Light aircraft cabin noise levels

Katamarino

Katamarino

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Katamarino
Has anyone ever measured dB levels inside a C182 or similar? The numbers I find online vary quite dramatically.
 
I have in my 180 and my old Cub. From 11 years ago- I tested the C-180 a few days later. Noise levels were 3-4dB quieter in the same ops.

FYI, I took my noise meter out in the plane tonight to identify my own noise levels. PA-12, 160hp w/8242 prop, and a Hot Rod muffler. 1200 rpm warm-up 85db. 2450 rpm cruise 98db. Full throttle 2700 rpm cruise 102db.
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My Apple Watch does it ,gives a warning when sound level is high,such as engine start.
 
Unless you have a real and calibrated sound level meter, you are basically using random number generators. You can get better microphones that help reduce the errors. You need a calibrated Type II microphone. https://www.amazon.com/MicW-Calibrated-Measurement-External-Microphone/dp/B00510Y3KC

My old iPhone 3GS was just about dead nuts the same as a professional, high end, SLM. But my iPhone 5 was more than 5 dBA off.
 
Indeed; that's why I hadn't bothered with any of the smart-phone apps.
 
The noise is primarily propeller noise. A reduction of RPM reduces noise in a 182.
 
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I picked up a $20 db meter on amazon in 2015 when I compared 172 vs 162 noise levels.
 
The noise meter I own is a tool, not a toy. It has A and C weighting and my results reported were in A mode. FWIW.
 
This in my 0-320 160hp 172 with a power flow exhaust that has no muffler. 106DB
IMG_72191.jpg

It was in the 90s in the back seat.
 
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midlifeflyer said:
@wayneda40 can tell you about his experiments with the surprisingly noisy DA40 (easily the noisiest of the 30 or so types I've flown)
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As Mark noted, the interior sound level in a DA40 can be quite loud. Interestingly much of that noise comes not from the engine, prop, or external airflow... but rather from the (nicely strong) panel air vents. Here's a brief report on my Experiment on DA40 Air Vent Noise Reduction.

A few summary numbers... Cruise at 9000’ MSL, full throttle, rpm 2450, ~135 KTAS, 24 degC (hot):
Both air vents closed 93.1 db​
Copilot air vent opened 103.2 db​
==> 10 db caused by opening an air vent!​

Fortunately, there is a decent treatment... put glider tape over the lower of the NACA air vents (this excellent idea was from another DA40 pilot):
grab14.jpg
... this drops the noise increment caused by opening the air vent from 10 db to 3 db... and only lessening the perceived air flow by about 25%.
 
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wayneda40 said:
As Mark noted, the interior sound level in a DA40 can be quite loud. Interestingly much of that noise comes not from the engine, prop, or external airflow... but rather from the (nicely strong) panel air vents. Here's a brief report on my Experiment on DA40 Air Vent Noise Reduction.

A few summary numbers... Cruise at 9000’ MSL, full throttle, rpm 2450, ~135 KTAS, 24 degC (hot):
Both air vents closed 93.1 db​
Copilot air vent opened 103.2 db​
==> 10 db caused by opening an air vent!​

Fortunately, there is a decent treatment... put glider tape over the lower of the NACA air vents (this excellent idea was from another DA40 pilot):
View attachment 120504
... this drops the noise increment caused by opening the air vent from 10 db to 3 db... and only lessening the perceived air flow by about 25%.
Click to expand...
I simply left the vents closed as much as possible and only opened them in short bursts or barely cracked open. Those vents may be loud but they also pass a whole lot of air.
 
mandm said:
What is RadioShack?
:)
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I know right? Sadly the younger pilots probably have never heard of Radio Shack. Are there any left in the US? We used to have one right across the street. Been gone for at least 10 years now.
 
Gary Ward said:
Sadly the younger pilots probably have never heard of Radio Shack. Are there any left in the US?
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I have a Radio Shack not too far from me but it isn't like the stores were years ago when CB radios were the hot ticket. "Tin-fouwa, good buddy!" :rolleyes:

Someone earlier mentioned the accuracy (or inaccuracy) of a smart phone app but my thinking is that the app on my iPhone is likely as good or better than Radio Shack meter tech from ~40 years ago ... :biggrin:
 
Daleandee said:
I have a Radio Shack not too far from me but it isn't like the stores were years ago when CB radios were the hot ticket. "Tin-fouwa, good buddy!" :rolleyes:

Someone earlier mentioned the accuracy (or inaccuracy) of a smart phone app but my thinking is that the app on my iPhone is likely as good or better than Radio Shack meter tech from ~40 years ago ... :biggrin:
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Yes I watched Radio Shack evolve over the years. They reminded me of Sears, just couldn't change with the times.

In 75 we were into CB radios and radio shack was the place to get em!
I bought my electronic repair parts from them years ago. Then I got my first direct TV sat dish from them around 1995. I used it first in my race car trailer to keep an eye out on the weather in the late 90s even before I had one at home. Then it was RC cars/toys as I remember and then cell phones and who knows what else. Eventually there was nothing there anymore that interested me so I quit going in. Plus all the knowledgeable sales people were gone. Then the next thing I know they closed up around here. I used to miss them more.
 
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Stewartb said:
The noise meter I own is a tool, not a toy. It has A and C weighting and my results reported were in A mode. FWIW.
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Make and model?

I have seen a lot of people using meters they thought were good ones, but were not.
 
Gary Ward said:
Yes I watched Radio Shack evolve over the years. They reminded me of Sears, just couldn't change with the times.

In 75 we were into CB radios and radio shack was the place to get em!
I bought my electronic repair parts from them years ago. Then I got my first direct TV sat dish from them around 1995. I used it first in my race car trailer to keep an eye out on the weather in the late 90s even before I had one at home. Then it was RC cars/toys as I remember and then cell phones and who knows what else. Eventually there was nothing there anymore that interested me so I quit going in. Plus all the knowledgeable sales people were gone. Then the next thing I know they closed up around here. I used to miss them more.
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Used to be one of the few consumer stores around in the late-90s/early-00s where you could actually find a good selection of LEDs/resistors/transistors/etc. for small electronics projects. I think I bought my first smartphone from them (Samsung Galaxy S II) back in 2011 or so because they had the best deal around. That was the last time I was ever in a Radio Shack, and I don't think it stayed open much longer afterwards.
 
During take off, my PA-17 is so loud you can't use the radio. I have to get it off the ground and throttle back to 2,200 rpm before you can hear anything.
Not ideal, but you learn to cope.
 
I’m using an iPhone (13 pro max) app, but my 182 shows 88db at 23/2300. I’ve got the -U motor and closed cell foam insulation
 
ktup-flyer said:
I’m using an iPhone (13 pro max) app, but my 182 shows 88db at 23/2300. I’ve got the -U motor and closed cell foam insulation
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I have a 12 and the NIOSH SLM app on it. I use it when checking the noise floor in recording areas but I've not tried it in the plane. Need to do that and see what I get. This app has a seeting for A, C, or Z frequency weighting ...
 
Gary Ward said:
Yes I watched Radio Shack evolve over the years. They reminded me of Sears, just couldn't change with the times.

In 75 we were into CB radios and radio shack was the place to get em!
I bought my electronic repair parts from them years ago. Then I got my first direct TV sat dish from them around 1995. I used it first in my race car trailer to keep an eye out on the weather in the late 90s even before I had one at home. Then it was RC cars/toys as I remember and then cell phones and who knows what else. Eventually there was nothing there anymore that interested me so I quit going in. Plus all the knowledgeable sales people were gone. Then the next thing I know they closed up around here. I used to miss them more.
Click to expand...
Inventory of 100,000 parts is expensive to carry in thousands of stores

I worked in one in 1979 and computer was hot hot hot. I guess they picked the wrong one to sell
 
Gary Ward said:
I know right? Sadly the younger pilots probably have never heard of Radio Shack. Are there any left in the US? We used to have one right across the street. Been gone for at least 10 years now.
Click to expand...
The Radio Shack near my house carried stuff like IC7404 and other common chips into the 90s. I admittedly don't have the need to buy ICs anymore, but it was nice they were available back then.
 
Radio Snack (as my kid called it given some unfortunate typography on their part) kind of jumped the shark with this commercial (as amusing as it was):

 
That will be the next thing that will be put upon GA: cutting down the noise. Not inside the cabin, nobody cares how we "rich people" suffer, but the exhaust and prop noise. I'm actually surprised it's not regulated now.
 
We kept our Radio Shack into the 200X's. I was dabbling in circuit design (strictly amateur level stuff), so it was nice to know if I needed an immediate resupply of resistors, etc, that it was available. It was more expensive than ordering off of ebay but could get them same day and only a few instead of the ebay 300x quantities.

As to the topic, "quite loud" should about cover the noise level in light aircraft.
 
SoonerAviator said:
Used to be one of the few consumer stores around in the late-90s/early-00s where you could actually find a good selection of LEDs/resistors/transistors/etc. for small electronics projects.
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And if you had the card you got a free battery every month!

It was sad... in the late 70s through the 80s the discrete electronic components were half the store and you could count on them having what you needed... then it was just the back wall... then a couple of cabinets... then just a couple of drawers... before becoming nothing but a second rate cell phone store.

Hard to compete with digikey and sparkfun.
 
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