[NSRCA-discussion] db Rules

[J N Hiller]

My local club went through a noise related closing back in the ballistic
pattern days. Reopening involved working with the county zoning commission
and reopening as a recreational airpark, or something like that, with
specified hours of operation and sound level restriction (100 DBa @ 3m). As
I remember there were references to sound level at the property line, yes
even in rural areas, which cover all type of activities with time if day
references. City and county sound limits may already exist and can be used
as a guideline or reference when negotiating with whomever.
Quiet fliers shouldn't be offensive beyond the immediate area but the
average 40+ size sport flier turning umpteen RPM's can be annoying even if
it's DB level is within limits.
In quieting the piped 60 I was running in the old AMA pattern I found the DB
level to be proportional to RPM's. Encourage / help the club members to run
larger props.
Jim Hiller


-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of Ron Van Putte
Sent: Wednesday, May 20, 2009 8:30 AM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] db Rules

That's highly unlikely.  Very few, if any, internal combustion
engines and even few electric-powered airplanes could meet a noise
standard of 78 dB at three meters.  The sound pressure level doubles
every six dB, so 78 dB is 1/8 the sound pressure level of 96 dB.
That's about the level of a mouse burp.

Ron

On May 20, 2009, at 10:20 AM, Duane Beck wrote:

> I hit send too quickly.   I meant to suggest that perhaps they're
> using the same distance.
>
>
> Duane
>
>
> ----- Original Message -----
> From: "Duane Beck" <duane.e.beck at comcast.net>
> To: "General pattern discussion" <nsrca-discussion at lists.nsrca.org>
> Sent: Wednesday, May 20, 2009 11:12:23 AM GMT -05:00 US/Canada Eastern
> Subject: Re: [NSRCA-discussion] db Rules
>
>
> p { margin: 0; }
> "...shall be 96 decibels measured at three (3) meters from the
> center line of the model..."
>
>
> ----- Original Message -----
> From: "Bob Kane" <getterflash at yahoo.com>
> To: "General pattern discussion" <nsrca-discussion at lists.nsrca.org>
> Sent: Wednesday, May 20, 2009 10:10:38 AM GMT -05:00 US/Canada Eastern
> Subject: Re: [NSRCA-discussion] db Rules
>
>
> <!-- DIV {margin:0px;} -->
> Do they have a distance parameter defined?  The dB number by itself
> is meaningless.
>
> Bob Kane
> getterflash at yahoo.com
>
>
> From: Scott Pavlock <f3aflyer7 at gmail.com>
> To: General pattern discussion <nsrca-discussion at lists.nsrca.org>
> Sent: Wednesday, May 20, 2009 8:19:03 AM
> Subject: Re: [NSRCA-discussion] db Rules
>
> Bob
>
> The club has set 78db as the standard for quiet flyers. Thanks for
> the info.
>
> Mike
>
> On Wed, May 20, 2009 at 7:09 AM, Bob Kane <getterflash at yahoo.com>
> wrote:
> From the AMA Competition Regulations for RC Aerobatics (I removed
> the text on motor type and scoring penalties)
>
> 4.2: Noise Limit. <snip> The maximum noise level for all classes
> shall be 96 decibels measured at three (3) meters from the center
> line of the model with the model standing on concrete or macadam,
> and 94 dB if an earth or short grass surface must be used All
> measurements will be taken perpendicular to the fuselage centerline
> on the right hand side of the model, with the nose of the model
> aircraft pointed into the wind, with motor running at full power;
> the microphone to be placed on a stand 30 centimeters above the
> ground and in line with the motor. No noise reflecting objects
> shall be nearer than three (3) meters to model or microphone. <snip>
>
> What actual dB number you use is up to the club. 94 dB would be too
> loud for a park flyer. You might want to measure an acceptable
> plane to see what the number is and use that as the standard. You
> could also measure a plane considered too loud and see what it
> measures. The tough thing is "loud" and "unpleasant" are not easily
> related.
>
> Bob Kane
> getterflash at yahoo.com
>
>
> From: Scott Pavlock <f3aflyer7 at gmail.com>
> To: NSRCA Discussion List <nsrca-discussion at lists.nsrca.org>
> Sent: Wednesday, May 20, 2009 7:28:05 AM
>
> Subject: [NSRCA-discussion] db Rules
>
> Our club has recently added more flying times for quiet flyers. But
> we need to have our planes db'ed before we can fly in these new
> very early hours.  Where can I find a set of guidelines on how a
> plane should be properly db'ed ?
>
> Regards
> Mike
>
>
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