Originally Posted by Wayne

With the current test that is not going to happen.

Seems pretty simple to me if planes that are deemed quiet in the air cant pass the test, the test is flawed and proves nothing.

Get rid of the test.

Exactly!!! The test that were posted a few pages ago is proof. Those same planes that wouldn't pass on the ground were quite in the air. Some that passed on the ground, were loud in the air. Go figure.

Rick

Rick, hope you didnt mind me posting what you had done as to testing.

Looks like IMAC is just getting better and better! Here is a little ironic fact. The day after the IMAC nats are over the Scale Nats start. You get bonus points for scale exhaust systems at that contest. Have you ever heard a DA 85 with scale P-51 manifolds?

I wonder how the folks in Europe are dealing with sound? They have some of the most densely populated countries in the world, with very little open space suitable for flying sites.

Below are the rules copied and pasted from FAIs F3M class. They are a lot tougher than anything IMAC has come up with. You will also notice they have a maximum weight of 20 KG. While I suspect many would not like a rule that includes a size or weight limit, [myself included] the day may be coming when it is needed for the SIG to survive.

5L.1.3.

General Characteristics of a large R/C Aerobatic Power Model Aircraft

Minimum overall span for monoplanes 2.1 m
Minimum overall span for biplanes............................. 1.8 m
Maximum flying weight without fuel............................ 20 kg

Paragraph B.3.1. of Section 4b (Builder of Model Aircraft) is not applicable to class F3M.
For Power device limitations, Noise rule, and Radio Equipment: See 5.1.2

The maximum noise level will be 94 dB(A) measured at 7 m from the centre line of the model
aircraft with the model aircraft placed on the ground over concrete or macadam at the flying site.
With the motor running at full power measurement will be taken 90 degrees to the flight path on the right hand side and downwind from the model aircraft. The microphone will be placed on a stand 30 cm above the ground in line with the motor. No noise reflecting objects shall be nearer than 7 m to the model aircraft or microphone. The noise measurement will be made prior to each flight. If a concrete or macadam surface is not available then the measurement may be taken over bare earth or very short grass in which case the maximum noise level will be 92 dB(A). In the event a model aircraft fails the noise test, no indication shall be given to the pilot, and/or his team, or the judges and both the transmitter and the model aircraft shall be impounded by the flight line official immediately following the flight. No modification or adjustment to the model aircraft shall be permitted (other than refuelling). The model aircraft shall be retested by a second noise steward using a second noise meter and in the event that the model aircraft fails the retest, the score for the preceding flight shall be zero. The flight time will be interrupted while the noise check at the flying site is being made. The competitor shall not be delayed more than 30 seconds for the noise check.

How many F3M contest did they have last year ? I would bet we had more contest in just the IMAC SE than they had all total. Not flying seems to be their answer to the problem.

Originally Posted by McFueler

How many F3M contest did they have last year ? I would bet we had more contest in just the IMAC SE than they had all total. Not flying seems to be their answer to the problem.

I do not know the answer to that question Mark, and I don't think you do either. I will attempt to find out.

Originally Posted by Dan_nO

Rick, hope you didnt mind me posting what you had done as to testing.

No problem. THat is why I posted. Pilots need to be informed.

<<I have only tested about 200 GS airplanes (SCAT/PRADO) and I dont see a problem getting under the limit set..>>

Gosh Gary, I ran SCAT for two years, and Bill ran it for three, and during that time I can't remember you ever testing 1, let alone 200 airplanes. And since I hosted the last scale aerobatics event at prado, and since there was only one event where planes were even tested there, and since I know for a fact that you weren't there as you didn't have an airplane or any contest responsibilities, I have no idea what the hell you are talking about. As for your previous comment about never knowing about any competitor who was sent packing - since you didn't fly IMAC (or even have an airplane), nor did either Bill or I ask you for your help, there would not have been much need for you to have attended. So excuse me if I don't place a lot of stock in your "extensive experience" regarding sound footprints of various engine muffler combinations.

folks, a 40% plane in europe is considered small....F3M competition does not represent the modeling community any more than IMAC represents it here.

What range did you do the test at 9 feet or 25 feet....grass surface or hard surface....

Originally Posted by Outlaw Pops

What range did you do the test at 9 feet or 25 feet....grass surface or hard surface....

The test we did were at 25ft. per IMAC rules. Over grass.

Rick

Thanks rick

Originally Posted by McFueler

How many F3M contest did they have last year ? I would bet we had more contest in just the IMAC SE than they had all total. Not flying seems to be their answer to the problem.

For the year 2010, here is the F3M calender JUST for France. I count 17 contests.

http://www.grossevoltige.com/calendr...-concours-2010

Please feel free to do your own reasearch, to include all of the other countries [Belgium, Germany, Italy, Spain and others] flying F3M in Europe. I'm certain it would add up to a substaincial amount of F3M contests using the sound criteria I copied and pasted in post 64.

I wonder how many of these contests could exist using IMAC rules? Furthermore, how many would tolerate ignoring the ground sound check, as IMAC has allowed to happen? Very few I suspect.

Question, in the rules for the bd being 96 and 98, who set those levels ? Was it AMA or IMAC

This is a partial repost from the IMAC website so it can be seen here also.

I was at the SC Regionals last year where Rick collected the table of data previously posted. I flew the plane that the table shows as the 2nd loudest by DB measurement on the ground.

"Advanced DA170 PIPES 29x12 6200 101"

The setup was a DA170 with RE3 pipes and Mejzlik 29x12N 3 blade and was measured using two separate meters showing 101 DB. No way could this plane qualify to fly at the NATS.

Two things of interest about this data are:

1) The plane has both pieces of equipment that a current RCP gives sound bonus points for (pipes & 3 blade prop). However, that setup failed the sound test miserably. Hmmmm????

2) Even though the plane failed the DB ground test I received six 10's and four 5's from the judges for in the air sound scores while flying sequences. Hmmmm????

What does this suggest???

It shows that throttle management and how you fly is what's key to sound for keeping things quiet. The fact that a plane is capable of exceeding outdated sound rules on the ground is irrelevant and doesn’t mean that it will be overly loud in the air!

BTW to my knowledge, AMA doesn’t require DB limits on sanctioned Fun Fly’s, Scale Bird Meets (super loud), Jet Fly’s, Pylon Races, general club flying, etc. so why is IMAC being singled out? If you are inclined to answer this question with PATTERN does this then just remember that IMAC doesn’t fly < 11 pound planes with glow/electric power systems. Not the same – they are apples & oranges.

Nobody seems to be fighting the concept of quiet flight. The resistance seems to be toward meaningless ground testing. IMAC does have a tool already in place to reward quiet flying through the judged sound score.

Is it perfect? No.

Does it need to be tweaked? Probably.

Is it better than a ground DB test? Absolutely.

Can it be effective at the NATS? Yes if used properly.

What does that mean? It means to not politically hide behind a ground test and have the judges grow some B^lls and hand out some zeros to excessively loud fliers even if they are big name pilots.

Holding pilots accountable for sound in the air will do more over time to keep things quiet than mandatory equipment rules or ground DB limits.