TexasAirBoss

My Feedback: (22)

I have an OS Max 61 with a Slimline muffler that is very loud. The muffler offers such little back pressure that I must use a Perry pump on the model. I was under the impression the rule states that my engine must have a muffler. But one member at our club has informed me that my engine is in violation of the sound rules. Our club has no specific sound rule. SO I am assuming that they must mean there is an AMA sound level rule. I do remember a 90db rule years ago, but I cannont find it now. Is there an AMA sound level rule at present other than the requirement to have a muffler?

Silent-AV8R

The AMA does not have any sound rules that affect general sport flying. A muffler is suggested but there are no requirements or rules. For competition both pattern and IMAC have sound rules, but those only affect actual competition. The membership manual has some suggestions and guidelines, but again, those are not actual rules and carry no requirement to be followed.

KidEpoxy

last I checked,
Silent is correct on all that stuff he just typed.

TexasAirBoss

My Feedback: (22)

Actually I just found the club's rule. If the effectiveness of the muffler is in question then the executive committee will decide if the muffler is legal. The model is 7 years old and for seven years it has been legal. I wonder if the committee ruled against my muffler but forgot to tell me.

KidEpoxy

Be sure to run just 5% nitro the day they db your engine .
Maybe add a couple inches of tubing as an Anti-Stinger,
or toss a big-bore section of Sillycone into the canister itself

Hossfly

Yes, PF the club rule so states:
"9. All reciprocating engines of .10 cubic inches piston displacement, or larger, will be
equipped with an effective muffling device. In those cases where the muffler's
effectiveness is in question, the Executive Committee will make a decision on an
individual basis."

Been that way for almost 15 years now. It has only been enforced once that I know of if any metal object hangs on the exhaust.

Now we have for 5 years been subject to a clique that somehow has a notion that their dozen or so own the facility and the other 90 or so are there just to pay the mortgage. Those runway blockers don't pay any attention to the rules stated on the flight stations so don't worry about it!

For all, these pictures are old and may contain some reworked words, however the messages are clear. They all have been replaced, but since the "elite" can't follow simple instructions, I no longer take pictures.

Of course PF you have an option to get this facility returned to the Jump-Starting Proud Club it once was. You know what is needed.

Don't know what happened to these images. Never happened before.

<<Moderator Edit:Post edited to fix a problem with image thumbnails appearing too large>>

TexasAirBoss

My Feedback: (22)

Gee Grandma ! What big pictures you have !

I'm not crazy about the "no low passes" rule. Especially with the pilot stations 30 feet from the runway and the runway being 50 feet wide. That is 80 feet in front of us that we can't do passes. That seems excessive. We should be allowed to make passes east of the centerline. That would still be 55 feet from the pilot stations. I'm not certain that I understand the concern with low passes.

And I think most people abide by the rules of the club. I haven't seen anyone intentionally breaking them. You were too cryptic for me to follow you.

Silent-AV8R

Club rules are an all together different thing. They can set any limits they choose to.

DavidAgar

My Feedback: (108)

Our club has a sound rule of 92 DB at 9 ft. I believe that this equation was at one time an AMA recommendation and our club adapted it in our rules and lease. We have discovered that most engines that run with the stock muffler will pass however most motor's with after market mufflers will not without some modifications. Good Luck, Dave

K-Bob

My Feedback: (1)

A ripping prop will get you every time.

tinner1

PilotFighter,
I have a Webra Speed 60 with an older "flow through style muffler, and it too didn't supply pressure to supply a Dynamix carb. I solved the problem by first plugging the open front end with an old 35mm film canister top, and then sawed notches and "pinched" in the reart cone to restrict the exhaust opening. Together they increased the muffler pressure enough to run a Webra Dynamix carb on the engine with no pump. Hope these ideas help.

If your club doesn't have specific rules governing noise levels I suggest you do what our club members all do, and it involves something as simple as common sense. If it sounds too loud it probably is. Your fields neighbors are the ones you really want to shield from noise, because they are the ones who will take action to shut your club down if the noise gets to be a problem. Sometimes an engine isn't the most noise either. I run a Webra Speed 60 with a muffled tuned pipe on my Dirty Birdy, and trust me the "prop" makes the most noise! Good luck with your finding a solution, and PM me if you need more on how I modified my muffler.

bkdavy

My Feedback: (1)

The only reference to a sound rule in the AMA is in the criteria for a Leader Club application, where one of the optional criteria is that the club has a sound rule, and then adds an example of "such as 90 db at 9 feet.

IMAC is changing their sound rule this year to eliminate any reference to a ground level sound check (formerly 96db at 25 feet). Nobody was doing the checks anyway. They are keeping the subjective inflight sound score, but giving the judges more latitude by allowing the judges to assign a 0-10 score, rather than just 0, 5, or 10. They are also increasing the K value of the sound score.

Brad

littlecrankshaf

My Feedback: (58)

The right answer!

KidEpoxy

"too loud" is unfortunately a very subjective term:
Neither the kid with the 2500w car stereo
nor Gun Nut Steve just back from an afternoon with his 41Blackhawk,
neither of them will consider a plane "too loud" when many others would.

Add in to that how some clubs have houses 20' past their no-fly line,
and other clubs are a half hour drive into BLM wastelands,
"too loud" becomes very much relative to the environment.

I recall a guy trying to get a club shut down claiming some neaby houses said it was too loud. What he failed to pint out was the cement factory/depot with gravel and cemet trucks between the club and the houses... 'too loud' in that case is trying to be so loud you can be heard over the deafening cement depot & trucks




If a city council wants to say a weedeater engine is too loud,
just what are thinking the "good" citizens eat weeds with?[8D]

TexasAirBoss

My Feedback: (22)

A friend of mine has the same airplane, same engine, and same muffler. But his muffler has brass tubes which have been JB Welded in the bottom of the Slimline muffler and act like flow restricters. He has adequate back pressure and his engine is much quieter. So I am going to modify my muffler to be like his. It is a much simpler system and requires no pump. I like that.

cj_rumley

Yes, it is very subjective. That is why the standards orgs (ANSI, ISO) have developed objective (can be physically measured) levels for sound that have been shown in exhaustive field studies to correlate well with subjective responses of humans - annoyance, interference with reading and speech comprehension, sleep, etc. HUD and many state agencies have model ordinances based in these objective standards that are recommended to local (city, county) political subdivisions, which have the final authority on what levels will be allowed, when and where. Some local public entities go it alone and cling to subjective descriptors in the ordinances that are not conducive to fair and consistent enforcement, but most do have objective levels specified in the codes and ordinances.
AMA is not a controlling authority, and cannot anticipate the actions of local entities that do have the authority. They tried early on (the 90 dBA @ 9 Foot rule), but it was based on rules applicable to specific communities and countries (ex. GB has national standards) and could not sensibly be generalized for all locales. Further, all model flying venues are not created equal, particularly as to distance from noise sensitive sites (residences, schools, hospitals...). A decision was made by the AMA Sound Committee circa 2000 to drop the fixed level that had been recommended and instead advise clubs/members to look up the applicable local noise codes/ordinances and do what it takes to comply with them.
Some AMA competition rules do specify sound level limits, as has been noted. The rationale is very sensible if you think about it. Lower permitted levels means more venues available to hold events, and importantly, practice for them. Look at pylon racing for an example of a class that does not (probably can not) have sound level limits. Few model flying venues can accommodate them due to noise levels generated. Ever notice in MA articles reporting on them that the class is perpetually dominated by just a few guys from Nevada?

tinner1

Since to some posters, facts fall on "deaf ears" I guess "too loud" would be "subjective". To use todays youth as a baseline for noise control is absolutely rediculous, unless you happen to be a youth. BUT to most people with some minute amount of common sense too loud is easily determined. If it offends anyone, especially a neighbor, it is too loud, and as I said earlier in my post...

KidEpoxy

Cletus
Since you and I both hit on the point
that the surroundings and location of you club set the standard as to what is 'too loud',
(by either good manners or legislative action)...
AND your referral to AMA being in no position to set the standard...

... we could say that 'too loud' is not up to the AMA at all.

What is 'too loud' for one place and set of folks
could very well be acceptable in other places and peoples

Such as flying in the CA desert BLM land,
if the planes seem loud start shooting shotguns at the club
to place the engine/prop noise in scale as to what is allowed out there
(havent seen an AMA rule against shooting guns on chartered club property as a non-aeromodeling activity)

I still recall the old folks in Fla that complained about the noise from a flying club
.... a SOARING flying club [:@]
Subjective terms at their best: Granny says them gliders are too loud

cj_rumley

KE,
It truly isn't up to AMA (except as noted previously, to promote widest participation in some competition events). Examples are as close to me as two club sites I fly at. One is in a quiet (average ambient level is abt 40 dBA) semi-rural neighborhood, and the club standard of 90 dBA @ ft by coincidence with the former AMA recommendation is needed to keep received levels at nearest residences below the daytime ordinance limit of 55 dBA with some margin, after accounting for spreading losses. The other club site property (within 10 miles of the first one) is adjoined by a freeway, and ambient level at the nearest residences is typically 65-70 dBA. Although located within the same county and zoning is such that the same limit on sound level applies, the ordinance is in effect trumped by the the ambient sound level - a cop with a sound meter simply couldn't measure the contribution of the model engines if it is below ambient. An additional allowance of 10-15 dB at site #2 is very large, the difference between power to the prop delivered by decent .45 (7.5 cc) two-stroke and that of a 50 - 80 cc gasser.

Tinner,

Re: "If it offends anyone, especially a neighbor, it is too loud, and as I said earlier in my post... ," that's a really bad situation to be in because when it is true, your model flying freedom is at the mercy of the most sensitive crabapple within earshot. People's tolerance for noise generated by the activities of others varies widely. The folks that set noise abatement standards know that and accordingly recommend levels that are acceptable to most people most of the the time, fully realizing that not everyone will be satisfied and for a small fringe element, no perceptible sound level would be low enough. Objective ordinances offer some protection for those of us that make the effort to find out what levels they allow, and abide by them.