One thing to add. I set up this plane originally with an OS-91FX with a tuned pipe. Since this was the first time I build it like that, I thought I could get away with hardmounting the header to the fuse.

Well, that was a mistake! The vibration of the (still running very rich) engine was terrible, and basicly the whole plane was shaken to pieces, or so it looked. The fact that the plane survived all that, and is still flying now (I think it has some 200 flights now) is only possible with an excellent built quality.