Muffler

[Gary0747]

I have a burnt out flame tube after 1200 hours. Should I expect longer life?  

Any recommendations on a repair facility?  Any of you Power Flow guys got one for sale?

200 hp Halon Wilson Studded  

Gary

67F

[mooniac15u]

8 minutes ago, Gary0747 said:

Any recommendations on a repair facility?

I had exactly the same problem. Dawley Aviation repaired mine quickly and affordably.

http://www.dawleyaviation.com

[jetdriven]

Who needs a flame tube. Remove the rest and run the muffler. 

[Gary0747]

Good point, I never thought of this.  Does the flame tube serve any purpose?

[aeromancfi]

Go with Dawley, they have the jigs to make accurate repairs and re-builds.  Did my whole system on a M20E 13 years ago with no problems since.

aeromancfi

[Guest]

10 hours ago, Gary0747 said:

Good point, I never thought of this.  Does the flame tube serve any purpose?

It's part of the internal structure of the muffler.  If it weren't needed the manufacturer would have left it out in the first place.

Clarence

[jetdriven]

Is it truly structural, or is it just to prevent a backfire from lighting the grass on fire? 

Additionally, it's hazardous. A few people have had a piece of that thing come loose and obstruct the outlet inside the muffler, causing a large power loss. 

[takair]

I can't find evidence right now, but I thought that Dawley will rebuild an exhaust and leave the flame tubes out.  I wonder if there is any other difference?  The flame tubes are a real nuisance, I suspect that at any given time a large percentage of the GA fleet is flying with degraded or missing tubes.  Has anybody seen any evidence that these missing tubes are degrading the rest of the exhaust?  The most compelling information indicates that the flame tubes are to prevent hot spots on the rest of the muffler, but I've not seen this when the flame tube has been missing.  I agree with Byron, it seems that the tubes cause a greater hazard when they break up than without them, but I can't say for sure....

[DXB]

Trying to learn what a flame tube is and what it does, I found the following:  http://www.knr-inc.com/knr_inc_joomla/shoptalk-articles/25-shoptalk/33-200012-inspecting-exhaust-systems

Per article, it keeps the outer can from degrading by directing hottest part of gas away from it.  No clue how well it serves that function.  But apparently the Powerflow mufflers don't have a flame tube. How did the OP figure out that his was degrading? Is it standard to take off the tailpipe periodically to inspect the flame tube?   My exhaust is original, and I look carefully for evidence of leaks whenever I'm under there, but I've no clue what's inside the muffler.

Edit: Never mind- I see it on the Mooney annual checklist.   

[carusoam]

The flame tube is a method of controlling heat to keep from damaging the exhaust system.  Design and selection of materials has changed over time...

a fair amount of high tech stainless steals have become cost effective and available for us end users.

Logic behind not ever going to an auto muffler shop in the past decade or so...

Best regards,

-a-

[N201MKTurbo]

The mufflers are originally constructed with two 304 SS tubes running completely through the "can". The tubes have holes drilled in them to let the exhaust gases escape into the can. Each end of each tube has a slip fitting formed to accept an exhaust riser. The tubes are welded to the can end plates and form part of the structure of the can. The outer shell of the can is welded on after the end plates are welded to the tubes. The tail pipe fitting is welded to the outside of the can.

The tubes that pass through the center of the can (flame tubes) can deteriorate and pieces can fall off. If you remove the tail pipe you can see all this through the tail pipe fitting.

I have seen repairs where the end caps are cut off and instead of two through tubes they weld on four stub tubes, that are capped, to the end plates. The end plates are then welded back on, in a jig. It is not as structurally sound as the original assembly, but strong enough. 

[Gary0747]

Found my missing flame tube during annual. My mechanic ran a camera up the 

exhaust pipe. Said he has found a lot missing this year and the risk is power loss if one blocks the muffler outlet.  

[jetdriven]

IDK, but my muffler is hollow inside and it has over 1500 hours on it and it doesn't appear to be degrading.  And no risk of something blocking the outlet inside. 

I read somewhere that taking that baffle out was a Roy Lopresti idea, and for all I know it came new that way. 

Edited May 17, 2016 by jetdriven

[N201MKTurbo]

41 minutes ago, jetdriven said:

IDK, but my muffler is hollow inside and it has over 1500 hours on it and it doesn't appear to be degrading.  And no risk of something blocking the outlet inside. 

I read somewhere that taking that baffle out was a Roy Lopresti idea, and for all I know it came new that way. 

A little more power and a little more noise.

[Guest]

Flame tubes do deteriorate over time, there is no risk of blocking the tail pipe exit if the muffler is inspected regularly and repaired when required.  Slipping a camera in the tail pipe is easy.

Power Flow systems do not have mufflers, they have tuned length pipes wrapped in a shroud.  They have a 100 hour requirement to remove and disassemble the system, clean and lubricate the slip joints to prevent pipe breakage.

Clarence

[garytex]

Mine on an F is stupid loud, especially on TO.  I wonder if a teenage hangar elf has been at my flame tubes?

[outermarker]

I am in the middle of getting new risers and muffler. There are 15 springs which connect the system. I got a price from one vendor who quoted me $100/spring. Of course he thinks either I'm really stupid or have really deep pockets, of which neither is valid. I tried looking in McMaster-Carr and couldn't find a direct replacement, then again, the dumb might have come out in me while looking. So, the question is, who has these springs? I don't want to re-use the old ones.

[takair]

6 hours ago, outermarker said:

I am in the middle of getting new risers and muffler. There are 15 springs which connect the system. I got a price from one vendor who quoted me $100/spring. Of course he thinks either I'm really stupid or have really deep pockets, of which neither is valid. I tried looking in McMaster-Carr and couldn't find a direct replacement, then again, the dumb might have come out in me while looking. So, the question is, who has these springs? I don't want to re-use the old ones.

I would call Dawley.  As I recall, they include them with a new exhaust and I think they could almost sell you the entire exhaust for the price of what you were quoted.

[Raptor05121]

Aerospace Welding Minneapolis will O/H a muffler for ~$800 with core, but dont expect it to last long. My system has seen them twice in the past 10 years if my logbooks are correct. Two other guys I've spoken to on here have also done business with them and their relatively low-time rebuilds have already started degrading. A full system is the better part of $3,000

[outermarker]

@ Takair: I spoke with Dawley last week. They don't have any of the hardware. I really thought McMaster-Carr would have them...they have everything else it seems.

 

[RLCarter]

18 hours ago, outermarker said:

I am in the middle of getting new risers and muffler. There are 15 springs which connect the system. I got a price from one vendor who quoted me $100/spring. Of course he thinks either I'm really stupid or have really deep pockets, of which neither is valid. I tried looking in McMaster-Carr and couldn't find a direct replacement, then again, the dumb might have come out in me while looking. So, the question is, who has these springs? I don't want to re-use the old ones.

I replaced several last year, my IA keeps a crap load of sets on hand, Spruce carries them. Sure they were not quoting you $100.00 for all 15 Spring & hardware sets?