Hi guys<o></o>
Our club is in a country town of 15,000 people and we are walking distance to the town centre. We are surrounded by houses where our downwind leg is halfway between the flight line and the nearest house. You can actually walk down the main street and occasionally spot our aircraft in the distance.
We had a round of internal stirrings about 2 years ago and what I found when we tested was that turbines would produce a greater sound pressure on a dB meter than your average 50cc gasser, however, as mentioned by Dave this is not a true representation.<o></o>
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The doomsday crew cried that we would lose our field because of the noise and that the neighbours would complain to the EPA (Environmental Protection Authority) so I started to take measurements at different locations around the field. This is the same style of test the EPA would conduct as a Decibel Meter is the only true way to measure Sound.<o></o>
What I found was that the sound pressure produced by our aircraft – prop or turbine only made a small amount of difference on the meter above ambient at the boundary of our field and by the time you got near the houses the variations in the normal background noise was far greater than that produced by any of the aircraft.<o></o>
This being the case, the EPA (who have measured us) agrees that there is no real case for a “noise” complaint, however we/you can still be tagged as a nuisance much like the guy mowing the lawn next to you twice a day and pressure from the local council (government) can push you out.<o></o>
To help tackle this we put on a public display twice a year with free entry (but make a very good income from food sales) to get the locals involved which seems to work very well.<o></o>
In your case Jan, I would go to a Dick Smith store a buy a basic dB meter and start looking at just how much noise can be measured near those that could complain.<o></o>