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