Noise regulations

[hillmanr2]

Our field is in jeopardy due to noise. We have a housing development heading towards us. Construction noise will hide us for this season but after that............
We are looking to actively control our noise this year to DB or less from M (20 ft). Do any of you fly at a site with a noise restriction lower than this level?

What are some good ideas to lower engine noise besides reproping to the point of poor engine performance?

Do any of you have a gasser with a low db rating? If so what did you do?
I Need some help. Any advice would be greatly appreciated.
PS: yes I know we could switch to electric
Thanks guys

[Biff]

Guys,we have strict and I do mean strict noise limits to fly at Triple Tree. Our big gassers have cans and 3 blade props. Getting the noise down to wisper quiet is easy!! You will see a touch of difference in performance but nothing bad. It's all bolt on stuff,,no voodoo magic. Da 150 on cans with a good 3 blade is quieter than most glow engines. Stay out of the throttle on horizontal lines and you're good to go. Trust me,,all this stuff has been well tested and is far easier than you might think. The smaller glow engines are the tough ones to get quiet.

[hillmanr2]

Any idea of the DB rating Biff? It would be greatly appreciated.

[3Dkid330]

I agree with Biff, I've flown a SX with a 3W 150 QS on Cans and a two blade, and it was by far quieter than any airplane with std. muffs. If it had a 3 blade, it would have been quieter than a large glow engine in the air.

Sorry to hear about the noise restrictions being imposed though.

[hillmanr2]

	Quote: Originally Posted by 3Dkid330
	Sorry to hear about the noise restrictions being imposed though.

Thanks. Unfortunately I'm one of the guys who has to impose it . We will however waive the rule for events. Like the IMAC comp

[toddblose]

At 20 feet my Kroma 180 is at 98db.
The motor has the 3w LLL cans and I am running the 32 x 10
Vess prop. Great performance

[Biff]

I think 96 is the best I've done on grass at 25 feet. Static testing means NOTHING! Some of the quiet ones get noisy in the air. Keeping the prop tips sub-sonic is the most important thing. Any set up will make big noise when the prop goes super sonic. This truly is some what subjective. Usually when you get to the point where something HAS to be done,catching up is tough. This thread is a call to everyone. At some point noise restrictions will be on the table at a club meeting. Noise diverter mufflers simply have a limited amount of time left. Police ourselves or others will!!

[red_z06]

For your reference:

DA50 with slimline pitts running 22x8 prop produce 103db at 9'
BME-110 with stock mufflers running bme 27x10 prop produce 108db at 9'

Tested with 2 uncalibrated radio shack db meter so actual maybe off a little.

[Michael]

On my local field ova the wet stuff we are regulated down to 82Db for our models, I`m please that this only applies as we as close to "noise sensitive" areas, this does however resistict the size models we can fly from this field. One big problem with the noise measurements is the frequency of the noise produced. After all would you rather hear a big gasser with a lower frequency or a small engine on a high frequency, nine times out of ten the big gasser would be considered quieter although the actual noise produced by the gasser is greater!

[Boulder]

Our field has the 98db @ 3 meters rule at all times. It isn't hard to meet that with cans and 3 blade props, like Biff said, it's a lot harder to meet those regs. with a large glow motor on a pitts.

[hillmanr2]

Okay, So high freqency is obviosly more anoying and sounds louder than low freq. Does high freq. noise travel farther?
I'm trying to come up with a fair test. If I took a db meter to the location of the closest lot to our field, which is up a hill and back a ways, and measured a small whiny 2 stroke as compared to a da-50 with a can muffler, and both had the same static noise ratings at 6m what would I find?