Homemade add-on .12 Mufflers

[Eric Perez]

Well, here we go again another weekend and more stuff gets tested.

This week we go after the noise problem. I've been doing a bunch of testing with my MACS .10-.15 pipe and have grown very fond of it. It makes my boats scream -but is also the loudest pipe I own

I can not afford to loose my test pond so I started looking over my extensive collection of rc car pipes and before I took the drastic approach I decided to try and make a small , lightweight muffler that would not require a 3-axis CNC mill to make.

Did some research on muffler desings and noticed how complicated it would be to make a working tuned resonance chamber in the muffler -so Idecided to go the "glass-pack" route and use a metallic-mesh medium that would cancel some of the noise without being overly resistrictive.

The little muffler did not make an "amazing" difference in the noise but it did take the high-pitch bite that the pipe had without the muffler. Engine seemed to run just like it did without the muffler -no radar gun, eye ball speed seemed tp be the same.

Here are the pics of the Muffler installed on my MACS pipe.

 

[Eric Perez]

Construction of the little-muffler

The body is a 35mm film canister. It has been cut in half to make the cylinder 1" tall.

The base (bottom) of the canister has a hole cut into it that will trap the groove on the small rubber grommet.

Take section of the stainless steel-sponge and stuff into the film canister. Cut the rest of the sponge off.

Cut a hole on the cap of the film canister.

Assemble the stuffed film canister and secure the cap with radio-box tape.

Wrap a wire-tie arround the tape to keep it from comming off.

Now slide the grommet end of the canister over the "tail-pipe" of your tuned pipe.

Use another wire-tie to secture the cannister to your pipe-hanger/mount.

That's it.

I've run my muffler for a couple of tanks and oil retention does not seem to be a problem, it makes it way out the back eventualy. You can make an oil-bleed hole on the bottom of the canister if you like.

If you need more noise reduction then try to use the full-length canister and give it a try.

I'm going to work on another style of muffler with (2) pieces of copper, this will be similar to the one that JD did the article on for RCBM. If weather is good I may have some info in a couple of days.

 

[Eric Perez]

Here is the pic of the mini canister-style muffler. Tried it "on the bench" sounds like a little dirt-bike! Very cool, now most of the noise is coming from the flex-drive.

I'll have some on-the-water test done this weekend.

Check out the mount-locking pin. It's all integrated into the same part.

I'm also experimenting with metallic meshes and sponges inside the canister

 

[wswatzell]

Very interesting. I might have to try something like that when I put my MAC pipe on my 12 rigger.

 

[XtremeRcBoats]

Jeryy Dunlap wrote once an article about the same type of add on muffler for outboard pipes. Still have one lying around but so far i never tested it.

 

[Mike T.]

I've made a number of smaller stinger mufflers for .21 monos and outboards. They were 6061 seamless aluminum tubing, held together with small screws and snap rings. The outer tubes were 1" or 1.25" diameter (actually smaller than the film can). Polishing to a mirror finish is an option. They can be taken apart to add stuffing, but I don't recommend using stuffing with a nitro engine (collects lots of oil). Not quite as "affordable" as the homemade mufflers but very tidy looking and last a long time. Generally, the smaller a muffler is, the less effective it will be.

One of the guys in our club makes a very lightweight but marginally effective muffler from a finger-sized aluminum cigar package tube with one hole drilled in the end. Some miracle epoxy adhesive holds it onto the pipe.

 

[Don Ferrette]

"Not quite as "affordable" as the homemade mufflers but very tidy looking and last a long time. Generally, the smaller a muffler is, the less effective it will be."

Mike, your mufflers are a BARGAIN for as nice as they are!!

 

[Mike T.]

Thanks, Don.