In article Ubw_b.390034$na.638038@attbi_s04, x wrote:
of one would resonate with the third harmonic of the other. But a
propeller and an engine are nowhere close to identical; their resonant
frequencies don't have anything to do with each other in the first place,

What resonance characteristics does a propeller have, and why?

Anything that is solid vibrates, and has resonant frequencies.
Beyond that, I haven't done any detailed analysis.


--
Norman Yarvin http://yarchive.net