises are not bouncing off walls :D
"More Blades=More Quieter" impeccable grammar
Testing with solid walls reflecting noise is like gunning the engine going through a tunnel. The noise is amplified. Better of trying out in the open with grass so it would be like open air flying.
Yeah this is quite a terrible test.
Is more quieter more quiet than quieter? I have heard some pretty loud 3 inch quads! I figured it came down to kv and pitch of blades. I have some drone using 2 blade setups and they are pretty quiet, but also low pitch and kv.
Hmmm...Interesting. Keeping in mind a "lower" pitch will penetrate more and travel further than a shrill pitch. Like the bass from a stereo can be heard thru walls while I won't be able to hear the high hat cymbals (or treble) from the drummer.
Normally yes, but we don't hear low frequencies as easy. I think these higher pitched noises sound "louder" than any low frequencies ever would to people. Animals hear it quicker as well.
Next time go to a high school and borrow their gym. Because it will get the base decibles down to nothing.Get three decibel Meters and use triangulation to get a 360 degree sound map. It will also get you a average sound per test.
You can measure diameter distances on the gym floor using tape.
I am 100 percent interested in multi blade props, as many as 10 per!
Have you tried to arc the tips of the blade to the forward side ?
Next time get a string and a bunch of weights and see if there's a difference in lift. That's the key !
See Elon Musk said the next version of Tesla will hover.. but he also states that current drones are too loud.
Fun video! May not be scientific or perfect, I'm no scientist, but totally fun video. Thanks!
Questo video te lo potevi risparmiare
I find your lack of face disturbing.
What's it's max altitude and payload ya
Yes more blades is always quiter
Owner: "Dog, bark!"
Dog: *barfs*
I wonder how prop size affects it?
I'm using the hex props on my cinego, but without the ducts and the control is amazing
I fly without ducts in my tycan, but its ok remove the ducts?
Wierd quads lol
Thanks for that awesome video!!! Merry Christmas and happy New Year to you and yours... I am flying the Diatone Taycan and have noticed the 5 blades seem much quieter than the 3 as well. I just switch back to 3 blades to see if it would help with hot motor issues. Will the 5 blade have a tendency to over prop the motors or will it not make a difference? Question 2: will the pid tune stay the same between props or will it have to be adjusted also. Thanks. P.s. the 12s build got me into to FPV and Freestyle. Thanks for that.
Interesting video. 6s ducted quads just sound angry. Thanks...👍🏻🍻👊🏻
Did you see one of my pics in that Calandar ? Wondering which one they chose
I would have honestly done this with a regular un-ducted quad. the ducts reduce a LOT of the noise.
and with regular quads, more props is louder to me. like a biblade is a lot quieter than a traditional tru.
Need to get me some 5 or 6 bladed props 😅 great vid. Happy new year 🤙🎆
When it comes to your drones and videos, why aren't you selling kits instead of the many parts needed? Putting together something that doesn't require 3 MONTHS for parts from China is a godsend!! Something that doesn't use a HUGE camera is something some of us might like better. Thanks.
A phone app decibel meter is pretty much useless.
But it was still a fun video and you got the point no?
ok but how many amps?? i tested the 5 blades and the 6 blades, the 5 blades are making my motors very hot and no improvement.. the 6 blades are very light so is not making the motors hot, but it take soooo many amps! the 3 blades props are the best. (for my testing..)
On the cine quad, do the props on one arm rotate in the same direction, or are they running opposite to each other? If they are opposite to each other, that would seem to me to be a source of excess noise, since they would be cutting through the "prop wash" of the first blade..
*4 blade vs 2 blade consume more energy but gives you more weight stability and against the wind 2blade saving battery & more recommended*
Actually the further you are away the less unpleasant the noise gets on higher pitched props, but more annoying when close by.
Happy new year Nurk wish you all the best
phones app are not accurate Db meter cause the mic saturate quite fast... but it give you a hint at least
dope watch!!!
Might want to just go with your ears on this. Sones and frequency are important.
I think 5 blade prop is not to much quiet but more softer than 3 blade prop.
i would also wonder about the prop pitch variable happy new year
The ducted thicc i will never get used to but i love it
The mic on the phone is on the display side...
i came for doggo and was not disappointed
You need a closed room to do the tests. The meter will work better that way too
I agree but If you do it in a closed room, it needs to be sound dampened and large enough to not affect the airflow into the ducts.
What I've always heard was that less props made a drone quieter. bigger props i know does make it quieter, or at least less noticeable, but for a small drone you need small props.
It's the absolute opposite of what you said.
yes
indeed
Christ that cine quad is loud. Like absurdly loud!!! I have to build one to piss my neighbor off!!! 🤣🤣🤣🤣🤣
It’s a love hate relationship we have. Lol.
Love the videos man keep them up. What Motors do you recommend with the squirt and with 4.2 and rpm filtering where should my tune be?