I can't speak about the OS but my experience from back when mufflers started to be used was that the McCoys didn't like to be muffled very much.  Back pressure and added heat soon cooked them and they didn't want to run normally.  I'd suggest another engine to muffle.  Perhaps you can pick up an Enya or newer OS on EBay.  I have a few K&B Stallions I'm eventually going to try to muffle.  They may handle it better.

Dave

I just got McCoy Redhead .35 and O.S. Max-II .15 engines to go on a couple of old C/L planes I'm refurbishing.  I'm looking for mufflers for them.  I see some custom strap mufflers being made, but at $35 or more for them, they're twice the $20 each I paid for the engines.  At that price, I'm better off buying new engines with included mufflers.  Can anyone point me to a budget way to make mufflers for these engines? Mark

Mark, regarding the steel fin OS Max-II .15, you may be able to use an Enya .15 muffler. It is like a universal in that it has a separate backing strap with two long screws. If you have a modeler nearby that already has a muffled Enya, might be able to see if his muffler would fit your set up. If it does, then shtterman http://myworld.ebay.com/shtterman?_trksid=p2047675.l2559 on E-Bay has a new one http://www.ebay.com/itm/221334202168 for $16.99 plus $3.90 shipping. You may also find a used one for less than that. An unmodified legacy Tatone Peace Pipe .29-.40 may also work on the .15.

Regarding the McCoy .35, IMHO (in my humble opinion), you'd want a large chambered free flowing muffler to prevent overheating and possible ruin. A legacy Tatone .29-.45 Peace Pipe muffler may work. Recently I checked my .35 RH and the unmodified opening will fit and can be opened up for better flow. Also, I checked mine and an MDS muffler I have would work. I bought it used and I think it is for a .28, but it is large chambered and heavy (3.1 ounces). I've attached a photo of my Testor .40 Series 21 Black Head with a YS muffler. Heavy and large, the muffler runs on it freely without overheating.

These occasionally come up on E-Bay and more or less go for song. I've bought a number for under $15 each shipping included. You have to careful though. One modeler did not show photos of the muffler exhaust entrance on two of his Tatone .29-.45's. When I received them, the opening was drilled/filed out large enough to make them useless except for a select few engines. Also, the sizes can be deceiving. The .09-.19 Peace Pipe has a 3/16" dia. exit hole and is small chambered, suitable for .09-.10 engines. It works fine on my Enya .09-III TV but wouldn't try it on larger. I've included a photo of the .29-.40 Peace Pipe on an Enya .19-VI TV. They use standard ANSI thread #6, #8 screws and straps can be made out of steel steel or brass if missing.

Good luck, and as usual, YMMV (your mileage may vary).

I agree with Dave's comments about mufflers on the McCoy .35.

As far as a strap for the OS why not just get some 1/16 x 1/4 brass (from the K&S rack in your local hobby shop)? You can put a 90 degree bend on one end, wrap the strap around the back of the engine to get the curve you need, put a second 90 degree bend on the other side of the strap then cut off the excess. Drill a couple of 1/8" holes throgh the strap to line up with the mounting holes in the OS engine. Run 4-40 socket bolts through the holes and you've got a perfectly usable muffler mounting strap. Very low cost, yet efective. Just a suggestion.

Eric Rule

I hear what you all say and you bring up an interesting point on the venerable Testor McCoy Red Head engines. Out where I live, the nearest home to the flying field is a farm house a quarter mile away, next about a mile. A quarter mile oval dirt track is next door. I can fly without mufflers and my restored S-1 Ringmaster .35 RH will fly without it. Otherwise it would be nose heavy. Flying close to the ground, noise doesn't travel as far, too.

I've looked at the muffler issue, because it is possible that I may fly one of these days where it is required. A simpler issue, I'm thinking that I ought to build some CL planes that use muffled engines to begin with.

Since I have several .35 RH's, once I wring out the S-1, will try the larger Tatone .45-.65 Peace Pipe on it. It is large chambered and has a 3/8" dia. exhaust exit with a 1/4" dia. aperture ring just inside that can be drilled out. It weighs 2.3 ounces.

The RH's are really nice running engines and I am very pleased with them. From all and various inputs, I gather that similar to the K&B Sportster Schneurle chrome plated aluminum piston running in an aluminum cylinder series, that anything to cause overheating most certainly will lead to their ruin.

Regarding heat treating, has anyone ever tried chrome plating the piston ala KISS (Krome plated Iron piston running in a Steel Sleeve)? 

George,

     One of our Circle Cutter club members, Bud Bodzioch, chrome plated a number of McCoy Red Head pistons.  They
worked quite well in the steel liners, which, as you point out, are fairly soft. 

I had a Tatone Peace Pipe on an Enya 35.  It would shake loose in one flight.   

I've used the Tatone Peace Pipe on the redhead. For one it barely fits and it wants to flip off due to the mating surface of the Peace Pipe not being quite wide enough. I had to lap the exhaust stack flat due to it not being flat.  I had it mounted in a Bi Slob. While the engine did work it didn't last long and I certainly suspect the heat was the culprit. The hole needs to be much much  larger. Ken

I've got the Tatone .29-.40 Peace Pipe on an Enya .19-VI TV. It has the hole drilled out. There, the chamber seems about right. A number of folk mentioned that these mufflers ruined a good number of engines back in their days. I gather that their chambers were too small and outlets restrictive.

One muffler that I've got that others have told me particularly bad is the Tatone Calument muffler. I've got the EM-4 for .09-.19, and it has a very small chamber. I used a Dremel-like tool to remove the internal baffles and still my Enya .19 and McCoy .19 RH ran hot. I drilled about 8 holes in it to convert to a "tongue" muffler, but all I did was basically make it useless as now it did not muffle well. I'll probably patch the holes with JB Weld and test it on a .09 engine, which in that case might work. Muffler isn't that light, either.