Quieter opertation tips anyone?

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Nothing is more reassuring than to hear the P3 returning home......BUT...is anyone employing any quieting techniques? and if so.... what....?
 

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I found this awhile back and cut it from a previous usage.
I'm sorry I cannot find the link or cite the source at this time:

"There are many sources of prop noise and they have varying levels of significance. The most annoying is the very distinct "shriek" that comes from shocks forming at the tips. Tip speed is a main factor in this noise source.
The airfoil, planform shape, and thickness at the tip are also important since they define the Mach number at which compressibility effects begin to become significant.
So the air does, indeed, accelerate beyond the rotational speed as dictated by these geometric factors and you will often find that keeping the tip speed below about Mach = 0.65-0.70 avoids the onset of shock waves and thus the noise associated with them for most hobby props."

So it seems that altitude, as bbfpv pointed out, is the best way to achieve your goals.
 

N017RW

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Well if they ask you can tell them you'll fly as high as you can since there's nothing else you can do.
At least you have done something to address their issue. ;)
 
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I was wondering if boat-propeller-style blades would help any? Any 3D modelers out there with 3D printers?
I have a 3D printer and have experimented with various printing materials, however I would never trust my Phantom to the structural integrity of a 3D printed prop no matter how well designed it was.
 
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@johnnyu i have the same issue. i hover the bird to ensure all is good then lift up high enough so i can't hear it....when landing, i usually hover above the 'home' point then come straight down - luckily the P3 has higher descent speed. Or sometime i wait for their Air conditioner unit start to take off.....those things are almost as loud as the bird...if not louder.
 

N017RW

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The motors and props are a tuned system.
You will not do better in terms of performance.
If you try to change one thing one or more other things will suffer.
 
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@johnnyu i have the same issue. i hover the bird to ensure all is good then lift up high enough so i can't hear it....when landing, i usually hover above the 'home' point then come straight down - luckily the P3 has higher descent speed. Or sometime i wait for their Air conditioner unit start to take off.....those things are almost as loud as the bird...if not louder.

I bought a pair of DJI 9450 pre balanced props which are a bit thicker. They are much quieter and according to healthydrones, they work wonders on my phantom.
 
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N017RW

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Good point.

They have more pitch than the 9443's so they require less RPMs for the equivalent lift/thrust.
 
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I bought a pair of DJI 9450 pre balanced props which are a bit thicker. They are much quieter and according to healthydrones, they work wonders on my phantom.
What improvements did you find with these according to healthydrones?
 
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its not so much me, but my neighbors who might not wish to hear this thing coming and going. just an added tidbit

I like that you're attempting to be courteous and, one day, I hope we have a solution; I'd use it, too. It would be very helpful filming nature, which I prefer...humans are icky. Heh.

Seriously, though, where I am, we have Harleys, loud mufflers, etc. periodically and I liken my noise to that. As long as I'm not in one place too long, I don't feel too bad.
 
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I found this awhile back and cut it from a previous usage.
I'm sorry I cannot find the link or cite the source at this time:

"There are many sources of prop noise and they have varying levels of significance. The most annoying is the very distinct "shriek" that comes from shocks forming at the tips. Tip speed is a main factor in this noise source.
The airfoil, planform shape, and thickness at the tip are also important since they define the Mach number at which compressibility effects begin to become significant.
So the air does, indeed, accelerate beyond the rotational speed as dictated by these geometric factors and you will often find that keeping the tip speed below about Mach = 0.65-0.70 avoids the onset of shock waves and thus the noise associated with them for most hobby props."

So it seems that altitude, as bbfpv pointed out, is the best way to achieve your goals.

This is not scientific by any means--subjective opinion, but changing to new props after about 150 flights and it seems that the balanced new props are quieter than the older ones -- or my hearing is getting worse-- :D:D:D:D the original were balanced also before I put them on--

I probably need to check the balance again on the originals to see if that was changed. I am relatively certain that an unbalanced prop would not only be a vibration issue, but emit more noise also.
 
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N017RW

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Try a blind test.

Have someone put on one type, test, swap, repeat, swap again or don't.

Then see.

But hey I believe ya, just a thought for future data collection.
 

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