A less noisy Mavic

[MHaneferd]

I think the only way to make the mavic more silent is to replacle the current props with three blade props, with a slightly stiffer material (carbone?) so it does not vibrate.

 

[mfc]

You can hear your neighbor mowing several hundred feet away with multiple fences, trees, etc between you and him.

Hmm, last week I did a flight in calm weather specifically to find out how far away a Mavic had to be to not annoy other people (e.g., out in the countryside). I flew it up to 200m away and up to 100m QNE and it was clearly audible at all times, both upwind and downwind. While at maximum distance I suspect many people wouldn't notice it, at 100m it would certainly attract attention and be annoying.

 

[Michael Ainsworth]

There's also a thing called sound compression, measure decibel level the same but sounds louder coming toward you than going away, used a lot in those noisy obnoxious commercials where it sounds like they are shouting at you. The actual decibel level is apparently not that loud but is perceived to be.

 

[AysJohnP]

Also don't underestimate the imbalance that "carefully" removing material from a prop will cause . I have several precision prop balancers from my 3D heli days and it takes a very small delicate swipe of sandpaper to upset the balance .

Dude. Have you seen the test videos where they cut a prop and then fly? The mavic will easily overcome the tiny balance issues that a "delicate sandpaper swipe" creates. I flew backward into my garage siding, fooling around like a dummy, and it kept flying. When I brought it down, the left rear prop was missing an inch and split down the middle ONLY ON ONE HALF OF THE ROTOR BLADE. If that's not a balance issue, nothing is.

 

[mfc]

Dude. Have you seen the test videos where they cut a prop and then fly? The mavic will easily overcome the tiny balance issues that a "delicate sandpaper swipe" creates. I flew backward into my garage siding, fooling around like a dummy, and it kept flying. When I brought it down, the left rear prop was missing an inch and split down the middle ONLY ON ONE HALF OF THE ROTOR BLADE. If that's not a balance issue, nothing is.

Yes, but this thread about noise -- which is reduced when the props are well balanced. The flight with the split propeller was not one of your quietest, I suspect.

 

[Dungbeetle]

I think any perceived noise reduction is 2% real and 98% in the mind.

 

[Malavic]

I think you will find that you can get a significant amount of noise reduction by cutting a sawtooth pattern into the trailing edge of the blades. Anyone who has looked at the engine nacelle on a Boing 787 will notice this immediately. The reason is fairly complex but it involves how the mixing of the air affects noise. You will also find this pattern on anything that moves air and is trying to be very quiet. It also is why special forces helicopters have shrouds around the blades on the tail rotor...it does essentially the same thing.

I suspect there is an ideal profile for the way the serrations or cuts have to be made, but I suspect even if it was done on only the outer 50% of the blade(i.e. highest rotational velocity) it will reduce noise the most.

 

[Sisko]

Each increase in db is roughly 33% louder than the last ( intensity/ what you hear ) so 5 db would be pushing 3 times as loud . Not likely . Measurement of pressure in db (what you feel ) takes roughly 6db to double .
Also don't underestimate the imbalance that "carefully" removing material from a prop will cause . I have several precision prop balancers from my 3D heli days and it takes a very small delicate swipe of sandpaper to upset the balance .

Do you know if DJI might provide precision props? Something that could improve performance or reducing nice?
Thx mate

 

[Sisko]

I think the only way to make the mavic more silent is to replacle the current props with three blade props, with a slightly stiffer material (carbone?) so it does not vibrate.

Does DJI sell this props?

 

[msinger]

Does DJI sell this props?

DJI does not sell three blade props.

 

[Brojon]

Also don't underestimate the imbalance that "carefully" removing material from a prop will cause . I have several precision prop balancers from my 3D heli days and it takes a very small delicate swipe of sandpaper to upset the balance .

In the bad old days you had to control it all - the Mavic has a pretty sophisticated regulation going for it.
Not saying there isn't any effect on motor life and other things - just that the Mavic is apparently able to compensate.