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Noise issues at club field

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Old 07-10-2008, 04:04 PM
  #1
jetboy
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Default Noise issues at club field

Jet folks,
The wise menat our mostly jet friendly club field have started pointing their decibel meters at some of the member's planes again and grounding those louder than 99db.

My search of turbine noise issues here on RCU resulted in very little discussion of how the best way to deal with the AMA noise recommendations with turbine aircraft.

I am looking for suggestions as to how to diffuse the potentially catastrophic situation for the future of jets at our field! I am not sure that I can properly sell the concept of perceived noise to the grown ups that are still trying to figure out what makes airplanes fly.

I am certain that this issue has surfaced at many of the fields where jets are flown regularly. I am hoping that we create a solution before the noise police ban jets completely[&o]. We have a club noise limit of 99 db at 9 meters that has not been enforced much until recently. So far the noise nazis have not been patrolling when I have been burning jet A. It is only a matter of time.
Any advice would be greatly appreciated!

Jetboy
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Old 07-10-2008, 05:44 PM
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Default RE: Noise issues at club field

Does your club bylaws specify wheteher or not the model has to be running to meet the 99 decibel level?

Im not being sarcastic but that was a loophole at a local club. The rules were not specific and didnt state wheteher or not the engine had to be running to be within the decibel requirement. The rule just stated the model could not be louder then a certain decibel. So we had them check it while the engine was shut off. It did piss off the noise nazis. [8D]
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Old 07-10-2008, 06:01 PM
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Default RE: Noise issues at club field

Ah yes...I remember flying at your field. I came out with an IMAC Extra and some old guy said my plane was too loud and had to pass a sound check of 99db. I said "OK...let's check it" and it made 97 no problem. He then said."Well...I just lowered the level to 96 so you can't fly. I then changed props, rechecked with the meter and it made 95db. He then said I had to make 94 so I put on a 3 blade and it made 94db.

After that, he asked what channel I was on and I told him "23 "which I was. I was then informed by him I could be expected to be shot down "because we have had some issues on your channel...actually on every channel you and your friends are on so you need to go home before you all loose your planes".

Yep...some of the more "mature" guys up there are some real winners.

Beave

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Old 07-10-2008, 06:53 PM
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Default RE: Noise issues at club field

That is B.S. I don't know how you walked away from that old man, Bevar. I would have back handed him for sure.[:@]

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Old 07-10-2008, 06:55 PM
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Default RE: Noise issues at club field

we have been having similar issues at our club but limited to prop planes. the real problem is perceived noise, not what can actually be measured. We have elected to deal with it along these lines, we assembled a group of respected fliers who the committee authorise to deem an aircraft as too noisy in the air, those people then assist the owner to reduce the perceived noise level in flight. We dont bring jets into noise testing on the ground as their perceived noise level in flight is not an issue.
Beave, your issue sounds like a club no normal person would want to be a member of!
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Old 07-10-2008, 06:59 PM
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Default RE: Noise issues at club field

Ya know...the funny thing was the OF was flying some really clapped out Lanier Lazer 200 with a G62 and pretty much no muffler of any type. It was really loud and when I asked him how high his plane tested at he told me to mind my own business.

I was pretty pissed but we decided it would have served no purpose to blow a gasket...arguing with that guy was like trying to shoot pool with a rope so we simply left and got some ice cream instead.

Beave

PS. We did get a few flights in before the stuff hit the fan so it was not a total loss of a trip.
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Old 07-10-2008, 07:11 PM
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Default RE: Noise issues at club field

We made an interesting discovery concerning turbine db levels at our field. We were conducting tests to determine appropriate levels/limits so as not to annoy our neighbors. We found that regardless of the turbine db level on the ground, the in-flight noise heard several hundered feet or more away was negligible. No so with props which can be very noisy even at a considerable distance. Must have something to with with the frequency or the way the sound is produced but we ended up eliminating all db restrictions for turbines. Even with a 98db limit for props, we get a complaint on them occasionally but none that I am aware of for turbines for the several years we have been flying.

Craig
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Old 07-10-2008, 07:51 PM
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Default RE: Noise issues at club field

I remember years back at my old club the OFs got heavy into noise testing when IMAC birds showed up. One day, I brought out my combat Pica Corsair (which they loved because it was a war bird) with a .21 of some sort that turned about 67 million RPM and screamed so loud that some of the deaf guys could hear it. On a lark we sound tested it and it blew an 86 at 9 foot. Yes...I said 9 foot.

Anyway...even thought it was the loudest thing most of them had ever heard it passed the sound test and I flew it to their cheers.

Hmmmmm....

Beave

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Old 07-10-2008, 07:52 PM
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Default RE: Noise issues at club field

Our club exempted turbines because their is virtually no noise when they fly.... unfortunately the field is too rough for jets, and surrounded by dry crops, so it is a moot point for that location..

Another loophole...dial down your max RPM to a couple of thou above idle, then run the test....after you pass and just before flying, crank the max rpm back up.......


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Old 07-10-2008, 08:18 PM
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Default RE: Noise issues at club field

My club did just the opposite of Craigs. We all have to meet 95 DB @ 9 feet no matter what kind of plane/ engine combination. We tested while guys were flying Giant Scale and jets; we could hear the planes but none of them tested over the theshold background noise at our property line. My guess is the OF's in the club got pissed off at the one jet gut other than myself and just set unreasonable limits for the jets. Until he showed up last year noone ever complained about my jet and we both have the same plane and engine, a Raction 54 /P-70 Funny thing is that the original complaint for noise was against the pilot of a 40% plane flying passed the home of the neighbor 1/2 mile from our runway who complained, and guess who still gets to fly at the field? Oh yea I forgot he was the club President at the time it happened.
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Old 07-10-2008, 08:19 PM
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Default RE: Noise issues at club field

[All I ask is for a chance to prove that money can't make me happy......]

Now I don't care who you are......That's funny!!!

Don
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Old 07-10-2008, 08:32 PM
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Default RE: Noise issues at club field

Thanks Don..... I'm still waiting for that chance!!

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Old 07-10-2008, 08:38 PM
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Default RE: Noise issues at club field

JetBoy:

Here is a very useful article about noise issues. In particular, take a look at the "Atmospheric Attenuation" section. This shows how various sound frequencies are attenuated by transmission through air and explains why high frequency noise is attenuated rapidly. That's why our jets sound so quiet when airborne!

http://www.nonoise.org/library/envnoise/index.htm

Hope it helps…

Dennis
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Old 07-10-2008, 10:58 PM
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Default RE: Noise issues at club field


Quote:
ORIGINAL: bevar

Ah yes...I remember flying at your field. I came out with an IMAC Extra and some old guy said my plane was too loud and had to pass a sound check of 99db. I said "OK...let's check it" and it made 97 no problem. He then said."Well...I just lowered the level to 96 so you can't fly. I then changed props, rechecked with the meter and it made 95db. He then said I had to make 94 so I put on a 3 blade and it made 94db.

After that, he asked what channel I was on and I told him "23 "which I was. I was then informed by him I could be expected to be shot down "because we have had some issues on your channel...actually on every channel you and your friends are on so you need to go home before you all loose your planes".

Yep...some of the more "mature" guys up there are some real winners.

Beave


I would have told that guy to go **** himself. What an ***
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Old 07-10-2008, 11:44 PM
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Default RE: Noise issues at club field


Quote:
ORIGINAL: bevar

Ah yes...I remember flying at your field. I came out with an IMAC Extra and some old guy said my plane was too loud and had to pass a sound check of 99db. I said "OK...let's check it" and it made 97 no problem. He then said."Well...I just lowered the level to 96 so you can't fly. I then changed props, rechecked with the meter and it made 95db. He then said I had to make 94 so I put on a 3 blade and it made 94db.

After that, he asked what channel I was on and I told him "23 "which I was. I was then informed by him I could be expected to be shot down "because we have had some issues on your channel...actually on every channel you and your friends are on so you need to go home before you all loose your planes".

Yep...some of the more "mature" guys up there are some real winners.

Beave


That's when you tell the old fart that you have many different prison shanks that you have in your flight box from when you were in jail for manslaughter at the tender age of 18 to 25... and have recently sharpened all the shanks.......

Gene
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Old 07-11-2008, 03:32 AM
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Default RE: Noise issues at club field


Quote:
ORIGINAL: DP01

JetBoy:

Here is a very useful article about noise issues. In particular, take a look at the "Atmospheric Attenuation" section. This shows how various sound frequencies are attenuated by transmission through air and explains why high frequency noise is attenuated rapidly. That's why our jets sound so quiet when airborne!

http://www.nonoise.org/library/envnoise/index.htm

Hope it helps…

Dennis
That's a really interesting link, Dennis! The company who wrote it, Brüel & Kjær, are well-known to us. A couple of their guys came across from Denmark to visit us several years ago, and bought a turboprop engine for use in their research. I know they are still using it - one of the guys phoned me a few months ago.

It's good to have something like that which explains why the jets sound quieter at a distance. We sometimes have customers who will be the first Jet owner at their field and they are concerned about the noise. It will be useful to give them a copy of the booklet.

Sara Parish
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Old 07-11-2008, 03:44 AM
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Default RE: Noise issues at club field

We had a 'ban the jets' attack from another committee member in our club all because he did not like the way committee decisions went against him.

It was the usual things, noise & the fire risk. I put together a document, which included noise testing & stats from the US JPA, & this was presented at a club meeting which made him look like a total idiot & made the attack on the jet flyers look like personal issues (which it was).

Send me a PM if you would like a copy of the document. - John.
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Old 07-11-2008, 06:28 AM
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Default RE: Noise issues at club field

Quote:
ORIGINAL: jetboy

Jet folks,
The wise menat our mostly jet friendly club field have started pointing their decibel meters at some of the member's planes again and grounding those louder than 99db.

My search of turbine noise issues here on RCU resulted in very little discussion of how the best way to deal with the AMA noise recommendations with turbine aircraft.

I am looking for suggestions as to how to diffuse the potentially catastrophic situation for the future of jets at our field! I am not sure that I can properly sell the concept of perceived noise to the grown ups that are still trying to figure out what makes airplanes fly.

I am certain that this issue has surfaced at many of the fields where jets are flown regularly. I am hoping that we create a solution before the noise police ban jets completely[&o]. We have a club noise limit of 99 db at 9 meters that has not been enforced much until recently. So far the noise nazis have not been patrolling when I have been burning jet A. It is only a matter of time.
Any advice would be greatly appreciated!

Jetboy

Let them measure the ISO way (europe)

lift aircraft 1 meter from the ground
Wind no more then 4 meters per second
stay at least 50 meters away from building to avoid reflections

measure 7 meters behind the exhaust DB meter 90 degrees oposite of thrust line.
Measure 7 meters pointing to the middle of the aircraft
Measure 7 meters in front of the aircraft again pointing 90 degrees oposite of nose

no count all values together devide by 3 and you have a honnest measurement.

i BET you wont get 99 DB.
and this is how it should be measured
PS: set measurement to slow , if you dont it will peak out at a high level insteade of a average peak
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Old 07-11-2008, 07:55 AM
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Default RE: Noise issues at club field

Ambient noise is measured in dbA and by idiot default it is also used for jet noise. Jet noise is meusured in dBC or even dBD.
What is A B C and D? Different freuquency response scales for differnt nois meusurements to compensate for noise perceived by HUMAN ear at different distance.
Look at a decent B&K sound pressure level meter and see the option for scales.
Biggest problem is to do measurement in open area. Almost impossible to do correctly. You better of with a jury deciding waht is too loud.
Anybody even know what dB SPL is?
Hint: log of 10micro Pascal
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Old 07-11-2008, 08:22 AM
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Default RE: Noise issues at club field

Jet Dudes,
Thanks for all the helpful replies! Dennis: Thanks, the booklet is a wealth of good information I think will be useful to at least postpone the OFs from shutting down turbine operations. The situation should take care of itself soon as the real problem is older than dirt.

Beave: I am sorry that you were treated as you described on your visit to our field but it does not surprise me.

John: Thanks, I look forward to your article.

Sandor: Have you ever used your method to measure one of your turbines? Any values?

I have an old Radio Shack DB meter. I was thinking of having it certified by calibrating it carefully using my Jetcat 120 at 120,000 rpm.

Having to do battle with the grownups takes a lot of the fun out of the hobby.

All suggestions still welcome.

Jetboy
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Old 07-11-2008, 08:29 AM
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Default RE: Noise issues at club field


Quote:
ORIGINAL: jetboy

Jet Dudes,
Thanks for all the helpful replies! Dennis: Thanks, the booklet is a wealth of good information I think will be useful to at least postpone the OFs from shutting down turbine operations. The situation should take care of itself soon as the real problem is older than dirt.

Beave: I am sorry that you were treated as you described on your visit to our field but it does not surprise me.

John: Thanks, I look forward to your article.

Sandor: Have you ever used your method to measure one of your turbines? Any values?

I have an old Radio Shack DB meter. I was thinking of having it certified by calibrating it carefully using my Jetcat 120 at 120,000 rpm.

Having to do battle with the grownups takes a lot of the fun out of the hobby.

All suggestions still welcome.

Jetboy

yes enclosed inside a fuselage
Wren SS / Flash 87DB
Simjet 3000 / L-39 89DB

Open (boomerang XL) Merlin 160 97DB

Merlin 160 Airworld L-39 91 DB

Turboprop pilatus porter 70DB (same levels as Electro)
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Old 07-11-2008, 08:31 AM
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Default RE: Noise issues at club field


Quote:
ORIGINAL: Moerig

Ambient noise is measured in dbA and by idiot default it is also used for jet noise. Jet noise is meusured in dBC or even dBD.
What is A B C and D? Different freuquency response scales for differnt nois meusurements to compensate for noise perceived by HUMAN ear at different distance.
Look at a decent B&K sound pressure level meter and see the option for scales.
Biggest problem is to do measurement in open area. Almost impossible to do correctly. You better of with a jury deciding waht is too loud.
Anybody even know what dB SPL is?
Hint: log of 10micro Pascal

yes and i bet in namibia they dont care to much eather?

overhere it is max 80DB for airplanes
funny when our "silent" diesel generator has a sticker on it 86DB.
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Old 07-11-2008, 09:41 AM
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Default RE: Noise issues at club field

One other thing that has worked well. Get involved in the club, join the BOD. Lobby everyone that you get along with at the club to vote with you and for you. Out of the 13 BOD members and officers at our club, half fly high performance aircraft (jets, giant scale acro, pattern) so we have a lot of influence. We also all get along better now.
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Old 07-11-2008, 10:35 AM
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Default RE: Noise issues at club field

We did a db test on my AD Mirage about 5yrs ago. We positioned a guy at the far side of the field and he gunned me several times flying by at a few hundred feet full power. It just about got in the 70`s for a reading.
V..
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Old 07-11-2008, 12:07 PM
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Default RE: Noise issues at club field

we also measured the noice at 700 meters

it was 40DB left

still people complain , i think not because of the noice.
but just because they dont like any kind of sport that they dont like...
so all in all if they want you out , they can..
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