Why Do Helicopters Work So Noisy?

After many reasons, from technical details to weather, actually When you hear how we were wrong You may be a little stunned.

walking around screaming helicopters Let’s take a closer look.

It is the air itself that creates the noise.

main rotor (the rotating part of the engine) is the main power source that keeps the helicopter in the air and moves it forward. As the rotor rotates, the blades air pressure drops and the air pressure below also increases. While this difference is what pushes the helicopter upwards, it is actually the element that makes the noise.

The air flowing around the wings to equalize the pressure heats up due to the low pressure and is trapped under the cooler, low-pressure air rising from below. interact the resulting vortex The vibrations that occur when it hits the next blade become the sound waves we hear.

There is also the thickness noise factor.

Displacement of air as it passes through the blade “thickness noise” It is defined as . While it is directed to the rotor plane, the lifting and drag force applied to the blades also occurs. this too “loading noise” and another element that makes sound.

We hear more of their voices as we land, right?

Yes because during landing and takeoff “wing vortex interaction (BVI)”A situation called , occurs. The interaction causes the rotor blades to re-encounter the air vortices they had previously created and the sound waves caused by this interaction to emerge. BVI, helicopter noise second most important source and can reach disturbing levels, especially during descent.

Let’s not ignore the mechanical parts.

The engine and other mechanical parts also add to the sound of the helicopter. Helicopter engines become a significant source of noise because they are generally operated at high power. Moreover gear boxes and other moving mechanical parts can also produce extra noise through friction and vibration.

Helicopter noise is actually not as loud as we thought.

When you think about it, when that sound echoes in our ears, it seems quite loud, right? However, the situation is not as we heard. According to the International Helicopter Association, a helicopter at an altitude of 150 meters The noise level is 87 decibels. At 300 meters, this noise is 78 decibels.

When you compare, you will understand better what we mean now. The noise levels of vacuum cleaners range from 63 to 85 decibels. Even the quietest one has a decibel of 65. So, when you look at it, helicopters can actually make as much noise as a vacuum cleaner.

Of course this is the decibel level helicopter contents It is not the same for . If you are there you may hear a little louder sound. That’s usually 97 decibels It happens around.

So why does it feel like there are more?

In our opinion, helicopter sound is quite disturbing. However, studies show that we hear it as if it were 2 times higher than normal. The reason for this is that the helicopter have a specific noise is shown.

Don’t helicopters have their share of technology?

Helicopter manufacturers, of course, come up with many designs for improvement. Changes in the shape and material of rotor blades also appear to help reduce noise. One of these examples is Airbus’ Blue Edge rotor blades.

As you can see in the image, the wings are with a tip curled back owner. This change is a technical detail designed to reduce noise generation.

New generation hybrid and electric aircraft is also being developed. Thanks to these helicopters, which are specially designed for urban environments, noise is kept at a reasonable level for people living in the area.

With the new methods developed, perhaps in the future we may see helicopters gliding noiselessly in the sky. noiseless helicopters Although it may seem like a dream at the moment, this is a real goal that engineers are working on.

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