I am getting close to finishing a scale spitfire and want to hide the exhaust. There is no after market muffler that will even come close to being able to hide in my cowl. I was thinking of making my own and if it goes well pipe it into the scale side exhaust. I was thinking of using brass or copper with silver solder. The engine is a TT.60pro.

Is there anything I should be aware of?. Will silver solder hold up ok?. Is there a specified formula for max. outlet opening, chamber capacity etc. As you can see this is my first attempt at constructing a muffler/exhaust diverter. After this project it's on to my 1?4 scale cub. Thanks for any help you can offer.
Peter.

The silver solder should be fine. Use the original muffler as to volume and outlet sizes. Regular solder will melt out up close to the engine.

Jim

Thanks W8YE.

Do you know if the TT60 pro. is finiky to exact back pressure for the pressurized fuel delivery. I know some engines can be pretty dificult. You seem to be quite into this forum and your opinion is trusted by most members. No pitfalls I should be aware of.

Be aware that copper alloys (brass etc) are susceptible (more than steel) to fatigue cracking due to work hardening. If you use copper, make sure to support the various tubing runs and branches with brackets. Steel is stronger, readily available, works well, and is easy to silver braze. The melt temperature of the braze alloy is a function of the silver content. More silver means a lower melt temperature. More silver is also what makes silver brazing easy to do. It's a compromise.

Good luck.

Peter,

I've only seen one TT Pro 61 and while it ran nicely, it was with the original muffler.

I've never read anything on here about them being finicky.

The TT PRO 46 is very popular but around here I've only seen one 61 and it was on a big trainer.

Good luck,

Jim

Hi!
The general rule is ...make it big!! More volume is better than small volume...you don't have to worry about any exact volumes... just aim for as large as you can make it...preferable as big as the original silencer or bigger. Exhaust opening ...somewhere around 8-10mm!
Steel is better than brass! but brass could ofcourse be used...but is is heavy and could become brittle!
Aluminum is better though, lighter but is not as good in suppressing noice. Harder to weld though!

Regards!
Jan K
Sweden

Thanks Guy's I feel I've got a good starting point.

Peter, I ran the exhaust out at the scale location on a Royal Bearcat I have. It worked fine as far as engine performance but if I had it to do again (and I just might) I'd just run it out the bottom of the fuse and save the scale exhaust for a gasoline powered plane.
The glow fuel makes a real mess and it even gets in under the wing saddle. Decals are starting to flake even though they're fuel proofed. The side of my plane is just drenched with oil after every run.
Just something to think on...

Thanks G.F.Reid;

I know what you mean. I hate cleaning that glow fuel, and no matter how well you think you have done, it seems to creep into something. The only saving grace for this plane is that I have fiberglassed it and the markings etc. will be painted on. It also will not be an every day flyer( if I get it up and down in one piece:-) ). Too many dam decisions, I guess everything in one way or another turns out to be a trade off. I think I will still try to make my own muffler and run it out the sides, and if the thing does not perform the way it should.......... well I guess that will make the decision for me.
Thanks again I value all your opinions.
Peter

Peter,

How goes your exhaust setup? What did you end up doing and how did it go? What plane are you putting this on? I'm curious because I'm trying to do a similar thing on my TF Corsair.

What's the flying weather like in BC?

Juice

Hi Juice

Well.....................I built the muffler with silver solder. It looks functional but pretty it is NOT. I have not tested it yet. I plan to run silicone tubes from the muffler to the metal exhaust stacks on the side. It is a spitfire and is completed with the paint. Some cockpit detail and the exhaust are what's left. The spit has a narrow nose and has presented some problems. Might bench run the setup in a week or two.

Here in BC. we have had a real warm winter (touch wood). Have done some flying, spads and gliders, but there is a inch or two of snow so that eliminates some of the trickier planes. Some guy's use ski's. This is really something for this area. We normally have 4 feet. In fact we hold the Can. record for the single greatest 24 hour snow fall (about 4 feet in 24 hrs.).

4 feet in 24 hours! Maybe stuff like this is why American's think Canadian's live in igloos instead of houses.

Let us know how your exhaust setup fairs after you bench run the engine and/or fly the spit.

Juice