O-320 3.5 crank speed vibration

Its kinda interesting to critically watch the rotational plane of a
brightly lit (daylight) propeller against a dark background, as someone
else varies the engine RPMs. I've seen the blade tips move like 1/2
inch out of plane at certain bad rpms.

nrp wrote:

Its kinda interesting to critically watch the rotational plane of a
brightly lit (daylight) propeller against a dark background, as someone
else varies the engine RPMs. I've seen the blade tips move like 1/2
inch out of plane at certain bad rpms.


Or a variable speed party strobe...

Sheds an interesting light on things like that.



Richard

Possible reasons for out of balance are
propeller static balance bad or
engine mounts bad.