Engine silencer
 

I have many engines I want to break in. Im in an apartment complex with detached garages so I have a spot to run them. My dilemma: how do I quite the engines down while running them so I dont get evicted from noise?

Ive seen photos of radiator hose attached to the muffler into a large metal can. Would that work?

Thanks!

RE: Engine silencer
 

Yes

RE: Engine silencer
 

It will also help collect the unburnt oil which can be messy when running on a test bed.

RE: Engine silencer
 

You can quiet the exhaust noise quite effectively, but you will still be making plenty of noise from the prop by itself! Hopefully your neighbors won't complain about that.

I experimented using an extension hose and catch bottle to contain the oil from the exhaust. The smoke was still there, but I did capture a lot of oil! Watch this video:

[youtube]http://www.youtube.com/watch?v=sEqXVix94Wc[/youtube]

RE: Engine silencer
 

That video helps, but I think it would still be too loud. Noise makers seem to get kicked out very quickly in my complex. I could run it in the garage with the door down to block the noise. How would I go about getting the exhaust out? Im thinking run a tube to a can on the floor to collect the oil and have another tube routed from the can to out of the garage. Like a chip separator in a dust collection system. Would that work?

RE: Engine silencer
 

Hi!
First of all you must remember that no modern ABN, ABC, or AAC engine really need running in!
"Running in" with these engines mearly means getting aguainted to the high and low speed needles.

But you might think of older (40 years or more) ringed engines...?

RE: Engine silencer
 

I would suggest that instead of building a silencer, you build a test bench that will fit into your car. Take the bench, engine, and fuel to your flying field and break it in there.

RE: Engine silencer
 

Modern Saito AAC engines are ringed and need a break in period. Click here to read the manual and learn how it's done: http://www.horizonhobby.com/ProdInfo..._manual-lo.pdf

RE: Engine silencer
 

The video was only to demonstrate the oil catching bottle, not noise reduction. If I wanted to reduce engine exhaust pulse noise completely I would do something like this:

Attach a header pipe, not a muffler, to the engine. To the header pipe, attach a silicone tuned pipe connector. From the connector, attach an expanded cone that terminates in a round pipe that is 2" in diameter. Using 2" diameter ducting hose, attach that to a small car muffler that has a 2" diameter inlet and outlet stub.

RE: Engine silencer
 

No engine is exempt from running-in, all machined parts to wear out together to get the perfect fit. Thus, no machine tools can do better. The principle for the machining of metals is the same as for more hundred years ago, only the accuracy is improved in our days machining tools. But the surface is not free of tool marks before the parts are adapted by running-in together for perfect fit.

We have chosen other materials than we used cast iron/steel as piston/cylinder material and we get shortened running-in time in modern model engines.

RE: Engine silencer
 

Hello; Years ago I bought an Irvine 40 Diesel around about the time when a cold snap with lots of snow occurred. I wanted to run the engine but couldn't do it outside. I found an old high-start,(a surgical rubber tube about 1/2 inch ID) and a little ice cream bucket half full of floor dry. I clamped the high start onto the muffler and ran it into a garbage can that had the floor dry in. I put a big Taipan prop on it and plumbed up a fuel tank. Then I moved it all near a door so I could put the garbage can outside and run the engine inside.

I fired it up and was amazed at how quiet the engine ran without any exhaust sound. It would idle nearly silently. I learned about tuning a Diesel while running out those first few tanks through. Eventually the heat from the exhaust melted the high start, which made a mess, but I just cut off the melted part and started again.

I don't think you can get away with confining the exhaust gasses in an alcohol engine like you can a diesel, I haven't tried this with a glow engine, but it works great with Diesels.

RE: Engine silencer
 

I have a GMS 47, 3 OS 40la, OS FS91 and 2 Magnum xl52 id like to bench run. I don't know anything about headers or tuned pipes. I could find a place to go run them at. I guess I'm being spoiled with wanting to run them at home. :)

Thanks for the info gents

RE: Engine silencer
 

The best idea is like someone else mentioned above and that is to make a portabel running-in bench and drive to a flying field to run your engines. The idea of running-in a new engine is nice and exciting but if you have modern engines longer running in is not necessary. Just bolt it to your planes, run a couple of fuel tanks thru them , for about 20-30min, and after adjusting mixture and main needles the engines should be ready for flight. Thats what i have done the last 10 years and worked great every time.
Running the engine in a garage is never good as it blows the dust and dirt around, makes to much noise no mather what you do and the engine can suck in dirt which will shorten the lifespann.

RE: Engine silencer
 

Yes, with ABC or similar engines you only need to run a couple of tanks on the ground. But ringed engines which is all of the four strokes, it will usually take more than a couple of tanks. On some planes extensive ground running at full throttle can be hard on the airframe, not many but a few.

RE: Engine silencer
 

It will not hurt anything to run more fuel thru an new engine but all mines and friends Saitos, OS, ASP......... fourstrokes have been in the air by the third tank of fuel. Fourstrokes generally run very reliable and predictable. The only trick is to set them up slightly rich on both needles. Both needles need to be adjusted from the factory settings before the first flight.

RE: Engine silencer
 

Good points. Also, it saves the glue joints and servos.

RE: Engine silencer
 

NOTE: A major part of noise comes from the Venturi !!! Lowest noise set-up I got when attached mufflers
to both (no jokes) the Exhaust and the Venturi(inlet of the carb). The mufflers I used were from
gas engines (lawn-movers, grass-trimmers or chain-saw). If one muffler is not enough per point,
you can put two in series and have real fan on the balcony in block of flats :D:D:D
One can have a good sleep even beside it (a bit of exageration indeed...but near the truth)

RE: Engine silencer
 

I believe the larger Saito's take over a gallon of fuel, according to some. It depends on how reliable you want to be. I do not want to dead stick if I can help it. In my experiance you could fly the plane after a couple of tanks, but it seems there is a period sometime after that where it becomes unreliable. Even the compression can get weaker as the ring shifts, the engine is operating in differant conditions, or needs retuning as it breaks in. An engine, not even ABC is completely broken in after a couple of tanks. A ringed engine will improve over a few gallons of fuel. So it just gets down to how reliable you want the engine to be.