Roger:
Thanks for the opportunity to share ideas on sound control this morning.
In my capacity as the Western Region Flying Site Assistance Coordinator
for the AMA, I find that noise complaints are the single most prevalent
cause of field losses across the country. While the advent of high
quality electric propulsion units has resulted in new fields in
high-density residential areas, the continued use of larger and noisier
gas/glo aircraft has had the opposite effect. Fields that have been in
use for twenty or thirty years are being lost because we modelers either
can't or won't control the noise we generate at the field. The "We were
here first" defense doesn't work.
What does work in many cases is a proactive effort on the part of
chartered clubs to reduce the annoyance factor associated with gas/glo
aircraft. In my experience, an absolute limit of between 93 and 98dB
has provided a level of protection for our flyers. The closer a field
is to a potential objector, the lower should be the agreed-upon dB
limit.
In your case, I see some serious potential problems...like loss of the
field altogether...unless noise limits are imposed.
Your field is very near a hospital. The hospital is expanding in your
direction. That's a clue to the club that noise had better be a top
consideration as you plan for the future.
As I understand the situation, your field, due to its proximity to the
City of Hope Hospital, is in "Zone H" as it relates to local noise
limitations. What "Zone H" means is that there is no objective noise
limit. The very subjective standard to which your club will be held is
the "I think that's too loud" standard. Your situation begs for
vigorous, decisive action in implementing and enforcing an acceptable
noise limitation on models flown at your field. What's acceptable will
be judged by those who hear the models, but who are not modelers.
I urge you to approach your club's governing body with a reasonable
noise limit suggestion for your particular location. Creative
muffler/propeller combinations can reduce the noise from an offensive
engine. Electric is a possibility, even on very large aircraft. Once a
limit is in place, test every aircraft at the field for compliance. A
common measurement set up is done on a hard surface, with the dB meter
9'10" (3 meters) directly left of the engine as you face the aircraft,
with the prevailing wind coming from the right. The microphone on the
measuring device should be 10-12" above the ground.
These suggestions are based on my experience. My experience tells me
that if the club does nothing in the face of the current hospital
expansion, I'll probably get the "Gee, Wes, can you help us find a new
field?" call in the near future.
Good Luck!
Wes De Cou
AMA Flying Site Assistance Coordinator
Western Region