Low noise props


#1

Hi, i would be interested to start a new topic : low noise props.

Reducing noise is my main interest in this top project. The main problem with this kind of motor is that props are turning fast and are generating quite a bit of noise. There are certainly new props (22’’ or 23’’ fitting OpenPPG) on the market with the increasing drone market, that offers new designs to reduce noise. Sound could also be studied to work in less bothering frequencys (lower frequencys are usuelly better).

Any ideas ?

Laurent


#2

Well larger props are always quieter and a bit more efficient. Also a wider prop would be quieter its just less efficient in most cases.


#3

I think the big issue is that our motors are pushing through dirty air. In RC, there is a huge noise difference between pullers and pushers. I try to build puller planes because they are so much quieter.

After that, you want a bigger, slower prop, and you can tell that some of the other e-ppg solutions are very quite with a single big prop. But they have some torque, and give up the potability and low-cost of openppg.

Remember that openppg uses pro-sumer parts, so if an ESC goes out (VERY common; they are hobby grade), it is only $100, not thousands if the ESC of a large prop goes out. The motors are likely to be bullet-proof except for the bearings.

Having said all that, I’d love to see some prop comparisons if we can find CW and CCW versions. Technically you could use all CW or CCW but you might get some weird torque. Might be worth trying to see if there is a substantial drop in dB; the tradeoff might be worth it.


#4


#5

WOAH! That looks awesome. Tell us more!


#6

Not much to say about it. It worked, the frame was way heavier than Paul’s (17lbs). The motor from Germany - prop from Europe too. A lot of torque and that why I love Paul’s machine. No regrets.


#7

Hey @Voltair do you still have plans or drawings for that frame still? It look like a good base to resurrect my two prop project onto. I haven’t access to carbon cutting but aluminium is easy to come by. PM me to prevent clogging of the thread if you like.

Cheers, Paul


#8

What a waste - sad!
So many hours and good material gone! And it was so pretty!
I think I am using too many!'s
Someone like Voltair could have used it. I would have paid shipping cost for it and signed a no liability waiver.
It is what it is I guess.
Cheers, Patrick


#9

Liability - when I recycle my old y school wings I cut all the lines. I used to scuba professionally and was drilling holes in my tanks when they were no longer passing inspection.


#10

I have noticed an interesting phenomenon with the noise while listening to my dad fly the OpenPPG:

It sounds as if there are vibrations being transmitted up through the lines to the wing, turning the wing into a giant speaker. I would assume this to be the case because of the odd pulses of reverberation that doesn’t sound like propeller noise.

I know there is almost no vibration from the electric unit, but maybe even that tiniest bit is enough to have such an effect?

It’s not like it’s making the unit any louder, but rather it just changes the tone a little bit. I just thought it was an interesting observation.