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Questions tagged [noise]

Questions related to aviation sound noise or regulations thereof.

1
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1answer
150 views

What causes the nose landing gear knocking noise on a Boeing 777 while taxiing?

The NLG knocking noise heard on taxi-in to stand, what could cause this knocking noise?
3
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0answers
243 views

What are the unique sounds emitted by Embraer E190-E2 on final?

I live close to an airport where these aircraft frequently land. When the E2 is between 2-3 thousand feet, something which I can only describe as whale moans, is heard. I say they are unique because ...
4
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0answers
125 views

In terms of noise, how does a steep climb-out compare to a noise abatement procedure?

For airports in populated areas, it is common to implement noise abatement procedures. In practice, this means that aircraft reduce thrust on departure, so that noise is reduced in proximity to the ...
15
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2answers
4k views

Are there any reported cases of noise from helicopters causing damage to property?

In the Netherlands, three cases have been reported of Chinook helicopters' rattle noise (low frequency sound) damaging solar panels. The Dutch defense ministry recognises this problem and the lawyer ...
6
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1answer
372 views

Is there any way to reduce the noise and vibration in a C-130 Hercules?

We are using C-130 B and E Models with T-56 A-15 engines and Hamilton Sundstrand 54H60-91/117 propellers. A lot of vibration and resonance are felt on these military version aircraft even after using ...
2
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2answers
343 views

What are ways to reduce drag and noise generated by the landing gear?

Apart from using fairings, what ways are there, or have been studied, but not necessarily implemented in reducing drag and noise produced by the landing gear, mainly for commercial aircraft with ...
2
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1answer
159 views

What is the maximum decibel noise level of a stage 4 rated engine?

I was just wondering if anyone is able to help me. I need to find out, what is the maximum decibel noise level of a stage 4 rated engine (as defined by the Federal Aviation Administration)? Some more ...
0
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2answers
405 views

What noises are considered worrying on a passenger flight?

As a typical 'nervous flyer', I often find myself asking crew about a noise that they say is completely normal during flights. The thing is, I've flown a lot and still hear new sounds sometimes! For ...
20
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8answers
6k views

Why are winches not used for towing commercial planes up?

In this video a glider is pulled up by a winch on the ground, like this: (Source) I would say you could apply the same principles with bigger planes, possibly even using sustainable energy sources. ...
0
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1answer
107 views

How to deal with the noisy cockpit?

From the pilot perspective I want to know how to deal with the noise in the cockpit on the turboprop aircraft while long-run flights. The reason is old type aircraft with bad headphones which doesn't ...
7
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1answer
125 views

Do noise abatement procedures have an impact on aircraft emissions?

The ICAO has imposed Noise Abatement Departure Procedures (NADP1 and NADP2) in order to limit the noise impact of departing aircraft on communities living nearby airports. Could noise reduction lead ...
17
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3answers
726 views

When a typical commercial airliner flies overhead, what is the actual noise we are hearing?

We're all familiar of the sound planes flying quite high overhead and you hear a faint drone, even when planes are lower to the ground you hear them scream at a slightly higher pitch, but what exactly ...
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0answers
115 views

How do active blades work on helicopters?

Can someone throw some light on 'active blades' as used in helicopters? I'm mostly interested in the use of piezoelectric material and actuators. How are the actuators able to sense the change of ...
3
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1answer
237 views

What are the rules in the UK about overflying built-up areas for fun?

I live in North London. It's not like we don't have a fair amount of noise pollution from the sky, with helicopters, and jets landing at LHR with a stupidly shallow glide path angle. But in addition,...
16
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3answers
3k views

Won't sonic booms prevent Space X's BFR intercity transport plan from being acceptable?

Considering that Space X have just announced that their BFR can take anyone anywhere in the world in under 1 hour, that would be enormous speed, does this rocket not produce sonic boom? If not is it ...
0
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1answer
885 views

How loud is a private corporate jet? [closed]

It's a movie/TV trope that people can talk to each other and even whisper on commercial airliners in flight. In a story, it’s pracical to confront the reality of the experience and have characters ...
9
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1answer
531 views

In a piston aircraft, how much noise is generated by the engine, and how much by the propeller?

I've been reading quite a few articles lately about how noise complaints from GA airports across the country. One of the common suggestions to fix the issue is to simply use an electric engine ...
8
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2answers
312 views

Are there any methods to predict the location of a jet aircraft from its sound?

At times there are military fighter aircraft flying overhead of my location (MiG-21Bis and Su-30MKI). The first indication of their presence being the sound, that obviously causes one to look up to ...
10
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1answer
1k views

Is ultrasonic noise from small turbines painful to pets?

A question on another SE site prompted me to search for 'Aircraft engines untrasonic noise dogs', but with not much success. The OP's dog barked like crazy at turboprops, but was not bothered at all ...
6
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1answer
923 views

Can an airplane flying above 35,000 feet be heard on the ground?

Can the sound produced by a commercial aircraft flying at 35000 feet be heard on the ground when the surroundings are quiet?
53
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4answers
12k views

Can I stop crop dusters repeatedly flying over my home?

I have a crop-duster spraying the fields around me often. He flies over my house no matter what field he is spraying every few minutes. I think he uses my house as a pivot point. The old pilot rarely ...
0
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0answers
522 views

What is the noise that the A320 makes on the ground? [duplicate]

I've noticed that planes in the A320 family make a sawing noise on reaching the gate. The link below may give you an idea of what I mean (although the A320 in the video is still taxiing). Is this a ...
3
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1answer
487 views

Are some airline's flights more noisy than others for security reasons?

LHR has published a table ranking the noise and pollution levels of the different airlines using the airport. At the bottom of the list is Israel's El Al. El Al, in their official statement, say that ...
10
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1answer
2k views

What causes the distinct sounds of a jet engine?

I live a few miles from a major airport (BOS), under the path that a lot of airplanes use to depart. The planes are somewhat low over my house -- high enough that it's not deafening, but low enough ...
5
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2answers
702 views

What noise reduction measures were taken in the time between hush kits and chevrons?

In older jets such as 727 hush kits are used in the engines to reduce noise. In very modern jets such as 787 or 747-8F, chevrons are used for the same purpose. What happened in between? The switch to ...
11
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2answers
711 views

Can an airport fine an aircraft for being too noisy?

I stumbled upon this article (sorry, in French!) stating that in order to avoid fines, Ryanair pilots start take-off procedures at the beginning of the runway (rather than at the "intersection"), with ...
10
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0answers
1k views

How loud was the Concorde's sonic boom at the ground level? [duplicate]

Before the Concorde was sent into retirement, their supersonic flight paths were restricted to the ocean because of concerns about sonic boom on the ground. But just how loud was this boom? Was it ...
18
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2answers
1k views

How do turbofan nacelle lengths compare?

For example, compare the JT9D and the PW4000 below (both from Pratt & Whitney, both on a 747): (Left, Right) The PW4000 has a longer forward nacelle, and a covered exhaust cone. On the inside—...
20
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4answers
6k views

Are seaplanes allowed to taxi in residential areas?

There's a small pond/lake behind my house. A sea plane was just going around it. It was very loud and got like 10 feet from the shore. It's just going in circles and won't take off and leave. This is ...
0
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1answer
300 views

How does a normal aircraft exhaust nozzle (the base model) generates a lot noise? [duplicate]

How does a normal aircraft exhaust nozzle (base model) generates noise and, whats the difference between the operation of the normal base model of aircraft exhaust nozzle and the new design of ...
2
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1answer
411 views

Which type of chevrons is applied on the B787?

Which type of chevron nozzle was applied on the B787? I'm really confused about whether if it's sawtooth or sine wave.
3
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1answer
586 views

What is the definition of “Sideline” in reference to aircraft noise?

The FAA has measured external aircraft noise levels and published the results in the Advisory Circular: AC 36-1H - Noise Levels for U.S. Certificated and Foreign Aircraft In the appendices, noise ...
8
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3answers
3k views

Why are light aircraft engines so noisy?

I live near an airport where students spend a lot of time flying circuits. During the base leg, pilots can be heard reducing engine revs prior to the final left/right turn to line up with the runway. ...
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0answers
97 views

What makes the “howling” sound from airliners? [duplicate]

Quite often I hear a kind of "howling" sound coming from airliners when I'm at a general aviation airport, which is located at 13nm from an international airport. Normally these airliners overfly the ...
7
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1answer
607 views

In what way(s) will making an airplane electric help to make it “quiet”?

In this blog I read about the Quiet Flight Initiative, which - if I understand correctly - will be quieter than a comparable carbon fueled plane at least in part because it is electric. It's an ...
4
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1answer
126 views

What factors come into play when reducing the total noise generated by a helicopter?

I simply cannot understand how a helicopter can be made quieter. What are the things that would considerably affect the noise signature of a helicopter ?
20
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3answers
6k views

Why don't airliners use noise cancelling?

Some cars have started using noise cancelling in their cabins, through the speaker system. It's a well established technique for dealing with low frequency noise like engine rumble and wind noise. So ...
6
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1answer
603 views

What causes noise when a plane is on the ground?

What's the loud continuous noise the plane is making when it's on the ground and the (jet) engines are visibly not running (spinning, at least) ? I was boarding and I thought it was perhaps a ...
2
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0answers
286 views

Can quadcopter-like UAVs ever get significantly quieter? Any candidate technology?

The light weight quadcopter and hexacopter UAVs that can cary say 2kg to 20kg payloads for "delivery" produce enough noise that a steady stream of pizza and book deliveries might not be so welcome in ...
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1answer
122 views

What is the applicable regulation for flying in a residential area? [closed]

What are the laws for flight in a residential area. Can I just fly around the neighborhood or do I have to have a flight plan? I have my own strip. I have had some noise complaints about just flying ...
8
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6answers
9k views

How do the cabin noise levels of the A380 and the 777 300 ER compare?

I couldn't find any official comparison for noise level (dB) in Airbus A380 versus the Boeing 777 300 ER. Does anyone have some info about it? Which one is better in terms of acoustic isolation?
5
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1answer
569 views

What is the major source of engine noise for non-propeller aircraft?

Sparked by this question: Take any non-propeller powered aircraft, when idle, the sound produced by the engines are fairly low pitched, and as the engine spins up, increasing in pitch before becoming ...
5
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1answer
656 views

What are the relative internal noise levels in various aircraft?

What are the relative noise levels in various aviation scenarios for observers seated inside an aircraft? I'm sure the specifics depend on model but I'm curious if any general trends can be drawn that ...
12
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2answers
1k views

Can noise from contra-rotating propellers be reduced by having a different number of blades on each propeller?

Heads up: This came from Wikipedia's page on contra-rotating propellers and it explicitly says citation needed: However they can be very noisy ... It is also helpful if the two propellers have a ...
7
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2answers
389 views

How much noise does flow separation cause?

I recently found the following image showing the different sources of noise in vehicles. I notice that Aerodynamics is actually quite a big part of vehicle noise, as shown below by the blue line: ...
17
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3answers
12k views

What causes descending aircraft to make a noise like a giant blown bottle?

I've lived for years about eight miles NW of Boston's Logan Airport. Although I can't say we get a lot of aircraft noise, once in a while, due to winds or air traffic, there will be a long line of ...
14
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3answers
4k views

Why does a jet engine acquire a metallic whine when in full power? [duplicate]

I had a flight yesterday on an AA Embraer ERJ-190. As the plane idled at the end of the runway there was the familiar high-pitched jet whistle, which increased in pitch as the engine started spinning ...
7
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3answers
3k views

Do quadcopter propellers break the sound barrier?

I recently bought a quadcopter and noticed every time I fly it there is this weird buzzing noise. I have heard this noise on other quadcopters around the same size as mine(4in by 4in). On an airliner ...
5
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3answers
378 views

Could older airplanes be retrofitted with engines with chevrons?

The 787 uses a variety of sound reducing mechanism including engines with characteristic chevrons: (Source wikimedia commons) Would it be possible for older airplanes to also have this type of ...
2
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0answers
94 views

How do the chevrons on engine nacelles reduce noise? [duplicate]

The B787 has these chevron-shaped teeth on the exhaust port of its engines to reduce noise. And according to the answer to this question they will be incorporated into the new B737's Can anyone ...