One of the biggest hurdles involved in getting drone usage adopted is the noise they create, and you can multiply this issue for drones that carry people. I'm guessing that you can just direct the noise upward and be fine.
Any thoughts etc on how to best do this?
Any thoughts etc on how to best do this?
Not sure if that is such a bad thing. You kind of want moving objects to make some kind of noise. Just like cars. So it scares away birds and makes sure people look up when they hear something. Of course you could use the rotor or basket designs off of low noise computer fans, which allow high pressure fronts to move through the basket of the fan instead of crashing into them. At least that is what my limited understanding of what is going on is going on...
Well with things flying autonomously, there shouldn't be much need for it to be heard to avoid it.
If there was a "funnel" with the propeller in the middle, and the opening(s) at the bottom were narrower than the wavelength of the majority of the noise generated, and the top was wider, would that direct most of the noise generated upwards?
If there was a "funnel" with the propeller in the middle, and the opening(s) at the bottom were narrower than the wavelength of the majority of the noise generated, and the top was wider, would that direct most of the noise generated upwards?
Is that so? I would have thought that violation of privacy and air navigation hazards are bigger issues. Banning their sale to morons might be a start.
😕 There is an air lane just beyond my residence, airliners are flying by every 5 minutes during certain periods of the day.
Drones all use several small diameter high-speed props, for compactness, and to get enough lift; that's the root of the issue. Larger diameter and lower tip speed would be a good start.
Mostly I prefer DF96's answer though.
Mostly I prefer DF96's answer though.
Enforce ducts on drones
A drone is much noisier than a Tesla car, we don't need more noise, and more appalling is why aren't drones enforced to come with a propeller guard, those high speed rotating propeller blades can cause serious harm to humans, a duct can the improve the much needed safety in this respect plus it has many other advantages too.
From Wikipedia:
Ducted fan - Wikipedia
A drone is much noisier than a Tesla car, we don't need more noise, and more appalling is why aren't drones enforced to come with a propeller guard, those high speed rotating propeller blades can cause serious harm to humans, a duct can the improve the much needed safety in this respect plus it has many other advantages too.
From Wikipedia:
- By reducing propeller blade tip losses, the ducted fan is more efficient in producing thrust than a conventional propeller of similar diameter, especially at low speed and high static thrust level (airships, hovercraft).
- By sizing the ductwork appropriately, the designer can adjust the fan to allow it to operate more efficiently at higher air speeds than a propeller would.
- For the same static thrust, a ducted fan has a smaller diameter than a free propeller, allowing smaller gear.
- Ducted fans are quieter than propellers: they shield the blade noise, and reduce the tip speed and intensity of the tip vortices both of which contribute to noise production.
- Ducted fans can allow for a limited amount of thrust vectoring, something normal propellers are not well suited for. This allows them to be used instead of tiltrotors in some applications.
- Ducted fans offer enhanced safety on the ground.
Ducted fan - Wikipedia
This problem involves knowledge of some very difficult principles of acoustics and fluid dynamics, it's a small group of people who could get tangible results on this they are probably not chatting here.
Exactly -- there's a few places that are closely looking extremely carefully at helicopter dynamics, but I doubt it's a big community (I only know a little bit about it because one of my uncles has done a few flow visualization studies with different groups)
And that's before getting into having a bunch of drones flying about and whether that's a good idea in the first place.
There's some interesting small autonomous flying devices out there...
Here's one that flies: Volocopter - Company
YouTube
Who wouldn't want one..? 🙂
Here's one that flies: Volocopter - Company
YouTube
Who wouldn't want one..? 🙂
Well, let's try to carve out the part most of us can think about. Black box the production of the sound for now, and assume they use ducted propellers. How would you go about getting the sound generated to reflect up at the sky while still allowing thrust?
Most of the sound will go where the thrust goes, so the simplest option is to turn the drone upside down.
I guess they are called drones because they make an annoying buzzing sound.
I guess they are called drones because they make an annoying buzzing sound.
Such an interesting language, English she is:
1. A male bee, especially a honeybee, that is characteristically stingless, performs no work, and produces no honey. Its only function is to mate with the queen bee.
2. An idle person who lives off others; a loafer.
3. A person who does tedious or menial work; a drudge: "undervalued drones who labored in obscurity" (Caroline Bates).
4. A remotely controlled or autonomous aircraft with no pilot on board. Also called unmanned aircraft system.
As for making them quiet - as said earlier, I think you'd want to avoid any moving vehicle being completely silent - especially with the number of borderline suicidally distracted drivers, cyclists and pedestrians. My son drives a BMW I3, and has had close calls in parking lots with ear-bud wearing pedestrians meandering randomly about.
1. A male bee, especially a honeybee, that is characteristically stingless, performs no work, and produces no honey. Its only function is to mate with the queen bee.
2. An idle person who lives off others; a loafer.
3. A person who does tedious or menial work; a drudge: "undervalued drones who labored in obscurity" (Caroline Bates).
4. A remotely controlled or autonomous aircraft with no pilot on board. Also called unmanned aircraft system.
As for making them quiet - as said earlier, I think you'd want to avoid any moving vehicle being completely silent - especially with the number of borderline suicidally distracted drivers, cyclists and pedestrians. My son drives a BMW I3, and has had close calls in parking lots with ear-bud wearing pedestrians meandering randomly about.
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