Brian, I know this is getting off topic, but you asked for some muffler details. I can't speak about Cal Tinkhams muffler design, but another club member volunteered to fabricate a muffler for my Backyard Rails F-7. The previous muffler (yes, we've tried several different types in an attempt to reduce the "lawnmower sound system") was nothing more than a round expansion chamber. It wasn't very effective.makinsmoke wrote:Carl, Can you give specifics on how he designed and built his muffler?
Brian
I'm attaching several photos of the muffler currently in use. From what I understand, the parts were designed and laser cut. I believe it comes down to adequate exhaust gas expansion area and multiple baffles without creating excess back pressure. The end result...I hear more of the mechanical locomotive noise now instead of the exhaust noise. And to that end, it's difficult to determine how fast/hard the engine is running without the exhaust noise. I'd say the redesign was success. I'm pleased with it...although I have to admit, I haven't seen the bill yet.
The photos should give you some insight as to what was done. For reference, the outer casing is a piece of 4x6" steel tubing. This not only was the material on hand, but the size fit in nicely between the hydraulic pump and the underside of the fiberglass body. After installation, I covered the muffler with ceramic wool insulation.
If you're looking for a "steam parallel", we run into the same situation with blast pipe nozzle sizing and the distance from the blast nozzle to the stack. So...in one case, we look forward to listening to the "chuff". In the other case, we're trying to eliminate (or at least minimize) the sound of a 2 or 4 cycle internal combustion engine. Hope this helps. Carl B.
I don't think they are Chloe drivers though, there's one too many spokes as far as I can tell, zooming in to the photo. It's quite a custom kit-bash of stuff though, there's probably Allen parts in there somewhere.
