How to prevent cracked muffler on 912uls

[Delta Whisky]

If this is a contest, then I win! The shame of it all, I read this thread a couple of weeks ago but failed to look as closely as I should have before its last flight. You can see from the picture, I should have bent down and looked really close - it appears that there should have been some evidence of the impending doom. (Its there now!)

And, the last contact the vagrant exhaust pipe made as it left its welded home was one of the new fairings on the good ol Monster Shock.

Empty exhaust hole.jpgMissing exhaust pipe.jpg

Now I need two things: the ability to rotate these pictures and a new exhaust muffler.

[Shadowrider]

Oh dang that stinks! Did you get to fly before it broke and test the new fairings out?

[avidflyer]

Wonder if you would dare to weld in another elbow? Add a patch on the end of the muffler with the correct size hole in it, weld in the new elbow, and then add the braces from edge of muffler to new elbow. I wish now I had put braces in mine when I had it at the welder. JImChuk

[Delta Whisky]

Dustin - your question touched on the irony of the planned flight. That day, Monday, showed hopes of being a relative calm day aloft and was the reason for the planned flight. I had previously made two flights in hopes of obtaining decent data but the turbulence makes the data suspect. None-the-less, I've started an analysis and, as soon as a head cold clears, I'll see if any part of what I have is useful.

Jim - Your idea has merit but one detail of what a close look into the muffler reveals gives me pause. I'll try to get a better picture the next time I'm at the airport but it appears the exhaust pipe/stinger is (or was) an extension of an internal pipe that runs the length of the muffler. This pipe contains numerous holes the exhaust gases have to pass thru on their way to freedom. If that is the case, four breaks were extremely clean and normal to the center line of the pipe.

[Dave S]

Found a photo which shows the small stinger brace I mentioned before that was part of the original design on the muffler that came with my kit. This is an earlier design ca. 2005. Don't know if that is currently used but it seems like a good idea. No cracks in the muffler body or the stinger weld to date.