Why are airplanes SO darn loud? Can't they put mufflers on them?

Question

Commercial and military aircraft fly over my house all the time. I can barely see the plane but I can sure hear them. Can't someone make mufflers for them? Why doesn't the EPA noise level section make mandatory sound pollution control requirements for aircraft?

Everyone that suggested that I move, is being unrealistic. Where would a person move to that never has any planes flying overhead? I've lived in 5 USA states and in Mexico and they all have planes.

My question is Can't 20th century technology make a quiet aircraft?

Answer 1

They do make noise level requirements. That is why they fly so far above you. If they flew at lower altitudes, they would be breaking the law. A little over 20 years ago, military craft would fly at super sonic speeds over farmland. Farmers complained about the sonic booms, which I enjoyed. The claims were that chickens quit laying eggs, cows milk was bad or the milk quit flowing, other livestock related complaints. Today, I no longer hear sonic booms. As far as the noise is concerned, that is directly related to energy and power. The more energy associated with a process, the more noise or light or heat produced. The more power used, or energy per unit time, then the more noise. Huge aircraft require incredible amounts of energy. The fuel consumption of a commercial air craft is similar to that of the number of cars required to transport the same number of people over roughly the same distance. How many people can some hold? If you pick one that will hold 150 people, that is roughly equivalent to (150/4) cars or 37 cars. That is a lot of power and fuel consumption over a 750 or 1000 mile trip. That is a lot of noise.

Answer 2

Unfortunately physics dicates that you can't make airplanes a whole lot quieter than they are now. the sound you hear is not the sound of the engines, but rather the sound of high velocity air exiting the exhaust nozzle and colliding with lower velocity air. This makes the ripping sound you hear behind the plane.

Because the airplane generates its thrust from accelerating air outward through the engine, slowing it down (while hushing the engine) would mean the engine could not make nearly as much power.

Efforts are underway to hush engines by combinins multiple layers of accelerated air at varying velocities, but the technology to do so is years away and prohibitively expensive (though in the future I would expect it to be commonplace).

EPA noise regulation regarding aircraft are very strict. If any aircraft is violating noise levels, they operator can receive a hefty fine. However this does not apply to military aircraft who are exempts from "Stage III" requirements (the ones that were implemented about 10 years ago to make airplanes quieter).

In the meantime, you may consider adding extra insulation to your house or moving out from underneath the departure path of an airport. Most noise pollution that originates at airports is extremely localized, and simply moving a few hundred yards farther might make a huge difference.

Answer 3

There are mufflers on them. The turbofans use cool air to mix with the hot and loud exhaust to quiet the engines. Modern turbofans are mixing even more cool air to be even quieter. There are 'hush kits' that are installed to silence the jets. The noise levels are internationally regulated by the International Civil Aviation Organization (ICAO) and the standards are getting tougher all the time.

Also, departure procedures for jets steer them away from urban 'noise sensitive' areas and require minimum altitudes above residential areas.

As well, the pilots practice noise abatement procedures by throttling back after takeoff. This was started by Concord pilots because it was very loud, but by throttling back, the Concord was actually more quiet than most jets of the era.

As for military planes, they don't have any noise regulations to follow. But neither do the police when they put the sirens on at 3am.

Answer 4

I live under the flightpaths for Heathrow and Gatwick airports. 30 years ago, when I was a child, the aircraft that flew over were so loud that they used to rattle windows and doors; Concorde was, in comparision to most of them, relatively quiet! Now if an aircraft flys over, even if we are out in the garden, it is perfectly possible to carry on a conversation, listen to bird song etc.

I know that there are a lot of older aircraft types (mainly used as freighters these days) that are not allowed to use European airspace due to ICAO noise regs. Maybe that doesn't apply where you are living?

Answer 5

I know what you mean. I lived in a trailer house on the end of a runway where F-16's take off and land all hours of the day and night. It gets a little annoying when talking on the phone (or just talking period) and two or three jets take off back to back. Watching a TV program is totally out of the question without use of headphones. But I am very fond of the protection the Air Force provides our country, so we just have to make the best of the situation. Overall, the Air Force is a very good neighbor to have and is very supportive of our community. I wouldn't have it any other way.

Mufflers? Just turn up the stereo. LOL

Answer 6

Great answers...another way modern jet engines comply with noise standards is acoustic dampining material. For example, just inside the inlet on a General Electric CF-6 engine there are tiny holes that act like a muffler in trapping the tiny sonic booms the inlet fan blades are making. Well this is how it was explained to me anyways.

Answer 7

i'm not positive why. you would possibly want to nicely be in a position to look up the justifications for this on any web content for this interest ingredient of vehicles and any forums those hobbyists submit at. i myself imagine they are stupid and a nuisance. i develop into hoping there's a noisy noise ordinance that could want to provide the police the alright to value ticket those with those loud mufflers.

Answer 8

That is the sound of freedom!! Cherish the noise, can you imagine
what shape we would be in if not for the brave aviators actions in time of war?? They( the military) must practice constantly to provide you with the freedom you enjoy.

Answer 9

The afterburners would melt a muffler

Answer 10

Not as bad as the little raspy "piss planes" from the budget flight schools in my area. They fly over all day long and I"m not even close to the airport.