Silent Rotors / Props
- Thread starter kmikesch
- Start date
N017RW
Premium Pilot
Most noise is associated with the tips exceeding the sound barrier. Then you have the frequency depending on RPM and blade count.
Changing disc diameter, pitch, and number of blades impacts efficiency which affects flight times.
This in turn requires redesign of the motor(s) and ESC firmware.
There's no real option for Phantoms as they are designed as camera platforms and are optimized for the task intended.
Changing disc diameter, pitch, and number of blades impacts efficiency which affects flight times.
This in turn requires redesign of the motor(s) and ESC firmware.
There's no real option for Phantoms as they are designed as camera platforms and are optimized for the task intended.
N017RW
Premium Pilot
Only use OEM props.
More is not better.
The system is tuned - props, motor, ESC f/w.
If you search site, plenty of horror stories with non-OEM props.
More is not better.
The system is tuned - props, motor, ESC f/w.
If you search site, plenty of horror stories with non-OEM props.
Not sure where you got that info from. To break the sound barrier on the P4 prop tips they would have to be rotating about 29000 rpm. The P3 was tested at full throttle at less than 9000 rpm. P4 was an improvement but not 3X+. It is nothing more than the sound of the air moving, no different than a desk fan.
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N017RW
Premium Pilot
There is more science to it. If your satisfied with a desk fan comparison so be it.
I was a bit unclear suggesting the Phantom props broke the sound barrier and meant to be more generic. But there's a great deal going on around a spinning blade and it is more involved than a simple tip speed calculation.
I was a bit unclear suggesting the Phantom props broke the sound barrier and meant to be more generic. But there's a great deal going on around a spinning blade and it is more involved than a simple tip speed calculation.
I left the science out of it trying to keep it simple. Your statement wasn't unclear it was incorrect.
N017RW
Premium Pilot
I was unclear on what I meant say.
But would like to learn more.
Please proceed if you have time.
But would like to learn more.
Please proceed if you have time.
I have time. If you were unclear on what you meant to say, what was it that you meant to say when you said "Most noise is associated with the tips exceeding the sound barrier"?
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Lmao... That cracked me up! So if I strap my desk fan to the desk and crank it up, it should fly? ha ha ha
It is reasonably quiet, clearly you've never been near a RC helicopter with a chainsaw motor in it...
N017RW
Premium Pilot
I had not reviewed this in a while. I conflated the creation of shockwaves near the tips with sound barrier in my hasty reply.I have time. If you were unclear on what you meant to say, what was it that you meant to say when you said "Most noise is associated with the tips exceeding the sound barrier"?
This is a source of prop noise.
Might consider also the sound generated as the downdraft from the props pass the rotor arms.
Those props are pushing a lot of air so I suppose anything that air is rushing past will also create additional sound...
Those props are pushing a lot of air so I suppose anything that air is rushing past will also create additional sound...
N017RW
Premium Pilot
I often find discussions here 'invitations' for the curious to do more research. Sort-of-a 'trust but verify' theme if you will. This leads to even more discovery often not imagined or anticipated.
Silence, stealth, etc. was not a design motive with these toys. Rather an easy, affordable, and efficient way for the every-man to achieve flight and an aerial perspective on the world and with great quality.
Bigger, slower rotating props will reduce noise but there's a premium than some aren't interested in paying.
As with all engineering there are trade-offs not to mention economics.
Who knew when buying one of these they'd learn about batteries, electronics, photography, radio theory, antennas, flight dynamics, operating in the NAS, etc., etc.?
Silence, stealth, etc. was not a design motive with these toys. Rather an easy, affordable, and efficient way for the every-man to achieve flight and an aerial perspective on the world and with great quality.
Bigger, slower rotating props will reduce noise but there's a premium than some aren't interested in paying.
As with all engineering there are trade-offs not to mention economics.
Who knew when buying one of these they'd learn about batteries, electronics, photography, radio theory, antennas, flight dynamics, operating in the NAS, etc., etc.?
We live by a hospital where medevac helicopters are very frequently flying over. there are normal sounding ones, some that are pretty loud, and a particular kind that is suspiciously quiet. i'll have to get a better look at it and try to identify it. Don't know if it is flying light or if it's just that type of helicopter...
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If you very lightly buff the edges of each prop with 1000 sand paper the noise will be considerably less!
