[NSRCA-discussion] Noise rules
Lance Van Nostrand
patterndude at comcast.net
Wed Jun 21 19:43:40 AKDT 2006
Well I'll just add that the amount of rain you've had has the most effect. 2-3 db over arable soil, 0 db reduction over the dried out concrete soil in Texas in the middle of a drought. You might get some amplification if you put your pipe over one of the bottomless cracks in the ground.
--Lance
----- Original Message -----
From: Gray E Fowler
To: NSRCA Mailing List
Sent: Tuesday, June 20, 2006 11:01 AM
Subject: Re: [NSRCA-discussion] Noise rules
Grass can kill 3 db....on a pattern plane where the exhaust exits down 2 inches above the turf. Not so much on higher exhaust sport planes.
Pattern planes are all about prop noise...especially on grass.
It is easier to pass NATS noise requirements on grass than hard surface even though there is a lower allowance for grass.
Gray Fowler
Senior Principal Chemical Engineer
Radome and Composites Engineering
Raytheon
"Michael Wickizer" <mwickizer at msn.com>
Sent by: nsrca-discussion-bounces at lists.nsrca.org
06/20/2006 10:37 AM Please respond to
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Subject Re: [NSRCA-discussion] Noise rules
Lance / Gray:
How does the 103 db at 10 feet over hard surface translate to a grass field
/ strip?
Thanks
Mike
>From: Gray E Fowler <gfowler at raytheon.com>
>Reply-To: NSRCA Mailing List <nsrca-discussion at lists.nsrca.org>
>To: NSRCA Mailing List <nsrca-discussion at lists.nsrca.org>
>Subject: Re: [NSRCA-discussion] Noise rules
>Date: Tue, 20 Jun 2006 08:20:26 -0500
>
>John
>
>To add to Lance's experience (he and I authored that specific noise rule)
>most of the loud boys start out having no idea how loud they really are.
>103dB is real easy to obtain , almost all of our planes are under 100. 3dB
>= 2X loud. The "A" weighting discards any sound below 500mhz. This is
>important as "bass" does not irritate but can easily place you over the
>limit. 1000 to 4000 is the most irritating to Mr Bob Complainer. This
>brings up problem #2 which is large supersonic prop tips. Guess what
>frequency they pop at??? right at 1000-2000 and now matter how quiet on
>the ground the plane is, a supersonic prop in a dive will not only piss
>off the neighbors but club members too. We dealt with this by limiting
>prop size...that is making the IMAC type planes go to 3 blades. You cannot
>believe the grief I got by putting this in place....a guy spends over
>$5000 on his plane and then bitches about having to buy a $150 prop. He
>ended up selling his whole rig...plane, 5th wheel to haul it and all. The
>prop issue is much more contrversial, and harder to regulate. Our rules
>state "no supersonic props" so if at the field and you hear it any club
>member can ask that person to stop flying. How to enforce that I do not
>know but luckily the rules alone got rid of all the problems...that is,
>nearly all those people quit, which was not the intention, but hey......we
>still have our field and only one psychotic lady to deal with-and the
>County/Judges on our side.
>
>We never have to check now. Like Lance mentioned if someone brings out a
>plane above 103dB you will know it immediately. By the way the IMAC planes
>4 years ago were 107-108 dB at 10 feet WITH supersonic props while flying.
> That is about 3.4 times louder than a pattern plane plus prop noise.
>
>A wise Vulcan once told me "The needs of the many outweigh the needs of
>the few", or something like that.....
>
>
>
>Gray Fowler
>Senior Principal Chemical Engineer
>Radome and Composites Engineering
>Raytheon
>
>
>
>"Lance Van Nostrand" <patterndude at comcast.net>
>Sent by: nsrca-discussion-bounces at lists.nsrca.org
>06/19/2006 10:30 PM
>Please respond to
>NSRCA Mailing List <nsrca-discussion at lists.nsrca.org>
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>Subject
>Re: [NSRCA-discussion] Noise rules
>
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>
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>
>
>John,
>I've been part of setting noise limit in 2 clubs. One because I was an
>officer and we put them in place just in time because when the complaint
>came in the town saw that we were being proactive. In the second, I got
>roped in because I had "experience". I've got the same sound meter that
>they use at nats. First rule is to get a great meter and spend the money.
> You don't want to make a rule that limits a persons flying if, when you
>go to enforce it, the defensive pilot points out the uncertainty of your
>equipment. McMaster Carr has a +- 1Db meter, which is as good as you can
>get. Its self calibrating too, which is important since it will probably
>be stored at your field in the cold and hot.
>
>Second: I 've measured tons of planes from close and far, upwind and down
>and talked to observers. You must not succumb to claims that you can
>measure from 25 feet (or more) and get reliable results. Way too many
>variables. Measer from 10 feet at a consistent location. use A
>weighting, slow response to average the results.
>
>Third: after doing this twice with different observers 103dB limit (10
>feet over hard surface) is reasonable. Thisis where both clubs ended up.
>It is a lenient threshold that few planes will exceed, but when they do
>you and everyone will know it. If the law still complains you can lower
>it, but no one will say you are being too restrictive with this. Even the
>loud boys will agree, but they'll probably violently oppose the concept of
>a noise rule.
>
>--Lance
>
>----- Original Message -----
>From: John Ferrell
>To: NSRCA Mailing List
>Sent: Monday, June 19, 2006 8:08 PM
>Subject: [NSRCA-discussion] Noise rules
>
>If someone out there has a set of noise rules for a general purpose RC
>club? Especially a set that works.
>
>I cannot expect the masses to conform to pattern numbers, but I need
>something to start with. "Reasonable" does not seem to mean the same thing
>to every one.
>
>
>John Ferrell W8CCW
>"My Competition is not my enemy"
>http://DixieNC.US
>
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