What is if any the noise level at club air fields? We cant seem to agree on what ama says about db levels

wolfpenny-

Maybe the reason you can't agree is because you're looking to the wrong authority for guidance. AMA's latest position is in a nutshell, comply with the standards of the community you are operating in. AMA is not the controlling authority for matters of noise abatement, your local community government is. In the US, the allowable levels are usually set by ordinance at the city or county level. You need to look into those local ordinances as a first step. The allowed levels are normally specified at the receptor's location, usually at the property line. As the received noise level diminishes predictably with distance between source and receptor, there is no one-size-fits-all number for allowable source level, which is what we measure and and have some control over.
AMA, while the sound committee chairman was Howard Crispin, recommended a limit on source level of 90 dBA measured at a distance of 9 feet from the source. This was copied from BMFA and DoE standards in the UK, and is based on a nominal distance of about 1/4 mile separating the source from the neighbor, which is in line with with a reasonable separation for safety reasons. It is important to bear in mind that nominal distance that was presumed, though it was rarely stated, to make sensible decisions as to whether it is applicable to you flying site. If your closest neighbor is 1/2 mile away for example, it would be overly conservative. The doubling of separation distance would allow operation at 96 dB source level while keeping the received level the same as for a 90 dB source at 1/4 mile. You don't want to be overly conservative, as that puts a limit on on the size of powerplants your models can use. The limiting factor will be the power absorbed by the prop (assuming effective mufflers are used), and that is directly proportionate to the sound level generated. To meet the 90 dB at 9 feet rule, you will be limited to IC power in the range of .40-.50 cubic inch displacement for 2-strokes, a little larger for 4-strokes. If that's what you have to do to comply with local ordinances, then of course do it or risk losing yor field. If the separation distance from the nearest potential complainant is significantly greater, then the 90 dB limit would be overly restrictive and unnecessarily ban larger engines - in which case the complaints will come from within your club.

Abel

As AP said, AMA doesn't tell you the general field rules. That's the host club's business.

AMA Contest Boards can require certain parameters if you fly competition under AMA rules.

For Example;

Pattern and Scale aerobatics:

PATTERN:•

4.2. Noise limit. Each reciprocating or rotary
piston internal combustion engine shall be equipped
with an effective silencer. 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 downwind side
of the model with the 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. A score penalty of
five (5) percent of the raw flight score shall be
assessed for those models registering over 96 dB, and
a 10 percent penalty for those registering over 98 dB.
The Contest Director shall have the option of deleting
the noise level requirement at any sanctioned
event.


5. Scale Aerobatic Sound Limits.

5.1. Maximum Sound
Levels. The maximum ground
sound level for all classes shall be:
96dBA measured on soft surfaces
and 98dBA measured on hard surfaces.
Contest Directors may implement
a correction factor due to
unusual conditions.

As you can see, the CD is given considerable latitude to do as local conditions require.

If you are anywhere close to houses there will be "Noise Problems". When I was a DVP in D-6 there was a Soaring Club down in NE Indiana that always had troubles with some neighbors adjoining the sod-farm where they flew. YEP it was NOISE. You can't win! Just do as well as you can and be ready to negotiate.

I seem to remember a "90 at 9" reccy by AMA. IOW it was 90 dBA at 3 meters, or ~9 feet. We had that rule here when we were in the city. Now we don't have a noise rule.

CR