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Mufflers for gas planes.

Old 01-31-2006, 01:48 PM
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cstevec
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Default Mufflers for gas planes.

I have always tried to keep my big gas airplanes as quiet as possible (without going crazy) but alas, not all of my fellow flyers share my concerns about this. In this day & age it seems to me that engine manufacturers should be able to come up with a decent IN COWL muffler that wouldn't rob an engine of too much power, while at the same time keeping noise levels at a minimum. Some do a better job then others. I have a BME 100 with stock mufflers that runs very quiet compared to other engines I have. Then the flip side of the coin, my ZDZ engines are loud unless I use a header & in-fuselage can style muffler. The inverted Pitts mufflers I have bought for them are much louder then other engine mufflers of the same type.

This came up as an issue to me recently when I invited a friend out to fly at a private field I had been flying at for a number of years. At the end of the day the landowner approached me and said that that day alone he had gotten 3 different calls from neighbors about the noise. I knew my fiends plane was pretty loud but I didn't realize it was as loud as it was. The end result was I lost my favorite flying field do to no fault of my own.

I don't mind spending the money for cannister setups if they are needed but it some either can't or won't. It just seems to me the manufacturers could come up with a better solution without sticking it to us poor modelers. If they don't do something soon, the way land is filling up with houses, flying areas may become hard to find.
Old 01-31-2006, 07:02 PM
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Default RE: Mufflers for gas planes.

I couldn't agree with you more......I came across one individual who just so happens to live in this area that makes quiet mufflers for his 40%+. I'll try and get more information about his business....I do know he flys at Sun Valley field in the Phoenix AZ area.

Jerry
Old 01-31-2006, 07:04 PM
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Geistware
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Default RE: Mufflers for gas planes.

I hate loud planes. I also agree with what you are saying. I have seen/heard planes with cans fly loud. Always due to the propeller. My BME is quiet. My friend's DA is a lot louder. I don't know if it is the difference in propellers or just that the engines are louder, I don't know.
Old 01-31-2006, 11:48 PM
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the-plumber
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Default RE: Mufflers for gas planes.

AMA publishes a little gem called "Sound and Model Aeronautics". Pretty spiffy tome, contains a lot of good ideas and practical ways to reduce sound emissions from models, like mousse can mufflers, sound measurement techniques (and what the numbers really mean), prop noise, etc.

Every bit of three bucks, and a really good addition for a modeling library.

Looks in the Webstore Catalog, under Books.
Old 02-01-2006, 12:05 AM
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cstevec
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Default RE: Mufflers for gas planes.

I kinda think the AMA should take an interest in the noise issue. If they were to bring a little pressure to bear...... Mebbe the engine guys would take the initiative.

I know that there are lots of places in the country that the amount of noise a plane makes isn't really an issue. Thing is, I don't think they are the majority anymore. Fields that were 20-30 miles out of town 20 years ago are now having housing developments springing up in the same vicinity. My clubs field is out in the country but they just started surveying the field next to us. Doesn't matter that we don't fly over that area. As soon as houses start going up, someone is going to complain. As soon as someone complains enough, we will be looking for a new field. They may not have a legal leg to stand on but no one likes to deal with the hassle & sooner or later the landowner cries Uncle.
Old 02-01-2006, 11:19 AM
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Default RE: Mufflers for gas planes.

In all the years I've been wrecking carefully assembled piles of balsa, and of all the clubs in which I've ever held membership, I can only recall one club which was successful in fending off noise complaints from a neighbor.

As part of that 'battle', the club initiated a field log book, where members had to log in and out of the flying field. It was APITA to get the members to do that, but in the end it paid off handsomely when the neighbor made a complaint on a day where no one had been at the field.

Even so, the club opted to move to another parcel of county land when it became available, to be even farther from any homes.

Now, there is a new starter mansion subdivision being built adjacent to the field, and noise complaints are becoming a weekly thing.

Indeed, we in AMA need to do a better job of convincing manufacturers and modelers to put the hush on loud engines.
Old 02-01-2006, 01:24 PM
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Default RE: Mufflers for gas planes.

Indeed, we in AMA need to do a better job of convincing manufacturers and modelers to put the hush on loud engines.
Well stated, Fred. If more people put the emphahsis on the "We in AMA..." this and a lot of other issues would go away.

Unfortunately, I can't completely agree with cstevec's statement
The end result was I lost my favorite flying field do to no fault of my own.
, since it was preceded by the statement
I knew my fiends plane was pretty loud...
.Perhaps he would still have the field to use if he had told his friend - who was there as a guest of his and he in turn was a guest at the owner's field - to bring the plane down (or not allow it to takeoff) because it was too loud. Personal responsibility is what we need more of for noise, safety, etc.
Old 02-01-2006, 03:14 PM
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Jim Messer
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Default RE: Mufflers for gas planes.

I have been flying a G-62 in a 1/3 scale J-4E Piper Cub for over ten years now with a stock muffler, and it is the quietest airplane you ever heard. If even one glo engine airplane is in the air at the same time, you can't even hear the sound from the G-62.

So - what is different? It's quite simple, and I have used the same set-up on other planes where the muffler system can be enclosed in the cowl.

I exhaust the gas from the standard muffler, through the slots, into a 1 1/2 dia. aluminum tube exhaust manifold, directed toward the firewall, with a sharp 90 Degree bend to the bottom of the airplane. The manifold is fitted to the muffler, by cutting away a part of the round cross-section, and that also extends to the front of the muffler so that propeller air is forced into the tube, the same as you would do to cool an engine. The outside air being rammed into the exhaust pipe, mixes with and cools the exhaust gases emitted from the engine, which decreases the gas volume, as well as the noise.

It's hard to explain, and I don't want to take the cowl off as I write, so is you don't understand what I am saying, I'll do a photo shoot when I can. I swing a 23 x 10 Mejlyck prop on this airplane.
Old 02-01-2006, 06:19 PM
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cstevec
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Default RE: Mufflers for gas planes.

You know what? You are right, I don't blame anyone but myself for losing the right to fly on that field. I knew the engine he had was pretty loud & I did nothing about it. I had mentioned to him on more then one occasion that he really needed to put a better exhaust system on it but hadn't had any effect. Then I turned around and invited him out to fly with me anyway, knowing what he would be flying. Sometimes your desire to do a guy a favor (or just to be a nice guy) overshadows your common sense. My friend was intimidated flying his 1/3 scale plane at our clubs field & frequently asked me if he could fly with me. I didn't have to say yes, and on reflection, probably shouldn't have.

Now that I have (hopefully) accepted enough responsibility for losing my flying field, maybe we can get back to the point of this post & come up with a way to get this fine organization of ours to invest a little more interest in helping our engine suppliers/manufacturers (and fellow modelers) to address this issue before fields everywhere start to dissapear.
Old 02-01-2006, 07:51 PM
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Default RE: Mufflers for gas planes.

Now that I have (hopefully) accepted enough responsibility for losing my flying field, maybe we can get back to the point of this post & come up with a way to get this fine organization of ours to invest a little more interest in helping our engine suppliers/manufacturers (and fellow modelers) to address this issue before fields everywhere start to dissapear.
While I firmly believe local noise control is up to the local club / group, and that my plate is far beyond full for any more Big Brother 'assistance', I will offer one place to start.

AMA leadership is, as I read the evidence, only really interested into developing the insurance and publication consortiums into major business arrangements to offer preferred options to a select few people.
Therefore the membership needs to clean house, using the ballot box. AMA leaders need to be interested in national promotion of the sport of model aviation, along with flying site acquisition and retention. You have a couple items about to hit you from AMA that are the epitome of knee-jerk reaction. The EC just this past weekend met again!!

As a hint, I expect air-conditioning in _ell before the membership exercises its responsibility.

You might get into the self-help mode if you want to keep your flying site/s. There are many good mufflers out there especially with some minor tinkering even less than Jim's proposal.
Old 02-02-2006, 06:08 AM
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Default RE: Mufflers for gas planes.

cstevec - I appreciate your words and sentiment. I wasn't trying to beat you up, just suggesting (as I stated earlier in the post) that we in AMA need to take an active role in what AMA is doing and considering doing. Perhaps a good place to start in trying to get AMA to consider getting more involved in noise issues is through the 'Flying site assistance' folks.

Flying site continuance and acquisition is one of the largest areas of concern, and perhaps you and they could draft some rules that would help the overall membership. After all, I doubt that the Pattern flyers were happy when noise restrictions were first imposed on them, but they lived with it and now it's simply accepted as a way of life for them in competition.
Old 02-02-2006, 07:30 PM
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Default RE: Mufflers for gas planes.

At some built up areas, the sight of a plane flying in the air causes fear. That translats in noise complaints and flyover property complaints.

RC boats of 8' long and weighing 80# are Cute. I have 1 and if I ask the parent if the kid would like to run it, they love me.

It is a attack from the sky thing, that strikes fear in some people.

I have NO idea how to get around that. [&o]
Old 02-03-2006, 01:29 PM
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Default RE: Mufflers for gas planes.

People are overly sensitive! I live a mile away from one of the clubs I belong to and you can barely hear the planes flying. In general, most people can't stand to see other people having fun! That is probably the root of most noise complaints. There is noting like a 40% screaming down the center of the runway. I love the sound of prop tips going supersonic! FYI- There is a skeet and trap club right next door to our flying field and you can hear them load and clear everyday. People complaining about model airplane noise haven't heard anything untill they've been woken up at 7:00am on a Sunday by a 21 shotgun salute!

Pull!
Old 02-04-2006, 07:32 PM
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Default RE: Mufflers for gas planes.

Some people just love to complain. Big money/popularity will put a stop to the complaints but that will never happen. Ive raced quads before and they now noise test that stuff even though most tracks are in the middle of bfe with probably most of the neighbors owning quads or dirtbikes themselves. Have you ever heard of nascar thinking about keeping things quiet? You never will either because its popular. How about a football game? I dont think anybody has ever had a stadium shut down because the noise bothered them. Model Airplanes? Yes people complain because its a hobby that is percieved to be geeks and small potatoes. Not to many people will get laughed at for complaining about rc. About the fear from the sky statement, I believe that to be true and the bigger it is the more fear even if the noise is the same as a 40 sized trainer, especially those with bad or loose mufflers. If only we would stand up for ourselves instead of rolling over so easily. I do agree though that the price of quiet systems for large gas engines is a little much, all the hobby stuff is really. I would think that the quiet systems would be easier to manufacture than the regular mufflers and even thought there might be a little more material that wouldnt outweigh the fact that its cheaper to make. I could go buy a titanium muffler for my quad for the price of a quiet syustem for my plane.
Old 02-05-2006, 09:59 AM
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Default RE: Mufflers for gas planes.

This comes down to two areas where the AMA should be exerting its influence and has completely failed to do so. One is with the engine manufacturers. People buy an engine, it has a muffler, so they assume that the noise level is "permissable". Same goes for an after-market muffler (OK, so it's a LITTLE louder, it should be OK). In fact, there is NO "permissable" noise level set except by local regulation. There should be at least an INDUSTRY standard set, or the AMA should set its own standard and recommend (or not) manufacturers who fall within the standard.

The other area is fighting the perception that model airplanes are excessively noisy. This one would require a large effort. The fact is that today's muffled engines make no more noise than a weed wacker, leaf blower, dirt bike, or anything else with an IC engine used by the general public. However, there is a public perception that they make at least twice the level of the aforementioned items if not more. How do you fight this? Public information campaigns, club open houses and things like that are a good start, but the AMA needs to be in the forefront of the effort. People listen to a Nationally recognized, official sounding organization a lot more readily than a local club.

So far, I'm sorry to say, I have seen little effort from the AMA on either front. They seem more concerned with selling me a credit card I don't need or sending me videos I didn't order and then expecting me to pay for them.

papermache
Old 02-05-2006, 10:38 AM
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Default RE: Mufflers for gas planes.

Acouple of negatives. A plane in the air 150' up sends ALL the noise over a broad area. There are no bushes or grass or etc. to absorb the noise.

As long as planes fly in the air , they will ALWAYS be 4 X as noisey by 1,000 people.

Could mufflers be built into the plane so you would not hear them??

OF COURSE!!!!!!!!!!!!!!

Bussiness people are the cheapest, lazyest, "I am not losing my site to noise" , people in the world. They have not and do not give a crap about anything but profit.
Old 03-05-2006, 12:38 PM
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Default RE: Mufflers for gas planes.

I have a welding service just for the modeler. Certified in TIG 28yrs exp in All types of metal and custom fab work. This means I can put that broken 'ear' on the alum case for the exh ,carb or motor mount back on to save a crashed motor. If you have a 'muffler can' from a different style motor that is Quiet I can weld the head stack from the motor you want to use. This might be an easy fix for some. Welds are guaranteed not to crack! Scott Dinger [email protected]
Old 03-05-2006, 08:19 PM
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cstevec
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Default RE: Mufflers for gas planes.

I flew my Aeroworks Katana (29%) today at the flying field with a group of guys. Since noise has become such an issue at the club, I decided to take along the db meter. Using the AMA contest guidelines, & with a dozen witnesses, we checked out some planes. Mine was 85 db. YS 110 with stock muffler, 94db. Little 25 cc gasser, 93 db. ( We checked that one the other day with a different prop at 93.5 db. It does make a difference.) I checked a 2 stroke glow plane from about 20 ft/ away while he was running it up 87 db. Based on what I saw today ( & prior experience) that one would have been the loudest of the bunch had it been tested the same way.

My engine? A ZDZ 60cc gasser. I put it on a tuned cannister & tried one of the new ZN line props from RC Showcase. How loud was it? 86 db. You really can make 'em quiet, just need to use your head.

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