3D Printed .020 muffler

I would fire up a 049 with the aluminum Car exhaust director/square pipe and use thermo gun to see how hot at peak RPM...I bet every 3d filament has data sheet on cold to hot range capability

Nice, maybe this could help

Y want To cast aluminium those custom parts its Not so hard like

Nice work, Jason. It kind of reminds me of the catalytic converter kits for cars that Midas Muffler of Gallup NM installed on our old 1984 Dodge Aries back in the 1990's, when it got to 100,000 miles and needed replacement. It came with a special rubber hose to connect the air tube to the converter. Over time, it would burn through, was a poor solution at best.

After the dismal problems with Midas in getting this corrected, I took my 1990 Dodge D-150 pickup to an independent shop run by a couple Navajos in Gallup. They welded the air tube (what Midas should have but would not do). They were fast, professional, welds and work would please any inspector. I took my Aries, and can't remember whether they fixed for free or for a small cost, but they welded the air tube, correcting the problem.

Don't know the temperature stability of your muffler material, but it does look very clean, well formed. It would be interesting to see how it performs, and if it will hold up sufficiently over time or not. If it can last say 2 seasons, then the trick may be to simply replace when needed.

But the muffler does have appearance appeal to it.

Made some tweaks for better fit. Will need to test it out. Material is good to 150C or 302F. So we’ll see it it has a melt down.

Looks Good Jason , fingers crossed

Nice work Jason. Assuming that this material holds up; I wonder if the first rendition's offset header/pipe might be less resistant to flow than the second design, by maybe causing a swirl-scavenging action?



Where one can't plan the indexing of the cylinders' exhaust ports.. and/or the indexing of the mufflers' outlet from engine to engine/model to model.. it could provide for more consistent performance.. if nothing else.

A crazy thought.. but you never know.

EDIT ADD; I see that a starter-spring won't fit with the 2nd design. Might it be worth printing a spacer-ring to fit the top of the crankcase? (for use without a starter-spring..) Were starter-springs prevalent on the Cox .020's? Were/are they available as an accessory?

What holds it on?...friction?.....I could go for a babe bee and tee dee .049 version!

Friction holds it on. I can make a version for the spring starter attached but probably not both. That small of a spacer would break pretty easy.

Cox International and EX have a .049 muffler version on their websites.

Is there anything inside that causes a muffling effect or is it more like an exhaust collector? I know the .049 version quiets things down some so perhaps it is just the same. Interesting to see how well it holds up.

Just a simple shape like the .020 muffler Cox made.

I always liked the twin exhausts on the gilbert engines?

I would like a few .049 twin stack aft facing for some custom TeeDee builds....I guess the fit is cylinder type dependent

wonder if Eastwood powder coat will stay put as a method to change color to red from black

Did you ever test it Jason?

Yeah I am interested as well. I also really like Fred’s “twin stack” idea.

+1 for Fred and Ron. Yes I'd like to see some running examples too! Just for FUN.

Y have tee dee .020 y like To try rc exaust valve wit that parts y want one

Fred, I can't comment on Eastwood's system. I'm aware of it though. I had a Eatwood shop located within 20 min from my home. It's since moved a bit further out but within 45 minutes. I had two Fox .35 crankcases done professionally. I was having my swingarm and other parts for my bike powdercoated and they did the Fox cases. One being powder blue and the other dark blue. The area around the exhaust stack is not looking so good. If you've ever seen ceramic glaze that appears bubbled, this is what it's starting to look like. The lighter powder blue case looks pretty good but it's showing some discoloration but not like the dark blue.

I would be surprised if it holds up-I think the exhaust gas temperatures are much higher than 150C....and i have physical evidence-though no temperature measurements-to back this up.

(1) many years back-in the late 80s I was running up a G-Mark 03 hummingbird-the one that looks a bit like a TD 020 on mild steroids....purely for convenience in bench running, I ran it without the muffler attached. I was running something of the order of 15% or 20% nitro and pulling 18,000 or thereabouts (this was the std model, not the R/C carb equipped one)-after a few runs I noticed a distortion at the top edge of the integral fuel tank-the exhaust gas was starting to melt the rim where it projected just above the crankcase....now the material is similar-but perhaps not identical to that used by Cox for the TD 010 and 020 tanks...but the exhaust was hot enough to cause damage....

(2) not a great deal later-ie early 90s I was flying FAI FF models-specifically the F1C 2.5cc class-and my first models were traditional wood designs...equipped with the typical engines of the day rossi 15s, Cox Conquest and Nelson 15s-I rapidly became aware that the front of the fuselage of the rear exhaust engine models-those with the Rossis or Conquest-became charred after a few runs-not black carbon-but definitely hot enough to scorch the wood-the sort of scorch mark you'd see from a too hot domestic iron left too long on a white shirt whilst ironing....so exhaust gas temperature is hot enough to scorch wood-even with light glass over covering-and i'm talking about run times of perhaps-30-40 seconds in total-that includes starting up, needling, setting and the actual in flight 7 sec engine run which prevailed at the time-and all this was on 80:20 FAI fuel....

So I'm not optimistic in a 3D plastic collector/muffler standing up to anything like prolonged use...unless you can produce the thing in metal. Note that there ARE some diesels out there with a plastic collector-the Sharma diesels made in India-but diesels run a lot cooler....

ChrisM
'ffkiwi'