making a molded carbon fiber header and muffler?

[Scott Richlen]

I was thinking of trying to make a molded carbon fiber header and muffler for my Ro-Jett 65 side exhaust.  My goal would to be to make a header that would mount to the side exhaust port and then curve around the cylinder head to mate up with a muffler body behind the engine.  I recall seeing a picture years ago of one of Windy's planes where he had something like this but in aluminum.  So far, my searching here has turned up a lot of molding props and things like that, but nothing on this topic.

Has anyone done anything like this?  How did you do it (what were the steps in the process of making it)?  What materials/products did you use?  How did it turn out?

Thanks!

[Howard Rush]

When I read this I thought it was crazy, but then I realized that I'd done it.  I made some carbon minipipes and headers for Nelson .15s.  I later converted the minipipes to mufflers when the rules changed.  I used 350 degree prepreg for the pipe and layed up the header from cloth and some high temperature resin.  They lasted for awhile, but not long enough for stunt.  The resin is extinct now.  I don't know of a replacement.  Your best bet would be to outsource the parts to Ed Skorepa in Utah. 

[Brent Williams]

Resin Services has some high temperature products that you might look into. 

https://resinservices.com/our-products/

[Dan McEntee]

  I have never worked with the  stuff, but just from what I see from tuned pipe use, which show "wear" and other decay eventually from use, It's not worth the effort due to the high heats right at the exhaust exit. Even with the correct high heat materials, I don't think it would last long enough to be worth the efforts. Run an engine at night some time with the muffler removed and look at what comes out of the exhaust. That is why the header at least needs to be metal. Tuned pipes are a ways away from the direct effects of the exhaust flame but still will degrade some over time. I don't think I have ever seen a composite exhaust of any kind in any type of motorsport.
  Type at you later,
  Dan McEntee

[EricV]

I seem to remember someone (ArkModusa?) had mixed carbon composite mufflers that held up for the old style side exhaust Stalkers. They were green? Anyway, I seem to remember they had a mix of aluminum and carbon... the metal in the high heat spots, and the carbon in the weight saving lower temp spots... like an aluminum mount, carbon tube, aluminum back plate, and carbon outlet angle tube... it's a fuzzy memory though, so you are getting what I am charging you for it. 

I've flown thousands of flights on Randy pipes and have yet to burn one out... but I run them as Randy tells you to... not screaming lean... and keep my tanks clean so I haven't had many if any lean runaways from crap in the needle... Carbon pipes hold up well enough, as long as you don't cut the aluminum header shorter than the stock length and use the high temp coupler with zip ties. I see no reason you couldn't do the same arrangement with a mini pipe or muffler on the end of the coupler and have it last.

Hope that helps,
EricV

[Scott Richlen]

I guess my challenge then is "how do I bend an aluminum tube to use as a header that mounts on the engine and then turns around the cylinder head to the back side of the engine?"

[Dan McEntee]

I guess my challenge then is "how do I bend an aluminum tube to use as a header that mounts on the engine and then turns around the cylinder head to the back side of the engine?"

      Windy had some one make them for him, and I think Randy Smith used to provide that type of custom header, so it has been done. You need to draw a full size layout of the pattern you need looking form the top, and from the side, any kind of elevation change you may need. You make the flange first, getting it all milled and drilled like you will need it. Then you bend the tubing to fit your outline. Plan on a length about twice what you will measure down the center line of the pipe, just to have some extra to hold onto and work with. You will squish the end where it will attach to the flange to fit there better there and allow for welding. Start fitting that end first, cutting and filing a little at a time. it's easy to cut more off, difficult to put anything back on!! Once satisfied with that end, se how it fit the model and then start cutting the other end to fit. Any " mid course corrections" at the bends can be dealt with by tweaking the tube if it's very miner, to making a cut and opening or closing the bend as needed and them welding up the cut. When you have the header finished, then you can attach a muffler and you may even find some one's after market model that may clamp on, or go with your carbon cannister concept. You could also make it an aluminum tube type also that is welded to the header. You ought to get all that done by lunch!!  I'm pretty sure Windy did a series of videos on ST.51 development where he ran the newer G-51 on a pipe. Check on YouTube to see if anyone has uploaded that one yeat. I don't remember if it's in the collection I am working on or not, but I don't think so.
  Type at you later,
   Dan McEntee

[Brent Williams]

Check with Randy Smith regarding your application.

https://stunthanger.com/smf/classifieds-92/new-side-to-rear-headers-and-header-mufflers/#msg535536

[Lauri Malila]

I think it could be done, but the part that is bolted to engine should absolutely be made of aluminium. Then the carbon S-part attached to it with either glue or some sort of an O-ring connection.
But being that close to exhaust port, you want to have a very good quality laminate with high carbon %.
Years ago I had many US-made carbon pipes, and I never understood why the laminate quality was so poor. As if there had been no compression at all, with very high resin %. No wonder they get pinholes and cracs in use.
In the end we ended up making our own pipes, using proper steel molds and mylar tape compression. They were wonderfully strong.
The only reason I could think to justify the poor laminate quality, would be better (worse, that is) heat transfer behaviour that seems to be beneficial in our use. But that can also be done with correct cooling, or insulating paint.
If I were to make pipes now, or the header S-tube, I’d use a metal- or a hard sacrificial male mold and silicone female piston compression, just like how we do carbon D-boxes, tailbooms and fuel tanks. That way you get the best possible compression. L

[Scott Richlen]

Thanks for the input everyone!  Looks like I'll be making this out of aluminum with the help of one of my buddies that can bend tubing, machine aluminum, and braze it.

[Lauri Malila]

Thanks for the input everyone!  Looks like I'll be making this out of aluminum with the help of one of my buddies that can bend tubing, machine aluminum, and braze it.

I think that’s the most elegant solution.😂L