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U.S. proposes to allow drone operation at night, over people

reuters.com

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Re: U.S. proposes to allow drone operation at night, over people

#61

Post by mediaman »

mikeash wrote: post #59
neaanopri wrote: post #53

Earlier quoted context omitted.

I don't see this happening. The propeller physics aren't changing. If you are using the quadrotor architechure, directly lifting your playload with no wings, there's a sound-per-kg number that can't be engineered away.

What makes a propellor different from a wing in this respect? Is it just because you have several of them next to each other and interfering with each other?

Both propellers and wings are fundamentally the same thing: airfoils.

However, air passes over a propeller much, much faster than over a wing, and creates shock waves in a way that wings don't.

Re: U.S. proposes to allow drone operation at night, over people

#62

Post by toufiqbarhamov »

mikeash wrote: post #59
neaanopri wrote: post #53

Earlier quoted context omitted.

I don't see this happening. The propeller physics aren't changing. If you are using the quadrotor architechure, directly lifting your playload with no wings, there's a sound-per-kg number that can't be engineered away.

What makes a propellor different from a wing in this respect? Is it just because you have several of them next to each other and interfering with each other?

It’s a combination of factors, one of which is that a prop is just out there, unshielded like the fans inside a jet engine (which still make a ton of noise in the case I’d high bypass models). Then there’s cortex shedding, which is mostly occurring along edges and tips. Airplanes also tend to fly at much higher altitudes except on takeoff and landing, or their noise would be an issue too. Finally you’re right that the number and arrangement of blades matters, because each blade produces some turbulence, vortices, etc which then interact with the next blade in sequence. All told the issue is just s high degree of aerodynamic noise. You get that with a wing and any aerodynamic body, and really if you’ve ever seen model jets fly you’ve heard the racket they make.

The major issue is that until drones came around, you didn’t have to worry very often about large number of high performance aircraft operating throughout civilian airspace, at very low altitudes in crowded areas.

Re: U.S. proposes to allow drone operation at night, over people

#63

Post by tareqak »

lutorm wrote: post #60
tareqak wrote: post #43

Will they have restrictions on the cargo that these drones are allowed to carry. I know that the drones themselves will probably have rechargeable batteries powering them. However, if 1. the drone is carrying cargo 2. the cargo isn't sufficiently secure to the drone 3. the cargo contains rechargeable batteries / some other component that can explode as result of high speed impact with a sufficiently hard surface 4. t…

There are existing rules for transporting hazardous materials by air. I don't know if those rules are general enough to also encompass unmanned aircraft.

That's a good point. Hopefully, those rules are applied and adhered to from the get go.

Re: U.S. proposes to allow drone operation at night, over people

#64

Post by thatcat »

mikeash wrote: post #59
neaanopri wrote: post #53

Earlier quoted context omitted.

I don't see this happening. The propeller physics aren't changing. If you are using the quadrotor architechure, directly lifting your playload with no wings, there's a sound-per-kg number that can't be engineered away.

What makes a propellor different from a wing in this respect? Is it just because you have several of them next to each other and interfering with each other?

A lot of things: the high rpm motor powering it, the combined area of the blade edge that is higher than the area of the wing edge, and the higher pressure differential between the air behind the propeller compared to the air in front of it. The sound results from this pressure differential collapsing so anything that increases the pressure differential will create more sound.

Re: U.S. proposes to allow drone operation at night, over people

#65

Post by eftychis »

chaostheory wrote: post #48
threeseed wrote: post #26

Earlier quoted context omitted.

Fans, helicopters etc have been around for decades and are still mostly loud. You can't escape the physics that moving air causes noise.

Energy efficient buildings tend to handle noise pollution better with their extra insulation. Not ideal, but there's always a solution.

I don't think it is a good idea for the sanity of people to tell them to stay inside and have really good sound insulation. We have to remember that sound pollution is a health issue and impacts people's lives. I have my doubts how efficient insulation one can get against air traffic -- from personal experience, it doesn't work.

Re: U.S. proposes to allow drone operation at night, over people

#66

Post by bigmattystyles »

cronix wrote: post #41

One thing the drones really need to do before being deployed en masse (besides safety) is to become relatively silent. They are quite loud. I can hear a single one from about 1/2 mile away. I can't imagine what it will be like if many are flying all over, at all times. It will be like everybody is living next to an airport - something I consciously choose to not live close to due to noise pollution. Quality of life w…

Tangent: I don’t think I’ve ever been more incensed than when I learned Harley Davidsons are quiet out of the factory and people make them loud. And while I can get a ticket for something trivial, I’ve never heard of someone getting a ticket for riding a motorcycle or car that’s obnoxiously loud and can be heard a mile away. My point, I guess, cities, townships, what have you, don’t care about noise.

Re: U.S. proposes to allow drone operation at night, over people

#67

Post by jMyles »

One of the most important roles for drones is fully independent observation of police that is very difficult to physically disrupt.

If independent, amateur, volunteer drone operators begin to observe nearly every outdoor police encounter in the United States, without the police being physically able to stop it, that alone will be a big enough victory to justify many of the side effects.

Let's ensure that observation of government agents, whether at a traffic stop or a huge gathering, becomes a regular, legal, celebrated practice.

Nobody stands to benefit more from this than honest, integral police officers who live in fear of reporting their less savory colleagues.

Re: U.S. proposes to allow drone operation at night, over people

#68

Post by kevin_thibedeau »

cronix wrote: post #50
_xerxes_ wrote: post #46

Earlier quoted context omitted.

Larger drones tend to be more quiet, or at the very least are perceived to be so due to the lower pitch sound made by larger, more slowly rotating propellers.

Helicopters have lower pitch and larger, slower rotating blades as well. They're not quiet, and they've had a lot longer to perfect the blade tech. My block gets about 15 deliveries per day from UPS/USPS/FedEx/Amazon/etc. Have you been near a drone, of any size, taking off and landing? It's quite loud. They're not just going to drop the package from the sky. They're going to be constantly landing and taking off to de…

Helicopters have a large airframe directly under the blades. That is part of the problem with their noise generation.

Re: U.S. proposes to allow drone operation at night, over people

#69

Post by codedokode »

First thing they should do is to cover propellers so that they don't hurt anyone. Most of the drones I've seen have no protection. The manufacturers and owners don't care about the safety at all.

Also, what if the drone flies into someone's window or a car? How do you identify the owner?

Re: U.S. proposes to allow drone operation at night, over people

#70

Post by ams6110 »

ProfessorLayton wrote: post #6

Lots of safety concerns are brought up, but I'm really curious how drones will play out in conjunction with noise and NIMBYism. Drones are loud, so I can't imagine that commercial drone activity (Especially at night) will happen without heavy pushback from locals. NASA did a study and found that the noise drones make is perceived to be more annoying than those from cars [1]. They acknowledge noise-based pushback as a…

In my neighborhood, a noisy drone would get shot out of the sky pretty quickly. Or even a not-so-noisy one, if it were spotted over someone else's property.
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