Hi All,
I have three planes (AeroWorks Edge 540, H9 P-51 and GP Minnow). OS 91Surpass is installed on all three. On the H9 P-51, I have an alluminium mount but on the other two, I have the regular nylon mounts that came with the kit. No issues with the muffler on the H9 P-51.

On the Minnow and the Edge 540, I have been having serious muffler issues. Either the muffler comes loose or the ELBOW that connects the muffler to the cylinder completely breaks apart. This is what I have done to the muffler in case many of you have questions:

1. I sent the mufflers to Clarence Lee to have an additional brass fitting glued to the muffler and the elbow.
2. Propellor is balanced
3. On both muffler end and the cylinder end I used Locktite before I tighten them
4. The spinner runs true when the engine is running
5. None of these engines have been in a crash, in fact they are fairly brand new. I would say I have about 20 flights on each of them
6. Using the TAC meter, the engine runs about 8700 RPM

Usually it takes about two to three flights before they come loose or break apart. Yesterday I flew the Minnow and after the second flight, I lost pressure and as I started to land I noticed the muffler hanging on the fuel line. When I landed, the elbow completely broke from the cylinder end.

I must say I have been working on these issue since last season. This has been very frustrating to say the least.

Question for everyone is, have any of you had these issues? Is so what do you do to solve to the problem. I am thinking of getting the Flex Pipe. Not sure this solution would help.

Any help would be apreciated!!

Kris