flybyjohn

My Feedback: (2)

I know there is a lot of information about these MCP's out there as I have been reading quite a bit of it lately getting ready to build a couple for some engines of mine. I played with rc combat for a short 3 month segment when I lived in a town that had a club with combat enthusiasts. I moved to another town and this club is not into combat but heavily into gliders and pylon racing so I got out of the combat business without a lot of experience.

Anyway, when I was building my combat ships, the folks there were using a mouse can pipe set up like detailed in my drawing, using the top method with the one piece header pipe. In all my searching about MCP I have not seen anyone build one like this. They are all the conventional way. Is there a reason for this? The only thing I could think of would be that the header pipe is not supposed to support the muffler weight, however, the can can still be mounted to the aircraft and the silicone sleeve will still isolate the vibrations from the header to the can.

Can anyone tell me why not to use this method for building a MCP. Is there something I am missing in the design of one of these pipes.

flybyjohn

My Feedback: (2)

One other thing I was going to ask about. I am planning on building my own headers. For my 46 and 52's I plan to use 3/4" OD aluminum tubing and for the 36's I plan to use 5/8" OD aluminum tubing. I don't know just what thickness of tubing I should go with. I have read in one place that Macs uses .035 wall thickness and OS uses .065 thickness. I can compromise and get .058 thickness if anybody thinks that will work. Should I go thick , thin or in the middle?

aspeed

I would go with the thinnest, for weight concerns. When you crash, the weight will break off the exhaust flange of the motor. If you like crashing, that is. http://www.spadtothebone.net/SPAD/Mufflers/ This is the way I would do the muffler. The hole in the front makes the wavelength longer like a real pipe, but in a smaller package. If using a header, your way looks good. More adjustable for sure.

Mr Cox

The first drawing works fine, but you want the inside tube to be much longer. It should almost reach the rear wall, that is the whole purpose of the design. It then acts as a folded tuned pipe, if you get the dimensions right.

flybyjohn

My Feedback: (2)

I had read that the tube should just go inside the can a little bit to make the engine have a broader power curve without being peaky. That is the way that all the examples are shown of the MCP that I have run across so far. I was also under the impression that the stinger (outlet end ) didn,t matter where it was on the can. Thanks for the info to straighten me out.

aspeed

Did you epoxy/JB weld, or use silicone on the header joint on that motor Mr Cox? I wouldn't think it would be strong enough. I am thinking of making some headers at some point. Looks like a Picco .05 or some car motor there.

Mr Cox

Yes, it is JB weld (the marine version) and it is not strong enough on its own for strength, I mainly use it to seal the structure. The front end of the tube is split and the header screws will engage i the Al-tubing too. Don't know what will happen in a crash but it kind of works for these small engines (here a Picco Zero 0.8cc car engine converted to airplane use).

The design of internals of the muffler all depends on what one is after, high power or high sound damping. For a boost in power, the inner tube should be long in order to emulate a folded tuned pipe. If one just wants a quiet muffler the header tube can end right inside the can. The position of the exit tube will affect the reflection in the folded pipe mode and the sound damping in a muffler mode. For more damping of the sound (in a regular muffler mode) the stinger can have its inner end starting near the muffler wall (where sounds waves have a lower pressure variation). It needs to start in the lower end though in order to drain out the oil.

flybyjohn

My Feedback: (2)

When I get around to building my headers, I am planning on using this Vulcan g-51 brazing rod. He has a video of using the stuff and it looks pretty easy with the flux. The aluminum braising rod wicks into all the cracks. I emailed them and the melting point is about 730-750 deg f. I have used the non flux stuff and it works but is a lot of work. This stuff with flux keeps the metal clean as you are heating it. I read on one of these forums that Macs headers uses low temp braising rod to build theirs. Don't know if it is true or not but just looking at their products it sure looks like it.

Mr Cox

Below is a picture showing the inside of an MVVS tuned muffler, this is what most people are after when making the moose can mufflers.

You can of coarse make a regular muffler and it will be a lot more quiet.

flygilmore

Check out the Profile Brotherhood site to see how a "real" MCP is made. They can make a HUGE difference!!!!

aspeed

Got a link? I found lots of stuff but no drawings or pics of any use.