What are the dB levels for 2003 in IMAC? I thought they were lower than last year.
Thanks
Craig

Ground tests don't mean much for Imac.
You can adjust your throttle travel to get under the db maximum.
That's perfectly legal.
The only thing that counts is the opinion of the judges listening while you are flying.

Working to make your plane quiet for the ground test is a waste of time. If you do a stack ranking of planes for noise with a ground measurement, you will find that the ranking is not the same in the air. Planes that are quiet on the ground can be loud in the air if the prop rips.

Same as last year. No change.

how do you test the DB?

I don't have any equipment for it or anything, and does it apply to all levels of IMAC

http://www.mini-iac.com/pages/SoundT...gSchematic.pdf

Here's a link showing you how it's done at the contests using a digital sound meter which is purchased through radio shack. (about $60)

Yes all contestants planes are required to go through the process. Like Diablo said above, overall it doesn't have a whole lot of meaning. Meters aren't really that accurate, same setup can read different from day to day depending on temp, wind, humidity, etc, etc. This was implemented because the ama required a solid number.

What you really need to do is aquire a setup that will be quiet in the air. IE, no ripping props, a quiet muffler system (most are now using cans). Your smaller engines, say 100cc and under may not require any special setup at all. You can also control it with your left hand, get out of the throttle when you don't need it. Your in flight air score will be your biggest factor.

I don't know if I'd come to that conclusion as gospel. It's gonna depend on how the judges perceive your plane in the air. I'd say if your prop rips on an upline, your under propped. If everyone else is running cans and 3 blades, and your running standard mufflers and a 2 blade and assuming you don't rip the prop at all, you could still receive an ok sound score, which won't get you grounded, while everyone one else could get a quiet score, which will be a penalty to you because of the way the sound score is weighted.

It's all gonna depend on what your comfortable with, what the judges bias is towards it (this is a subjective score), how sensitive the field is you'll be flying at, etc.

Practically all of us that compete regularly are doing everything we can to get our planes as quiet as the current technology will allow us in our region. You should attend a contest in your region, ask questions, and get opinions from the guys you'll be flying with. They'll be glad to talk to you about it.

Go here >>> http://www.mini-iac.com/pages/SoundTaskForce/stf.asp for information on IMAC sound rules, how they are tested, and other great info.

Thanks for all the info. All is good as long as the prop doesn't rip.
Do they count against if you are on an upline and the prop rips?

Thanks