I just had this happen a week ago with the same muffler. Mine came apart where the header bolts to the engine. It fell off in flight and I had a tail heavy bird to land. I have the pieces, I have tried to contact them twice. I purchased it from National Hobby (now out of business) at a good price. I have had it for a while but put it in my plane and it failed after 3 months and 100 flights!.