OS FS header pipe
12-18-2009, 07:16 PM
#1
OS FS header pipe
Bill, I own two of the OS .91 FS engines, to date I have had four headers break on one of them and two on the other. Today when the new header, about 15 flights, broke off I wasn't able to save my plane when the engine flamed out. I understand the vibration and weight of the muffler is a problem but they all break in the same place, right on the last thread at the engine. Is there another type of header that I can use to cure this very nasty problem?? This doesn't happen with my other OS 1.20s, just the .91s and it's always a surprise when they go sailing off.
12-21-2009, 10:19 AM
#2
My Feedback: (11)
RE: OS FS header pipe
You may need to check the airframe to see if it's allowing the engine to move around. When you have a large muffler at the end of a small pipe, and the engine's moving around, the mass of the muffler will flex the pipe to the point where the pipe fatiques and breaks. You may want to secure the muffler to the airframe to help support it.
12-22-2009, 11:33 PM
#3
RE: OS FS header pipe
Thanks Bill but after I posted this I gave it some thought and came up with a good answer, operator error!!! I have been using the GP adjustable motor mount on this plane/engine combo plus had the engine mounted way in the front of the mount. I think it's called harmonic vibration plus mount flexing. My stupid!!! I'm building a replacement plane and buying the correct OS metal mount that is pre drilled for the engine. I have a couple of the .91s and when I give it some thought I have been doing and using the same mounts and having the same problem. I don't have the problem on my 1.20s and have the correct OS mounts for them. A bit more money for the correct motor mount will save me a lot of trouble.
