Buzz, Buzz

[Dale W]

I swapped my engine from a rear facing to a front facing config. Now I get quite a vibration that 'buzzes' the canopy pretty good. This is going on with just the engine running, but does seem to affect the gyro holding when flying around (duh).
I removed the one way air filter as it was more of a 'no way' than anything else and put in 1&1/2 loops of tubing off that vent to handle any inverted drainage.
One thing I did notice is that when I look through the plug hole (plug out obviously), I see a ~1/32" dimple (looks almost like a pinhole, but doesn't go thru the head) and was wondering if that is there on any of the other 'standard' 230 engines?
Anyway, if you have any suggestions on what to check, please throw them my way. The bird is apart on my workbench again...
By the way, when it flys, this this is very stable, but touchy at the same time. Circuits and playful flight is actually fun again, and I haven't had this much fun since my Milli!
Dale

[bigrcr]

Make sure that you are not lean as this may buzz the airframe/canopy a bit. The canopy "floats" a bit on the stand offs and can get a buzz if touching something on the motor for instance. Check to make sure the canopy is off of the secondary coil and carb fitting as well as well as anything else it can buzz off of. The canopy buzzing (amplifying a resonance) can upset the gyro.
The "dimple" in the piston is normal and is part of the regular casting of the piston (it does not go through) and no, you ain't done nothin' wrong! :D

Later,

[Dale W]

Thanks John.
I did have to recut the canopy and it was a much snugger fit with more engine parts facing foreward. I'll go over the canopy and mounting to see what I can find. That does sound like a logical suspect. I run the engine at about 1&1/4 on the low and 1&1/2 on the high. It seems to like it there.. still a little sluggish but its only got a gallon through it and still running the 36:1 Yamalube.
Thanks for putting my mind to rest on that little dimple. I was hoping I didn't have something else to worry about.
Thanks again, Dale

[bigrcr]

:wink: