My Thunder Tiger mufflers keep shearing the threaded rod. I have tried reinforcing with JB weld, loosening the lock nuts, tightening the lock nuts, tig welding etc. When I went to the last Tiger Stick contest I looked around and saw multiple airplanes with modifications to their Thunder Tiger mufflers. It seems that this is a cronic problem (loss of back half of muffler in flight). When I approached Ace Distributors about the problem they said that no one else has complained. How could this be? Our club alone has enough front halfs to go into production (if we could just find our back halfs). Everyone is giving up and buying Tower Hobbies mufflers. The problem is that the competitions we attend require a stock muffler. Please help me collect data or take it upon yourself to contact ACE and convince them that the muffler needs reengineering.

I have to agree with you. My TT muffler gave up the goast about the 4th engine run. They local guys learned to have their mufflers welded shut with the OS engines that are much worse than the TT, the long bolt is smaller. Find a shop that will weld for you at a reasonable pice, should be $15.00 or less. Its worth the price to resolve the hastle. Will send Ace a complaint per your request. O.S. did not listen to their liner pealing problems, but did warrante them to a point. The Irving muffler is longer with the same type of connection, have had no problems with any of mine in 3 years. Just a matter of metal quality I guess. Unless we get into their pocket by requesting replacement as part of the warranty, the problem will probably continue?

My OS 91fx snapped the rod THREE times !!!!
We corrected this problem be replacing the rod
with 10/24 all thread with 9 small rubber gromets
on the all thread inside the muffler...
Re taped the muffler ends..

Metal fateige caused by vibration is the problem..
Now have another 325 hard 3d flights on the motor
and ALL IS WELL ....[sm=sunsmiley.gif]