Muffler for model i.c. engine

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Brian,

It's a different experience to hear the mechanical sounds of the engine without so much of the exhaust noise, but I don't have an opinion as to which is "better." As a hot-rodder you probably liked some cars with loud pipes and others powered by the same type engine with different sound.

I will just say that I follow what you are building and like the journey as much as the destination in each project.

Thank You again for your contributions to the hobby.

--ShopShoe
 
Make a muffler stuff it with a brass chore girl, rather like a heavy duty glass pack. Build one with a reservoir and add a drain plug to the bottom.
 
brian, i have made homeade mufflers for generators and other briggs powered equipment similar to a glass pack muffler for a car, big pipe for the outside casing, smaller pipe for the inside, drill holes all on the smaller tube weld smaller tube with end plates inside the larger tube and pack all around with steel wool on the inside the weld up the other end plate. made a huge difference on that last onan generator that was given to me for free but had a straight pipe on it that would deffen you when you fired that thing up. wonder if that would do as good as the baffled approach you are using?
 
I won't build another muffler. This one was just a "what if", where I was bored and wanted to try something just to have something to do. My opinion is that yes, a muffler works, but doesn't make enough difference to justify the work required to build a muffler.
 
Brian
I want to make a larger carb and looking at yours I would like to scale it up from your design. May I have the the file on it.
Thank you
Nelson
 
I made a muffler for the Lynx. I wanted the in and out to be coaxial.

A pipe run through a larger pipe with the annular ring space between of the same cross section as the small pipe ID. The small pipe is plugged in the middle.
A line of radial small holes is drilled from neat the input up to the plug, same thing from plug to outlet end bur 180* off.
Exhaust goes into small tube, through little holes, swirls around and forward to reenter the small pipe and out to atmosphere.

Never tried with and without to assess the attenuation, mostly for look.
 
Exhaust noise much reduced, though as you point out in the video it leaves the mechanical noise more prominent. Nice work!
 
It's more of an expansion chamber than a muffler, but it sounds good, and this one was big enough to put a rain top on it. I've put these on all my engines, but the others were kind of small.
If it works, here are some pictures:

IMG_0810.JPG IMG_0813.JPG IMG_0816.JPG IMG_0817.JPG IMG_0819.JPG IMG_0818.JPG
(Mechanically, this is the "Zero-6" from Model Engine Builder in 2006, but cosmetically it is nothing like the original)
 
Brian
Mufflers have more good reasons other than noise, they produce a back pressure that can make a engine run better.
Thanks for all you do.

Sockets
I like that stand up pipe with the flapper on top. Very nice and a good looking engine.

Nelson
 
Have a look at O.S model engine mufflers. Not much to them at all, just an expansion chamber basically. Inlet and outlet have the same cross-sectional area with a fat tube in between. There is a 90 degree change in flow direction, not sure if that makes any difference. I think it's just there so the muffler doesn't stick way out to the side.
 
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