Two broken mufflers...

[three.dee]

Hello everybody,

I am new to gasser helicopters and I have a problem.
I own an ALIGN T-Rex 700N with a Helibug conversion to gasser with a Zenoah 26 PUH modified by BH HANSON.

Everything is running ok, the motor works well, the helicopter is fun, loads of power for a gasser, but here comes my problem: my mufflers keep breaking. I broke two mufflers until now, a RJX and a Torpedo Slim 4 and I still have no ideea why.

Anyone else had problems with their mufflers, why did I broke them?
Can you recommend me a good muffler?

I am starting to think that the motor is not tuned well by me. I tuned it up using the manual and my experience in nitro helicopters. The result feels good, but I'm thinking that maybe I have a big temperature and that's why my mufflers keep breaking. I do not even know what temperature should I have on the motor. I know for the nitro engine what temperature I should have but I know on gassers is bigger but don't know how big... Do you know where I can find some tune-up advices?

Thank you in advance!

[Azalin]

I saw 2 broken muffler pictures before. One of them was an RJX and other was a JR (if i'm not mistaken). The owner of the JR welded the broken area and continuing to use it.

Maybe the design of these mufflers are wrong. One side is long and heavy weight but other side is short and light weight. Of course the long side has more stress than the opposite. Maybe you should try the new Century V5.

[Jeff396]

I was the owner of the RJX muffler that broke. I also believe that mine broke due to excessive heat which in my case was caused by an air leak in the motor. I will fix it but I bought another one as I like the sound so much. I'm just not going to mount either of them until I figure out a way to support the rear of the muffler. The material at the thicker part of the muffler that actually bolts to the motor is WAAAAAAAAAY thin!

Jeff

[three.dee]

I had an interesting answer on PM and it seems that my problem might come from the oil that I use and it makes perfect sense. I will try with a better type of oil.

Meantime, I have also discovered that my engine tune-up wasn't that good. I made the mistake of setting the engine using the Zenoah manual, but the engine was modified by BH Hanson. I talked with them and they were very nice and provided me with the approx. needle position.

I have also ordered a Zimmerman pipe.

After I try the three modifications from above, I'll write here if it works and if my problem has been eliminated.

Thank you all for your help so far!

[Azalin]

I am using Castrol fully synthetic oil without any problems. You might find it easily.